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Oil on plug 6 and more

D

DaveColborn

Basic User
City
Youngstown
State
OH
What do I need to diagnose or do first.

I understand everything is attached and each system may matter to the other in the overall running of the vehicle. Here's what I've got.


82 CJ8 258. Carter BBD with no stepper motor.

Burning a little oil (blue exhaust) and plug number six is wet with oil. all plugs are black and carbon covered after being cleaned recently. it's only been running at an idle or in my driveway, no highway driving. carb is rich going to get a rebuild,

Vacuum hoses/vapor lines are questionable. The vapor canister lines are unhooked to the vacuum and gas tank, but are hooked up to the PVC and carb

Starts and runs easily when cold or hot (45-80F so far) Electric choke seems to work like it should. Idles down as it gets warm and i tap the throttle.


I removed the air pump (emissions??) as there was no belt running it, and thus inop. There was a canister on the passenger side of the valve cover which I removed also. The hose that left the canister went to a tube on the drivers side rear of the valve cover, and it seems to suck air while running. I closed this off with duct tape until I figure out if there is more I can/should remove or can/should replace.

Oil will smoke up from the filter on the front of the valve cover, the second hole on the valve cover when I pull out the PCV valve out smokes, and the back when I pull out whatever it is plugging it there smokes. Looks like a pcv valve with an rubber hose in an elbow that went to a garden hose and was run down towards the ground.

I added some sea foam to the gas and oil about a month ago. Getting ready to change the oil out on a sunnier day.

Compression is:

1-135
2-135
3-135
4-140
5-129
6-145

This is according to a harbor freight compression tester, with all plugs pulled, wire from the coil pulled, gas pressed to the floor, turning over 4-5 times each.


I assumed I would get lower pressure from 6, but am guessing it is not the rings but the oil finding another way into the cylinder from the top actually giving it a better seal and thus higher pressure.

Trying to do as much of this myself as it has been pretty enjoyable thus far.

Any (more) help is greatly appreciated.
 
I put a vacuum gauge on the back of the carb on the port that goes to the choke pull off.

21 hg. Steady no fluctuation.
 
Im not sure about the AMC motor but there oil seals on the valve stems that get old and fail. On Fords they are domed shape and slide over the valve stem.
 
Had the valve guide seals replaced on a 258 two months ago. I didn't like the blue smoke when first starting it up. The old seals were the domed shape ones and they were brittle. The new guides that replaced them were different. More like a little tire. If your exhaust is blue all the time then it could be more than just valve seals.
 
Thanks for the replies.
Is it possible to diagnose what exactly is going on?
What should I address first to have better results with everything else?
Does the compression test suggest that the rings are passable?
If the rings are good, would that leave valve seals or head gasket?
 
Im thinking its your valve seals... its not a hard job to replace them and I would assume there is a detailed procedure somewhere on the net. You will need an air compressor, there is a spark plug adapter connected to the air compressor that will keep the valves from falling down into the cylinder (its not happened to me and Ive replaced the seals on a couple motors), there is a "pry" tool to compress the valve springs so you an remove the keeper bushing and remove the springs so you can replace the seals. You will need to replace the valve cover gasket. its a good afternoon job...good luck
 
Thanks much. I just changed the oil and filter. I had 10w-30 with seafoam in it. Started it up with 10w-30 and much less blue in the exaust to where I can only see a huff once in a while once it warmed up. I will do the valve guide seals, then rebuild the carb and see what I have.
skiptown said:
Im thinking its your valve seals... its not a hard job to replace them and I would assume there is a detailed procedure somewhere on the net. You will need an air compressor, there is a spark plug adapter connected to the air compressor that will keep the valves from falling down into the cylinder (its not happened to me and Ive replaced the seals on a couple motors), there is a "pry" tool to compress the valve springs so you an remove the keeper bushing and remove the springs so you can replace the seals. You will need to replace the valve cover gasket. its a good afternoon job...good luck
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