Not sure where to post this...
I have a L05 engine rebuilt from TBI to carb in an off topic car.
The water pump is short, so I can't use the original timing marks. A short pump makes it impossible to read the adavance at 12'o clock on the harmonic balacer.

I bought an after market ignition timer like this:
http://www.summitracing.com/parts/sum-164800/overview/

And an adjustable timing light like this:
http://www.summitracing.com/parts/sum-g1059

Found a new TDC point for the new pointer, by adding a piston stopper (modified spark plug) on piston No 1, turned the crank until it stopped, made a mark, turned the other way until stop, made a new mark, set the new TDC mark halvfway between the two.

Started up the engine, turned the distributor until the engine run fine, aimed the timing light against the balancer an twisted the switch on the light until the timing marks stays together.
Trouble is that I read 60 degrees of advance with vacuum! What's wrong?

Of course, I suspect my new TDC mark to be wrong, but the original timing mark on the balancer is app 12 o'clock (impossible to see 100%) when my new timing mark is level with the new pointer, and isn't that correct?

The engine runs fine. No knocking, no valve ticking at all. But I would like to have a more accurate timing than I have now.

 

Probably, nothing. Sounds quite resaonable in fact, for cruising RPM (3000 or higher).

The REAL question you should be asking is, how does it run?

The engine does not whup out a "light", look at a mark, then check to see what sheet metal wrinkles are in stamped into the shell it's wrapped in, and then whup out a "book" with some "spec" for that trim package, and then make up its mind how it's going to run. No, it's much simpler than that.

All it cares about is, if the spark occurs in the correct relation to piston motion. And it will TELL YOU in no uncertain terms if it's unhappy.

If I may paraphrase one of The Great Ones in a completely unrelated field, but whose wisdom applies here:

"If it RUNS good, it IS good".

By extension, if it DOESN'T run good, then whatever "number" some "mark" shows, is NOT good. "Accurate" measurement only matter when you ALSO know what your "target" is.

LISTEN TO THE ENGINE. Let IT tell YOU what the "timing" should be, instead of YOU deciding arbitrarily what it should be. THE ENGINE knows when it's right or not.

 

Roll the old balancer mark up against the TDC mark on the old timing pointer manually. Then make your "new" TDC balancer mark and tab read the same- 0*. Ta da! Same TDC indication as before, just in a different location where you can actually see it.

I think your out-foxed yourself with all the moving and measuring.

 

from using a tbi timing cover on an l03 and a l05 this is the only timing tab i could find that put it in the right place. i also put on an msd timing tape on the balancer. this got it in the correct place for a carb swap.

http://www.jegs.com/i/Mr-Gasket/720/...oductId=744171

 

This is how I have done it:





My mark is in silver and DTC should be when the silver mark is level with the after market pointer. Found it the old way by using a piston stop on piston No 1, turning the crank etc...

I could make it 100% correct if I knew which of the teeths on the factory pointer on the photos is TDC?

 

the numbers should be stamped on the old marker

 

The deepest "V" on the factory tab, is 0.

 

Started up the engine, turned the distributor until the engine run fine, aimed the timing light against the balancer an twisted the switch on the light until the timing marks stays together.
Trouble is that I read 60 degrees of advance with vacuum! What's wrong?


could it be that your timing light is 60 degrees adjustable? quite a coincodence.

 

i was kind of thinking the same thing

 

It is adjustable.
I have to adjust it to 60 degrees to make the marks on the balancer and pointer becomes level.

Sofakingdom: Thanks for the tip about the deepest "V" being 0!
I think that must be the "V" closest to the camera on the photos (or the right one when facing the front of the engine).

 

yeah you will have more advance points then retard ones.

 

does it advance more if you rev it up?
it could be that the mechanical advance is all in plus vacuum plus initial=60*