cold "clunk" ??

[theHIGHLANDER]

When I 1st start my 31 it has a bit of a clunk engine noise that goes away when I release the clutch and goes away within a few minutes of warm up time. Rear main? I've seen some shim discussions about rear mains. Any input? It runs great, just a wee bit of clatter on the valve side of things, the noise never returns until it cools completely. Hit me with your best guesses, and I'm not sure I even need to do anything about it.

[colin1928]

Does it sound like piston slap a common cold problem

[Joe K]

Can you tell by looking at your front pulley if you have excessive crankshaft movement forward-back? Pushing on the clutch SHOULD push the crankshaft to forward - and maybe captivating the loose motion?

The thrust bearing area of the Model A engine is NOT the stong link. And many rebuilders unwittingly make it (free play) too large.

Joe K

[V4F]

start it without pushing the clutch , let it warm up , then see if its there ......

[Tom Wesenberg]

To check for end play in the crankshaft, I could just watch the pulley move back and forth while the engine was running on my 29, which had the center babbit gone. You could have someone step on the clutch and release it, then you push the crankshaft rearward with the hand crank, and feel for any freeplay or watch the front pulley for freeplay.

[theHIGHLANDER]

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It's an audible deep clunking noise. I depress the clutch to start it because I think it's easier on the starter not turning the heavy trans oil. It's in sync with the idle RPM and is immediately gone when the clutch pedal is released. In a matter of minutes, more when it's really cold, it's gone whether or not the pedal is depressed. I know cold piston slap sounds pretty well. My 725HP BBC had it and so did my 95 Trans Am. This ol friend doesn't have that. I'll try the visual thrust inspection and it'll be easy as I run around with no hood on it. Actually a lot of the parts are not on it (!) but it's fun to run around in as is.

[colin1928]

I think you may need to take close look at clutch pilot bearing and throw out bearing
if it is only there with the clutch depressed

[tbirdtbird]

"I depress the clutch to start it because I think it's easier on the starter not turning the heavy trans oil."

But you could do it just once to try to help with the diagnostic process.......

[theHIGHLANDER]

Originally Posted by tbirdtbird

"I depress the clutch to start it because I think it's easier on the starter not turning the heavy trans oil."

But you could do it just once to try to help with the diagnostic process.......

And I have which is how I determined what I did. Not so bad in last year's heat wave