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I still have pinging problems with my 512
#964119
04/02/11 01:32 AM
04/02/11 01:32 AM
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Joined: Jun 2009
Posts: 659
Boise Idaho
Boise Chall
OP
mopar
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OP
mopar
Joined: Jun 2009
Posts: 659
Boise Idaho
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the 512 in my 72 Challenger is still pinging on me. The motor is a 512 stealth aluminum heads Holley 950 HP carb Comp cams XE295HL-10 cam, 11.3:1 compression, MSD 6Al, MSd Billet distributer, 3,200 Rpm Stall,2"TTI headers, 3" pipe to 3" Flowmaster 40 series , 3:55 gears. Timing is 16 initial 32 total all in by 2,800 RPM. The pinging occurs at about half throttle and it's a pretty loud ping The things I have done to try to solve the problem are
1. Brought the timing down from 34 total to 32 total
2. Upped the primary jets 4 sizes
3. increased the power valve from 2.5 to 3.5
4. Added 5 gallons E85 ( 110 Octane )to 10 gallons of 91 octane
5. went up 2 heat ranges on my plugs
Nothing helped at all I'm at a loss on this problem. Could it be that I'm bringing my timing in too soon? if all of my timing is in at 2,800 and my stall is 3,200 could I be too far advanced when the stall comes in? My engine temps are 185-190 and pretty steady, At this point I'm willing to try anything. I prefer not to tear the motor down but at this point if I need to I will before the pinging tears the motor apart for me.
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964128
04/02/11 09:05 AM
04/02/11 09:05 AM
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Joined: Jan 2007
Posts: 7,664
IN
ahy
master
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master
Joined: Jan 2007
Posts: 7,664
IN
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Quote:
1. Brought the timing down from 34 total to 32 total
2. Upped the primary jets 4 sizes
3. increased the power valve from 2.5 to 3.5
4. Added 5 gallons E85 ( 110 Octane )to 10 gallons of 91 octane
5. went up 2 heat ranges on my plugs
Comment on the E85 - it is high octane but lower energy per gallon. Adding it to the fuel mix effectivly leans out the mixture. Even with the bigger jets you may have leaned it out overall with the E85. Two or three gallons of 110 race gas added to pump premium should help without leaning the mixture. That and reading the plugs and likley going to a colder plug should quiet it down.
Also, ping at half throttle suggests the timing curve is too aggressive. A slow mechanical advance with full advance delayed to 3000 RPM may help.
The other benefit of adding the race gas is it should run without hurting itself while you get the plugs, timing and mixture dialed in.
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964130
04/02/11 09:31 AM
04/02/11 09:31 AM
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Joined: Jan 2003
Posts: 74,976
U.S.S.A.
JohnRR
I Win
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I Win
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Quote:
I don't know my Cranking pressures. Maybe that's why I can't solve this problem I don't know the important info like pressures and piston height
Who built this engine ? you need to know what you are dealing with.
Also what or who gave you the idea to dump E85 in there ? It's not the same as mixing in 110 race gas. You either build it to run on E85 , or on Gas , you can't really mix the 2 , but the fact that you have e85 you might want to think about converting to it .
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964131
04/02/11 10:36 AM
04/02/11 10:36 AM
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Joined: Mar 2007
Posts: 3,277
West Coast, USA
jbc426
master
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master
Joined: Mar 2007
Posts: 3,277
West Coast, USA
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Put a compression tester on it and find out what it's cranking. E85 is not what you need to increase pump premium's octane. To effectively increase your octane, try running some % of 100 octane unleaded or add 110 octane leaded to your tank. You will have to rejet no matter what you do when you start blending your fuel, so be consistent with the mixture once you get a ratio that works. You may want to get a knock sensor to detect detonation and a wideband with data logger. FAST has a nice wideband unit.
I only drive my car for fun and rarely burn more than a tankful a month, so I intentionally opted for high compression (12.8 to 1 @ 225psi cranking). I've always liked how it runs with it, and I don't really care about the cost difference to run high compression because of the performance trade off. I don't drive the car that much. Also, I know you can't get 100 octane unleaded everywhere, so I had a larger tank made to extend my cruising range.
I do have to pay about 1/2 again more for each gallon of the fuel to meet the octane requirements. I was going to mix 110 octane unleaded, but that's illegal in California now. Fortunately, my motor likes the 100 octane unleaded at about $6.50 a gallon.....and rising, but I knew this going in. Sounds like you didn't know your compression is too high for normal pump gas.
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Re: I still have pinging problems with my 512
[Re: DAISYDUSTER]
#964134
04/02/11 12:52 PM
04/02/11 12:52 PM
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Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Like what a few guys have already said, get rid of that swill gas you have now, and put some real gas in it. I'm betting the compression is higher than you think. 0 deck? I would have CC the engine after I had the heads on, when I put it togeather so I knew for sure what the compression is. Get good gas first. Like what already said, I'd start with a straight 110 leaded. You maybe be able to blend down from there, but at 11+-1 gonna need more than prem pump gas. Hopefully you have someone nearby who sells race gas at the pump or buy it by the drum. Speed and horsepower cost $$  We have a place nearby that sells 100 octane unleaded and 110 leaded at the pump, makes it nice. 
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Re: I still have pinging problems with my 512
[Re: ahy]
#964141
04/02/11 06:26 PM
04/02/11 06:26 PM
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Joined: Nov 2003
Posts: 3,426
Dandridge TN
Dabee
master
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master
Joined: Nov 2003
Posts: 3,426
Dandridge TN
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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. 
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964142
04/02/11 06:48 PM
04/02/11 06:48 PM
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Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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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.
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964143
04/02/11 11:13 PM
04/02/11 11:13 PM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
master
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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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 10:31 AM.
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964154
04/04/11 10:17 AM
04/04/11 10:17 AM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
master
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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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 10:19 AM.
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964157
04/04/11 05:49 PM
04/04/11 05:49 PM
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Joined: Jan 2003
Posts: 74,976
U.S.S.A.
JohnRR
I Win
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I Win
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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.
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964162
04/04/11 07:20 PM
04/04/11 07:20 PM
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Joined: Jan 2003
Posts: 74,976
U.S.S.A.
JohnRR
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I Win
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Quote:
I put 6 gallons of no corn 91 octane gas and I didn't mention this in my last post but I put 2 gallons of 110 octane race gas in it also
Roll the timing up ... 
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Re: I still have pinging problems with my 512
[Re: Boise Chall]
#964170
04/05/11 11:21 AM
04/05/11 11:21 AM
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Joined: Jan 2003
Posts: 74,976
U.S.S.A.
JohnRR
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Quote:
Could the rattling of the pistons from the pinging have kept the rings from seating? I have to thank everybody that helped with this problem. I feel like I have a car I can drive and enjoy now 
What is your total timing set at ?
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Re: I still have pinging problems with my 512
[Re: Challenger 1]
#964177
04/05/11 01:20 PM
04/05/11 01:20 PM
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Joined: Jan 2007
Posts: 780
Woodinville, WA
Viol8r
super stock
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super stock
Joined: Jan 2007
Posts: 780
Woodinville, WA
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Quote:
Why not PCV? There's nothing wrong with it, it don't hurt performance and it insures that you don't blow gaskets out and oil all over. Hook one up, as soon as you said oil out of the dipstick tube, I knew you didn't have one.
You can hookup 3" hoses and it's gonna do the same thing.
Agree........you need a PCV, -10 plugs or -6 NGK and 34-36 degrees total timing. If its mostly street driven, all in by 2500rpm. You were just running to hot of a plug.
I run 11:1 on pump gas with -6 NGK on the street, -7 for the track.
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. I have a 493-0 deck-84cc milled to74cc,runs on 93 octane . 
My stroker took a while before the blowbye stopped. And yes the detonation could have kept the rings from seating, however the most common cause is a rich condition whereas the cylinder walls get coated with gas and it washes the oil off. Not only will this cause the rings not to seat it could possibly put a lot of stress on the rings causing premature failure. Drive it for a few days now that you've got the detonation solved and run another compression check, it should be a little better. Look for a weak cylinder, which might indicate a problem. My engine finally settled out with 200 +/- 10 lbs.
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