4.1 timing tab question

[czimpel]

I used a stock 4.1 14 bolt(pan) timing cover on my 4.1 build, but it seems like the cast in timing marks are off from the 3.8 timing tabs. Does this sound right?

 

[ek02]

The timing marks are not cast in the cover on the 4.1. They use the nylon bolt on tab same as the 3.8 even fire. You may have an early odd fire cover. The marks were cast in on those covers.

 

[czimpel]

That would make sense.

 

[Nick Micale]

Cast-in timing marks on the cover were used on early Buick V-6 engines.

 

[czimpel]

The timing marks are not cast in the cover on the 4.1. They use the nylon bolt on tab same as the 3.8 even fire. You may have an early odd fire cover. The marks were cast in on those covers.

Cast-in timing marks on the cover were used on early Buick V-6 engines.

Do either of you know if those marks are correct or are they off from what a 109 block is?

 

[earlbrown]

The only way to know is to measure. Luckily for us the spark plug hole is oriented so that a dial indicator can reach down pretty square with the piston.

 

[ek02]

I have read that the difference in timing marks is 18 degrees. I have more info at home, but I'm out of town untill Tuesday. It would be better to use the right cover. You may be able to remark the balancer if you have a lot of work in the odd fire cover.

 

[ek02]

I cant find any other reason that an odd fire cover will not work except for the 18 degree difference in TDC marks. The passages may be smaller in the early covers due to a smaller supply passage in the early blocks.

 

[czimpel]

I did the Earl Brown mods to the cover.
I found true TDC yesterday and remarked the balancer with the correct 0˚ mark. I just wanted to verify my balancer/CPS were in the correct orientation. They were, so that's one thing off the table for tracking down my KR issues.