Trouble shooting pinging at WOT

[grdprx]

I got one of these self contained electronic distributors that doesn't need the ecu box or the ballast resistor.  Does anyone know how to adjust the mechanical advance on it?  I got it 5 years ago I think, I'd have to look for the box in my mess of a garage.
My initial timing is at 18*, but it peaks at 28-30* at high rpm; not into the sweet spot of 36*.  I've been fighting some WOT pinging for quite awhile.

[PlainfieldCharger]

I think if you advance more to 36 your pinging will get worse. What about looking at what your secondaries jetting on your carb. Is your initial timing set with the vacuum advanced plugged when you check the timing?

[grdprx]

I'm not running the vaccum advance.  I haven't messed with the carb at all on the car...  Never tuned a carb before, this is my first carbureted car.

[scratchinfotraction]

I have not had my hands on that kind of dist yet but IIRC it will be like a MSD with the springs/weights on top and easy to get at.

look at speedmaster79 for the advance adjusting kit for that dist.

I just got the non vac RTR pro-comp dist but have not had it out yet.

I did my stock points dist with the advance limiter plate from FBO. got the tunning book and a limiter plate/spring kit for 40$

reading the book help me a lot with the timing on my 440 with the whiplash cam.

I am at 18* initial with the limiter plate on the 18* slots with light springs (2-silver) for a total of 36* all in by 2400rpm.

I am also running a RTR firecore dist and now I have it set at 18* initial and just need to set the mech advance next...Philips screwdriver and slid the locks over to limit the mech advance..EZ PZ on this style mech dist.

get a vac gauge on it with the timing light give it all the initial it wants then limit the mech advance

the tuning book also goes over how to set the carb up for a base line setting.

[grdprx]

I'm starting to think my issue might be too small of a carburetor.  I have an Edelbrock 1406, I thought it was a 650 cfm, but on Summit, it says it's a 600.  

So, I may be getting too lean at the higher rpm, causing the pinging  Adjusting the jets may not help on the smaller carb...

[justcruisin]

Pretty easy to see if your timing is in the ball park, put a timing light on it and bring the revs up to 3000. Those distributors aren't the best quality but they seem to do the job. To adjust the mechanical advance there should be a plastic bung on the side of the distributor - remove it and rotate the shaft until you see a vertical metal tab, there will be another at 180 degrees, you need to bend these inwards to reduce the advance, they generally have to much advance. Make sure you don't bend the spring tab next to it.

[BSB67]

I'm starting to think my issue might be too small of a carburetor.  I have an Edelbrock 1406, I thought it was a 650 cfm, but on Summit, it says it's a 600.  

So, I may be getting too lean at the higher rpm, causing the pinging  Adjusting the jets may not help on the smaller carb...

At the risk of being redundant, Carb size has nothing to do with being lean!!!!

[cdr]

that looks like a 440 source dist, there is a black plug in the side of the body, there are tab stops for the weight, bending the tabs in shortens the curve, mine now has 9 deg , my initial is 25, total 34 i think it is the same as a pro comp.

[heyoldguy]

Total lack of information here to give any appropriate advice to cure the problem of detonation. I'm beginning to think maybe a tire pressure change or rotation might be the fix.

Dump the present distributor. It is best used as a door stop, and get a FireCore ready to run.

How is the engine built, heads, compression, camshaft?

[grdprx]

Total lack of information here to give any appropriate advice to cure the problem of detonation. I'm beginning to think maybe a tire pressure change or rotation might be the fix.

Dump the present distributor. It is best used as a door stop, and get a FireCore ready to run.

How is the engine built, heads, compression, camshaft?

Thanks for the advise!  I think I'll put my 295 50 15s on the front and do pop wheelies down the boulevard!
Whoop dee do!

I've got a mildly built 440, k56 engle cam, stock iron heads & intake.
I don't know what the compression is.  I'm on a budget with my rolling restoration, I can't afford to throw $$ for the best of everything.  This distributor has run great in the car.  I'm trying to learn how to fix my problem.  I've researched and there is a lot of information on here, so I'm trying to soak it all in.
This is my first carburatored car, I'm trying to figure this out with help from here.

Thank you CDR, I'll take a look at the distributor soon.  I've had an issue come up with the rear end recently, so this project has been kicked to the back burner.

[grdprx]

I'm starting to think my issue might be too small of a carburetor.  I have an Edelbrock 1406, I thought it was a 650 cfm, but on Summit, it says it's a 600.  

So, I may be getting too lean at the higher rpm, causing the pinging  Adjusting the jets may not help on the smaller carb...

At the risk of being redundant, Carb size has nothing to do with being lean!!!!

Was just a thought, I'd read on here of 440s being starved for gas at wot because of too small a carb.  Didn't want to be chasing an issue that wasn't resolvable with my current equipment.  I'll see if I can't figure out how to adjust with the suggestions I've gotten.

[heyoldguy]

K56 intake lobe is 224 @ .050" according to the information I have. Pretty small cam, I can't help but think you are on the edge of dynamic compression for pump premium gas. Unknown compression eh, what is the cranking compression? Do we know the piston deck height and/or part number and the cylinder head cc's or casting number? Right now I would think that adding timing advance will only exacerbate the detonation at WOT.

[BSB67]

I'm starting to think my issue might be too small of a carburetor.  I have an Edelbrock 1406, I thought it was a 650 cfm, but on Summit, it says it's a 600.  

So, I may be getting too lean at the higher rpm, causing the pinging  Adjusting the jets may not help on the smaller carb...

At the risk of being redundant, Carb size has nothing to do with being lean!!!!

Was just a thought, I'd read on here of 440s being starved for gas at wot because of too small a carb.  Didn't want to be chasing an issue that wasn't resolvable with my current equipment.  I'll see if I can't figure out how to adjust with the suggestions I've gotten.

Too small of a carb is an air restriction.  Likely will cause a reduction in peak horsepower.  Fuel metering is controlled by jets, PVCRs, IFRs, IAB, HSB idle mixture screws.along with other details of the fuel metering circuits in the carb.

Your ping can be due to a bunch of stuff, and I think the topic is covered regularly.

Possible causes:
Fuel delivery problems (can be ten reasons for this)
low float level
Carb too lean
Spark plugs too hot
engine too hot
incorrect ignition timing
Cylinder pressure too high
poor gas
Exhaust blockage (failed muffler)

Possible solutions:
run a cold manifold
cooler plugs
cooler thermostat
improve cooling system
decrease compression
retard cam
larger cam
Different fuel
Reduce timing

[c00nhunterjoe]

"Starving" an engine for fuel is not an accurate term, nor diagnossis. The size of the carb simply means the maximum amount of air it CAN flow. There are so many factors to take into account here but for the sake of this arguement i will say this;
  My guess is your "mildy built" 440 probably has junk pistons in it. I doubt you have anywhere near 10:1, but lets just say that you do. There is no reason on 93 or even 89, that you are pinging on at 30 degrees of timing. And that 600 or 650 carb WILL NOT cause it to run lean. For the avg joe, it is actually easier to make a larger carb run lean on a mild motor then a smaller one simply because the smaller carb cant physically flow the extra air a big cube motor needs to run lean in 90% of the cases.

Most of your problem is probably the stock i take running egr gasses, cooking the fuel i. The cast iron intake

[grdprx]

Got a compression tester today, dialed in at 120 psi.
Pistons are KB 184, .060 over.  Spark plugs are the NGK XR5s.

I'm currently working on replacing the differential, I'll post back once I've got her back on the road and can tinker a bit with it. 

[c00nhunterjoe]

The math is not adding up. 120 psi on a that grind cam and 30 degrees of total timing shouldnt ping on 87. Recheck your timing. Pull a plug and see if its lean, then make a wide open pass and shut it off immediatly and pull a plug again.

[BSB67]

Got a compression tester today, dialed in at 120 psi.
Pistons are KB 184, .060 over.  Spark plugs are the NGK XR5s.

I'm currently working on replacing the differential, I'll post back once I've got her back on the road and can tinker a bit with it. 

Well, compression/cylinder pressure is not your problem.  Your problem should be easy to fix, you just need to find it.

[c00nhunterjoe]

Yeah, that sounds like the typical 8.5:1 motor. I suspect that either the timing is not where he thinkgs it is, or there is a fuel pump/pushrod problem