Re: I still have pinging problems with my 512
[Re: ahy]
#964141
04/02/11 05:26 PM
04/02/11 05:26 PM
|
Joined: Nov 2003
Posts: 3,596 Dandridge TN
Dabee
master
|
master
Joined: Nov 2003
Posts: 3,596
Dandridge TN
|
Quote:
ping at half throttle suggests the timing curve is too aggressive. A slow mechanical advance with full advance delayed to 3000 RPM may help.
I had the same pinging issue with my street 512. Similar build only with Indy EZ heads and Gear Venders. I recurved the distributor, MSD billet. I had the silver springs installed to get full advance at 1800 RPM. Good for a race engine not so good on the street. I replace one of the silver springs with a blue spring to slow down the advance. Problem solved.
|
|
|
Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964142
04/02/11 05:48 PM
04/02/11 05:48 PM
|
Joined: Aug 2003
Posts: 8,716 Baltimore/Denver
64Post
master
|
master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
|
Quote:
I'll have to check my Idle vacuum again but I think I have 9" at idle in gear Holley recommended the 2.5 power valve.
I believe a 4.5 PV is recommended with 9" of vacuum in gear, not to suggest this your only problem. General rule of thumb is half of the idle vacuum.
I agree with the other suggestions of fuel, and possibly slowing the curve.
|
|
|
Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964143
04/02/11 10:13 PM
04/02/11 10:13 PM
|
Joined: Mar 2008
Posts: 5,746 Ontario, Canada
Dodgem
master
|
master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
|
No my holly books say 1.5 to 2.5 below in gear idle vacuum so a 6.5 would likely be spot on. you use 2.5's om 300 @ .050 roller cams!! You must have misunderstood or the 3.75 a hour kids are confusing you! Thrust me try a 6.5 the 1/2 vacuum numbers are for real stock cams with 17 in gear vacuum so 1/2 is 8.5 Power valve is $9 and won't hurt anything (you probaly have a 6.5 laying around) quick and easy to try an cannot hurt anything. If it was a 8.5 with 9: vaccum it might flutter open at idle and be a bit rich but a 7.5 and down will be just fine.
Last edited by Dodgem; 04/03/11 09:31 AM.
|
|
|
Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964154
04/04/11 09:17 AM
04/04/11 09:17 AM
|
Joined: Mar 2008
Posts: 5,746 Ontario, Canada
Dodgem
master
|
master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
|
I tell you stick a 6.5 power valve in it and it will be way better under light throttle acceleration!! since you will always be pulling over 2.5 inches of vacuum at light acceleration you have no power enrichment system so it will be lean. Lean= ping Your cam is no where near big enough to run a 2.5 power valve you only need one to 1.5 number in gear above the power valve rating to keep it closed in gear idle. so 9 - 1.5 = 7.5 but a 6.5 will work good.
Last edited by Dodgem; 04/04/11 09:19 AM.
|
|
|
Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964157
04/04/11 04:49 PM
04/04/11 04:49 PM
|
Joined: Jan 2003
Posts: 75,326 A gulag near you.
JohnRR
I Win
|
I Win
Joined: Jan 2003
Posts: 75,326
A gulag near you.
|
Quote:
Ok I put the Champion RC12YC plugs in I had RC14YC plugs in it previously. I put 6 gallons of no corn gas in it I' going to go take it for a ride and see how it does. My initial timing is at 16 with a total of 30 but it still cranks hard like the timing is too far advanced. Ill let you know how it does.
Your total timing should be higher than that ,it's going to be too hot in the chambers and you are going to end up with detonation more than likely... still .
I thought you were going to confirm top dead center? I wouldn't be skipping steps because you are looking for a quick fix.
|
|
|
|
|