55-TO35-Z134 Engine Knock

TimAP

Member
Hi, engine started knocking, it does not
go away or decrease with plug wire removal.
It sounds like its coming from rear of engine
at starter/bell housing area.
Not 100% sure but think its a rear main bearing.
What do you think?
Thanks,
Tim
 
oops, was going to send an audio of the knock,
but not sure I know how or the upload part is not
working.
Tim
 
Does holding the clutch with it in gear make a difference? If so, the noise is in the transmission.

Has the oil pressure dropped to near nothing at warm idle? If so, there probably is a bearing problem.

That pulling plug wires has no effect is pretty good evidence it is not piston/wrist pin/rod related.

Mains usually knock under load, rattle at higher RPM, loose oil pressure at idle, leak oil externally.

Have you checked the valve train and lash adjustment?

Is the front pulley bolt tight?

Look inside the oil filter for sparkles, sure sign of bearing failure.
 
Does holding the clutch with it in gear make a difference? If so, the noise is in the transmission. CHECKED OK

Has the oil pressure dropped to near nothing at warm idle? If so, there probably is a bearing problem. 20-23 psi-COLD, 18-20 psi-HOT

That pulling plug wires has no effect is pretty good evidence it is not piston/wrist pin/rod related.

Mains usually knock under load, rattle at higher RPM, loose oil pressure at idle, leak oil externally. NO UNUSUAL PRESSURE LOSE AT IDLE, HIGHER RPM-KNOCK OR RATTLE DOES NOT GET LOUDER.

Have you checked the valve train and lash adjustment? ADJUSTED VALVES IN THE SPRING, NO UNUSUAL SOUNDS WITH STETHOSCOPE.

Is the front pulley bolt tight? HAVE NOT CHECKED YET

Look inside the oil filter for sparkles, sure sign of bearing failure. NOTHING UNUSUAL IN OIL OR FILTER.

Its hard to pin point the knock, sometimes sounds like its in the rear, sometimes in the governor area using a stick, pipe and stethoscope. Not 100% sure it is a bearing, but what else could it be.
Oh.. Last Fall, Plasti-Gauged The Rod bearings and were all within tolerance.

Thanks guys for the response ,
Tim
 
As Steve said, and the easiest thing to check is the front crank bolt. Really put some pressure on it to make SURE it is tight.
 
Just thought I would post the pics of bearing clearance as I go for whoever
would be interested.
I made a small puller to to remove this bearing cap
instead of beating and prying the hell out of it.

.002"-.003" Looks Good To Me
a239877.jpg
 
My 1957 TO 35 was making a motor noise,
Noise would come and go, I was sure it was a rod knocking,

Turns out the large bolt that holds the crankshaft pulley had back off for some reason,

Tighten it up and the noise was gone,
Dodged a bullet on that one,
 
From this description, nothing clearly points to bottom end failure.

One other thing to check would be under the timing cover. Those have a cage that contains the balls in the governor. That cage is prone to break, sometimes a piece will get caught in the timing gears. It can break a tooth or embed in the gears causing a knock.
 
It's such a hard knock, like pounding a hammer on a cement floor, I checked front pulley and it was tight.
I might as well pull front cover being I have it assesable.
 
Well, checked all rod and main bearings and they check out good.
Knock is still there, havent removed front cover yet to check out
governor.
But just curious,

What Would Cause That Knock in The Governor Area??
What can be Hitting in There??
If Thats The Area.

I just cant pinpoint the knock by ear, it seems
to come from clutch area sometimes to depending on what
ear I use, as far as that goes, it comes from every area I listen to..

I dont want to remove front cover unless I have to.

Any tips on isolating the noise if its the governor?

Thanks,
Going Crazy Tim
 
The retainer in the governor can break and the balls can rattle around causing a noise. Here's what mine looked like when I tore it down, only 3 of the 10 balls were in place. :(
BillL
 
The governor worked fine, I can see where that would cause alot of rattle type noise, I think, but I have a hard knock, unless its a main bearing, but I used plasti-gauge on all the bearing and they are with in the specifications, so I dont know!!!
 

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