Hello Listers: I have an engine "vibration" & higher speed rattle sound
I decided to write to all of you because of everyones VAST knowledge about
"Engines"
This is an slightly "off List" subject that has plagued me for two years
now!
It is about an engine, being internaly or externaly balanced?
This engine is not a military engine but a 2.2L dodge caravan
I doo have 4 jeeps, one being and '42MB though !
There are Two parts to this email.
I will start at the beginning of the problems ..it may help with your
diagnosis???
Therefore, I hope someone can help me.
The circumstances regarding this engines problems / knock / and subsequent
vibrations... are baffling to say the least?
Two years ago I had someone pull the 2.2L Dodge 4 cyl. from my old Dodge
Caravan.
This engine had an enormously loud knock.(s)
It would come... it would go?
Totally at Random.
Sounded just like a conn. rod bearing in volume but it was NOT affected by
load.
It would sound like it was in the 1st or 2nd. cylinders then later... the
3rd. or 4th cylinder.
Weird!
I took the engine apart.
I started by pulling the head but did not look at it... as I have NEVER
heard a head knock ...ever!
I then pulled the pan and the rods and pistons...
Nothing wrong !
I was pissed!
What could it be?
Now back to the head... overhead cam shaft & bearings were fine also!
Then I saw it.
Looking into the ports, the valve guide bases appeared highly polished and
badly chipped !
The problem within the head ...that in three cylinders the valve guides had
broken free and randomly bounced up and down with the valve. (for a minute
or
two, at each occurance)
This would cause an enormous noise & a huge amount of oil burning blue
smoke.
The noise was unbelievable.
Then suddenly, as quick as it happened the guide would jam up into the head
again for a few days (or more)
The engine would run silently until a day or two later when a different
guide would drop.
This ruined the bottom of those guides ...shattered them in fact!
The pistons were deeply pitted also. The cylinders were not marked,
fortunately.
This engine was already a rebuild from Chrysler with only 40k miles on it.
So I put $100 into the head to have new valve guides with retainer clips.
Problem solved, so now for the next problem....
The above story is the background for my next question. (problem)
At 40k miles the engine was perfect (except for the valve guides)
While apart, (at 40k mi) I replaced just the connecting rod bearings &
rings anyway...
but not the mains bearings.
I left the crank in place. as there was NO apparent wear on the journals. (I
have done this with many engines over the years with excellent & great long
range success)
Pistons were fine "cylinder lip" was totally minimal at best.!
I deglazed the cylinders.
However, now when put back together this engine has an annoying VIBRATION.
This was / IS a new problem.
I asked many about what would case this... !
Nobody, including the local dealer could help... regarding this vibration.
The engine has run for two years now. Constant vibration
After about 1 yr. it has developed what appears to be bearings rattling.
This only occurs at mid to higher revs.
However, it does not seem that the conn. rod bearings are smashing
themselves to pieces?
It's been about two years now!
This is an horrible grinding rattle as the engine builds (mid to higher)
revs in each gear.
There is NO difference with the sound at hot or cold engine temps.
This does NOT occur at lower revs under load like the conn. rod bearings
"knock"
So, now to engine balancers???
I have NO info regarding engine balancing?
Would it be possible for the torgue converter to be bolted in the wrong
(unbalanced) position ?
Are the flywheel / torgue conv., a balanced pair at the factory?
Would this higher engine speed rattle be the, rear MAIN bearing being
slowly worn
out?
(I've never heard what worn main bearing(s) would sound like)
I've never heard that noise!
Also,
There is NO harmonic balancer on the front of this engine!
My other caravan has the Japanese 2.6L Caravan engine. The 2.6L DID have an
internal balancer "gear driven" weight shafts!
But, my present Caravan has the 2.2L american engine.
So, would ANY of you know if the constant vibration is caused by the
mis-aligned
Torgue Conv.
There are small weights welded onto the converter?
This constant vibration can even be felt in the steering wheel the door arm
rests etc.!!!
It exists in nuetral and when being driven?
I do know one thing however... that the flywheel will "only bolt on" in
"one" position. So, it can't be the flywheel?
Finally, if you know of "anyone" with this type of experience I would
appreciate you asking them for me.
Sorry for the length of this email.
However, I'm about to tear the engine apart once again... and, if it is a
"balance problem" I would hate to rebuild it the same way, ending up with
the same vibration problems.
Regards
Rob Pearson aussierob@odyssey.net
42mb jeep
3, CJ2As
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