But why complicate things at this point. 
L79 timing question
Thread Starter
Burning Brakes
Joined: Jan 2007
Posts: 960
Likes: 25
From: Middlesboro KY
After talking with Paragon, it turns out that the repro distributor was built by Chicago Corvette. I've spoken to CC and they've offered, at no cost, to correct the problem. I double checked it yesterday and by removing the springs and an initial advance of 10 degrees, I can only achieve 24d btdc. With that said, the mechanical advance is limited to 14d. Should I advise CC to correct it to achieve 26 - 28 degrees mechanical advance?
Thanks,
Bill
Thanks,
Bill
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Race Director
Joined: Apr 2005
Posts: 11,290
Likes: 2,148
From: Bowling Green, Kentucky
After talking with Paragon, it turns out that the repro distributor was built by Chicago Corvette. I've spoken to CC and they've offered, at no cost, to correct the problem. I double checked it yesterday and by removing the springs and an initial advance of 10 degrees, I can only achieve 24d btdc. With that said, the mechanical advance is limited to 14d. Should I advise CC to correct it to achieve 26 - 28 degrees mechanical advance?
Thanks,
Bill
Thanks,
Bill
If they can get you 28 degrees centrifugal advance in the distributor, that would be excellent. If they can get it to come all in by 3000 RPM that would be outstanding..
However, you can easily play with various springs from ACCEL or others to achieve the 3000 RPM later on.
But try and get both items changed if they will do it for you. Perhaps you agree to a small, additional charge for the quick advance versus the factory number (5100 RPM).
Larry
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
After talking with Paragon, it turns out that the repro distributor was built by Chicago Corvette. I've spoken to CC and they've offered, at no cost, to correct the problem. I double checked it yesterday and by removing the springs and an initial advance of 10 degrees, I can only achieve 24d btdc. With that said, the mechanical advance is limited to 14d. Should I advise CC to correct it to achieve 26 - 28 degrees mechanical advance?
Thanks,
Bill
Thanks,
Bill
Thread Starter
Burning Brakes
Joined: Jan 2007
Posts: 960
Likes: 25
From: Middlesboro KY
Changing springs and weights are one thing but the limited advance, as I understand it, will require a more extensive change to the internal components. Besides, I think they should stand behind their product and not expect the customer to have to perform radical alternations to make it close to what they presented as fitting the 327 SHP.
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Thread Starter
Burning Brakes
Joined: Jan 2007
Posts: 960
Likes: 25
From: Middlesboro KY
Thread Starter
Burning Brakes
Joined: Jan 2007
Posts: 960
Likes: 25
From: Middlesboro KY
As I mentioned, Chicago Corvette has offered to correct the problem with the distributor. I thought is would be more appropriate for Paragon to deal with their vendor since I purchased the distributor from them. I suggested to Paragon that I return the distributor to them and they forward it to CC. The owner of Paragon has refused to take the lead and is leaving this up to me to handle directly with CC. I am both surprised and disappointed in Paragon. Thank goodness the item didn't come for China or Mexico since I don't speak either language. I pray CC will be more professional than Paragon. FWIW
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
As I mentioned, Chicago Corvette has offered to correct the problem with the distributor. I thought is would be more appropriate for Paragon to deal with their vendor since I purchased the distributor from them. I suggested to Paragon that I return the distributor to them and they forward it to CC. The owner of Paragon has refused to take the lead and is leaving this up to me to handle directly with CC. I am both surprised and disappointed in Paragon. Thank goodness the item didn't come for China or Mexico since I don't speak either language. I pray CC will be more professional than Paragon. FWIW
Don't expect your distributor back anytime soon.
Thread Starter
Burning Brakes
Joined: Jan 2007
Posts: 960
Likes: 25
From: Middlesboro KY
Unless the "football" on top of the mainshaft and the contour of the weights are seriously mis-matched, the maximum centrifugal advance is determined by the limit pin on the bottom of the "football" traveling in the limit slot on the autocam, and the pin may or may not have a rubber bushing on it. If it has a bushing, remove it and see how much more centrifugal advance you get (you're 12* short of what you should have). 
Race Director
Joined: Apr 2005
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From: Bowling Green, Kentucky
Larry
Le Mans Master
Joined: Feb 2008
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From: Folsom CA
I agree, with the springs off he has taken RPM out of the equation. His 36 at 2500 would be maxed with no springs pulling the timing back. This will be great for max power.
I would now look at the curve with Springs back on and watch when the timing hits max advance to see if more improvement is available. Is it all in at 2,500 or 5,100 with the springs properly hooked up. I think he ought to know.
I think his off idle performance while coming off stop lights would be better with the low RPM timing pulled back so idle was closer to 10 rather than 21 with the vac disconnected. 21 with vacuum is fine. Maybe I read it wrong.
I wonder if GM was smarter than us by holding the max advance till 5,100 RPM.
Most builders I know today will have max centrifical advance all in by 3,500 tops.
I would now look at the curve with Springs back on and watch when the timing hits max advance to see if more improvement is available. Is it all in at 2,500 or 5,100 with the springs properly hooked up. I think he ought to know.
I think his off idle performance while coming off stop lights would be better with the low RPM timing pulled back so idle was closer to 10 rather than 21 with the vac disconnected. 21 with vacuum is fine. Maybe I read it wrong.
I wonder if GM was smarter than us by holding the max advance till 5,100 RPM.
Most builders I know today will have max centrifical advance all in by 3,500 tops.
