Pinging

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spinman_1949

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This is the second issue with the 1969 GTS.

So far I can not offer a lot of info.

I do know the engine has a solid lifter cam. Owner says 3/4 Isky. He will try contact the guy that built the engine.

It is pretty lopey at idle, but it never stalled on the trip home in heavy traffic and it runs cool.

But oh my the ping. The worst when you get on it and it drops into second. Serious ping.

When I test drove the car I told the owner it pinged. He and his supposedly expert mechanic put it off as my confusing ping with a solid lifter valvetrain noise. Ticks me off cus I told him I know what the hell ping sounds like. But this guy rarely drove the car and I don't think he ever got on it or had it on the highway. Enouugh of the ***** session.

I know some of the questions you guys are going to ask.

What is the compression.
What is the cam.
What carb.
What is timing set at.

I will try to find out asap.

I do have a timing light so I should be able to provide that soon.
The rest may take some time.

But it will help if I can get some direction on this from the pro's as well. I know the basics, just been a long time since I wrenched on a car.
 
You might want to find out if it has hardened valve seats. In other words does it run on pump gas. Might be as simple as timing and adding more octane to the fuel.
 
Demon,

The owner claims it was built to run on pump gas. I think I will start with timing.
 
That's a good place to start. After that, try a tank full of 91 octane. Your problem might just go away.
 
I run mine on 93 I still get ping when Im on it hard so I mix 1 gallon of 112 to every tank full problem solved. My timing is 19 initial 36 total all in about 2700.
 
O God, here I go again with my simple diagnostics that everyone seems not to like.

Back the distributor off (clockwise) about a quarter inch and try it.
If it's better or gone, then you know exactly what it was and why it was doing it.
 
trailbeast said:
o god, here i go again with my simple diagnostics that everyone seems not to like.

Back the distributor off (clockwise) about a quarter inch and try it.
If it's better or gone, then you know exactly what it was and why it was doing it.
Click to expand...

xs2 ! :D
 
TrailBeast said:
O God, here I go again with my simple diagnostics that everyone seems not to like.

Back the distributor off (clockwise) about a quarter inch and try it.
If it's better or gone, then you know exactly what it was and why it was doing it.
Click to expand...

Hey that works...

I'd check where the initial timing is before doing anything, especially if your idle quality is good. Then find the total number that works, using above method, and tailor mechanical advance to hit your total number.

You might want to back it off just a bit more than where you no longer hear pinging. There could be inaudible pinging, better safe then sorry.

Verify where the total timing number is now. Please don't pick a RPM number and stop. Rev the engine up until it stops advancing. Some of the MP distributors go as high as 4K before they quit advancing. It may be really high, if it is you may want to start fresh by figuring out a total number that works, then get into what the engine like best for initial.
 
Want to ask some more questions.

First I found out the second owner put the carb on this engine. It is a 670 CFM Holley Avenger. Plus I now see he is the one that added the ignition as well. The reason I bring this up is because I do not know if he properly matched the carb or the ignition to this engine with the cam it has. So I am posting some pictures. I am also wondering about the intake. It looks stock to me. If I recall correctly the AVS was a spreadbore with small primaries and larger spread secondaries.

http://www.ebay.com/itm/68-DODGE-PL...Parts_Accessories&hash=item3cc87c604a&vxp=mtr

Well the manifold in this engine sure looks like the one in this picture. And there is an aluminum plate to deal with the spreadbore. The carb is vacuum secondaries which is good. Now as to the ignition. Can someone please identify and tell me how hard it will be to limit the mechanical advance if I need to. I will not be able to do the ping test until I get the brakes fixed and insurance on the car. Need to transfer registration and pay fees too. Yuck !! CA has big fees.
 

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spinman1949 said:
OK OK !!!

Took all those pretty pictures for nuthin. Geez :violent1::toothy8:
Click to expand...

Pretty much....Need to know where your timming is.

My guess,your at 36 or above total timming.

Set it at 34, and see how it goes.














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Ok its purdy,ya got to know this site is very help full all eager to help,also your coil should not be on its side.As for your mech advance goes you have 2 choices 1 buy a dizzy that is already set up for you 200 bucks,2 take the dizzy apart weld up the slots to limit the travel.I took my dizzy to the engine builder I have told him I want to get as much of 22 at idle and 14 mech gives me 36 total,I also installed a Mr gasket advance springs to give me a faster advance.I also don't use vacuum advance not to concerned about fuel mileage thatsssssssss going to be an issue for you also.
 
Well I have one of those fancy timing lights that lets you dial in the advance. So at first I freaked. 35 degrees at idle. Then the old school came back and I plugged the vacuum advance. So initial is 22 freeking degress. I am not going to do anything until I can get a wrench on the adjuster and back this sucker off at least 8 degrees. My guess it will not even idle at that though. Never worked with a holly so I may need some help here. I presume idle is still just butterfly position or is there a separate idle circuit.
 
DON'T DO THAT.

Find where the total number is now.

If it idles and starts OK now, I'd leave the idle timing where it is. Set it at 8 or back it off 8 and it may or will run like crap!
 
Jet ur carb up 1 or 2 sizes is ur car a auto or 4 speed ? Your pinging because over heating or low octane or timing is to retarded I would much rather have the benefit of vacuum advance in auto or 4 speed , better fuel economy and starting .. Pull a plug out check heat range for that motor also see if its orange or clean .. I own a 69 GTS 340 X heads stock manifolds eddy 650 AFB its a screamer Orange box ECU IGN .. I run on 89 Octane on highway to work ...
 
22 @ idle is not too bad depending on your cam dont freak.My 360 with the MP purple cam 280 474 loves 20 at idle.Also as said tell us your total @ 2500 rpms or 3000.
 
OK here is what I have. I have now set initial to 12 BTDC. Had to increase idle but that is with the vacuum still disconnected. So I dialed in 12 degrees on the timing light and at idle it set right at TDC. Then I dialed in to 38 degrees. That is around what most of you think is good for total mechanical advance. Brought the engine up to around 4000 and I am at the mark being hit at 10 degrees BTDC. So that is 48 total. I am lucky I did not grenade this motor. So I am guessing the best thing to do is spend some coin and put an adjustable mechanical advance unit in. Unless you guys think 48 degrees is OK. No way will it run at TDC at idle. I tried it and it stumbles and pops. It seems to idle even a bit better with 12 degrees as opposed to 22 degrees which is where it was when I started.

OK suggestions. I can not drive it yet.
 
Small blocks generally like the timming set at 12-34,give or take a couple degrees.
Unless your at the track,really no reason to go over 34-36 degrees for the street.
Unless your into pinging,overheating ect.
 
I will buy most of what you offer except for the retarded part. PING is pre ignition. It can be octane related of course. The higher the octane the slower the burn. So you have to retard timing to fight ping. On modern engines that have ping sensors that is exactly what the computer does when the ping sensor sends it a signal. It will retard the timing until the ping sensor shuts up. Of course it could be running too lean as well, but I suspect it is too much advance. And I am not talking vacuum. I am talking mechanical. Not sure if you know this but your engine has both. The vacuum advance is only available at idle and once you get into a higher vacuum cruise mode. The instant you open the throttle to any adequate level for acceleration you lose all vacuum advance. One reason you are supposed to disconnect your vacuum advance when timing a car.
 
It's gonna run like junk at idle for now, dial it back to 34 total without vac advanced hooked up and take it for a drive. If it doesn't ping, twist a bit more in and see what happens. 34 is usually a pretty safe place for timing an open chambered SB engine.

You can alter the mechanical in the mopar distributor. Some are easy, others are harder. You have a welder so you can do the harder ones.
 
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