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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: markzepp820 on March 31, 2007, 11:39:00 pm

Title: oil fouled
Post by: markzepp820 on March 31, 2007, 11:39:00 pm

I have a 79' chevy truck with a 350 thats been recently cutting out. So I pulled the spark plugs and 4 out of 8 were oil fouled. What could be the problem(s) to half my plugs getting oil-fouled?
thanks in advance,
Mark
 

Title: Re: oil fouled
Post by: 123 pugsy on April 01, 2007, 06:52:00 am

Were they all from the same side?

Title: Re: oil fouled
Post by: joesgarage71 on April 01, 2007, 07:36:00 am

I take it she gots high miles. Its getting worn out, time to rebuild, you might go a step or two hotter on the plugs to help it burn the oil off.
Steve

Title: Re: oil fouled
Post by: Lt.Del on April 01, 2007, 11:08:00 am

Hey Mark, Joesgarage is right.  Get a hotter plug.  

If rebuilding the engine or getting a new crate engine is out of the picture right now, or, even something as relatively inexpensive as rebuilding the cylinder heads to replace the oil seals and guides, you can use a hotter plug to burn off that oil on the plugs.

Before putting in my 383 stroker, my 350 had over 160,000 miles and I had to use hotter plugs due to it missing on the 8th cylinder.

They worked awesome!  The ones I originally used was

Champion RV17YC However, for a hotter plug, the great one is Champion 4113 Truck plug...they are all black.  Go to NAPA and ask for these.  They may have to order them but for an engine like yours, they are well worth it.

The hotter 4113 is on the right....

 

SgtDel
aka "Andy"

www.delbridge.net

1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4

Edited by: SgtDel  at: 4/1/07 10:38 am

Title: oil fouled
Post by: markzepp820 on April 01, 2007, 10:53:00 pm

thanks for the info. My 350 does have alot of miles on it(187,000). Everything else besides the motor is in good shape. In the near future, I want to by another 350 for it. But I will try those hotter plugs you all talked about, until then. Also, how do hotter plugs work?

             thanks,
                       mark

Title: Re: oil fouled
Post by: SUX2BU99 on April 03, 2007, 02:15:00 pm

I believe it has to do with the length of the insulator, which is that little snout above the electrode. See how much shorter it is than the colder plug on left? I'm forgetting the reasons for it, but I think the insulator length of the plug is affected by the temperature of the combustion chamber when the plug fires. Hotter plugs can cause knocking though. In engines that have a tendancy to knock, colder plugs can be used.

Title: Re: oil fouled
Post by: VileZambonie on April 03, 2007, 07:27:00 pm

Yes you are correct it is the surface area of the insulator on the combustion chamber side that determines the spark plug heat range.

How often do your plugs foul? Before you run a hotter plug you might want to consider the side effects. If you drive this truck on the highway or pull heavy loads then absolutey do NOT run a hotter plug.

Title: Re: oil fouled
Post by: markzepp820 on April 04, 2007, 12:56:00 am

the plugs are starting to foul more sooner now. I do alot of stop and go driving.  
                                mark