Will a car start at 19 degrees initial advance?

[Gerald L.]

[Terry D.]

Re: Will a car start at 19 degrees initial advance?

If you google finding TDC there are lots of articles and videos to do this, not rocket science, well worth your time to have this knowledge and make your car run better.

[Gene M.]

Re: Will a car start at 19 degrees initial advance?

You shouldn’t mess up a plug wire. Just look at intake the fire order is there 18436572.

[Gerald L.]

Re: Will a car start at 19 degrees initial advance?

Thanks to both. Initial advance is not 19, rubber banded the weights and got 12 with vacuum line plugged. I would think that is pretty accurate against the zero on the timing tab or very very close. So finding TDC with a piston stop tool will be a winter exercise. I am also happy that the weights bring in their full 24 degrees before 2800 rpm, and accept that they bring in about 7 at idle. Using a B26 VAC really improves idle stability as recommended.

[Gene M.]

Re: Will a car start at 19 degrees initial advance?

With 12 initial and 7 from mechanical at idle plus a few from full time vacuum at idle, your eyes might burn a bit as pulling into garage.

[Duke W.]

Re: Will a car start at 19 degrees initial advance?

Using a B26 VAC really improves idle stability as recommended.

The 12" B26 may not pass the Two-Inch Rule with the Duntov cam (I am assuming that your engine has an OE equivalent Duntov cam, but have no idea.) I have always recommended the 8" B28 for ALL OE mechanical lifter SB cams.

Duke

[Gerald L.]

Re: Will a car start at 19 degrees initial advance?

Duke, I apologize, you do say one can not do better than the B28 for this 63 L76 engine. At an 850 idle rpm the vacuum pulls 15 mmHG in my tests and so the B26 appears to conform. I acknowledge that if I dropped the idle speed down to the correct 700 spec it would not pass the Two-Inch Rule. A quick online search for a new B26, ie Echlin VC1810 (or DV1810, D1312C or GM PN88924985) suggests these animals are not easy to find. In the meantime, I think I shall see how much mechanical advance I can get out of the 850 idle. Target would be an idle advance of 28, 12 initial and 16 from the B26. Gerry

[Duke W.]

Re: Will a car start at 19 degrees initial advance?

15" @ 850 seems high for a Duntov cam at that engine speed, but whatever the reason the 12" B26 does pass the Two Inch Rule.

Aggressive centrifugal curves on SHP engines usually have a few degrees centrifugal at idle speed. For example the OE curve on 365/375 HP engines (start @ 700, 24 @ 2350) adds 2-3 degrees at 900 idle speed, and high overlap cams like low thirties total idle advance. You're a bit above that, but as long as there are no drivability or detonation issues, it's probably okay.

The only thing I suggest is that you increase total WOT advance higher in the 36-40 range. I usually shoot for 38-39 and if there is no detonation, good to go.

In your notes you mentioned the Mr. Gasket 928G spring kit. Based on the latest info I have from others who have done careful measurements the black springs are the lightest, gold the stiffest, and silver in between.

What's currently installed?

Good job on the testing and documentation. You captured all the important data.

Duke

[Gerald L.]

Re: Will a car start at 19 degrees initial advance?

Duke, I appreciate all of your input on my individual project, you are kind to so easily share your experience and knowledge. I will take your idle and WOT advance suggestions as a goal to work towards. Do I know the existing distributor springs? No. The cam? No. I am taking the position that the data will tell the story and work from there with what I have.

Moving initial timing to 14 and removing as much mechanical as I can will achieve 30-32 idle at 850 rpm, and 38 WOT, hoping a spring combo to accomplish that won't push the max out beyond maybe 2800 - 3000 rpm. And do road testing. As Roseanna Roseannadanna would say, "It's always something!" This distributor needs its driven gear rotated 180 to advance the timing further. Winter tasks await.

Thanks so much. Gerry