How to find TDC on BBC

[Centralia69Camaro]

What is the easiest way to find TDC, In the old days i remember sticking a screwdriver down the spark plug hole on the compression stroke and when it was at the top that was TDC. But with this BBC the spark plug is not at a very good angle to do that. I do have timing marks on the dampener from 0 to 60 and a mark the builder drew on around 32 but im not sure if thats a timing mark or TDC?

[andrewb70]

Do you want it at TDC on the compression stroke? If so, put your finger firmly up against the spark plug hole and have someone rotate the engine in the proper direction (I always forget what that is, so someone else will have to help with that). You'll feel the pressure building against your finger as it comes up to TDC on the compression stroke, then just line it up with the zero on the balancer. If you want TDC on the overlap stroke, rotate another 360 degrees from there.

Andrew

[mmosley]

I would hope your builder put that there as a timing mark. You can ask him if 0 on the balancer is 0. It should be.

Otherwise, you can use this:
http://www.summitracing.com/parts/pr...FYREaQoduC0Apg

Gently turn the engine by hand with a ratchet until it touches. Mark the balancer. Turn it the other way until it touches again. Mark the balancer. Half way between the two marks is TDC.

[mmosley]

If you are just trying to find out which time at TDC is compression you can use the old plug the finger with the hole... or with the valve cover off TDC for #1 will occur after the intake valve closes.

[Centralia69Camaro]

Do you want it at TDC on the compression stroke? If so, put your finger firmly up against the spark plug hole and have someone rotate the engine in the proper direction (I always forget what that is, so someone else will have to help with that). You'll feel the pressure building against your finger as it comes up to TDC on the compression stroke, then just line it up with the zero on the balancer. If you want TDC on the overlap stroke, rotate another 360 degrees from there.

Andrew

OK so the zero on the balancer is TDC. OK Ill start there.

[pokey64]

I would hope your builder put that there as a timing mark. You can ask him if 0 on the balancer is 0. It should be.

Otherwise, you can use this:
http://www.summitracing.com/parts/pr...FYREaQoduC0Apg

Gently turn the engine by hand with a ratchet until it touches. Mark the balancer. Turn it the other way until it touches again. Mark the balancer. Half way between the two marks is TDC.

I built my own version of this with an old spark plug.

[chpr1972]

Just for your info , if the builder marked 32 on the damper that is the max timing he thinks that the motor needs for break in. It is to give you a starting place to "fine tune" That does not include the vacuum advance. You need it to give you better gas mileage. You need to ck with him but about 14 degrees of initial timing will get you started. Also pick his brain for all the tuning info you can get.