Author Topic: Plugs are fouling  (Read 13581 times)

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Ratbird

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Plugs are fouling
« on: January 25, 2014, 11:43:40 PM »
I have a 410 FE Mercury build. We are at high altitude, 6800 feet. The intake is an Edel RPM performer - carb is a Edel 750 with the correct metering needles and jets for my altitude. It has a medium cam and CJ valves, and headers. I have a Pertronix ignitor and new set of Accel plug wires. I haven't yet gotten my Pertronix coil. When I do I'm going to try a little wider plug gap. Meanwhile I have adjusted the idle mixture screws to be as lean as possible cuz of the high altitude. I adjusted the dizzy by stretching the springs a little and have managed to get it down to all in at about 3300 RPM - all in is 38 degrees. At 2500 rpm it is at about 35 degrees. My initial timing is at 12-13 degrees.

Can anyone recommend some plugs that won't foul as easily as the stock plugs?

Thx in advance, Dave J
1959 T-bird - rat kind of a thing
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fastback 427

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Re: Plugs are fouling
« Reply #1 on: January 26, 2014, 12:07:34 AM »
Stock heads? Meaning the big ones? What are you running now for brand and number?
Jaime
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Ratbird

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Re: Plugs are fouling
« Reply #2 on: January 26, 2014, 09:08:08 AM »
They are c4ae-6090g. They have CJ size exhaust valves. The intake valves are stock size.
It's a 390 with a 428 crank so the motor isn't a "true 410". I'm going to order some distributor springs (if I can find some) to try to get closer to all in at 2500-2800 rpm's. Can initial timing cause fouling? I was running it around 11 degrees, but when I went up to 13 I got a huge improvement in power so that's where it's at right now.

thx, Dave
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Lenz

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Re: Plugs are fouling
« Reply #3 on: January 26, 2014, 10:00:43 AM »
Could cam timing be an issue?  A few degrees in the wrong direction or even straight up might be too late depending on who manufactured it.  I'm no expert on this issue but I'm sure some on this forum are.  I've seen noticeable power gains in an otherwise stock engine by simply replacing a stretched out timing chain.
Len Zielinski
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My427stang

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Re: Plugs are fouling
« Reply #4 on: January 26, 2014, 10:10:29 AM »
What are you running for plugs and how are they fouling, shiny and wet, glazed oily? 

It takes a LOT of fuel to foul a plug unless you have an ignition issue
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Ross
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Ratbird

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Re: Plugs are fouling
« Reply #5 on: January 26, 2014, 12:41:32 PM »
I'll pull a plug here shortly and look at them to see what they look like. They are stock from Autozone for a 390, "Bosch".
The cam is Lunati's version of the CJ cam. The motor is new, and has about 400 miles on it. I've been messing with the timing, dizzy curve, and vacuum advance canister trying to get it tuned in. The timing chain is a pre-stretched dual roller and had about 300 miles on it when I took it in to be re-built as a 410. The builder told me to run it at about 10-12 degrees initial timing. Can going up around 13 maybe be causing the fouling?
 
Here's the thing, I was talking on the www.Squarebirds.org forum and one of the guys told me that I should get a Pertronix flame thrower coil to go with my Pertronix ignitor electronic ignition (points replacement). He said if I got some good plug wires and the coil I could open the plug gap on my plugs and get more spark. I have not done this yet. However I did advance the timing some and that gave me a LOT more power. Sooooo, I'm also thinking I'll get new/better plugs. I have had two plugs foul so I thought I would ask if there are some plugs that are better than others when it comes to fouling out.

I'm new to the car and engine work so I thought I would ask. I didn't really find anything using "Google"

Thx, Dave Jones
1959 T-bird - rat kind of a thing
FE 410ci bored .030 over, 4 sp toploader
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jayb

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Re: Plugs are fouling
« Reply #6 on: January 26, 2014, 01:07:38 PM »
For what its worth, my opinion is don't waste your time with the plug gap.  I have run some extensive experiments in the past on the dyno, and a larger plug gap has never shown any more power than a standard .035" gap.  The theory sounds good, but it just doesn't work.  In your case, a bigger gap would probably lead to more plug fouling anyway.

Figuring out why they are fouling is key to understanding your problem, as Ross mentioned.  I'm betting it is oil.  Post some pics of the fouled plugs when you get them out.
Jay Brown
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Ford428CJ

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Re: Plugs are fouling
« Reply #7 on: January 26, 2014, 01:09:54 PM »
I wouldnt use a Bosch plug in a FE at all. You need a set of Autolites 45's. They work much better then the Bosch!

Second, Leave your timing alone. Its a great starting point. 13 initial and 38 total
Wes Adams FORD428CJ 
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Ford428CJ

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Re: Plugs are fouling
« Reply #8 on: January 26, 2014, 01:11:24 PM »
For what its worth, my opinion is don't waste your time with the plug gap.  I have run some extensive experiments in the past on the dyno, and a larger plug gap has never shown any more power than a standard .035" gap.  The theory sounds good, but it just doesn't work.  In your case, a bigger gap would probably lead to more plug fouling anyway.

Figuring out why they are fouling is key to understanding your problem, as Ross mentioned.  I'm betting it is oil.  Post some pics of the fouled plugs when you get them out.

Lets see a picture of the plugs... That will tell the story on whats going on.... JMHO
Wes Adams FORD428CJ 
03 F-250 Crew Cab 4x4 6.0 and 35's
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Lenz

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Re: Plugs are fouling
« Reply #9 on: January 26, 2014, 02:29:33 PM »
I'd go a big plus one on switching to the Autolite plugs no matter what else you do.  I tried a set of Bosch in my '06 F150 and they seemed OK for a few months.  I picked up an occasional miss, thought it was the wires.  A friend told me to dump the plugs and go with Autolites, turned out he was right.  I've had them in for a good year now with no issues.
Len Zielinski
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Ratbird

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Re: Plugs are fouling
« Reply #10 on: January 26, 2014, 04:20:20 PM »
Thx Gents,
I pulled a plug and they are tan and dry. I didn't take pictures cuz it takes me a while to up load to this computer, but they look just like they should according to this picture I googled.


A couple of weeks ago I looked at the plugs and they looked like the "fuel fouled" one in these pictures. I readjusted my Edelbrock carb idle screws to run more lean and that must have cleaned them up. At our altitude I need more air.

I'll definitely get a set of the Autolite 45's. I also won't mess with the gap either. As soon as I get the plugs, coil, and vacuum advance module and springs I'll start over with the tuning and see if that and the Autolites help.

Appreciate the help! If they start fouling out after my work I'll get back to this string.

Thx, Dave J 
1959 T-bird - rat kind of a thing
FE 410ci bored .030 over, 4 sp toploader
pure fun

bn69stang

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Re: Plugs are fouling
« Reply #11 on: January 26, 2014, 05:35:20 PM »
I agree with 428 c j , get the autolites and the timing sounds ok for here but get the other coil , im thinking your coil may be a little weak and spend some money on a good set of wires  jmo .. Bud
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cammerfe

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Re: Plugs are fouling
« Reply #12 on: January 26, 2014, 05:51:35 PM »
A replacement on the plugs may solve your problem.

FWIW, performance FE engines, back in the day, used to like 10 degrees in the distributor and 18 initial for a total of 38. (10X2+18). As you noted, more initial creates response.

KS

cjshaker

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Re: Plugs are fouling
« Reply #13 on: January 26, 2014, 09:51:25 PM »
Tan and dry sounds normal. You'll notice that too rich shows black and dry like in the picture. Unless you see black (not blue) smoke coming out of the exhaust during normal running or acceleration, it probably isn't fuel fouling. Too much fuel will also show up as a heavy, black, dry soot in the tailpipe. Black and wet (oily) indicates an oil problem.

If they truly are tan and dry, I would not lean it out any more yet. Idle mixture is easy to set and generally won't cause any plug fouling unless it's really rich and spends a lot of time idling. After initial idle mixture is set, by just slowly turning them in until the engine starts to stumble, then backing off a 1/4 turn, leaning them out more will have little to no effect on the plugs. And idle mixture itself will have no effect once the RPMs are increased when driving.

Pictures would still help.

Doug Smith


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Ratbird

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Re: Plugs are fouling
« Reply #14 on: January 28, 2014, 06:28:31 PM »
Got the correct 40K 1.5 ohm coil last night. I have the Autolite 45's and new Accel plug wires. I also got a new vacuum advance canister.
I work 4 tens so it's dark by the time i get home from work. I'll install the hardware this Friday, re-tune, and see how it goes.

thx a ton, Dave J

1959 T-bird - rat kind of a thing
FE 410ci bored .030 over, 4 sp toploader
pure fun