Have a vacuum advance question when timming.

[Dougsters]

When I bought car(66 289 C code C4) I checked timming and it was at 0 BTDC relized a month latter vacuum adv. module was ruptured so replaced unit. So I advanced initial to 6 degrees BTDC but did not check total advace @ 3000 RPM,s. My question is if vacuum advance adds 10 degrees and mechanical/cent. is around 22 degrees is it possible to have a initial at 0 BTDC assuming the total was 32 o @ 3000 RPM ? Going to check total tommorow since I only had 2k RPM/Dwell tester last time. Any advice on setting up timming? Should I go to 10 o initial as engine is bone stock . Thanks in advance.

 

[2+2GT]

Stock timing is 6° BTDC at idle. There is a lot more to timing than "total". I'd suggest having the distributor professionally adjusted, it'll make a big difference.

 

[Dougsters]

Thanks for info & specs >

Stock timing is 6° BTDC at idle. There is a lot more to timing than "total". I'd suggest having the distributor professionally adjusted, it'll make a big difference.

Question if previous owner drove with initial timming at 0 Deg.BTDC not knowing Vac. advance was in-operable so I cann't believe I drove home 75 miles set that way ? I guess the 289/timming is very forgiving.Would you use the 2000 RPM per specs for total advance or 3000 RPM as other's I've read use to set total. TX

 

[2+2GT]

Yes, the engine will run fine with the timing at 0° (TDC) but mileage and performance will suffer.

Those specifications are intended to be used with the distributor mounted in a distributor machine.

"Total advance" adjustment is a kluge used by people who have no access to such a machine. Total advance is only a small part of the adjustment, the curve, or rate, at which both the vacuum and centrifugal advance arrive there is far more important, making the difference between the engine being a dog or a tiger. If no shop in your area has such a machine in this day of computers, there are places where you can send them.

 

[PoppyMod]

Hi,

If you are serious about having your dizzy, both, checked for optimal operation and determine it's performance potential, then, send it to a specialist. I had mine rebuilt a couple of years ago. If you don't already have someone in mind, PM me. I didn't think it expensive for what I got in return and learned about it. This is even more advisable when building a performance engine.
Happy Trails!