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Re: Speculation, please?

On Mon, 1 Dec 2003 14:19:24 -0800, "CRWLR" <beerman@yahoo.com>
shared the following:

>A lifter that was about to collapse permantly might present this sort of
>symptom before it finally went bad.
>
>A lifter has small springs and valve thingies inside that cause the oil to
>flow through in a controlled manner. They can fail internally and then the
>lifter is stuck in a collapsed condition (because it fails to open the valve
>when the cam lobe rises), then the next time the cam comes around, that
>valve doesn't open properly, or at all, and the result is a lost power
>stroke. This can happen for a few lifters in a row, or one lifter
>repeatedly. It could be noisy when this happens, and is more likely to
>happen at high engine speeds than low ones.

Yeah, that's *exactly* what happened on that old Pontiac I had that I
mentioned. That's why I said the noise reminded me of when some
lifters went bad on that car.

> You might be able to drive
>around town for years and never even know the lifters were not happy, but
>get out on the freeway and get the engine speed up to a high level and the
>lifters can not react as quickly and the time for them to react is shorter.
>
>I can't recall a test for lifters, sorry. That is, they should be able to be
>pressed on the bench, and should rebound without delay, but you have to pull
>them to do this test, and then you may as well replace them if you suspect
>they are bad. What I can't recall is a test that you can do while they are
>still in place.
>
>I do believe you can get to the lifters without a complete tear down of the
>motor. If my memory is correct, they live under a plate that is under the
>intake manifold. You may need to pull the rocker arms and pushrods, but I
>don't think you have to pull the heads, as you would on the I6 motor that
>you passed on.

That's exactly how it was for my Pontiac. I removed the rocker arms,
pulled the pushrods, removed carb and intake along with the plate
(windage tray) under the intake and was able to fight the lifters out.
It was obvious which ones were dead when I did that but of course I
replaced the whole set. I'm hoping it will be something less major
than that, but I can handle the lifter replacement if that's it. It's
amazing the racket lifters can cause when they start to go.. :-)

>
>
>
>
>
>"travis" <travist34removethis@hotmail.com> wrote in message
>news:dbdnsvk49fvd3st4jmf61cnnc912vj23ft@4ax.com.. .
>> On Mon, 01 Dec 2003 17:48:30 GMT, "c" <c@me.org> shared the
>> following:
>>
>> >
>> >
>> >"travis" <travist34removethis@hotmail.com> wrote in message
>> >news:f5vmsvstc3ggcrdu8od070q4ehsnk91bbg@4ax.com.. .
>> >> I'm worried about my CJ5. Yesterday while driving home from the
>> >> trails I got out on the highway and got up to about 75 mph in a hurry
>> >> to merge, then slowed down to about 65. Maybe 30 seconds later
>> >> several LOUD bangs/knocks (about 10-15 maybe) came from what sounded
>> >> like under the hood. With each bang there was a dramatic power drop
>> >> for a fraction of a second. This happened really quickly like within
>> >> 25-30 seconds or so. I let off on the gas and it seemed to help a
>> >> little bit. Each time I'd ease back on the gas the bangs would
>> >> return. I slowed down to about 50 mph and the banging sound went
>> >> away. I slowly sped back up to about 60 mph and made it the rest of
>> >> the way home without incident. I noticed when this all was happening
>> >> that my oil pressure stayed steady and my water temp was also steady.
>> >> Then... when I was driving to work this morning I heard 3-4 loud
>> >> bangs within less than 10 seconds while driving at about 65 mph on the
>> >> highway. I felt the same power drop and again noticed oil pressure
>> >> and temp remained unchanged. The problem "went away" again. I'm
>> >> thinking maybe it's backfiring through the carb (I'll check for burn
>> >> marks around the air cleaner later today) or maybe...just maybe...I
>> >> seem to recall a similar feel/sound from about 12-13 years ago when an
>> >> old Pontiac I had did something like this... turned out it had a
>> >> couple of lifters that were about to give up the ghost, or pretty much
>> >> had given up the ghost by the time I opened up the motor and replaced
>> >> them. Can y'all speculate on best-case/worst-case scenarios? Sorry I
>> >> can't give a better description of the sound. Ideas of stuff for me
>> >> to look at? Thank you in advance for input.
>> >>
>> >>
>> >> --
>> >> Travis
>> >> http://jeepadventures.dyndns.org/jeep.html
>> >> Happy trails!!!
>> >> :wq!
>> >
>> >Could be lean fuel mixture, late ignition timing, broken valve spring, or
>a
>> >cam lobe going bad. I'm sure there are others, but this is a start.
>> >
>> >Chris
>> >
>>
>> Could any of those things you listed "come and go," though? If it was
>> lean, wouldn't it be lean all of the time? Late ignition
>> timing...hmm...maybe an intermittent vacuum leak causing the
>> distributor to not advance when it should? Hmm... Broken valve
>> spring? I can't see that causing this problem to show itself for 30
>> seconds and then let me drive it 1/2 hour without showing up again.
>> Cam lobe going bad? I also think that would be a more persistent
>> problem than what I'm seeing. I like the late ignition timing idea,
>> though. I'll have to poke around and look for a vacuum leak. Thanks!
>>
>>
>>
>> --
>> Travis
>> http://jeepadventures.dyndns.org/jeep.html
>> Happy trails!!!
>> :wq!

--
Travis
http://jeepadventures.dyndns.org/jeep.html
Happy trails!!!
:wq!

Re: Speculation, please?

Ditto.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Roy J wrote:
>
> Ignition problem, it's cutting out on at least one cylinder, when
> it comes back it fires all the unburned gas that has accumulated.
> Time to change points (if yours has them), cap, rotor, wires, and
> the ignition module (if you have one)

Re: Speculation, please?

Also I noticed I
> could feel a very slight "pulse" on my right foot that was on the gas
> pedal each time the bang noise occurred, but could not feel that same
> pulse on my left foot... which makes me think the carb is somehow
> involved here, like it's backfiring through it maybe. Still not sure
> at all.
>

is it possible you got some water in your tank? you had just lengthened your
fill pipe, could have taken in some water around the join. is your backfire
more like a sputter?

--

bill
00 TJ
-I only come across as stupid part of the time-

Re: Speculation, please?

On Mon, 01 Dec 2003 16:53:04 -0800, L.W.(ßill) ------ III
<----------@cox.net> shared the following:

> Ditto.
> God Bless America, ßill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>Roy J wrote:
>>
>> Ignition problem, it's cutting out on at least one cylinder, when
>> it comes back it fires all the unburned gas that has accumulated.
>> Time to change points (if yours has them), cap, rotor, wires, and
>> the ignition module (if you have one)

Man, I hope it's that easy.

--
Travis
http://jeepadventures.dyndns.org/jeep.html
Happy trails!!!
:wq!

Re: Speculation, please?