Plugs are fouling

[Ratbird]

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

[fastback 427]

Stock heads? Meaning the big ones? What are you running now for brand and number?

[Ratbird]

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

[Lenz]

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.

[My427stang]

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

[Ratbird]

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

[jayb]

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.

[Ford428CJ]

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

[Ford428CJ]

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

[Lenz]

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.

[Ratbird]

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 

[bn69stang]

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

[cammerfe]

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]

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.

[Ratbird]

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

[Ratbird]

OH!
One more thing. Can anyone tell me why having your "all in" timing start around 2500-2800 rpms improves performance? What is so bad about having it come in at 3500 rpm? Does it improve throttle response maybe?

Sorry again for my lack of knowledge and dumb questions.

Dave J

[cjshaker]

Having the most advance that you can get away with will give the ignited fuel mixture more time to expand before the piston travels over top-dead-center and starts on the downward power stroke. That in turn produces more push (or pressure) on the pistons downstroke, which produces the most power to the crankshaft and wheels. The result of more pressure/power on the piston is more horsepower and torque. So yes, throttle response is greatly increased due to the increased pressure, or power being produced. I hope that's clear enough to understand.

So it's a fine balance between getting the most power and not going too far on advance where the expanding combustion pressure is pushing back down on the piston BEFORE it gets to TDC and starts on the power stroke. Then you will lose power FAST as the piston is trying to push the crankshaft backwards against the other cylinders.

Generally, FE engines will handle "all in" at 3000rpm just fine, so you are producing the most power you can from 3000 on up to max rpms. Some engines can handle it a little earlier, some not so much. It depends on many factors (compression, heads, temp, rear gear, weight, altitude etc), but 3000 is considered the acceptable area of "all in". The only way to know where the limit is is to play with it and see what the engine can handle, but once maximum advance is determined and a loss of power occurs it needs to be backed off immediately. It doesn't take long to damage rod bearings because the extreme pressure will overcome the capacity of the oil to cushion the bearing and start to destroy it.....if it doesn't knock a hole in the piston, or try to push the piston through the side of the cylinder wall.

IMO, 2500 is pushing it. It's best to start at 3000 and go from there unless you have considerable experience with a particular combo. Aluminum heads and modern combustion chambers can also handle earlier timing....and less total, to make full power. So you can see, there are no hard set rules. Start at a generally safe level and see what the engine wants and can handle. And always err on the side of caution.

[428GT500]

When I installed the igniter II, Pertronix said that you should always install their coil. I bought both.

[Ratbird]

Thx gents. Yeah, I bought the ignitor back when I had the original 390 in the car. I only just bought the 40K flame thrower coil that goes with it - should help, definitely won't hurt.

I understand what you're saying about advance Doug. And that you don't want it to spark too soon as to push the piston backwards. What I don't really get is why you want the "all in" (38 degrees by timing light) to happen at 2500 rpm instead of gradually building up to "all in" at say 3500-4000. My "all in" wasn't happening until ~4000 rpm. So I pulled one of the distributor springs (there is one thicker one and one thinner one) and I stretched it just a little so it would come in a little sooner. Now it comes all in at around 3300 rpms. How does having the spark earlier supposed to help?  At some point in the lowest rpm range the early spark will do like you said and happen too soon and try to blow the piston backwards. It seems to me that you would want the earlier spark to advance gradually up through the RPM range. Does that make sense? (I don't convey in writing just exactly what I'm trying say.)

What's concerning to me is that since stretching the spring and getting "all in" to happen at around 3300 rpm I feel a vibration in the motor! That can't be good. Should I go back to say all in at around 4000 rpm? That seems way too late for what I read everywhere. And of course I can't "un-stretch" the spring so I'd have to find a new one.

thx, Dave     

[jayb]

I can't imagine how a change in timing would cause an engine vibration, unless it is detonation from too much advance.  Detonation usually doesn't feel like a vibration.  To be safe I'd get a replacement spring and go back to the original advance curve, and see if the vibration disappears.  If it doesn't, you may have picked up a new problem.  If it does go away, I think I'd leave the advance where it is...

[Ratbird]

thx Jay, yeah the motor revs and moves the car with the same power, and I imagine detonation wouldn't do that. I'll definitely get some new springs just to be safe. I'll get the big ones and little ones and try adjusting the curve with those as opposed to the crap shoot of stretching the springs. I wish I had a car buddy of some sort - being 55 years old, and only just now getting into the car scene means that EVERYTHING that I come across is new to me and I have no experience with any of the symptoms. But it's FUN! Always loved these cars when I was a kid, that's why I went with an old FE instead of a typical crate motor 302 or 351. Love that big block sound.

Any ideas on what the vibration could be with a 400 mile new motor? I've been careful with it and done everything as I should according to the builder.

thx again, Dave J 

[cjshaker]

I would start with Jays advice about replacing the spring. I can't see the timing causing the vibration either, but to be on the safe side and to eliminate it as the culprit. Vibrations can be tricky to isolate. First, have a look at your damper and make it looks ok visually. No looseness, wobble etc.

If it passes the visual test, you'll have to describe the vibration in as much detail as you can. It may be totally unrelated to the engine.

[Ratbird]

Hm, doesn't seem to upload or post anything. I'll try one picture at a time. Sorry for the excessive posting Gents.

[Ratbird]

Installed the new (and correct) Pertronix coil, Autolite 45 plugs, new vacuum advance canister, and Accel plug wires. Re-tuned and timed everything over and over to the point where it's running and staring real nice. Even stretched the large timing curve spring a little more as you can sort of see in this picture. Have you ever seen badging like this?

As for the vibration, I installed a new fan clutch, do you think this could cause a noticeable vibration? It even feel like it vibrates while idling but just barely. I just dropped it off at my local mechanic to have new tires put on the front and to get an alignment - hopefully that helps.

I found this car that I might make a project. It's a 63 Falcon (Sprint?) It has a running 6 cylinder and a 3 on the tree. Can anyone tell me if the Z-bar and clutch hardware will work it I put a 302 or 351 in it? Also, what does it take to go from a 3 lug wheels and axle to a 5 lug set up?

Hopefully these pix upload. This is my 2nd attempt.

[Ratbird]

next picture

[Ratbird]

Last one

[Heo]

Dont sure about the clutch parts but to go to
5 lug Wheels use the complete mustang V8
suspension its a bolt on if remember right

[machoneman]

[As for the vibration, I installed a new fan clutch, do you think this could cause a noticeable vibration? It even feel like it vibrates while idling but just barely. I just dropped it off at my local mechanic to have new tires put on the front and to get an alignment - hopefully that helps.]

Sure, it could be the fan or clutch, Heck, who knows the quality these days of what parts they put in those white boxes. To check, take off the fan & clutch and bolt the pulley back on (likely you'll need shorter bolts and a few washers). Amazing how long one can run the engine, especially if you're in a colder climate, before it gets hot. Run it around the block a few times while watching your temp gauge and see if the vibration disappears. If the fan itself is out of balance that's a harder one to detect. 

[Lenz]

Hope I didn't miss it but gotta ask, is the vibration most noticeable under load, at cruising speed or all the time?  That info could help sort this out.  As stated above, the more detailed description you can give the better.

[Ratbird]

Thx Bob, that fan idea is great, and easy.

Lenz, I forgot to give a better explanation.
It kind of feels like the engine is out of balance, the faster it revs the more it vibrates - whether sitting still or cruising down the road. The builder did the external balance by drilling out spots on the flywheel. I know nothing about how a motor would feel if it was out of balance so it's hard to say. Now that I have it all back together and tuned nicely it seems to be less noticeable. Maybe it's even gone and my imagination is just playing tricks on me. I'll see if I can get a second opinion tonight from my father in law. He's know cars a lot better than I do.

[Ford428CJ]

Plug looks good. It might be a little on the hot side. You can tell by the grounding strap color. The perfect or ideal color change should be at the radius of the strap.  When the plug is to hot. It is closer to the threads. And opposite when its too cold of a plug. It will be closer to the tip of the grounding strap.

Also a good way to tell if you have the right heat rang plugs for your ride! JMHO 

[Ratbird]

Thx for the feed back Wes. I'm going to play with the timing some more today, before the football starts.

Dave J

[Ford428CJ]

Your very Welcome Dave! Glad I could help out