Author Topic: Top Dead Center (Read 4753 times)

RWPerry · « **on:** July 06, 2006, 07:57:38 am »

On a 1.6l TD, what is the best way to position the no. 1 piston at TDC without the transmission attached?
The transmission provides a mark to line up with the position mark on the flywheel. Without the transmission how do you establish the position of the no. 1 piston?
Thanks,
Rex Perry

QuickTD · « **Reply #1 on:** July 06, 2006, 08:18:04 am »

Cut a chunk from a junkyard tranny that holds the timing pointer and bolt it to the block, thats probably the easy way. A 4 speed will work fine and they are worth nothing. Another method would be to use a dial indicator on the top of the piston (if the head is off). turn engine to approx TDC zero the indicator move crank back and forth a bit to make sure you're zeroed, then turn crank so indicator reads .100 or some easy to remember number, mark the block at the flywheel TDC mark. Turn crank opposite way past TDC to the same value and place another mark on block. Now measure halfway between and place your TDC mark.

If the head is on you could remove the cam and prop a valve slightly open on #1 cylinder to act as a dead stop. Procedure is much the same as the indicator method. Turn crank in one direction until it stops against valve (gently please) and place mark on the block at the flywheel TDC mark. Rotate in opposite direction and repeat. Measure halfway between marks to determine TDC.

RWPerry · « **Reply #2 on:** July 06, 2006, 10:01:56 am »

Is the timing pointer on the transmission case located half way between the two upper mounting bolts?
If that is the case, an indicator block could be fabricated with a mark centered between the bolts. Bolting it to the engine would simulate the transmission case.

regcheeseman · « **Reply #3 on:** July 07, 2006, 02:36:47 am »

Quote

Is the timing pointer on the transmission case located half way between the two upper mounting bolts?

Nope.

I had this exact same problem and ended up just bolting the transmission up.

RWPerry · « **Reply #4 on:** July 07, 2006, 04:53:18 am »

Thanks for the input. I am in the process of finding an old transmission case to cut up.

LeeG · « **Reply #5 on:** July 07, 2006, 11:55:03 pm »

Maybe someone could measure up position of the pointer relative to bolt holes in block?

Master ACiD · « **Reply #6 on:** July 08, 2006, 02:34:05 am »

when you cut up an old transmission for this use, try and cut it so that you keep the front of the bellhousing intact where the starter drive mounts. this way you can bolt a flywheel on as well and start the motor out of the car for testing purposes.