Tdc help
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,504
Likes: 73
From: Georgetown TX
Tdc help
1989 l98
My brain is over loaded on research, so I need just a very simple way to find TDC on number 1 cylinder with intake off, so distributer is also out. I finally feel confident about how to set pre load, but I just need to be sure I'm at TDC before I start or every adjustment will be wrong. It took me for ever to understand how to adjust preload, but with lots of help from members on this forum, I now think I have it down
My brain is over loaded on research, so I need just a very simple way to find TDC on number 1 cylinder with intake off, so distributer is also out. I finally feel confident about how to set pre load, but I just need to be sure I'm at TDC before I start or every adjustment will be wrong. It took me for ever to understand how to adjust preload, but with lots of help from members on this forum, I now think I have it down
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,504
Likes: 73
From: Georgetown TX
I did that while having wife hold her finger over the hole, but she kept telling me she felt air each time crank came around to TDC. Now that I am thinking about it, I didn't have any of the valve train gear on. That would mean both valves would always be shut and air would come out of plug hole no matter what. I am such a dumb s%%t
Last edited by mlm0; Jun 10, 2016 at 10:52 PM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Make a paper ball put it over #1 spark hole bump starter ,do not crank it, when air blows paper ball using a wrench rotate balancer until timing mark aligns with 0 on timing tab. Or with timing mark on 0 if both valves are closed and you can spin push rods with fingers it's tdc#1 if not its tdc #6. So rotate crank one turn and it will be tdc#1.
Last edited by Kevova; Jun 11, 2016 at 01:43 PM.
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
Make a paper ball put it over #1 spark hole bump starter ,do not crank it, when air blows paper ball using a wrench rotate balancer until timing mark aligns with 0 on timing tab. Or with timing mark on 0 if both valves are down and you can spin push rods with fingers it's tdc#1 if not its tdc #6. So rotate crank one turn and it will be tdc#1.
Melting Slicks
Joined: May 2014
Posts: 2,891
Likes: 591
From: New Port Richey FL
The op states he has no valvetrain gear on the car. All valves are always closed. The cylinder will blow air out of the plug hole during both compression and exhaust strokes. To the op, loosely put the valvetrain gear on and look at the rockers as the motor is turned. When rockers are both down on tdc#1, you are where you want to be.
I would think with Intake off you could look rite into the cam lobes or drop in the 2 lifters and see valves are in the compression Directly.
Here is a link on how to just take what he said about the rockers and translate to lifter position
