Author Topic: Setting Base timing on M42? (Read 4102 times)

RIPDOTCOM · « **on:** December 12, 2007, 03:30:11 PM »

I have finally found the problem. The timing was screwed and the timing chain must have jumped. My questions is, "How do I set the base timing" I need to know exactly the position the cams need to be in, as well as the sprokets and the crank. I am so damn close to getting this thing fixed I just need some help getting everything lined up. The previous owner must have removed the cam sprokets as well so I need to know the position the sprokets need to be in as well.

Thanks

cecotto · « **Reply #1 on:** December 12, 2007, 04:19:18 PM »

Quote from: RIPDOTCOM;39334

I have finally found the problem. The timing was screwed and the timing chain must have jumped. My questions is, "How do I set the base timing" I need to know exactly the position the cams need to be in, as well as the sprokets and the crank. I am so damn close to getting this thing fixed I just need some help getting everything lined up. The previous owner must have removed the cam sprokets as well so I need to know the position the sprokets need to be in as well.

Thanks

Cylinder 1 (front) at TDC

Camlobes at Cylinder 1, poining towards each other...

Arrows on sprockets pointing upward

Use a ruler on the square, on the back of the camshaft to set them square.

Tighten everything up.

Rotate engine 720-degree, double check everything.

check out the procedure in the factory manual before doing your work:
http://m42club.com/forums/showthread.php?t=964

RIPDOTCOM · « **Reply #2 on:** December 13, 2007, 08:04:50 AM »

Do the Cam lobes need to be pointing directly at one another on cylinder #1? or should they be slightly upward, This answer will completely solve my problem I think.

Quote from: cecotto;39336

Cylinder 1 (front) at TDC

Camlobes at Cylinder 1, poining towards each other...

Arrows on sprockets pointing upward

Use a ruler on the square, on the back of the camshaft to set them square.

Tighten everything up.

Rotate engine 720-degree, double check everything.

check out the procedure in the factory manual before doing your work:
http://m42club.com/forums/showthread.php?t=964

FL318i · « **Reply #3 on:** December 13, 2007, 08:12:08 AM »

something like this // \\

RIPDOTCOM · « **Reply #4 on:** December 13, 2007, 10:55:08 AM »

Put it all back together. Fired right up. Still real lopey. Would a weak tensioner allow the exhaust cam to follow a little extra and cause it to run bad or do I just need some fine tuning on the sprokets? Everything lined up nice and neat but I could compress the tensioner with my hands and put it back in uncompressed.

m42mccabe · « **Reply #5 on:** December 14, 2007, 10:09:56 PM »

The tensioner sounds done to me. Usually have to use a vice to get them compressed.

I would just put a new one in cause they're cheap and easy to replace.

strad · « **Reply #6 on:** December 14, 2007, 11:08:22 PM »

Man, if your tensioner's that far gone seems like you'd hear a hellish slapping noise from the chain. I would agree that the spring should be stronger than your hand though.

RIPDOTCOM · « **Reply #7 on:** December 15, 2007, 06:43:59 AM »

Doesnt matter anyway, I did what I should have done in the first place. Compression test. Cylinder #1 is dead. Pulled the head and the valves are bent. Scew it , I have another excellent running 91 318 and a 325. Im just going to do a M20 or m50 engine swap and turbo it. I really wanted to turbo a M42 but its gonna $500 more just for the damn manifold.

Author Topic: Setting Base timing on M42? (Read 4102 times)

m42mccabe