Hey all.. I am trying to find the most accurate way to find TDC while the engine is fully assembled and in the car without removing a head. any suggestions greatly appreciated!

Chris

 

Take off the valve cover, also take out #1 spark plug, as the piston approaches TDC, have someone look at the rockers. Since #1 could be TDC compression, or TDC exhaust, if its almost at tdc and while you approach the valves are still moving, its at the exhaust stroke. You should be able to move the crank and the rockers stay still.

Also referencing

Intake: 1, 2, 5, 7
Exhaust: 1, 3, 4, 8

these rockers should be completely up

 

a piston stop works well

 

To get close to top dead center, watch the rocker arms as you turn the engine over. During overlap, as the exhaust valve is closing and the intake valve is opening, you are close to TDC.

To find actual TDC, use a piston stop. (threads in place of the spark plug). Turn the engine over by hand until the piston contacts the stop. Make a timing pointer and mark the dampner, or mark the flywheel in relation to the bellhousing. Turn the engine over the other direction until the piston contacts the stop again. Mark the dampner/flywheel again. The center point between your 2 marks is TDC.

 

Thanks all!

Intmd8,

thats exactly what I was looking for! trying to get the dual synch distributor and balancer in synch with what the engine is doing.. right now in the DFI the timing is reading 29* (where it should) but my timing light is hitting around 65* BTDC.. I am very sure my timing tape is off as I had to crudely guess at getting it close and figured I could dial it in after it was started.. runs great where its at now but I would like to be able to more accurately pin point where my true engine timing is in relation to the DFI tables.

so basically like you said just install piston stop, rotate until piston hits it, mark balancer at the pointer, rotate opposite direction until it hits again, mark balancer at pointer and in between the two marks is my TDC. thanks a million.. then just set 0* on y timing tape at this point and check my timing again with the DFI locked to say 20*.. from here I can adjust the dizzy until the balancer is reading 20* and lock it down.. this should synch my Dual Synch and my Gen 7 PCM and i will be alot closer to what the timing tables are really doing under the hood!

one last question.. I am guessing I can do this using number 6 piston right same same to number 1 I think? cool? also.. guessing I need to back the rocker arm nuts out to keep valves from hitting the stop...

Chris

 

1 and 6 do travel up and down in tandem... for balancer marking purposes you could use either one.