I completed additional tests tonight which cause me confusion or clarity depending on how you look at it. First the results:

I did a test to test the fuel pressure to see if there was a loss when I shut the engine off. The fuel pressure after shut off did not go down. In fact it went up. I smelled for a gassy smell in the oil but couldn't smell any. My nose is not that good though so that's not very accurate.

Additional Leak Down test results. I decided to try to determine if the air leak was with the rings or the valves so the theory was to test for leak down on the problem cylinder (#2) and then squirt some oil in the cylinder
and turn it over a few times, then test again (I never got to this stage in the test, no squirting of oil). If the numbers went up then it would point to the rings and if there was no change then more than likely the valves. What I got was totally different results from before. Here they are:

#1 = 9%
#2 = 7%
#3 = 11%

Numbers are rounded. Got too late to run the compressor in my complex so I could only get through the first three.

Variables. I did only two things different from the last tests and that is first, I had added the BG 44K and have driven it about 10 to 15 miles and second, I warmed the engine before testing.

Another test was to listen for air coming from the valve train or other places. I got a stethoscope and listened around various areas and couldn't detect a sound of leaking air. The sound of the air going into the cylinder was so noisy I wasn't able to detect any other sounds. For a control test I was able to hear perfectly the air leak coming from my compressor hose so I know the stethoscope works well.

At this point I'm thinking my problem lies in the head. That oil is dripping down the valve guide when it sits or runs and goes into the chamber when the valve opens.


An additional update. I took it today to JeepsRUs (a local jeep shop) and paid them a fee to put it on the DRB II. He found no errors with regards to engine firing or injectors. All values were normal. In addition, he took out the 6 degree advance he previously put in when I was trying to get rid of what I thought was ping so now the MPI Kit is back to 14 degrees advance per stock MPI Kit specs. Now the engine runs even better but still have the oil problem.


After I left JeepsRUs I drove it to the swap meet driving highway and city miles. I had put a set of fresh plugs in the night before so they were pretty clean as of this morning. When I arrived at the swap meet I took a look at #2. It looked ok, not fouled and just a touch of black around the element so I put it back in and walked around the swap meet for an hour or so. When I got back to the parked jeep I again took a look at #2. This time I saw fresh oil around the threads of the plug the heaviest being at the top most thread and on the washer that comes on spark plugs. Now, how did this oil get there? I checked to make sure it wasn't coming down from the valve cover into the spark plug hole and no, there was no oil on the
outside of the head in this area. It couldn't have come up from the block, could it? The only thing I can think of is it's coming down from the valve guide and as it drips down and flows past the plug opening the warm/hot oil gets drawn up into the plug thread. Does this make sense?

I wiped the plug clean and drove it back home and did the same test. Looked at when I got there and let it sit for an hour and looked at it again. This time I didn't see the oil but it could be per chance that I landed on TDC for that cylinder and the valves were closed.


Comments?

<img src="/forums/images/graemlins/drunk.gif" alt="" /> Comment.. Well, I never!
Big Jim

it sorta makes sense.. it sounds like your engine is in good shape i never even thought to tell you to make sure the engine is warmed up..... it needs to be warm when you do ether a CLT or a compression test. as for the oil at the top of the plug...WTF its magic. i do beilieve you should pull the head and have the guides replaced and check for cracks.

Ok, this is my plan as I'm running short on time. I have a 4.0L head in the back yard that needs to be reworked a bit so I'm going to put that into service instead of reworking the 4.2L head. I'll need to get a 4.0L exhaust manifold and new head bolts made specifically for the conversion. This was a future planned conversion but now has been moved forward to be done now. In the meantime, I'll give the BG 44K another day to see if it's any carbon can be cleared up that might be causing problems.

Question:
While I have the head off is there anything I can do to evaluate the condition of the piston/cylinder/rings on any of these cylinders? That is, if I move the piston back and forth to view any slop, is that a viable test? Can I measure to determing how many times, if any, the cylinders have been bored over? Anything else I can do? Thanks for any insights and suggestions.

i'd be warry about swapping in somthing then immediatly releying on it. as with any complex mod, things are going to go wrong. if you need to rely on somthing rely on the old head that smokes a bit, rather than a new head that isn't designed to be there. with your compression and leak down results, there isn't going to be a mechanical failure for a while... most likely. the head swap should wait until you have a couple of weeks where you can be without your jeep if/when somthing does go wrong. you can usually use a good set of dial calipers to measure the upper most part of the cylender bore, but you will need a different instroment to measure deep into the bore. you can usually do a good visual and see if you have any serious damage. there will be carbon build up on the top of the piston, but if you see one diofferent from the others, let is be suspect. a leaky ring will have the carbon on the sides of the psiton partially removed. you should be able to see the last honing marks. on my 88 isuzu with 190K on it you can still see the orignal honeing marks. if you can see the honing marks and some areas look more warn that others you might have a problem, but the top of the cylender wares faster than the rest so don;t be too alarmed if the marks are week there.