Carl

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
>>
>>
>
>

Carl

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
>>
>>
>
>

Carl

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
>>
>>
>
>

Dave Milne

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
> >>
> >>
> >
> >
>
>

Dave Milne

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
> >>
> >>
> >
> >
>
>

Dave Milne

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
> >>
> >>
> >
> >
>
>

Carl

Dave,

Try filling the cooling system and running it with the radiator cap off.
If the coolant has a lot of small bubbles once the thermostat is open,
you're getting cylinder pressure in there. A cooling system is only designed
to hold 15psi, so it doesn't take much to over pressureize it and blow the
cap off. Please note that you should fill the radiator when the engine is
cold, and start the engine with the cap off.

Also try getting a cooling system pressurizer tool. It hooks up to the
radiator cap and has a pump so you can pressure test the cooling system.
Pump it up and watch the gauge, then check your oil.

Let us know what you find,

Carl


"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
>> >>
>> >>
>> >
>> >
>>
>>
>
>

Carl

Dave,

Try filling the cooling system and running it with the radiator cap off.
If the coolant has a lot of small bubbles once the thermostat is open,
you're getting cylinder pressure in there. A cooling system is only designed
to hold 15psi, so it doesn't take much to over pressureize it and blow the
cap off. Please note that you should fill the radiator when the engine is
cold, and start the engine with the cap off.

Also try getting a cooling system pressurizer tool. It hooks up to the
radiator cap and has a pump so you can pressure test the cooling system.
Pump it up and watch the gauge, then check your oil.

Let us know what you find,

Carl


"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
>> >>
>> >>
>> >
>> >
>>
>>
>
>

Carl

Dave,

Try filling the cooling system and running it with the radiator cap off.
If the coolant has a lot of small bubbles once the thermostat is open,
you're getting cylinder pressure in there. A cooling system is only designed
to hold 15psi, so it doesn't take much to over pressureize it and blow the
cap off. Please note that you should fill the radiator when the engine is
cold, and start the engine with the cap off.

Also try getting a cooling system pressurizer tool. It hooks up to the
radiator cap and has a pump so you can pressure test the cooling system.
Pump it up and watch the gauge, then check your oil.

Let us know what you find,

Carl


"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
>> >>
>> >>
>> >
>> >
>>
>>
>
>

DougW

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