How can I tell what cam is in my old 86 4.2?
05-21-2004, 11:23 PM
#1
Guest
Posts: n/a
How can I tell what cam is in my old 86 4.2?
I just had a strange sight.
Someone was sorting out the front of my garage for me and my old 86 4.2
is sitting on a dolly waiting for me to do something with it and they
had to move it.
I took the flywheel off in the dark when I pulled it apart.
I look at the back when they moved it and I'll be darned if there isn't
a new sealed 'frost' plug on the end of the cam shaft!
Say What? I 'thought' the engine was original, but it sure was a
'thumper' at idle. That is one of the reasons I was going to rebuild
it. In order to get it halfway smooth I had to rich the mix bad, so I
let it thump. The 'new' engine just purrs in comparison but it wasn't
too bad.
This old engine went like a bat out of hell with the old heavy steel
body on it. Even better than my 'new' one although it is no slouch
either.
I pulled it because it was leaking like a sieve when I did a frame up
rebuild. I was planning on refreshing the bearings, etc. when I found
an engine with 40k for $400.00 so I just parked it on the dolly and put
the 'new' one in.
Before I pulled it, I checked the compression and it was 145 - 147 all
across. When I parked it I opened up a couple bearing journals and the
bearings looked new, but I didn't think much of it. I needed the oil
pan, the 'new' engine's oil pan had rust holes through it.
So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
apart. 99% chance they are original.
I am now wondering just what that old engine was....
I can pull a main and a rod bearing and see if they match the factory
stamps on the block for the original ones, but I don't want to pull the
cam out.
I am thinking I should be able to use say a protractor on the crank and
see how many degrees the crank turns for the time one specific valve is
in movement.
Cams are sold by the duration of the valve openings aren't they?
I am thinking I should be able to turn the crank while checking the
rotation angle to see if I have a stock cam or say an RV cam or a
highway cam.
Anyone know?
Thanks,
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Someone was sorting out the front of my garage for me and my old 86 4.2
is sitting on a dolly waiting for me to do something with it and they
had to move it.
I took the flywheel off in the dark when I pulled it apart.
I look at the back when they moved it and I'll be darned if there isn't
a new sealed 'frost' plug on the end of the cam shaft!
Say What? I 'thought' the engine was original, but it sure was a
'thumper' at idle. That is one of the reasons I was going to rebuild
it. In order to get it halfway smooth I had to rich the mix bad, so I
let it thump. The 'new' engine just purrs in comparison but it wasn't
too bad.
This old engine went like a bat out of hell with the old heavy steel
body on it. Even better than my 'new' one although it is no slouch
either.
I pulled it because it was leaking like a sieve when I did a frame up
rebuild. I was planning on refreshing the bearings, etc. when I found
an engine with 40k for $400.00 so I just parked it on the dolly and put
the 'new' one in.
Before I pulled it, I checked the compression and it was 145 - 147 all
across. When I parked it I opened up a couple bearing journals and the
bearings looked new, but I didn't think much of it. I needed the oil
pan, the 'new' engine's oil pan had rust holes through it.
So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
apart. 99% chance they are original.
I am now wondering just what that old engine was....
I can pull a main and a rod bearing and see if they match the factory
stamps on the block for the original ones, but I don't want to pull the
cam out.
I am thinking I should be able to use say a protractor on the crank and
see how many degrees the crank turns for the time one specific valve is
in movement.
Cams are sold by the duration of the valve openings aren't they?
I am thinking I should be able to turn the crank while checking the
rotation angle to see if I have a stock cam or say an RV cam or a
highway cam.
Anyone know?
Thanks,
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
05-21-2004, 11:54 PM
#2
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
"Mike Romain" <romainm@sympatico.ca> wrote in message
:
: Cams are sold by the duration of the valve openings aren't they?
:
: I am thinking I should be able to turn the crank while checking the
: rotation angle to see if I have a stock cam or say an RV cam or a
: highway cam.
:
They're sold by lift and duration. Check the lift at the rocker arm. If it
run lumpy, it probably has a long duration - good luck measuring that!
-Brian
05-21-2004, 11:54 PM
#3
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
"Mike Romain" <romainm@sympatico.ca> wrote in message
:
: Cams are sold by the duration of the valve openings aren't they?
:
: I am thinking I should be able to turn the crank while checking the
: rotation angle to see if I have a stock cam or say an RV cam or a
: highway cam.
:
They're sold by lift and duration. Check the lift at the rocker arm. If it
run lumpy, it probably has a long duration - good luck measuring that!
-Brian
05-21-2004, 11:54 PM
#4
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
"Mike Romain" <romainm@sympatico.ca> wrote in message
:
: Cams are sold by the duration of the valve openings aren't they?
:
: I am thinking I should be able to turn the crank while checking the
: rotation angle to see if I have a stock cam or say an RV cam or a
: highway cam.
:
They're sold by lift and duration. Check the lift at the rocker arm. If it
run lumpy, it probably has a long duration - good luck measuring that!
-Brian
05-21-2004, 11:54 PM
#5
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
"Mike Romain" <romainm@sympatico.ca> wrote in message
:
: Cams are sold by the duration of the valve openings aren't they?
:
: I am thinking I should be able to turn the crank while checking the
: rotation angle to see if I have a stock cam or say an RV cam or a
: highway cam.
:
They're sold by lift and duration. Check the lift at the rocker arm. If it
run lumpy, it probably has a long duration - good luck measuring that!
-Brian
05-22-2004, 12:53 AM
#6
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
05-22-2004, 12:53 AM
#7
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
05-22-2004, 12:53 AM
#8
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
05-22-2004, 12:53 AM
#9
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
'96 4.0 litre is 253:
http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
several places at near 290 degrees, but can't find that fact now. You'll
need a degree wheel to bolt to where you stole the balancer from:
http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
and stick a feeler gauge under the rockers, and mark their tight
duration on the wheel. chalk it, and note it accurately so as to more
easily see the overlap.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just had a strange sight.
>
> Someone was sorting out the front of my garage for me and my old 86 4.2
> is sitting on a dolly waiting for me to do something with it and they
> had to move it.
>
> I took the flywheel off in the dark when I pulled it apart.
>
> I look at the back when they moved it and I'll be darned if there isn't
> a new sealed 'frost' plug on the end of the cam shaft!
>
> Say What? I 'thought' the engine was original, but it sure was a
> 'thumper' at idle. That is one of the reasons I was going to rebuild
> it. In order to get it halfway smooth I had to rich the mix bad, so I
> let it thump. The 'new' engine just purrs in comparison but it wasn't
> too bad.
>
> This old engine went like a bat out of hell with the old heavy steel
> body on it. Even better than my 'new' one although it is no slouch
> either.
>
> I pulled it because it was leaking like a sieve when I did a frame up
> rebuild. I was planning on refreshing the bearings, etc. when I found
> an engine with 40k for $400.00 so I just parked it on the dolly and put
> the 'new' one in.
>
> Before I pulled it, I checked the compression and it was 145 - 147 all
> across. When I parked it I opened up a couple bearing journals and the
> bearings looked new, but I didn't think much of it. I needed the oil
> pan, the 'new' engine's oil pan had rust holes through it.
>
> So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> apart. 99% chance they are original.
>
> I am now wondering just what that old engine was....
>
> I can pull a main and a rod bearing and see if they match the factory
> stamps on the block for the original ones, but I don't want to pull the
> cam out.
>
> I am thinking I should be able to use say a protractor on the crank and
> see how many degrees the crank turns for the time one specific valve is
> in movement.
>
> Cams are sold by the duration of the valve openings aren't they?
>
> I am thinking I should be able to turn the crank while checking the
> rotation angle to see if I have a stock cam or say an RV cam or a
> highway cam.
>
> Anyone know?
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
05-22-2004, 01:21 AM
#10
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Mine is supposed to be a stock 1986 258 USA built engine modified for
the Canadian market. No cat needed. No air pumps, etc....
No clue where the Jeep actually came from. It was hot purple/pink for
it's first coat of paint. You know, a 'Barbie' Jeep.
None of the engines you list match mine, thanks anyway.
Mike
"L.W.(ßill) ------ III" wrote:
>
> Hi Mike,
> The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
> http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
> '96 4.0 litre is 253:
> http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
> several places at near 290 degrees, but can't find that fact now. You'll
> need a degree wheel to bolt to where you stole the balancer from:
> http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
> and stick a feeler gauge under the rockers, and mark their tight
> duration on the wheel. chalk it, and note it accurately so as to more
> easily see the overlap.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > I just had a strange sight.
> >
> > Someone was sorting out the front of my garage for me and my old 86 4.2
> > is sitting on a dolly waiting for me to do something with it and they
> > had to move it.
> >
> > I took the flywheel off in the dark when I pulled it apart.
> >
> > I look at the back when they moved it and I'll be darned if there isn't
> > a new sealed 'frost' plug on the end of the cam shaft!
> >
> > Say What? I 'thought' the engine was original, but it sure was a
> > 'thumper' at idle. That is one of the reasons I was going to rebuild
> > it. In order to get it halfway smooth I had to rich the mix bad, so I
> > let it thump. The 'new' engine just purrs in comparison but it wasn't
> > too bad.
> >
> > This old engine went like a bat out of hell with the old heavy steel
> > body on it. Even better than my 'new' one although it is no slouch
> > either.
> >
> > I pulled it because it was leaking like a sieve when I did a frame up
> > rebuild. I was planning on refreshing the bearings, etc. when I found
> > an engine with 40k for $400.00 so I just parked it on the dolly and put
> > the 'new' one in.
> >
> > Before I pulled it, I checked the compression and it was 145 - 147 all
> > across. When I parked it I opened up a couple bearing journals and the
> > bearings looked new, but I didn't think much of it. I needed the oil
> > pan, the 'new' engine's oil pan had rust holes through it.
> >
> > So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> > apart. 99% chance they are original.
> >
> > I am now wondering just what that old engine was....
> >
> > I can pull a main and a rod bearing and see if they match the factory
> > stamps on the block for the original ones, but I don't want to pull the
> > cam out.
> >
> > I am thinking I should be able to use say a protractor on the crank and
> > see how many degrees the crank turns for the time one specific valve is
> > in movement.
> >
> > Cams are sold by the duration of the valve openings aren't they?
> >
> > I am thinking I should be able to turn the crank while checking the
> > rotation angle to see if I have a stock cam or say an RV cam or a
> > highway cam.
> >
> > Anyone know?
> >
> > Thanks,
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
the Canadian market. No cat needed. No air pumps, etc....
No clue where the Jeep actually came from. It was hot purple/pink for
it's first coat of paint. You know, a 'Barbie' Jeep.
None of the engines you list match mine, thanks anyway.
Mike
"L.W.(ßill) ------ III" wrote:
>
> Hi Mike,
> The stock detuned for SMOG '75 Rambler is 256 degrees of duration:
> http://www.riversiderebels.com/amccf/tech/six_specs.htm The stock '87 to
> '96 4.0 litre is 253:
> http://www.jeep4.0performance.4mg.com/tech_specs.html The TJs I've read
> several places at near 290 degrees, but can't find that fact now. You'll
> need a degree wheel to bolt to where you stole the balancer from:
> http://www.hotrodder.com/kwkride/degree.html Key with Top Dead Center,
> and stick a feeler gauge under the rockers, and mark their tight
> duration on the wheel. chalk it, and note it accurately so as to more
> easily see the overlap.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > I just had a strange sight.
> >
> > Someone was sorting out the front of my garage for me and my old 86 4.2
> > is sitting on a dolly waiting for me to do something with it and they
> > had to move it.
> >
> > I took the flywheel off in the dark when I pulled it apart.
> >
> > I look at the back when they moved it and I'll be darned if there isn't
> > a new sealed 'frost' plug on the end of the cam shaft!
> >
> > Say What? I 'thought' the engine was original, but it sure was a
> > 'thumper' at idle. That is one of the reasons I was going to rebuild
> > it. In order to get it halfway smooth I had to rich the mix bad, so I
> > let it thump. The 'new' engine just purrs in comparison but it wasn't
> > too bad.
> >
> > This old engine went like a bat out of hell with the old heavy steel
> > body on it. Even better than my 'new' one although it is no slouch
> > either.
> >
> > I pulled it because it was leaking like a sieve when I did a frame up
> > rebuild. I was planning on refreshing the bearings, etc. when I found
> > an engine with 40k for $400.00 so I just parked it on the dolly and put
> > the 'new' one in.
> >
> > Before I pulled it, I checked the compression and it was 145 - 147 all
> > across. When I parked it I opened up a couple bearing journals and the
> > bearings looked new, but I didn't think much of it. I needed the oil
> > pan, the 'new' engine's oil pan had rust holes through it.
> >
> > So this Jeep had 135 or maybe it was 145,000 miles on it when I tore it
> > apart. 99% chance they are original.
> >
> > I am now wondering just what that old engine was....
> >
> > I can pull a main and a rod bearing and see if they match the factory
> > stamps on the block for the original ones, but I don't want to pull the
> > cam out.
> >
> > I am thinking I should be able to use say a protractor on the crank and
> > see how many degrees the crank turns for the time one specific valve is
> > in movement.
> >
> > Cams are sold by the duration of the valve openings aren't they?
> >
> > I am thinking I should be able to turn the crank while checking the
> > rotation angle to see if I have a stock cam or say an RV cam or a
> > highway cam.
> >
> > Anyone know?
> >
> > Thanks,
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
