Timing mark

Posted By: 1toolguy

Timing mark - 07/19/09 06:56 PM

Just wanted to make sure I'm doing this right. Using a piston stop and some math I have determined that my balancers TDC mark is off 5-degrees ATDC. So I should use the 5-degree BTDC mark on my timing cover as "0" correct?

Posted By: RapidRobert

Re: Timing mark - 07/19/09 07:16 PM

If I am reading you right your 5 degrees off which is alot unless the dampener has slipped(happens but is rare). What I do is turn the crank to the 5BTDC mark(approach it slow & dont go backwards) then screw in the stop until I gently but solidly hit the piston then turn the crank CCW & if it hits the stop @ 5ATDC I'm good & if not post what you get

Posted By: 1toolguy

Re: Timing mark - 07/19/09 07:18 PM

I'll double check later in the week and get back to you.

Posted By: Anonymous

Re: Timing mark - 07/19/09 08:32 PM

Quote:

If I am reading you right your 5 degrees off which is alot unless the dampener has slipped(happens but is rare). What I do is turn the crank to the 5BTDC mark(approach it slow & dont go backwards) then screw in the stop until I gently but solidly hit the piston then turn the crank CCW & if it hits the stop @ 5ATDC I'm good & if not post what you get

This is really not a good way to do this. The reason is, that anywhere from 10* on down to TDC, the piston moves rather slowly near the top compared to the damper. You are much better off screwing the stop IN (longer) so that the piston is further down. Just make two marks, one for each stop, and TDC is halfway in between. Make a third temporary mark halfway inbetween---the new TRUE TDC, and bring it up to 0 on the pointer. Now you can see where the old mark is in relation to the damper.

Posted By: RapidRobert

Re: Timing mark - 07/19/09 08:53 PM

yes the piston does moves slower closer to TDC but if the piston hits the stop at the same distance on either side of TDC(& halfway between the contact points is showing TDC on the marks) I wouldn't think that it would be more accurate if you started further away imnho but if I am wrong on this then I definitely want(need) to know.EDIT after some thought yes 5 is going to be in that dwell area so further away(maybe at the edge of the tab on each end) or farther is correct. Thank you for the enlightenment.