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TR4/4A timing chain "slap" in TR4a

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hlub34a

Freshman Member
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I have a 67 4a that developed a curious noise at idle once it reaches operating temperature. My mechanic "stethoscope" isolated the noise to the front of the engine. When engine speed is raised, the noise disappears. Engine has about 97K, is this a symptom of a loose timing chain?

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hlub
Sounds like you have a badly worn timing chain. If you dont replace it the next symptom will be an oil leak at the front of the engine from under the grease on the timing cover where the chain tensioner wears a hole inn the sheet metal cover. Probably no other damage unless the chain breaks completely !!! (mabe some gear wear)
Good luck
Ken
 
More likely a busted timing chain tensioner, IMO. BTDT.
 
I agree with Randall. There's a lot of room between even the loosest chain and the cover so that it wouldn't "slap."

But the tensioner rides directly in contact with the chain and the chain will wear two grooves right through the tensioner. And then the tensioner wears right through timing cover on the passenger side.

Pull that puppy. Mark the position of both gears and replace, minimally, the chain and tensioner. But optimally both gears as well. There's a guy on ebay selling complete kits for $89, ebay id is trguru. You'll also need a gasket and front seal unless trguru has that too.

If you need pictures, I just did this this past weekend on my 3A.
 
If you get the noise at idle but it goes away when the revs increase it MAY be a loose gear on the oil pump driveshaft. Tractor engines are known for this. The woodruff keyway wears and allows the gear to 'rattle'...I had this noise on TS 74011 L and nobody could figure it out. I drove the car for 11 years with out repairing it. BUT if the woodruff key breaks you will loose oil pressure and spark...

The noise the loose gear makes mimics a piston pin rattle almost exactly.

It's worth looking into. You would need to remove the oil pump because , I think, the shaft pulls out from the bottom of the engine.
 
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