Mike Romain

What a drag....

On a remanned engine, that just screams faulty cleaning work. That
strongly implies dirt or metal shavings have plugged up one or more oil
passages which caused the cam to burn off. If it was just dirt in the
lifter, the pushrod would still be moving with a loud clacking noise at
it hit the rocker.

The only fix I know is a complete tear down with each oil channel's flow
verified before reassemble. Just putting another cam in it will end up
with the same result likely.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

MikeG wrote:
>
> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
> popping out of carb. Found out that the # 1 cylinder exhaust valve and
> rocker/pushrod were not moving. Exchanged intake pushrod and rocker with
> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
> problem......collapsed lifter, round camshaft lobe or other???? TIA Mike

Jeff Strickland

Collapsed lifter would be my first guess. As I went to look for the lifter
hiding in the bottom of a very deep hole, I might find the real problem, but
I think the lifter is where you need to start. I am not sure why you would
swap a rocker or the push rod, but checking for a bent push rod makes sense.
If the pushrod was straight, I would have kept looking for the lifter, and
not bother swapping the rod and rocker.




"MikeG" <justme@idontknow.com> wrote in message
news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
> popping out of carb. Found out that the # 1 cylinder exhaust valve and
> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
with
> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
> problem......collapsed lifter, round camshaft lobe or other???? TIA
Mike
>
>

Jeff Strickland

Collapsed lifter would be my first guess. As I went to look for the lifter
hiding in the bottom of a very deep hole, I might find the real problem, but
I think the lifter is where you need to start. I am not sure why you would
swap a rocker or the push rod, but checking for a bent push rod makes sense.
If the pushrod was straight, I would have kept looking for the lifter, and
not bother swapping the rod and rocker.




"MikeG" <justme@idontknow.com> wrote in message
news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
> popping out of carb. Found out that the # 1 cylinder exhaust valve and
> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
with
> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
> problem......collapsed lifter, round camshaft lobe or other???? TIA
Mike
>
>

Jeff Strickland

Collapsed lifter would be my first guess. As I went to look for the lifter
hiding in the bottom of a very deep hole, I might find the real problem, but
I think the lifter is where you need to start. I am not sure why you would
swap a rocker or the push rod, but checking for a bent push rod makes sense.
If the pushrod was straight, I would have kept looking for the lifter, and
not bother swapping the rod and rocker.




"MikeG" <justme@idontknow.com> wrote in message
news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
> popping out of carb. Found out that the # 1 cylinder exhaust valve and
> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
with
> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
> problem......collapsed lifter, round camshaft lobe or other???? TIA
Mike
>
>

Jeff Strickland

Collapsed lifter would be my first guess. As I went to look for the lifter
hiding in the bottom of a very deep hole, I might find the real problem, but
I think the lifter is where you need to start. I am not sure why you would
swap a rocker or the push rod, but checking for a bent push rod makes sense.
If the pushrod was straight, I would have kept looking for the lifter, and
not bother swapping the rod and rocker.




"MikeG" <justme@idontknow.com> wrote in message
news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
> popping out of carb. Found out that the # 1 cylinder exhaust valve and
> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
with
> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
> problem......collapsed lifter, round camshaft lobe or other???? TIA
Mike
>
>

MikeG

Thanks for the very informative replys. As much as I can tell, and my
limited logic on this, the majority of answers I have received is pointing
to a rounded camshaft. I grounded out the coil, so that the engine would
not start and 'jiggled' the rocker arm while cranking. It never got tight.
I was able to look down the small push rod hole and observe the lifter. It
was not doing a thing. I changed the rocker and push rod just incase one
was bent etc. that I could not detect with my eye. The push rods were of
equal length, and straight when rolled across the floor. The major concern
now is that: if by chance the oil passage to that lifter or all lifters for
that matter are clogged with crud of unknown substance, I don't feel safe
unless I somhow clean them all out. Perhaps not ideal with the engine
installed, and 2nd...what has happened to all the metal that was ground off
of the cam? I know most of it is suspended in the oil, the filter probably
has taken out some, but I am sure it circulated throught all the bearings.
Last oil change was about 1000 miles ago, and I am guessing that this grind
down has taken several thousand miles. Never noticed anything unusual in
the oil. So.....my strategy will be to first pull the head, then the lifter
and look at the cam. Priced a cam yesterday = $200.00 Yipes. Stay
tuned!!!! TX Mike



"Jeff Strickland" <spamcatcher@yahoo.net> wrote in message
news:8tudnYedjsiUgxPfRVn-2w@ez2.net...
> Collapsed lifter would be my first guess. As I went to look for the lifter
> hiding in the bottom of a very deep hole, I might find the real problem,
> but
> I think the lifter is where you need to start. I am not sure why you would
> swap a rocker or the push rod, but checking for a bent push rod makes
> sense.
> If the pushrod was straight, I would have kept looking for the lifter, and
> not bother swapping the rod and rocker.
>
>
>
>
> "MikeG" <justme@idontknow.com> wrote in message
> news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
>> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
>> popping out of carb. Found out that the # 1 cylinder exhaust valve and
>> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
> with
>> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
>> problem......collapsed lifter, round camshaft lobe or other???? TIA
> Mike
>>
>>
>
>

MikeG

Thanks for the very informative replys. As much as I can tell, and my
limited logic on this, the majority of answers I have received is pointing
to a rounded camshaft. I grounded out the coil, so that the engine would
not start and 'jiggled' the rocker arm while cranking. It never got tight.
I was able to look down the small push rod hole and observe the lifter. It
was not doing a thing. I changed the rocker and push rod just incase one
was bent etc. that I could not detect with my eye. The push rods were of
equal length, and straight when rolled across the floor. The major concern
now is that: if by chance the oil passage to that lifter or all lifters for
that matter are clogged with crud of unknown substance, I don't feel safe
unless I somhow clean them all out. Perhaps not ideal with the engine
installed, and 2nd...what has happened to all the metal that was ground off
of the cam? I know most of it is suspended in the oil, the filter probably
has taken out some, but I am sure it circulated throught all the bearings.
Last oil change was about 1000 miles ago, and I am guessing that this grind
down has taken several thousand miles. Never noticed anything unusual in
the oil. So.....my strategy will be to first pull the head, then the lifter
and look at the cam. Priced a cam yesterday = $200.00 Yipes. Stay
tuned!!!! TX Mike



"Jeff Strickland" <spamcatcher@yahoo.net> wrote in message
news:8tudnYedjsiUgxPfRVn-2w@ez2.net...
> Collapsed lifter would be my first guess. As I went to look for the lifter
> hiding in the bottom of a very deep hole, I might find the real problem,
> but
> I think the lifter is where you need to start. I am not sure why you would
> swap a rocker or the push rod, but checking for a bent push rod makes
> sense.
> If the pushrod was straight, I would have kept looking for the lifter, and
> not bother swapping the rod and rocker.
>
>
>
>
> "MikeG" <justme@idontknow.com> wrote in message
> news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
>> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
>> popping out of carb. Found out that the # 1 cylinder exhaust valve and
>> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
> with
>> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
>> problem......collapsed lifter, round camshaft lobe or other???? TIA
> Mike
>>
>>
>
>

MikeG

Thanks for the very informative replys. As much as I can tell, and my
limited logic on this, the majority of answers I have received is pointing
to a rounded camshaft. I grounded out the coil, so that the engine would
not start and 'jiggled' the rocker arm while cranking. It never got tight.
I was able to look down the small push rod hole and observe the lifter. It
was not doing a thing. I changed the rocker and push rod just incase one
was bent etc. that I could not detect with my eye. The push rods were of
equal length, and straight when rolled across the floor. The major concern
now is that: if by chance the oil passage to that lifter or all lifters for
that matter are clogged with crud of unknown substance, I don't feel safe
unless I somhow clean them all out. Perhaps not ideal with the engine
installed, and 2nd...what has happened to all the metal that was ground off
of the cam? I know most of it is suspended in the oil, the filter probably
has taken out some, but I am sure it circulated throught all the bearings.
Last oil change was about 1000 miles ago, and I am guessing that this grind
down has taken several thousand miles. Never noticed anything unusual in
the oil. So.....my strategy will be to first pull the head, then the lifter
and look at the cam. Priced a cam yesterday = $200.00 Yipes. Stay
tuned!!!! TX Mike



"Jeff Strickland" <spamcatcher@yahoo.net> wrote in message
news:8tudnYedjsiUgxPfRVn-2w@ez2.net...
> Collapsed lifter would be my first guess. As I went to look for the lifter
> hiding in the bottom of a very deep hole, I might find the real problem,
> but
> I think the lifter is where you need to start. I am not sure why you would
> swap a rocker or the push rod, but checking for a bent push rod makes
> sense.
> If the pushrod was straight, I would have kept looking for the lifter, and
> not bother swapping the rod and rocker.
>
>
>
>
> "MikeG" <justme@idontknow.com> wrote in message
> news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
>> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
>> popping out of carb. Found out that the # 1 cylinder exhaust valve and
>> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
> with
>> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
>> problem......collapsed lifter, round camshaft lobe or other???? TIA
> Mike
>>
>>
>
>

MikeG

Thanks for the very informative replys. As much as I can tell, and my
limited logic on this, the majority of answers I have received is pointing
to a rounded camshaft. I grounded out the coil, so that the engine would
not start and 'jiggled' the rocker arm while cranking. It never got tight.
I was able to look down the small push rod hole and observe the lifter. It
was not doing a thing. I changed the rocker and push rod just incase one
was bent etc. that I could not detect with my eye. The push rods were of
equal length, and straight when rolled across the floor. The major concern
now is that: if by chance the oil passage to that lifter or all lifters for
that matter are clogged with crud of unknown substance, I don't feel safe
unless I somhow clean them all out. Perhaps not ideal with the engine
installed, and 2nd...what has happened to all the metal that was ground off
of the cam? I know most of it is suspended in the oil, the filter probably
has taken out some, but I am sure it circulated throught all the bearings.
Last oil change was about 1000 miles ago, and I am guessing that this grind
down has taken several thousand miles. Never noticed anything unusual in
the oil. So.....my strategy will be to first pull the head, then the lifter
and look at the cam. Priced a cam yesterday = $200.00 Yipes. Stay
tuned!!!! TX Mike



"Jeff Strickland" <spamcatcher@yahoo.net> wrote in message
news:8tudnYedjsiUgxPfRVn-2w@ez2.net...
> Collapsed lifter would be my first guess. As I went to look for the lifter
> hiding in the bottom of a very deep hole, I might find the real problem,
> but
> I think the lifter is where you need to start. I am not sure why you would
> swap a rocker or the push rod, but checking for a bent push rod makes
> sense.
> If the pushrod was straight, I would have kept looking for the lifter, and
> not bother swapping the rod and rocker.
>
>
>
>
> "MikeG" <justme@idontknow.com> wrote in message
> news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
>> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
>> popping out of carb. Found out that the # 1 cylinder exhaust valve and
>> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
> with
>> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
>> problem......collapsed lifter, round camshaft lobe or other???? TIA
> Mike
>>
>>
>
>

Jeff Strickland

I discounted the possibility of the rounded cam shaft because I like to
think the problem will always be the cheapest thing to fix. In this case,
even if the cheapest thing isn't the broken part du jour, it rests right on
top of it. If the cam is rounded off, odds are good that the lifter will be
seriously worn too.





"MikeG" <justme@idontknow.com> wrote in message
news:bOrje.55821$IO.43814@tornado.tampabay.rr.com. ..
> Thanks for the very informative replys. As much as I can tell, and my
> limited logic on this, the majority of answers I have received is pointing
> to a rounded camshaft. I grounded out the coil, so that the engine would
> not start and 'jiggled' the rocker arm while cranking. It never got
> tight. I was able to look down the small push rod hole and observe the
> lifter. It was not doing a thing. I changed the rocker and push rod just
> incase one was bent etc. that I could not detect with my eye. The push
> rods were of equal length, and straight when rolled across the floor. The
> major concern now is that: if by chance the oil passage to that lifter or
> all lifters for that matter are clogged with crud of unknown substance, I
> don't feel safe unless I somhow clean them all out. Perhaps not ideal
> with the engine installed, and 2nd...what has happened to all the metal
> that was ground off of the cam? I know most of it is suspended in the
> oil, the filter probably has taken out some, but I am sure it circulated
> throught all the bearings. Last oil change was about 1000 miles ago, and I
> am guessing that this grind down has taken several thousand miles. Never
> noticed anything unusual in the oil. So.....my strategy will be to first
> pull the head, then the lifter and look at the cam. Priced a cam
> yesterday = $200.00 Yipes. Stay tuned!!!! TX Mike
>
>
>
> "Jeff Strickland" <spamcatcher@yahoo.net> wrote in message
> news:8tudnYedjsiUgxPfRVn-2w@ez2.net...
>> Collapsed lifter would be my first guess. As I went to look for the
>> lifter
>> hiding in the bottom of a very deep hole, I might find the real problem,
>> but
>> I think the lifter is where you need to start. I am not sure why you
>> would
>> swap a rocker or the push rod, but checking for a bent push rod makes
>> sense.
>> If the pushrod was straight, I would have kept looking for the lifter,
>> and
>> not bother swapping the rod and rocker.
>>
>>
>>
>>
>> "MikeG" <justme@idontknow.com> wrote in message
>> news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ...
>>> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
>>> popping out of carb. Found out that the # 1 cylinder exhaust valve and
>>> rocker/pushrod were not moving. Exchanged intake pushrod and rocker
>> with
>>> the exhaust, same problem. Nuts and bridge are tight. Any opinions on
>>> problem......collapsed lifter, round camshaft lobe or other???? TIA
>> Mike
>>>
>>>
>>
>>
>
>