Fouled Plugs?

Silverscout

Silverscout

Member
Ive started to replace my spark plugs, which are about 4 years old. I've seen fouled plugs before but not with this type of deposit. #7 looks like it has a sand deposit. Any insight to whats going on?
 

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Thanks bill. Haven’t done the other side yet, most likely tomorrow. Cutting and making the wires is a slow process. The engine was rebuilt about 6 years ago and has less than 10k on it.
 
It keeps me in the garage and away from my screaming kids. That and I've yet to find a kit with the proper length to make it look tidy. Its an 8 mm msd kit which has the plug side aleady made, which when its done, will look clean.
 
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I changed to the 8mm plug wires on my 68 Travelall. Changed the standard IH (Ford) Holley distributor cap and rotor to the larger Ford duraspark II style that has the 'male' connectors on the cap, same style connectors as on the sparkplugs. The plug wires were for the 1979 Scout II that came with the prestolite distributor. All wires seemed to be correct length out of the box. None had excess length - except for the #7 wire as it should be.
 
Those plugs look normal for a engine that is burning some amount of oil and one that see's too little highway time. An engine will self clean for the most part if it has good cylinder pressure and heat even if it burns oil.

The deposits can be cleaned with a good hard highway drive a couple times a week.
 
I think Robert is recommending an italian tune up. These sv motors are a huge chunk of cast iron and take a long time to warm up. Less than 10k in 6 years says a lot of short trips to me. The 345 in my t'ette pinged like crazy, until it was used for some heavy towing and it's never done it since.
 
Thanks for the input fellas. This past weekend it spent 45 minutes on the freeway at speed. It doesnt get driven too often these days but it spends time on the freeway.

Here are the passenger side plugs. They look like they were all pulled from different engines.
 

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I would swap in some new plugs and take her for a normal drive on a highway. Pull the plugs that were oily black and built up and see what the new ones look like. They should all look clean and white like the old clean ones... If you end up with some black ones you have an engine issue. Could be ignition but hard to say.
 
Robert, I took your advice and pulled the new plugs. Yesturday I took the Scout for a drive (mixed highway and city driving). The plugs on the bottom are the new ones with approximatly 40 miles on them. They look pretty worn for such a short trip.
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Here are my thoughts on what you are seeing....

Don't think its all a carburetor problem...
Firing order 1-8-4-3-6-5-7-2.
On your new plugs taken from your photos-
1= dirty
8= clean
4= clean but a bit of color
3= dirty
6= clean
5= clean
7= dirty
2= dirty
since # one is dirt they should alternate clean and dirty through the firing order if you had a poor 1/2 of your carb but they don't.

I would do a compression test while you are in the find the problem mind set.. The engine was rebuilt but after 10k miles it is a good time to see how things are doing.
Did you do the rebuild yourself? Were valve stem seals installed?

If you have time could you give us some details of your engine systems, like carb, ignition etc?
 
Thanks Robert, I really appreciate the time.

The motor was rebuilt by a local builder in sf. He has a good reputation and seemed to have an understanding of the 345. The engine was rebuilt to stock specs, no special treatment. I'm running a prestolite/pertronixs distributor, edelbrock 1406 carburetor, .035 gap in the spark plugs, 8 mm wires. Basically stock-ish.

I'll do a compression test as you recommend.

Thanks.
 
If the plug problem was carb related, the 2 center plugs on one side and the 2 end plugs on the opposite side are fed from the same side of the carb.
Might consider a visit with the engine builder even if it is out of warrantee.
 
Bill,
we are saying the same thing just the referance we are using it different. I am using the fo you are using phsyical location..

The dual plane manifold alternates every other cylinder fired to right and left barrel on the carb.

Silver,
if the oem oring seals were used only that is likely the reason for the oil carbon buildup on the plugs. . what year is the engine/heads?
 
My 2 cents is if the engine is otherwise running fine then just leave it alone. My Travelall had spark plugs in it that looked worse than yours yet still ran like a top. Aside from the other sound advice that you have received you can check with the engine builder and see if he sealed the rocker assembly bolts that go into the intake runners. If not the engine will suck in oil around those bolts and cause what you see on the plugs.
 
Thanks all for the responses. It's appreciated.

Just an idea, could it have anything to do with a high zinc oil?

I'll run the truck as it is, it seems to run strong with sufficient power. Ill let you know what the compression is when I get a moment. It May just be an issue of new plugs every year.
 
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