OK I did a compression test and all cylinders had 120 psi except 1 and 3 they had 110 and 115. The only cylinder that fouls out the plug has 120. Is this good compression and does this mean its possibly the valve seals causing the plug to foul thanks for the help guys.
piston rings
- Thread starter martin53
- Start date
-
My engine will puff smoke if I rev it hard but its black smoke. I'm not burning oil its still full just getting oil on some pluggs the one plugg that fouls the most has 120 psi. I haven't done a compression test with oil as mentioned it was getting late hopefully I can get to it today or tomorrow.
Inertia
Well-Known Member
You mention an oil fouled plug.. as I mentioned in post #12.. (now I know why I'm tiring of this place)..
Is the oil accumulated on one side of the plug,, or generally evenly oil coated,, same for other plugs..
Oil accumulation on one side indicated bad valve guide, and/or seal..
Evenly coated with oil would indicate rings..
If you're thinking that replacing the intake manifold gskts may stop oil consumption,, that doesn't hold true on a /6..
The two manifolds don't need to be separated unless there's a leak in their mating gskt.
Definately de-glaze if you re-ring..
hope it helps.. cheers.
Is the oil accumulated on one side of the plug,, or generally evenly oil coated,, same for other plugs..
Oil accumulation on one side indicated bad valve guide, and/or seal..
Evenly coated with oil would indicate rings..
If you're thinking that replacing the intake manifold gskts may stop oil consumption,, that doesn't hold true on a /6..
The two manifolds don't need to be separated unless there's a leak in their mating gskt.
Definately de-glaze if you re-ring..
hope it helps.. cheers.
nm9stheham
Well-Known Member
The cylinder-to-cylinder variations are decently good. The one cylinder that is fouling the plug could have worn rings but still have good compression because if the oil ring is bad then it will continuously oil the top and 2nd oil rings and make them seal well. So that part is not conclusive. Which cylinder is fouling?
I don't think adding oil and compression testing will make much difference but it is worth doing for completeness if you like; it usually is done if a cylinder is down to like 80 psi....
In my experience, a plug fouling is generally a bad oil ring. But changing the valse seals on that one cylinder is a quick job so I would try it. It might be that the seals are old and hard, and that particular one has completely fallen apart so that cylinder's intake valve has no seal at all anymore. So I would do that first; it is sooooo much easier.
If that does not work, then next I would suspect a possible sticking oil ring. I would take the plug out and move that cylinder down in the bore and pour in maybe half a pint of Marvel mystery oil and let it set overnight. Then turn the engine over (by hand preferably) with the plug still out to make sure the MM oil is not still in that cylinder; push it out as much as you can. Don't crank with the plug in case a lot of the MM oil is still in that cylinder; you don't want it to hydrolock and break things.
Those are the easy things to try first before pulling the cylinder head, pan, etc., and trying the ring change. You could also try a plug de-fouler/non-fouler to see how that works; I can't predict how good/bad that will work out.
I don't think adding oil and compression testing will make much difference but it is worth doing for completeness if you like; it usually is done if a cylinder is down to like 80 psi....
In my experience, a plug fouling is generally a bad oil ring. But changing the valse seals on that one cylinder is a quick job so I would try it. It might be that the seals are old and hard, and that particular one has completely fallen apart so that cylinder's intake valve has no seal at all anymore. So I would do that first; it is sooooo much easier.
If that does not work, then next I would suspect a possible sticking oil ring. I would take the plug out and move that cylinder down in the bore and pour in maybe half a pint of Marvel mystery oil and let it set overnight. Then turn the engine over (by hand preferably) with the plug still out to make sure the MM oil is not still in that cylinder; push it out as much as you can. Don't crank with the plug in case a lot of the MM oil is still in that cylinder; you don't want it to hydrolock and break things.
Those are the easy things to try first before pulling the cylinder head, pan, etc., and trying the ring change. You could also try a plug de-fouler/non-fouler to see how that works; I can't predict how good/bad that will work out.
Well I'll pour some marvel mystery in the spark plugg and change the valve seals and see what happens I want to get it right so I can drive up to a show we go to every summer its like an hour and a half drive and don't want to get stranded. Should I change out just the intake valve seals or exhaust as well. Thanks for the help guys.
nm9stheham
Well-Known Member
Won't hurt to do both, and won't be too much work to do them all. Once you pull the rocker shaft, they are all ready for it. Do you know how to keep the valves closed with the 'rope in the cylinder' trick?
The Felpro valve stem seals come in boxes of 8 each as they also are used on some V8's.
The Felpro valve stem seals come in boxes of 8 each as they also are used on some V8's.
nm9stheham
Well-Known Member
Something maybe 5/16" or 3/8" and flexible (floppy) that can be fed into the spark plug hole easily. Lower the piston, feed in some rope into the plug hole and bring the piston back up in the cylinder by hand 'til the rope pushes up against the valves. This is to hold them closed and keep them from dropping into the cylinders when you remove the valve springs and retainers.
This is all after removing the rocker shaft. Do this by unscrewing the 7 bolts 1/4 to 1/2 turn at a time in order to allow the spring pressures to release evenly. When you re-install after changing the valve seals, do the same thing: turn each bolt down a bit at a time to draw the rocker shaft down evenly.
Once the shaft is off, remove the rockers, bolts and separator rings and lay them out IN ORDER and keep them in order. Keep the bolts in order in the shaft; the long one has to go in the back hole.
If you use the old lever style compressor, then put the shaft back in place without rockers and separator rings, and snug the bolts down; this will be your leverage point to use the compressor tool to compress the springs one at a time. Stuff paper towel down in each hole where the pushrods come up so you don't drop a keeper down there.
Sometimes the keepers in the retainers will stick; I use a deep socket and gently smack the retainer with the inverted socket and hammer. Needle nose pliers will be good to pull the keepers out.
This is all after removing the rocker shaft. Do this by unscrewing the 7 bolts 1/4 to 1/2 turn at a time in order to allow the spring pressures to release evenly. When you re-install after changing the valve seals, do the same thing: turn each bolt down a bit at a time to draw the rocker shaft down evenly.
Once the shaft is off, remove the rockers, bolts and separator rings and lay them out IN ORDER and keep them in order. Keep the bolts in order in the shaft; the long one has to go in the back hole.
If you use the old lever style compressor, then put the shaft back in place without rockers and separator rings, and snug the bolts down; this will be your leverage point to use the compressor tool to compress the springs one at a time. Stuff paper towel down in each hole where the pushrods come up so you don't drop a keeper down there.
Sometimes the keepers in the retainers will stick; I use a deep socket and gently smack the retainer with the inverted socket and hammer. Needle nose pliers will be good to pull the keepers out.
BillGrissom
Well-Known Member
Excellent result. Too many people jump into removing the head of a perfectly good engine (without testing first), then screw up things, or end up letting it sit for years. I think the Wheeler Dealers show gives the best balance of what repairs and upgrades to pursue.
nm9stheham
Well-Known Member
Good deal. I rated that as a long shot but an easy thing to try. Valve seals and guides typically don't get so leaky as to foul plugs, so your valve guides may be pretty worn. Keep and eye on it, and perhaps put a head rebuild in your long term plans.
Next step I would do is also easy: Take a can of Sea Foam or Rislone and slowly dribble half of it down the carb while revving the engine to keep it running. This will clean off intake valves and maybe free sticky rings. (It will smoke like heck and is quite entertaining too.) Put the other half in the crankcase and drive it to also help sticky rings, unless you have already added marvel Mystery oil or something to the oil. I think that a couple of oil and filter changes at 500 mile intervals are in order for your engine just to help clean things up a bit.
How many miles are on your engine?
Next step I would do is also easy: Take a can of Sea Foam or Rislone and slowly dribble half of it down the carb while revving the engine to keep it running. This will clean off intake valves and maybe free sticky rings. (It will smoke like heck and is quite entertaining too.) Put the other half in the crankcase and drive it to also help sticky rings, unless you have already added marvel Mystery oil or something to the oil. I think that a couple of oil and filter changes at 500 mile intervals are in order for your engine just to help clean things up a bit.
How many miles are on your engine?
Not sure on the miles its out of a 78 dodge truck. I'm trying to get info on the tranny. From what I'm told its an A309 trans. I need to figure out how the swifting works like what's directions first second and third are. Once again thanks for the help
-
