Author Topic: oil fouled plugs (Read 8276 times)

willard · « **on:** February 23, 2011 - 06:01:06 PM »

Motor rebuild 200 miles ago (70 383, KB400 pistons, 906 heads, lunati 602 cam, slightly milled block and heads to get 9.5:1, pistons 0.025 below deck).
Plugs fouled with oil, starts firing only 2-3 cylinders then slowly the rest comes back to life. Exhaust spits with black residue. Almost all plugs are black with oil, also oil on plugs threads. However there's no blue smoke when I floor it while driving, at startaup theres only white (condensation - low temperatures) gases...

Pulled off the intake - no evidence of oil running from the valey pan.

However look at the pistons - a mark under exhaust valve. The valve seals were brand new mopar ones (black type). Should I pull of the heads and get the modern viton seals installed or is it a deeper problem with worn valve guides (I don't think so as the shop checked it while rebuilding the engine).?

Can it be an effect of prolonged idling and 2 months of storage?

femtnmax · « **Reply #1 on:** February 23, 2011 - 11:57:40 PM »

Willard - Look for blue smoke when decelerating quickly from higher rpm in gear. Have someone follow the car to see if there is blue smoke...this would be oil pulled past the piston rings. Oil smoke just after start up is oil past the valve guides. The oil on your piston tops I would say is from blow by past the rings. Take a look at the PCV valve, is it or the pcv hose wet with oil?? If yes, that is oil past the rings.
Did you use moly or cast iron piston rings?? The moly rings should have seated right away if cylinder wall finish was done properly. For moly rings to seat quickly... I don't lather the cylinder walls with alot of oil on short block assembly, just a light coat of WD-40 or ATF. How much oil did the engine burn during the 200 miles? That being said...
You don't have many miles on the engine. I am a believer in seating piston rings by running the engine kind of hard for the first several hundred miles. THis means of course get on that gas pedal and run the engine thru the gears. Decelerate in gear to pull oil past the rings and wash the cylinder walls down, then get on the gas again and repeat. I take my new rebuilds to a nearby mountain pass and run the vehicle up/down the pass a dozen times or more...pushing the engine fairly hard to make those rings seat.
Have you done any of this this???
If the plateau finish on the cylinder walls was not done correctly the rings may never seat properly. You have already put 200 miles on the engine, a little late to expect to make rings seat...the cylinders may already be glazed over.

Chevy was having a problem with rings not seating when they first came out with high nickel blocks back in the 50's-early 60's. As a factory fix they recommended using mild abrasive to help the rings to seat. It does work. If your interested pm me and I'll send the info. But not everyone accepts this method even though one of the "big 3" used it to good results.
This is all just my opinion, I'm sure plenty of folks may jump on ths one, there are many ways to fix the problem, some more easy than others if you have plenty of $$$$ (one idea: disassemble the short block, rehone the cylinder walls, and install new rings).

willard · « **Reply #2 on:** February 24, 2011 - 02:31:33 AM »

Thanks for the reply.

The rings were speed pro moly (http://www.summitracing.com/parts/SLP-E-233K030/) and the first problems occured after the travel back from the shop (100 miles) - I described it in another topic : http://www.cuda-challenger.com/cc/index.php?topic=72444

Then I hauled the car back to the shop and they shimmed the rocker shafts and replaced the valley pan (as I thought it was oil sucked that way).

Here in Poland we are in the middle of winter so I can't drive the car now - I also have to wait 2 weeks for new head gaskets. So I can make another road test within 3 weeks I guess. Will check if the oil is below desired level, however I don't remember if it was full or in the middle of scale when I received the car back.

The interesting thing is I see no smoking on acceleration like it was just after the resto - so the new valley pan cured that problem. What frustrates me is the unability to start the engine after over 15 minutes after shutdown - it starts firing only 2-3 cylinders and shakes, and if it doesn't stall I have to feather the throttle to make other cyliders alive. I swapped the plugs for new ones on one side and here is the result after less than 30 miles (cyls 1,3,5,7 - omit te champion one - this wasn't replaced as autolite is too long and my socket cant get between it and the PS gearbox).

I have a bunch of problems with this engine - IMO it lacks power but I eliminated all causes, even rebuild it with new pistons, rings, degreed cam (was dead spot on), checked compression (140 psi after rebuilt), adjusted timing (thisis funny as at idle the rpms smoother up to 40 deg advance), new distributor, ecu, wires, etc...

femtnmax · « **Reply #3 on:** February 24, 2011 - 09:18:12 AM »

Willard - the champion plug does not look like it has been firing.
The engine will lack power until the piston rings seat. The piston tops are washed clean over most of the top, with the oil deposits in the middle. The large washed clean area suggests there is a lot of oil going past the rings.
I would strongly suggest rehoning the cylinders and installing cast iron rings...why, because the cylinders were not prepared properly to seal the moly rings, so they won't do any better if you have them do the job again.
You could hone the cylinders yourself. You can do it with the engine still in the car. Take all the pistons out, wrap towels around all the rod journals on the crank. Wrap tape around the towels to be sure to keep honing debris away from the crankshaft. Hone the cylinders with a course hone, around 200-220 grit. Make several passes with the hone (each pass is up & down the cylinder one time). Then remove and clean the honing stones, and wipe down the cylinders. Repeat honing and cleaning a few more times until the cylinder finish has the same look everywhere.
When done honing, clean the cylinders real well with a good cleaner...whatever you have been using to clean parts. Then oil the cylinders with a very light coat of oil such as WD-40 or automatic transmission fluid. Check ring end gap of rings in cylinders, and reassemble the engine.
The engine won't make its peak power until the rings seat. Check your spark plug wires on another engine the runs good to see if one of the wires is bad.
Let me know if you need more details. Hope this helps.

willard · « **Reply #4 on:** February 24, 2011 - 10:11:25 AM »

Thanks for your help. Unfortunately I have very little space in the garage and I'm unable to do such a scope of work like disassembling the bootom end. However the engine was rebuild by a shop and I have receipt so they are still responsible for their job. I'm really pissed off as hauling the car gonna cost me another 300 bucks...
I think I'm gonna reassemble the heads when the gaskets arrive and test drive with brand new plugs and check for oil consumption and smoke on acceleration/deceleration. But first I'll do the compression check without and then with oil - this should be the final evidence.
PS
The car felt only little better after pistons swap than before when it had around 8:1 CR.

72cudamaan · « **Reply #5 on:** February 24, 2011 - 12:03:10 PM »

If the machine shop can't hone the cylinders so there is no need for "breaking in the moly rings" then I would find a good shop to do it and make the first shop foot the bill. Are you sure that you aren't pouring gas down the cylinder walls with the carb?

willard · « **Reply #6 on:** February 24, 2011 - 01:03:51 PM »

Quote from: 72cudamaan on February 24, 2011 - 12:03:10 PM

Are you sure that you aren't pouring gas down the cylinder walls with the carb?

That is possible when not all cyliders were firing due to fouled plugs, but no 1 cyl was firing OK and the piston looks better. As far as honing - take a look at the photo - the cyl walls are honed, not flat.

femtnmax · « **Reply #7 on:** February 24, 2011 - 03:29:12 PM »

Quote from: willard on February 24, 2011 - 01:03:51 PM

As far as honing - take a look at the photo - the cyl walls are honed, not flat.

The comment from 72cuda about fuel wash is a good question. How is the carb jetted? Can you install your carb on another engine that is in good running condition, and verify the carb mixture is good/not too rich??

Yes, the hone pattern looks reasonable, though can not tell the plateau finish required for moly rings. On the one cylinder notice the thick black deposit above where the top ring stops travel up the cylinder. A small piece of the deposit has flaked off. That is too much OIL deposits, from only 200 miles of use. The next cylinder back looks good as far as too much oil deposit. So maybe you have a few cylinders that need some more time to seat the rings. Run the car kind of hard and seat those rings in. Don't kill the engine, but definitely push it.

When you go back together, I would suggest wiping all oil off each cylinder, rotate the crank so you can get to as much of each cylinder as possible. Do NOT add any more lube to the cylinders, just wipe them clean and put the heads on, etc.
Before installing the heads, look down the intake ports. If there is a LOT of oil deposits on the backside of the intake valves then maybe there is some leakage past the valve stem seals. I would guess you will see some, but not an excessive amount. Take a picture down one of the intake ports, lets take a look.

willard · « **Reply #8 on:** February 25, 2011 - 02:42:49 AM »

Tha carb is ok and was jetted with O2 sensor. Some raw fuel could get to the cylinders when I was checking cranking pressure but no that much to clean the pistons.

A noobish question - if pistons' tops are washed with oil why are they shiny aluminium and in the same time the oil leaves a burnt black film on the cyl walls above rings and on the plugs and combustion chamber?

I'll closely inspect the heads (intake side) for oil.

Aussie Challenger · « **Reply #9 on:** February 25, 2011 - 06:56:51 AM »

From what I can see of the hone marks I think that they are too flat, should be more angle also another thing is the PCV valve working properly, check the vac. pipe to see if oil is present.

cwestra · « **Reply #10 on:** February 25, 2011 - 07:10:43 AM »

Quote from: Aussie Challenger on February 25, 2011 - 06:56:51 AM

From what I can see of the hone marks I think that they are too flat, should be more angle also another thing is the PCV valve working properly, check the vac. pipe to see if oil is present.

I was thinking the same thing on the honing. Seems like there should a greater angle between the hatching. Closer to 45�.

ireland383 · « **Reply #11 on:** February 25, 2011 - 05:38:06 PM »

Button it back up and run it hard! I'm running the KB400's as well. How much did you have the heads milled? You should have more than 140 cranking psi. I had 150 with my Stealth heads I cc'd at 86, then milled them .030 to get 80cc and now have 165 psi. It'll come together in time. Make sure that valley pan is sealed good. I had a problem at first. I didn't use the paper gaskets and found out since milling I needed them.

willard · « **Reply #12 on:** February 26, 2011 - 05:18:39 AM »

I had the heads just surfaced as they cc'ed at 84- 86 cc. The block was cut only a little as we found some pitting by one water channel. After that the pistons were just 0.024 down the hole and using a 0.020 steel gasket the motor should have around 9.5:1 CR.
The 140 cranking psi was dissapointing as before rebuild I had 110-130 with the lowcomp pistons. I havent changed the cam so the presuure readings are linked with pistons swap only.
I was almost sure the cam was retarded but I degreed it and it is ok with the cam specs (lunati 60302). Then a spacer felt into the intake runner of the head

and I had to remove the head what showed the burnt oil problem.

I read @ moparts that you (ireland383) had the same problem with oil on plugs and it was intake. Mine was sealed very well.
Today I'm gonan inspect if the PCV tube is full of oil and make some more photos of cylinder bores and pistons.

ireland383 · « **Reply #13 on:** February 26, 2011 - 06:37:56 AM »

You could try a leakdown test to rule out rings, valves, and seals.

willard · « **Reply #14 on:** February 26, 2011 - 08:47:10 AM »

No access to compressor in my garage - valves were lapped, new valve seals. Is it possible that oil rings fail while compression rings seal ok? I had approx 140 psi +/-5 on every cylinder (warmed engine, WOT).
I also repost my question: if pistons' tops are washed with oil why are they shiny aluminium and in the same time the oil leaves a burnt black film on the cyl walls above rings and on the plugs and combustion chamber?

Author Topic: oil fouled plugs (Read 8276 times)

willard

oil fouled plugs

femtnmax

Re: oil fouled plgs

willard

Re: oil fouled plugs

femtnmax

Re: oil fouled plugs

willard

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72cudamaan

Re: oil fouled plugs

willard

Re: oil fouled plugs

femtnmax

Re: oil fouled plugs

willard

Re: oil fouled plugs

Aussie Challenger

Re: oil fouled plugs

cwestra

Re: oil fouled plugs

ireland383

Re: oil fouled plugs

willard

Re: oil fouled plugs

ireland383

Re: oil fouled plugs

willard

Re: oil fouled plugs