Excessive crank end play 59A
 

Would excessive crank end play produce a rhythmic knocking sound when the engine is running with clutch engaged (foot off clutch pedal) and then when clutch is Dis-engaged (foot pressing down pedal) the rhythmic knocking stops until clutch is engaged.

Re: Excessive crank end play 59A
 

excessive end play most likely will make some noise. Sometimes caused by someone in the past
banging on the front pulley - the rear main bearing does not like that. I say that cause
you say pushing down on the pedal it stops: It stops because you are now pushing on
the rear main (rear) thrust side. Only thing now is somehow with a pry bar push back
on the front pulley now pry pulley toward radiator and watch for movement. This movement is measured in thousands somewhere around .004 to .006 or 7 go to the
book. If you see movement you need a new rear main bearing. If you see .00? thou
you have special eyes .004 is a sheet of typewritter paper.

Re: Excessive crank end play 59A
 

If nothing looks obvious I would check for a transmission problem.

Re: Excessive crank end play 59A
 

If the crank has been ground my guess when doing the mains they were sloppy and rubbing the side marking more clearance. Just limit the time using the clutch and at lighst put in neural .

Re: Excessive crank end play 59A
 

Worn transmission bearing or a chipped tooth?
Can you hear it when moving slowly in low gear? Does it change with accelerating or decelerating?

Re: Excessive crank end play 59A
 

The sound is present all times except when depressing the clutch pedal - then the noise stops until you release the clutch pedal. The engine performance is very good and so is oil pressure. The engine oil was rather clean - though the transmission oil was very low (constant slow leak)

Re: Excessive crank end play 59A
 

I had a similar problem with my '51 Ford, only it was more of a rattling noise than a knock. Like yours, the engine performed well and had excellent oil pressure. After a while, I decided to not take any chances and swapped in a '51 Mercury engine that I had. Because the pans were different, I had to swap them between the engines. When I cleaned out the Ford pan, I found a chunk of the rear main thrust flange about an inch long lying in the bottom of the pan. I know that's what it was because I had a set of new in the box bearings I could compare it to. I talked to my machinist about it, and he said it might be a defective bearing, but most likely, an "assembly error".

Not saying this is what you have, just giving an example of what can happen with these old engines.

Re: Excessive crank end play 59A
 

If the the clutch is in or trans is out of gear and you rev the engine and you don't hear it. I'd look at the transmission. Possibly the throwout?


Why do you think you have crank play? has it been measured?

Re: Excessive crank end play 59A
 

Measure how far the crankshaft moves forward when you push the
clutch in. Motor not running see how far front pulley moves. G.M.

Re: Excessive crank end play 59A
 

if the spring that pulls the to bearing back breaks the bearing can slide foreward and rattle around till you push on the clutch

Re: Excessive crank end play 59A
 

They are pretty stout springs but not "not" subject to breaking. Interesting.


GM good idea.

Re: Excessive crank end play 59A
 

i had a 350 chevy you could measure the end play with a tape measure.only noise you would hear is a clunk when you step on the clutch. it's the same way with my Model a

Re: Excessive crank end play 59A
 

My rear crank journal face was worn and excessive clearance between the rear main thrust bearing. The machine shop built it up (weld) and reground the face. Perfect. Just remember when you depress the clutch the rear main bearing is pushing hard against the side of the crank so don't sit at a light holding the clutch in. JMO
John