How did you solve your pinging problem?
Thread Starter
Pro
Joined: Apr 2005
Posts: 618
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How did you solve your pinging problem?
I've posted this topic about pinging off and on, several times. I still have pinging.
Short history: Original 11:1, 350 hp engine; rebuilt in 2006: bored .030 over, same qjet carb and dist, new identically specd camshaft from GM... I realize my compression is more than 11:1 now, with the 30-over bore. How much more, I don't know.
I run only Sunoco 93, or BP 93 or Shell. I started using Max Lead 2000, which has improved the power and helped with the pinging, but it still pings under heavy load. It doesn't seem to matter what rpm range. When you bury your foot in the pedal, you get pinging. The secondaries hardly even get time to open, before you hear it, and have to lay off...
Here's what I've done to-date:
The only thing left I am going to try is, to block the heat crossover in the intake manifold, using the little blocker plates that come with the gasket set. I will try this within the next 2 weeks.
I'm just about done trying to tune this myself. I may end up taking it to one of two Corvette shops in MD and see if they can help.
If you solved your pinging issue, I'd like to hear what you did. Thanks -
Short history: Original 11:1, 350 hp engine; rebuilt in 2006: bored .030 over, same qjet carb and dist, new identically specd camshaft from GM... I realize my compression is more than 11:1 now, with the 30-over bore. How much more, I don't know.
I run only Sunoco 93, or BP 93 or Shell. I started using Max Lead 2000, which has improved the power and helped with the pinging, but it still pings under heavy load. It doesn't seem to matter what rpm range. When you bury your foot in the pedal, you get pinging. The secondaries hardly even get time to open, before you hear it, and have to lay off...
Here's what I've done to-date:
- Had Lars rebuild distributor and carb in 2006
- tried to tune it using Lars' paper
- experimented with different springs on advance
- bought an adjustable vacuum advance
- used Max Lead 2000 (Tetraethyl lead additive)
- experimented with running with vac advance disconnected
- experimented with different total timing
- currently at 30 deg total timing
The only thing left I am going to try is, to block the heat crossover in the intake manifold, using the little blocker plates that come with the gasket set. I will try this within the next 2 weeks.
I'm just about done trying to tune this myself. I may end up taking it to one of two Corvette shops in MD and see if they can help.
If you solved your pinging issue, I'd like to hear what you did. Thanks -
Safety Car
Joined: Jun 2005
Posts: 3,775
Likes: 4
for me, it was carbon build up that was causing the pinging. i had my timing heavily retarded, barely could put my foot on the pedal, etc.
before i started spending 40 bucks for a couple gallons of 110, i dumped a bottle of seafoam down the carb. as soon as i was finished, the car was done pinging and it had stopped dieseling, something that it had done with out fail ever every time i turned the car off for the last year.
now i have a nice holey double pumper on it, run at 36*, use 93 octane, and can floor it going up steep hills all day long and theres no pinging.
just noticed you said the motor was freshly rebuilt. never mind what i had to say, this was on a 65k 40 year old motor.
of course with our motor being over 11:1, thats probably getting well past the point of being able to run 93.
before i started spending 40 bucks for a couple gallons of 110, i dumped a bottle of seafoam down the carb. as soon as i was finished, the car was done pinging and it had stopped dieseling, something that it had done with out fail ever every time i turned the car off for the last year.
now i have a nice holey double pumper on it, run at 36*, use 93 octane, and can floor it going up steep hills all day long and theres no pinging.
just noticed you said the motor was freshly rebuilt. never mind what i had to say, this was on a 65k 40 year old motor.
of course with our motor being over 11:1, thats probably getting well past the point of being able to run 93.
Team Owner
Joined: Nov 2004
Posts: 20,709
Likes: 25
From: Sorrento Italy
I never had this problem with my vette but i did indeed had it with my Tvr (V8 5 ltr engine), there were multiple causes:
Lean mix (wrong ecu set up)
Overheat
worn distributor
wrong timing
I've cured overheat with a larger alu radiator and a scoop on the hood (and on top of this also an oil cooler...)
I've change the dizzi.
I've tuned a tornado ecu by a specialist.
Timing: it is a key iussue, i dont trust the timing set up with the strobo pistol, the only way is manual...once you've taken care of all other iussues that eventually could contribute to create a pinging situation you set your timing to a standard figure then you warm up the engine and run the car...if it pings then you retard it moving the dist backwards...until it doesnt, when it doesnt then you advance it just a mm...until it does again under full load, then you go back just a bit and you're done.
Bad quality fuels (specially on a 11. comp engine) and a lean mix could cause pinging too, but i guess you've worked out these iussues already.
Lean mix (wrong ecu set up)
Overheat
worn distributor
wrong timing
I've cured overheat with a larger alu radiator and a scoop on the hood (and on top of this also an oil cooler...)
I've change the dizzi.
I've tuned a tornado ecu by a specialist.
Timing: it is a key iussue, i dont trust the timing set up with the strobo pistol, the only way is manual...once you've taken care of all other iussues that eventually could contribute to create a pinging situation you set your timing to a standard figure then you warm up the engine and run the car...if it pings then you retard it moving the dist backwards...until it doesnt, when it doesnt then you advance it just a mm...until it does again under full load, then you go back just a bit and you're done.
Bad quality fuels (specially on a 11. comp engine) and a lean mix could cause pinging too, but i guess you've worked out these iussues already.
Instructor
Joined: Sep 2007
Posts: 198
Likes: 0
From: Colorado Springs Colorado
Which head gaskets are you using?
While you are pulling the intake, I would suggest using a head gasket that gave you .030 to .040 quench. With the compression you're running now, your squish needs to be close to .030. Hope this helps.
While you are pulling the intake, I would suggest using a head gasket that gave you .030 to .040 quench. With the compression you're running now, your squish needs to be close to .030. Hope this helps.
Thread Starter
Pro
Joined: Apr 2005
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I'm using the steel-type gaskets. So you're suggesting I use a head gasket that has a bigger cylinder diameter (ie .030 bigger), or is it .030 thicker? Thanks!
Drifting
Joined: Oct 2005
Posts: 1,331
Likes: 479
From: Appleton Wisconsin
If your using a flat tappet cam I would go with a bigger one it will relieve the cylinder pressure and stop the pinging. They aren't that expensive, and its easier than replacing the heads or pistons
Instructor
Joined: Sep 2007
Posts: 198
Likes: 0
From: Colorado Springs Colorado
Air,
No, your quench distance is measured from your piston top to head, or head gasket thickness. The smaller this distance is, (up to a point), the less chance you'll have detonation (ping). The smaller distance promotes intake charge swirl, creating a better burn. Lots of info on quench, google it. I'm confident it'll help with high compression, and it's only a head gasket change away.
No, your quench distance is measured from your piston top to head, or head gasket thickness. The smaller this distance is, (up to a point), the less chance you'll have detonation (ping). The smaller distance promotes intake charge swirl, creating a better burn. Lots of info on quench, google it. I'm confident it'll help with high compression, and it's only a head gasket change away.
Instructor
Joined: Sep 2007
Posts: 198
Likes: 0
From: Colorado Springs Colorado
Oops!
I just Googled quench, and it only displayed something about hot iron and cold water. so, here is a thread to get ya started.
http://www.ls1tech.com/forums/showth...ghlight=quench
I just Googled quench, and it only displayed something about hot iron and cold water. so, here is a thread to get ya started.
http://www.ls1tech.com/forums/showth...ghlight=quench
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Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Tight quench will help. Also try a 160 degree thermostat and make sure your seals around the radiator are all in place and sealing well. Running cooler will help a lot.
Here is some info on running higher compression and having your engine live.
http://www.popularhotrodding.com/tec...ech/index.html
Here is some info on running higher compression and having your engine live.
http://www.popularhotrodding.com/tec...ech/index.html
Last edited by 63mako; Mar 4, 2008 at 12:29 AM.
Thread Starter
Pro
Joined: Apr 2005
Posts: 618
Likes: 0
Tight quench will help. Also try a 160 degree thermostat and make sure your seals around the radiator are all in place and sealing well. Running cooler will help a lot.
Here is some info on running higher compression and having your engine live.
http://www.popularhotrodding.com/tec...ech/index.html
Here is some info on running higher compression and having your engine live.
http://www.popularhotrodding.com/tec...ech/index.html
Hey, that's an excellent article, especially since I'm such a novice on this topic. Thanks!
I've got a 180 thermostat in in now; I'll try a 160, as well as blocking the cross over on the intake.
What about spark plugs? Should I be look at something other than stock? I'm using the R44T's now.
Thread Starter
Pro
Joined: Apr 2005
Posts: 618
Likes: 0
Oops!
I just Googled quench, and it only displayed something about hot iron and cold water. so, here is a thread to get ya started.
http://www.ls1tech.com/forums/showth...ghlight=quench
I just Googled quench, and it only displayed something about hot iron and cold water. so, here is a thread to get ya started.
http://www.ls1tech.com/forums/showth...ghlight=quench
Wow! That's a topic I knew nothing about. Guess an old fart still can learn something new, thanks!
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
I would try the aluminum radiator first. Mine dropped the temps better than 30 degrees,and easily keeps my 406 cool. If that doesn't work,(which I'm sure it will),set your sights on a bigger cam,which will bleed off the cylinder pressure. I run 254@.050 in a 10.1:1 406 with no pinging what so ever. I do have aluminum heads though,which would also help.
If you run hard in the cool morning air(before the engine gets hot),does it ping?
If you run hard in the cool morning air(before the engine gets hot),does it ping?
Safety Car
Joined: Oct 1999
Posts: 4,101
Likes: 10
From: NorCal
All the cooling suggestions are valid and will probably solve your issue, but with my essentially identical situation in my BOSS 302 it took a better cam that bled off some compression to solve it. Even with the best cooling, it would start to ping under (heavy) load whe fully warmed up with 8 degrees initial and 36 degrees all in at 3800. Now I run 42 degrees total and it's fine for street use and all I have to do is add leaded 100 Sunoco when I race it. Makes way better power as well. It's a Doug Herbert cam out of SC and I can get you the specs if you want. Granted, the flow caracteristics are a bit different, but generally it all applies.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Hey, that's an excellent article, especially since I'm such a novice on this topic. Thanks!
I've got a 180 thermostat in in now; I'll try a 160, as well as blocking the cross over on the intake.
What about spark plugs? Should I be look at something other than stock? I'm using the R44T's now.
I've got a 180 thermostat in in now; I'll try a 160, as well as blocking the cross over on the intake.
What about spark plugs? Should I be look at something other than stock? I'm using the R44T's now.