What should my timing be set at to stop pinging at wot

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inertia said:
Man,, I have lived your frustration thru 40 yrs,, 69 Swinger 340, I bought new, built it out to, 12.5, tried diff dizzies, timing total never more than 35/36, went to big cam, it pinged, then biggest cam avail, 336/341 deg, trying to flood the ping outa it, nope, -then trimmed pistons twice, it pinged, -changed to bigger J heads, it pinged, tried playing with cam timing,, and... tried the water spray with washer pump, still pings.. . . . lol... It's always pinged, it just got slower,, still pings today..

It used to run 13.2s,, 2/10th's off the NHRA record at that time,, It won me a lotta hardware... lol

It will prob ping when I finish putting it back to stock.. specially with todays gas..

oh,, through all the tear downs, after a couple of hundred runs, AND a daily driver,, I never saw any sign of piston damage,, not one ... so I let it ping..

guess nitrous is outta the question... lol
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Will play with the timing , see if it can help , as long as it doesn't run like a 3 legged dog .
I hope I'm as lucky as you and no damage with the pinging , it is not severe but I hear it . Don't want those ceramic coated Mahle forged pistons ruined .
 
Keep this in mind as well. Most cam manufacturers grind in 4* advance to start. Then, the cam card has you advance it another 4*. That's eight damned degrees. That's what advancing the cam timing does. It raises cylinder pressure.
 
Your intake valve is closing is 39* after bdc. Thats really not a lot. Retard the cam and timing or get a better cam for your setup.
 
try colder spark plugs, I run racing NGK plugs, 8 range, they got 9 and 10 in stock at Summit and Jegs, only $2.50 each plug, the higher the number the colder the plug. Retarting the cam timing is good also. 2 less degrees spark timing will help.

8 is pretty cold, you might want to try 9 but I think 8 is good up to 11 to 1, not certain, I know 10 is for like 13 to 1

If you get booster get the for off road only type--if customs lets it in ?

I think your Canadian gas isn't quite as good. I know many moons ago I went from the Detroit area in the USA to Windsor Canada and ran low on fuel and got some of your expensive gasoline, darn motor ping all the way home each time I gave it lots of throttle, same rated octane at the pump

Make that $2.69 each plug
http://www.jegs.com/i/NGK-Spark-Plugs/739/R5672A-8/10002/-1?parentProductId=753645
 
jerry6 said:
That is not something I want to do , is there any good octane booster , or anything else that would have it run at optimum timing ? Hate to run it de-tuned ! Had to do that with my old 440 , when I got good gas 104+ it ran great , hated it on anything less , had to knock timing back 10 deg at least . Pissed me off running like that .
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Yes, there are ways to boost octane. It is not possible to get much of a boost from a 12 ounce bottle of anything you want to be near.

Toluene is the magic in a can. Toluene was used straight up as a fuel in F1 for a while. It has an octane rating of 114, and is very resistant to detonation. It mixes well with unleaded gasoline.

A blend of 4 gallons of 94 octane gasoline and one gallon of toluene will take you to 97 octane (R+M/2) for the total of 5 gallons. 8 gallons of 94 & 4 gallons of Toluene will take you to 100 octane.

Toluene is available at most paint stores, hardware stores etc.


Colder plugs may help. You can go very cold with a hot ignition.

Also, check your vacuum advance. Put a tee fitting in the line, and plumb a gauge to where you can see it while driving. At WOT & high rpm it is not impossible to generate enough velocity to pull the vacuum advance into operation - even though it does not move at 5000 rpm in neutral with the timing light. I have seen it happen, depending on where the line is connected.

If you see say 7 inches of vacuum @ WOT & 5000, grab your vac pump & see how far the vac advance is moving with 7 inches applied.

B.
 
Thanks guy , going to try timing , then will put in the old petronix distributor , see if it helps , maybe the mopar rebuilt I put in is not good .
 
Some of my customers use Price Chemicals Super Street. It's a nitro blend and even works with cats. Some of these engines have over 200psi. and no ping and in use for years. Price says to mix 1 Qt to 10 gals. but we have found depending on application you can mix to 15 or 20 gals. Alittle expensive and you buy by the case, still cheaper than racing fuel and we have used it at test and tunes when the fuel truck was not there. Price Chems. phone # is 334-277-5470. Don't know what shipping to canada would be. Just another option. Good Luck!!
 
Changing dist is not going to help--unless the timing curve is slower.

That tight stock converter is not helping, you are lugging the engine--even on gear shifts, hit 2nd gear the engine is lugged down by the tight low stall converter. It needs a 10 inch 3,000 stall, driven lightly with those 3.73 gears and small tires it feel close to stock but when you give it more throttle it will allow the engine to loosen-rev up and it be less likely to ping.

Give it a shot if you like but I think you may have too..

put those NGK racing plugs in
retard spark timing 2 degrees--give it 32 total
retard the camshaft timing 4 degrees
get a 10 inch converter

Car will be quicker and less incline to ping...if it then seems to never ping then try 34 degrees total spark timing again
 
RPAGAN said:
Some of my customers use Price Chemicals Super Street. It's a nitro blend and even works with cats. Some of these engines have over 200psi. and no ping and in use for years. Price says to mix 1 Qt to 10 gals. but we have found depending on application you can mix to 15 or 20 gals. Alittle expensive and you buy by the case, still cheaper than racing fuel and we have used it at test and tunes when the fuel truck was not there. Price Chems. phone # is 334-277-5470. Don't know what shipping to canada would be. Just another option. Good Luck!!
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Yeah octane booster is another option but I know leaded gasoline is totally banned in Canada for race track use, I'm 99% sure on that--at least that was the talk a few years back. Maybe there is a loophole but good luck finding it.

I'm not sure if any good off road octane boosters are sold now in Canada--or allowed passed customs. If sold get a case or two
 
I run 94 octane in my 408(410)(.040 over pistons),timing is at 38*.I have my cam degreed at 108 it,s a custom grind with .631 lift,eddy heads.Dizzy is locked out.Never get pinging at WOT.Maybe try alittle more advance as 34 seems low for such a high compression engine.JMO.:cheers:
 
dodge freak said:
Changing dist is not going to help--unless the timing curve is slower.

That tight stock converter is not helping, you are lugging the engine--even on gear shifts, hit 2nd gear the engine is lugged down by the tight low stall converter. It needs a 10 inch 3,000 stall, driven lightly with those 3.73 gears and small tires it feel close to stock but when you give it more throttle it will allow the engine to loosen-rev up and it be less likely to ping.

Give it a shot if you like but I think you may have too..

put those NGK racing plugs in
retard spark timing 2 degrees--give it 32 total
retard the camshaft timing 4 degrees
get a 10 inch converter

Car will be quicker and less incline to ping...if it then seems to never ping then try 34 degrees total spark timing again
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I do a lot of city and highway driving , is the 3000 stall converter going to kill gas mileage , now i get between 22-26 mpg on the highway , put about 15,000 miles a summer on the car , don't want to go broke driving the car
 
pettybludart said:
I run 94 octane in my 408(410)(.040 over pistons),timing is at 38*.I have my cam degreed at 108 it,s a custom grind with .631 lift,eddy heads.Dizzy is locked out.Never get pinging at WOT.Maybe try alittle more advance as 34 seems low for such a high compression engine.JMO.:cheers:
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More advance ? Wouldn't it ping more ? My old 440 I had to retard timing to stop the pinging , bumped it up when using race gas .
 
You can try a set of N19V Champions.

You have not said what RPM range you have WOT pinging in. Is it above a certain RPM, or pretty much any time you open a secondary?

B.
 
jerry6 said:
More advance ? Wouldn't it ping more ? My old 440 I had to retard timing to stop the pinging , bumped it up when using race gas .
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That was my thought as well, I believe you said you are running 10* initial. Bump it up to 16 or even 18 and limit the distributor advance some more.

I run my pretty much bone stock 318 with the exception of a larger cam and headers at 16* initial.
 
Find the nearest station that sells E-85 and if it's reasonably close, buy or modify a carburetor to run on it...
 
It boils down to one thing. You have too much cylinder pressure. You can take timing out of the distributor and that will stop the spark knock, but it won't run with all the power it could.

You can handle it in one of two ways. You can run race gas, which I don't think you wanna do. So that leaves taking cylinder pressure out somehow. This is why I recommended retarding camshaft timing.

Retarding camshaft timing will have NOWHERE near the effect of power loss as taking timing out of the distributor. I don't believe you're going to be able to limit the distributor advance enough to get it to stop spark knocking. But I would try that first.

If you have vacuum advance, remove the vacuum line. This will stop the vacuum can from pulling in anymore timing. BUT, it really only works at part throttle and I bet you're not spark knocking then. So, that leaves physically changing something.

If you limit the distributor's mechanical advance and remove the vacuum line from the advance can and that does not do it, what I would do is try to back off on that camshaft timing. I recommend using a compression gauge when you do it.

First, get a base reading before you begin. Then when you get it down to the camshaft, retard it 4* and try it again. I bet you'll see a significant enough difference that it will run on pump gas with no spark knock. It's worth a try.
 
right it is not knocking part throttle , just the upper rpm range , 3800 up maybe a bit higher /
Not sure we have E-85 up here , at least never seen it at any station . . Hope it does not rain friday so i can get to the shop and tet out some of your ideas . Thanks , will let you know how it goes . .
Worse comes to worse AI'll change the heads , something Aluminium sounds good .
 
Badsport said:
That was my thought as well, I believe you said you are running 10* initial. Bump it up to 16 or even 18 and limit the distributor advance some more.

I run my pretty much bone stock 318 with the exception of a larger cam and headers at 16* initial.
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Had it at 16 , would ping part throttle , 14 same 10-12 only pings up high full throttle .Really driving me nuts , scared to hammer it , don't want to kill the pistons .
 
jerry6 said:
right it is not knocking part throttle , just the upper rpm range , 3800 up maybe a bit higher /
Not sure we have E-85 up here , at least never seen it at any station . . Hope it does not rain friday so i can get to the shop and tet out some of your ideas . Thanks , will let you know how it goes . .
Worse comes to worse AI'll change the heads , something Aluminium sounds good .
Click to expand...

Well the other option if playing with the distributor doesn't work would be to recam it. But honestly, I think changing the cam timing would be the better way comparing those two. But again, all this heavy work is puttin the cart before the horse, as you may get it nailed down through working with the distributor. Good luck with it.
 
If it only happens above 3800, check the vac advance, and the distributor curve. Find someone with a distributor machine, and have a good look at the curve.

Given the fuel economy you have, there is plenty of advance. Either you are still adding mechanical advance above 3800, or the vac advance is coming back in.

As intake velocities increase, it is possible to generate vacuum across a port from flow - even though the flow is at near atmospheric pressure. It does not take much vacuum to move the timing a couple of degrees, and if you are on the ragged edge already...

Look at all the basic stuff first before you pull the timing set or the heads.

B.
 
Found the problem , was not getting enough vacuum from port on carb ., hose from port on brake booster is now used and got the vacuum advance working properly , have it at 14 , 34 total and no more ping . Sometimes it's a simple problem . Hammered it up to 129 mph , short blast on empty highway , lasted about 12 sec from 50 -129 no pinging at all . Car is fast , I could get in trouble driving it .
Thanks for all the ideas guys . It's the 3 rd time I've tried fixing. the problem
 
That's great. Glad to hear it was somethin simple.
 
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