360 v8 Compression check
10-08-2006, 01:22 PM
#21
Guest
Posts: n/a
Re: 360 v8 Compression check
Dave Milne wrote:
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only. Trouble is, I think something is pressurising the coolant and I
> can't work out what it is. Cylinder pressures are uniform, no steam
> coming out the exhaust, no mayo in the oil, no oil in the water.
> Everything points to not having a problem were it not for the fact
> water is coming out of the expansion tank ! Occams Razor says it is
> me replacing the inlet manifold 3 weeks ago, but I've just redone the
> inlet manifold gasket yesterday (new Felpro gaskets both times with
> RTV around both sides of the gaskets around the water jackets and
> exhaust as per instructions), and that didn't solve the problem.
bad radiator cap not holding pressure?
--
DougW
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only. Trouble is, I think something is pressurising the coolant and I
> can't work out what it is. Cylinder pressures are uniform, no steam
> coming out the exhaust, no mayo in the oil, no oil in the water.
> Everything points to not having a problem were it not for the fact
> water is coming out of the expansion tank ! Occams Razor says it is
> me replacing the inlet manifold 3 weeks ago, but I've just redone the
> inlet manifold gasket yesterday (new Felpro gaskets both times with
> RTV around both sides of the gaskets around the water jackets and
> exhaust as per instructions), and that didn't solve the problem.
bad radiator cap not holding pressure?
--
DougW
10-08-2006, 01:22 PM
#22
Guest
Posts: n/a
Re: 360 v8 Compression check
Dave Milne wrote:
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only. Trouble is, I think something is pressurising the coolant and I
> can't work out what it is. Cylinder pressures are uniform, no steam
> coming out the exhaust, no mayo in the oil, no oil in the water.
> Everything points to not having a problem were it not for the fact
> water is coming out of the expansion tank ! Occams Razor says it is
> me replacing the inlet manifold 3 weeks ago, but I've just redone the
> inlet manifold gasket yesterday (new Felpro gaskets both times with
> RTV around both sides of the gaskets around the water jackets and
> exhaust as per instructions), and that didn't solve the problem.
bad radiator cap not holding pressure?
--
DougW
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only. Trouble is, I think something is pressurising the coolant and I
> can't work out what it is. Cylinder pressures are uniform, no steam
> coming out the exhaust, no mayo in the oil, no oil in the water.
> Everything points to not having a problem were it not for the fact
> water is coming out of the expansion tank ! Occams Razor says it is
> me replacing the inlet manifold 3 weeks ago, but I've just redone the
> inlet manifold gasket yesterday (new Felpro gaskets both times with
> RTV around both sides of the gaskets around the water jackets and
> exhaust as per instructions), and that didn't solve the problem.
bad radiator cap not holding pressure?
--
DougW
10-08-2006, 01:23 PM
#23
Guest
Posts: n/a
Re: 360 v8 Compression check
If you are burning the water, the spark plug in that cylinder will look
like new.
How old is the rad cap? A bad one can let too much water into the
overflow and not suck it back when it cools down. So can a leak in the
line from the rad to the overflow. It might not drip when the coolant
is coming out of the rad as it warms up, but it might allow air to be
sucked back in when the system is supposed to be sucking coolant back as
it cools down.
Even if it fills the overflow, when the rad cap is working, it will
'unfill' it as it cools down. If not it is a bad cap or air leak.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
Dave Milne wrote:
>
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again. If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
like new.
How old is the rad cap? A bad one can let too much water into the
overflow and not suck it back when it cools down. So can a leak in the
line from the rad to the overflow. It might not drip when the coolant
is coming out of the rad as it warms up, but it might allow air to be
sucked back in when the system is supposed to be sucking coolant back as
it cools down.
Even if it fills the overflow, when the rad cap is working, it will
'unfill' it as it cools down. If not it is a bad cap or air leak.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
Dave Milne wrote:
>
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again. If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
10-08-2006, 01:23 PM
#24
Guest
Posts: n/a
Re: 360 v8 Compression check
If you are burning the water, the spark plug in that cylinder will look
like new.
How old is the rad cap? A bad one can let too much water into the
overflow and not suck it back when it cools down. So can a leak in the
line from the rad to the overflow. It might not drip when the coolant
is coming out of the rad as it warms up, but it might allow air to be
sucked back in when the system is supposed to be sucking coolant back as
it cools down.
Even if it fills the overflow, when the rad cap is working, it will
'unfill' it as it cools down. If not it is a bad cap or air leak.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
Dave Milne wrote:
>
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again. If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
like new.
How old is the rad cap? A bad one can let too much water into the
overflow and not suck it back when it cools down. So can a leak in the
line from the rad to the overflow. It might not drip when the coolant
is coming out of the rad as it warms up, but it might allow air to be
sucked back in when the system is supposed to be sucking coolant back as
it cools down.
Even if it fills the overflow, when the rad cap is working, it will
'unfill' it as it cools down. If not it is a bad cap or air leak.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
Dave Milne wrote:
>
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again. If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
10-08-2006, 01:23 PM
#25
Guest
Posts: n/a
Re: 360 v8 Compression check
If you are burning the water, the spark plug in that cylinder will look
like new.
How old is the rad cap? A bad one can let too much water into the
overflow and not suck it back when it cools down. So can a leak in the
line from the rad to the overflow. It might not drip when the coolant
is coming out of the rad as it warms up, but it might allow air to be
sucked back in when the system is supposed to be sucking coolant back as
it cools down.
Even if it fills the overflow, when the rad cap is working, it will
'unfill' it as it cools down. If not it is a bad cap or air leak.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
Dave Milne wrote:
>
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again. If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
like new.
How old is the rad cap? A bad one can let too much water into the
overflow and not suck it back when it cools down. So can a leak in the
line from the rad to the overflow. It might not drip when the coolant
is coming out of the rad as it warms up, but it might allow air to be
sucked back in when the system is supposed to be sucking coolant back as
it cools down.
Even if it fills the overflow, when the rad cap is working, it will
'unfill' it as it cools down. If not it is a bad cap or air leak.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
Dave Milne wrote:
>
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again. If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
10-08-2006, 01:37 PM
#26
Guest
Posts: n/a
Re: 360 v8 Compression check
Air in the cooling system can do that. V8 intake manifolds can be bled by
removing the temperature gauge sensor, a heater hose or as a last resort the
thermostat housing. Pour in coolant until you are absolutely sure that the
engine is full, and this should eliminate air as a source of the problem.
Make sure that whatever you use on your gaskets says "works with ethylene
glycol" somewhere on the container.
Earle
"Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again.
If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do
a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
>
>
removing the temperature gauge sensor, a heater hose or as a last resort the
thermostat housing. Pour in coolant until you are absolutely sure that the
engine is full, and this should eliminate air as a source of the problem.
Make sure that whatever you use on your gaskets says "works with ethylene
glycol" somewhere on the container.
Earle
"Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again.
If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do
a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
>
>
10-08-2006, 01:37 PM
#27
Guest
Posts: n/a
Re: 360 v8 Compression check
Air in the cooling system can do that. V8 intake manifolds can be bled by
removing the temperature gauge sensor, a heater hose or as a last resort the
thermostat housing. Pour in coolant until you are absolutely sure that the
engine is full, and this should eliminate air as a source of the problem.
Make sure that whatever you use on your gaskets says "works with ethylene
glycol" somewhere on the container.
Earle
"Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again.
If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do
a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
>
>
removing the temperature gauge sensor, a heater hose or as a last resort the
thermostat housing. Pour in coolant until you are absolutely sure that the
engine is full, and this should eliminate air as a source of the problem.
Make sure that whatever you use on your gaskets says "works with ethylene
glycol" somewhere on the container.
Earle
"Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again.
If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do
a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
>
>
10-08-2006, 01:37 PM
#28
Guest
Posts: n/a
Re: 360 v8 Compression check
Air in the cooling system can do that. V8 intake manifolds can be bled by
removing the temperature gauge sensor, a heater hose or as a last resort the
thermostat housing. Pour in coolant until you are absolutely sure that the
engine is full, and this should eliminate air as a source of the problem.
Make sure that whatever you use on your gaskets says "works with ethylene
glycol" somewhere on the container.
Earle
"Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again.
If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do
a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
>
>
removing the temperature gauge sensor, a heater hose or as a last resort the
thermostat housing. Pour in coolant until you are absolutely sure that the
engine is full, and this should eliminate air as a source of the problem.
Make sure that whatever you use on your gaskets says "works with ethylene
glycol" somewhere on the container.
Earle
"Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> Hi Carl,
> Engine was warm. Lowest reading was about 7.75 bar on one cylinder
only.
> Trouble is, I think something is pressurising the coolant and I can't work
> out what it is. Cylinder pressures are uniform, no steam coming out the
> exhaust, no mayo in the oil, no oil in the water. Everything points to not
> having a problem were it not for the fact water is coming out of the
> expansion tank ! Occams Razor says it is me replacing the inlet manifold 3
> weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> Felpro gaskets both times with RTV around both sides of the gaskets around
> the water jackets and exhaust as per instructions), and that didn't solve
> the problem.
>
> "Slightly baffled" Dave
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > Dave,
> >
> > Was the engine warm or cold? I'll second the uniformity. So long as
> they
> > are all close to 8 bar, I wouldn't really worry about it. You can try
> > putting a few drops of oil in each cylinder and trying the test again.
If
> > the numbers rise your rings are a worn.
> >
> > However, with 8bar and uniformity, I wouldn't worry.
> >
> > Carl
> >
> >
> > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > Thanks Doug & Earle.
> > >
> > > Dave
> > >
> > > "DougW" <post.replies@invalid.address> wrote in message
> > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > >> Dave Milne wrote:
> > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > >>
> > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > >> rating than the V8.
> > >>
> > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > >> > surprised it is so consisently low. That was a dry test - didn't do
a
> > >> > wet one.
> > >>
> > >> Consistency (psi +- 10%) is what your looking for in a compression
> test.
> > >>
> > >> - Run the engine till it gets warm to the touch.
> > >> - I find it easier on the battery with all the plugs out.
> > >> - Hold the throttle all the way open or the engine won't breathe.
> > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > >>
> > >> FWIW, I do a compression test each time I change plugs. Except this
> > >> time, the hose on my compression tester sprang a leak. :( 160-165 is
> > >> what the I6 gets when warm.
> > >>
> > >> --
> > >> DougW
> > >>
> > >>
> > >
> > >
> >
> >
>
>
10-08-2006, 02:13 PM
#29
Guest
Posts: n/a
Re: 360 v8 Compression check
Pretty well what I was doing, so will continue a bit longer.
Can't tell on the gasket - I used the black RTV which came with the Felpro
gasket the first time round, and the second time round it didn't come with
any so I used the bog standard Orange Hermetite RTV.
Dave
"Earle Horton" <anglocapitalista@usa.com> wrote in message
news:45293724$0$28990$a82e2bb9@reader.athenanews.c om...
> Air in the cooling system can do that. V8 intake manifolds can be bled by
> removing the temperature gauge sensor, a heater hose or as a last resort
the
> thermostat housing. Pour in coolant until you are absolutely sure that
the
> engine is full, and this should eliminate air as a source of the problem.
> Make sure that whatever you use on your gaskets says "works with ethylene
> glycol" somewhere on the container.
>
> Earle
>
> "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> > Hi Carl,
> > Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only.
> > Trouble is, I think something is pressurising the coolant and I can't
work
> > out what it is. Cylinder pressures are uniform, no steam coming out the
> > exhaust, no mayo in the oil, no oil in the water. Everything points to
not
> > having a problem were it not for the fact water is coming out of the
> > expansion tank ! Occams Razor says it is me replacing the inlet manifold
3
> > weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> > Felpro gaskets both times with RTV around both sides of the gaskets
around
> > the water jackets and exhaust as per instructions), and that didn't
solve
> > the problem.
> >
> > "Slightly baffled" Dave
> >
> > "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> > news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > > Dave,
> > >
> > > Was the engine warm or cold? I'll second the uniformity. So long
as
> > they
> > > are all close to 8 bar, I wouldn't really worry about it. You can try
> > > putting a few drops of oil in each cylinder and trying the test again.
> If
> > > the numbers rise your rings are a worn.
> > >
> > > However, with 8bar and uniformity, I wouldn't worry.
> > >
> > > Carl
> > >
> > >
> > > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > > Thanks Doug & Earle.
> > > >
> > > > Dave
> > > >
> > > > "DougW" <post.replies@invalid.address> wrote in message
> > > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > > >> Dave Milne wrote:
> > > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > > >>
> > > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > > >> rating than the V8.
> > > >>
> > > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > > >> > surprised it is so consisently low. That was a dry test - didn't
do
> a
> > > >> > wet one.
> > > >>
> > > >> Consistency (psi +- 10%) is what your looking for in a compression
> > test.
> > > >>
> > > >> - Run the engine till it gets warm to the touch.
> > > >> - I find it easier on the battery with all the plugs out.
> > > >> - Hold the throttle all the way open or the engine won't breathe.
> > > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > > >>
> > > >> FWIW, I do a compression test each time I change plugs. Except
this
> > > >> time, the hose on my compression tester sprang a leak. :( 160-165
is
> > > >> what the I6 gets when warm.
> > > >>
> > > >> --
> > > >> DougW
> > > >>
> > > >>
> > > >
> > > >
> > >
> > >
> >
> >
>
>
Can't tell on the gasket - I used the black RTV which came with the Felpro
gasket the first time round, and the second time round it didn't come with
any so I used the bog standard Orange Hermetite RTV.
Dave
"Earle Horton" <anglocapitalista@usa.com> wrote in message
news:45293724$0$28990$a82e2bb9@reader.athenanews.c om...
> Air in the cooling system can do that. V8 intake manifolds can be bled by
> removing the temperature gauge sensor, a heater hose or as a last resort
the
> thermostat housing. Pour in coolant until you are absolutely sure that
the
> engine is full, and this should eliminate air as a source of the problem.
> Make sure that whatever you use on your gaskets says "works with ethylene
> glycol" somewhere on the container.
>
> Earle
>
> "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> > Hi Carl,
> > Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only.
> > Trouble is, I think something is pressurising the coolant and I can't
work
> > out what it is. Cylinder pressures are uniform, no steam coming out the
> > exhaust, no mayo in the oil, no oil in the water. Everything points to
not
> > having a problem were it not for the fact water is coming out of the
> > expansion tank ! Occams Razor says it is me replacing the inlet manifold
3
> > weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> > Felpro gaskets both times with RTV around both sides of the gaskets
around
> > the water jackets and exhaust as per instructions), and that didn't
solve
> > the problem.
> >
> > "Slightly baffled" Dave
> >
> > "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> > news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > > Dave,
> > >
> > > Was the engine warm or cold? I'll second the uniformity. So long
as
> > they
> > > are all close to 8 bar, I wouldn't really worry about it. You can try
> > > putting a few drops of oil in each cylinder and trying the test again.
> If
> > > the numbers rise your rings are a worn.
> > >
> > > However, with 8bar and uniformity, I wouldn't worry.
> > >
> > > Carl
> > >
> > >
> > > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > > Thanks Doug & Earle.
> > > >
> > > > Dave
> > > >
> > > > "DougW" <post.replies@invalid.address> wrote in message
> > > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > > >> Dave Milne wrote:
> > > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > > >>
> > > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > > >> rating than the V8.
> > > >>
> > > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > > >> > surprised it is so consisently low. That was a dry test - didn't
do
> a
> > > >> > wet one.
> > > >>
> > > >> Consistency (psi +- 10%) is what your looking for in a compression
> > test.
> > > >>
> > > >> - Run the engine till it gets warm to the touch.
> > > >> - I find it easier on the battery with all the plugs out.
> > > >> - Hold the throttle all the way open or the engine won't breathe.
> > > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > > >>
> > > >> FWIW, I do a compression test each time I change plugs. Except
this
> > > >> time, the hose on my compression tester sprang a leak. :( 160-165
is
> > > >> what the I6 gets when warm.
> > > >>
> > > >> --
> > > >> DougW
> > > >>
> > > >>
> > > >
> > > >
> > >
> > >
> >
> >
>
>
10-08-2006, 02:13 PM
#30
Guest
Posts: n/a
Re: 360 v8 Compression check
Pretty well what I was doing, so will continue a bit longer.
Can't tell on the gasket - I used the black RTV which came with the Felpro
gasket the first time round, and the second time round it didn't come with
any so I used the bog standard Orange Hermetite RTV.
Dave
"Earle Horton" <anglocapitalista@usa.com> wrote in message
news:45293724$0$28990$a82e2bb9@reader.athenanews.c om...
> Air in the cooling system can do that. V8 intake manifolds can be bled by
> removing the temperature gauge sensor, a heater hose or as a last resort
the
> thermostat housing. Pour in coolant until you are absolutely sure that
the
> engine is full, and this should eliminate air as a source of the problem.
> Make sure that whatever you use on your gaskets says "works with ethylene
> glycol" somewhere on the container.
>
> Earle
>
> "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> > Hi Carl,
> > Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only.
> > Trouble is, I think something is pressurising the coolant and I can't
work
> > out what it is. Cylinder pressures are uniform, no steam coming out the
> > exhaust, no mayo in the oil, no oil in the water. Everything points to
not
> > having a problem were it not for the fact water is coming out of the
> > expansion tank ! Occams Razor says it is me replacing the inlet manifold
3
> > weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> > Felpro gaskets both times with RTV around both sides of the gaskets
around
> > the water jackets and exhaust as per instructions), and that didn't
solve
> > the problem.
> >
> > "Slightly baffled" Dave
> >
> > "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> > news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > > Dave,
> > >
> > > Was the engine warm or cold? I'll second the uniformity. So long
as
> > they
> > > are all close to 8 bar, I wouldn't really worry about it. You can try
> > > putting a few drops of oil in each cylinder and trying the test again.
> If
> > > the numbers rise your rings are a worn.
> > >
> > > However, with 8bar and uniformity, I wouldn't worry.
> > >
> > > Carl
> > >
> > >
> > > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > > Thanks Doug & Earle.
> > > >
> > > > Dave
> > > >
> > > > "DougW" <post.replies@invalid.address> wrote in message
> > > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > > >> Dave Milne wrote:
> > > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > > >>
> > > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > > >> rating than the V8.
> > > >>
> > > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > > >> > surprised it is so consisently low. That was a dry test - didn't
do
> a
> > > >> > wet one.
> > > >>
> > > >> Consistency (psi +- 10%) is what your looking for in a compression
> > test.
> > > >>
> > > >> - Run the engine till it gets warm to the touch.
> > > >> - I find it easier on the battery with all the plugs out.
> > > >> - Hold the throttle all the way open or the engine won't breathe.
> > > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > > >>
> > > >> FWIW, I do a compression test each time I change plugs. Except
this
> > > >> time, the hose on my compression tester sprang a leak. :( 160-165
is
> > > >> what the I6 gets when warm.
> > > >>
> > > >> --
> > > >> DougW
> > > >>
> > > >>
> > > >
> > > >
> > >
> > >
> >
> >
>
>
Can't tell on the gasket - I used the black RTV which came with the Felpro
gasket the first time round, and the second time round it didn't come with
any so I used the bog standard Orange Hermetite RTV.
Dave
"Earle Horton" <anglocapitalista@usa.com> wrote in message
news:45293724$0$28990$a82e2bb9@reader.athenanews.c om...
> Air in the cooling system can do that. V8 intake manifolds can be bled by
> removing the temperature gauge sensor, a heater hose or as a last resort
the
> thermostat housing. Pour in coolant until you are absolutely sure that
the
> engine is full, and this should eliminate air as a source of the problem.
> Make sure that whatever you use on your gaskets says "works with ethylene
> glycol" somewhere on the container.
>
> Earle
>
> "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> news:Z7aWg.31347$r61.2165@text.news.blueyonder.co. uk...
> > Hi Carl,
> > Engine was warm. Lowest reading was about 7.75 bar on one cylinder
> only.
> > Trouble is, I think something is pressurising the coolant and I can't
work
> > out what it is. Cylinder pressures are uniform, no steam coming out the
> > exhaust, no mayo in the oil, no oil in the water. Everything points to
not
> > having a problem were it not for the fact water is coming out of the
> > expansion tank ! Occams Razor says it is me replacing the inlet manifold
3
> > weeks ago, but I've just redone the inlet manifold gasket yesterday (new
> > Felpro gaskets both times with RTV around both sides of the gaskets
around
> > the water jackets and exhaust as per instructions), and that didn't
solve
> > the problem.
> >
> > "Slightly baffled" Dave
> >
> > "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> > news:l6SdnSW8ottbu7TYnZ2dnUVZ_o-dnZ2d@comcast.com...
> > > Dave,
> > >
> > > Was the engine warm or cold? I'll second the uniformity. So long
as
> > they
> > > are all close to 8 bar, I wouldn't really worry about it. You can try
> > > putting a few drops of oil in each cylinder and trying the test again.
> If
> > > the numbers rise your rings are a worn.
> > >
> > > However, with 8bar and uniformity, I wouldn't worry.
> > >
> > > Carl
> > >
> > >
> > > "Dave Milne" <jeep@_removethisbit_milne.info> wrote in message
> > > news:Jp9Wg.31319$r61.20498@text.news.blueyonder.co .uk...
> > > > Thanks Doug & Earle.
> > > >
> > > > Dave
> > > >
> > > > "DougW" <post.replies@invalid.address> wrote in message
> > > > news:MC8Wg.32151$iA5.14083@dukeread11...
> > > >> Dave Milne wrote:
> > > >> > Any one got the specs for a compression check on a 360 v8 '91 ?
> > > >>
> > > >> Got me. 160 is "normal" for the I6, but it has a higher compression
> > > >> rating than the V8.
> > > >>
> > > >> > I'm only getting 8 bar (~ 115 psi) pretty consistently across all
> > > >> > cylinders. I would have expected about 140-160 psi and am a bit
> > > >> > surprised it is so consisently low. That was a dry test - didn't
do
> a
> > > >> > wet one.
> > > >>
> > > >> Consistency (psi +- 10%) is what your looking for in a compression
> > test.
> > > >>
> > > >> - Run the engine till it gets warm to the touch.
> > > >> - I find it easier on the battery with all the plugs out.
> > > >> - Hold the throttle all the way open or the engine won't breathe.
> > > >> - Cranking time varies, but most go with 5-10. I usually do 5.
> > > >>
> > > >> FWIW, I do a compression test each time I change plugs. Except
this
> > > >> time, the hose on my compression tester sprang a leak. :( 160-165
is
> > > >> what the I6 gets when warm.
> > > >>
> > > >> --
> > > >> DougW
> > > >>
> > > >>
> > > >
> > > >
> > >
> > >
> >
> >
>
>
