OK, I want to check my timing as of paul yaw specs. They are for a 13b 26 BTC Leading and 16BTC trailing. I am going to mark my pulley and I am measuring 31 MM from the original TDC mark which is 5 degree ATC to get my Leading mark of 26BTC. ANd I am subtracting 10mm from my leading to get my trailing of 16BTC. Because I want a 10 degree split.

This is on an 86 13b with a holley conversion, and I don't have the vacuum advance hooked up. Can I still set the timing correctly and will it be even worth it? I know you are supposed to set it at 4000 RPM and all that stuff. And if you didn't know, the pulley is about 360MM around so, saying that 360 degrees in a circle equals one degree per milimeter. So thats how I got my numbers, maybe not be the most accurate to start with, but I am just trying things out. I am just curious if this will work with my set up. And how, if the vacuum advace dashpot isn't hooked up, if it will work correctly.

 

BUMP... Does anyone have a clue? Yes I have searched.. if it works.. must of the time it doesn't for me.. I just want to know if I can still set the timing like this if I don't have a vacuum advance hooked up...

 

I have never timed my seven, although I guess I should.
Are you doing the direct fire setup of just retiming your motor? Your judgment sounds good about the 1 mm per degree.

 

Rather than pulling the pulley of and doing all that hard work, just get an advancing timing light. You can just use the stock timing mark and advance the light. I dont' have my vacuum advance hooked up and I plan on advancing mine to the 26/16 without it.

 

A metric tape measure eliminates a lot of work too.

 

Sounds like your on the right track. Why not just measure from the 0 mark? Or is there not one on a 13B? Vacuum advance isint a factor when your timing it at 4000 rpm's. Rotaries dont like advancing timing lights. Do it with new pulley marks.

 

because the 0 mark on the 13b is at 5 degrees ATDC. SO I think i will go do it tonite. There is no need to take the pulley off. I have a mm tape measure, and can just wrap the tape around the pulley and figure out the degree from there. ANd then paint it from there.. just curious how close it will actually be. when i set it. hopefull close, because it is running really well, just want to check it before the 1/8 mile strip on sunday.

 

And why don't rotaries like advancing timing lights?

 

They have a problem with crosstriggering for some odd reason so they operate erratically. Been told this from many people I trust. Hell even alot of regular old timing lights dont work well on rotaries for the same reason. Only my cheapie works on my cars, my nice one sits and gathers dust.

 

Hehe yep. Cheapo works the best.