misfiring ?

[Anonymous]

after a good check because the engine is misfiring more and more ,did find that all the spark plugs look great ,exept nr 3 ! this 1 is verry oily . when getting this spark plug out and look ad it , almost oil is dropping of it ? it,s not from the valve gasket leaking ore something .outside and head gasket are verry clean , no oil leaking outside !

wat is my problem ? i did a complete head rebuild a time ago . runnig great after the first firing up , til now , misfiring more and more , and it is not the ignition ore coil , got a dura ll distributor with a MSD 6A and mallory coil, cheking the spark plug cables , there a firing right , no misfiring there !!
head gasket leak ? piston rings ? btw the oil in the engine looks clean , no dirty mes ore white glow in it ! looks verry clean .
do i looking ad a complete engine rebuild with new piston and rings ? ore just a leaking head gasket after the rebuild ?

gone take some pic from the spak plug , the nr 3 [ oily ]and a normal one when engine did run !

 

[CobraSix]

I'd do a compression check on #3...some oil is normal. Mine have oil on the threads all the time, but never on the electrode. That's a problem I believe.

Also, maybe pull your valve cover and make sure the valve seals (the rubber boots on top of the guides) are still in place. I was having a bad problem with that on my old head. They wouldn't stay in place on #6 valves.

Good luck.

Slade

 

[Anonymous]

compression test was good , al cyl almost egal ! cyl 3 almost more then the rest !
put comression on al the cyl with the piston in top possition, no leaking valve,s too ????
but after disconnecting the blow of tube with a bypas valve on the valve cover , the engine is starting to run faster , i dont get it ??
al piston are looking verry clean on the top site exept nr 3 , you can see oil is on top and the piston is black on top , the others are nice yellow and dry ! car is stil running good and pulling good , but misfiring, and when it those , it seems it is only using 5 cyl , gone put in tomorrow some new spark plugs and spark cable,s and a new bypas vale , btw my oilpressure meter is also down ,
some one now howmuch a complete rebuild set wil cost for the 3,3 ??

 

[Anonymous]

It sounds like you could have a bad valve guide, valve seal, or partial ring failure. There are not too many ways oil can get into the combustion chamber.

You did a compression test. What were the numbers? You said they were all very close to each other. Try a wet test. squirt some oil in the hole then run compression, if it goes up significantly, then you have a problem.

These are your possibilities as I see them

1. Bad valve guide
2. Bad valve seal (as Slade mentioned)
3. Partial failure of oil ring

Try the wet test and let us know how it goes. Also post the compression numbers of the dry test. We need to know if the numbers are low or not.

Also, what carb are you running? These engines are notorious for running rich in the middle and lean on the ends. The black you are seeing on the pistons could be from your mixture in combination with oil. This can be deceiving and make the problem look worse than it really is. I would be less concerned about the color of the piston, and more concerned about the condition of the plug, and results of both compression tests.
Let us know how it goes.

Bill

 

[Anonymous]

first the compression test card , not verry clear but you can see , btw it is in BAR !

the carb is a holley 1904 , big log intake D8 head ,

gone make some pic of the spark plug,s , my battery,s are empty from the camera , gone reload them !

wil gone do the wet test tomorrow , because the tools are in my friends garage , got acces to it tomorrow again , and i,m adding my chrome valve cover tomorrow so when it is of i can see what is a possible problem in there !
btw thx for the tips already , wil let ye now how it go,s !