Hot Rods Plug Fouling?

The engine is Gen 1, 392 Hemi. Mild upgrade cam, block bored .60 over, just enough to clean it up. The engine was built to run MSD Box. Kept giving me trouble so I removed the Box, and no real noticeable change in performance? However, there is an issues with plugs fouling in about 5000 miles. I am running an MSD Ready to Run distributor, Blaster coil, and Autolite 65 plugs. I do not want another MSD Box!! Any suggestions?
Thanks,
Jack

 

Have you considered checking out Accell? I know a few people who are very happy with their product.


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I used to run Accell plugs and coil in my '69 Superbee back in the day.

 

How are they fouling? Oil? Carbon?

 

Carbon. Tip black as tar.

 

is the heat range correct?

 

Equivalent of a Champion 12 I believe.

 

Just throwing it out there as another thing to check...my 82 Chevy pickup constantly fouled plugs and it turned out to be the modulator on the turbo 400 trans had a pinhole in the diaphragm and was sucking oil into the intake.

 

I really do not know. The plugs are Autolite 65, plug recommended by the engine builder. He also recommened the MSD box, but I figured just something else to cause a problem, so I eliminated it?
I read a long post before I posted this thread. In a nutshell, I understood the fouling could be caused by plug lenght and temp. The plugs I use are long reach. I also read it to mean, the lower the plug number, the higher the temp range?

 

????, the tranny is A727TF. I do notice tranny fluid on my garage floor, and lately a slight smell of oil inside the car?

 

727 does not have a vacuum modulator, so that is not your problem!

I don't know enough about Hemis to recommend a plug. Hopefully someone else will

 

Seems to me if the plug heat range is in the ballpark then AFR is where the focus should be.

 

Are all the plugs fouling ? If not, which ones are bad, and which ones stay clean ?
Black and fluffy, or black and sticky wet?
Is the choke opening fully when warm?

How is the crankcase ventilation being managed?

According to Autolite and the Internet those plugs would be correct for a 1957 392 Newport.
http://www.autolite.com/Productfind...ID=261&year=1957&engineID=17856&productTypes=

 

What induction ya got?

 

All 8/ Black & Fluffy/ Don't really know about the choke?/ Ventilation currently breather on filler tube. Have MoonEyes with PCV port breathers going to install this winter.
breathers

 

2 -- 500 CFM Edelbrock, automatic choke on front carb.

 

Plugs I just removed, heat range 4. New Autolites 65, heat range 5.

 

May be too much for your mill.....you try timing & tuning again?

 

Gas or oil fouling?

The box or other ignition components are probably not the problem. The first thing to check is the plug in question or plugs. Are they firing consistently? If that it the case then ignition is not the problem at all and you should be looking else ware.

If you are showing weak spark at the plug in question I would next check the wires. It could be a simple case of a bad wire. Take your OHM meter and check each plug wire, you should show somewhat close to the same resistance on each wire, the longer wires showing a little more. If you bought good wires (like say any performance wire on the market) you can actually know the resistance per foot, it will be wither on the packaging or the advertisement for the wires. Calculate the resistance by the length of the wire and see how close you come.

I could go through the entire ignition system but you should be able to find trouble shooting info if you look.

The real problem may just be that you are running fat and need to rejet.

 

also we might want to ask about how you drive...is there lots of idling? do you spend most the time on the highway?

 

LOL I left that one out.

 

A warmed over hipo motor and ignition usually needs a step cooler in heat range, a "stock" plug in a stock setup will be "just right" except for extended highway speed use.

 

I'd say 75 highway, 25 not. I live in a verrrry rural area, so traffic not a real big issue, except Friday's from about 3PM to 7PM. But it is close to a daily driver, I don't own a trailer, and I'm too damned old to not drive it as often as I can, I have thought about that being part of the problem.

 

You can adjust the idle mixture to lean it out under those conditions, and usually highway driving won't foul plugs unless it's really really rich.

Have you looked at a plug after driving on the highway for a long stretch, and not idling? just to see if they clean up from use?

 

From the naked eye, all plugs look to be the same. I don't own any fancy diagonostic equipment or tools. The wires are relatively new 8mm Accell universal wires. I realize may be overcarbed, but 500 CFM, bout as low as I can go. I aso realize would probably perform better with a single 650, but I just can't get over the WOW factor of multiple carbs.
I know, if deep down I think I know the answer to my problem, I should not be bothering you guys, but was hoping for a simple, quick, cheap fix, which is impossible when messing with hot rods. View attachment 3646554

 

I think it could be rich, as it burns my eyes after idling in the garage a little while. I have attemted adjusting the mixture screws, but notice no real change. I have thought about you driving idea, the problem is, I live about 8/10ths of a mile off the highway, down a dirt driveway, which requires a lot of idling?

 

go for a long drive, pull off the road and stop in a safe place, look at the plugs.

If the idle won't get any leaner, then you probably just have a carburetion issue. Are the float levels set? etc

 

Smaller jets in the carbs.