M5 undersize rod bearings

[AlanK]

Have an M5 that has a knock I believe in a rod bearing. Does anyone know what undersized bearings are available yet? I havent tore into it yet but hope to when I get a moment. Im guessing from the age of it Im sure the crank has been ground before.

 

[Joe Pro]

Rod bearings and mains are available from the usual sources. But I would not jump to the conclusion that the crank has already been ground. Many old MM's are still turning stardard bearings. Also even if someone had "rebuilt it" that also usually does not mean they turned the crank.

If the journals mic out then why have them turned. Many people also just put standards in because they dont want to pull a crank.

I am not as familer with the 336 as the samller engines, but are you sure its a rod knocking and not a piston pin? or even piston slap?

 

[AlanK]

Im guessing number 1 rod at the moment as it is in the front of the engine when running. At cold start it is a little more prominant but within a few seconds of oil pressure rising it disappears but returns when warm. Havent got the oil pan off yet but did take out the oil filter canister and I can feel some play on number 1 rod. Hope to get at it soon.

 

[bjz]

One of the rod bearings is worn out it happend on my ZTU. There was play and when i took of the rod the bearing was worn down to nothing.

 

[Moline Man G1]

before you pull the pan you might check camshaft end play. theres a big jam nut with a inner adjusting bolt on the front of the engine. if thats loose it will knock.tighten up and back it off i think 1/8 turn.

 

[Moline Man G1]

to be clear on my previous post. the cam can get end play from normal wear, we had a u do that.it started knocking, an old mm mechanic told us to check end play.that fixed it, by loose i meant the cam not the adjusting nut. hope that helps.