Oil Is Foul!! ing

[Bluzilla]

100_3165.jpgHere I go, my Stage 2 has been together since 1996. I retired from racing in 1997, then fired the car back up in the summer of 2009. Since then I have been fouling plugs like crazy. After posting what I believed to be fuel fouled, turns out it is actually an oil foul issue, thanks to revisiting the spark plugs a month after removing them, only to find them still wet (with oil-including their threads). It pays to were glasses. I removed the intake manifold, looked into the runners and they were as dry as can be, and dry to the touch all the way to intake pocket. Then it gets bad, all intake valves have oil coked on the stems and backside, a few valves that were closed actually had a slight oil puddle half way around the valve at the seat. I decided to do a cylinder leak down test today. I loaded 90psi into each cylinder and here is the results. Keep in mind I had already pulled the intake, so I could not reach operating temp. #1=85lbs, #2=85lbs, #3=85lbs, #4=81lbs, #5=80lbs, #6=80lbs, #7=81lbs, #8=82.5lbs. Now that being said, while I was testing, since I have the intake off, I was looking at the head gasket area, and #2,#5, #6 all leaked into the valley (air bubbles). I squirted oil from a pump can on the gasket parting line just to make sure. THEY LEAK. So, its probably a good time to give details, 1970 Block, .040 copper gaskets with o-ringed deck, 13.25:1, .038 Arias dome pistons, Crower 7.250 Billet rods, Sealed Power file fit moly rings, Block Girdle, Stage 2 open chamber tall port prototype heads, (2 of 5 made) from what I recall, 308s cam with the 1996 production of Chevy solid lifters (they may have the less desirable oil band location), 1.65 roller rockers, T/A intake, 9375 Dominator, oil mods including rear block feed, 3-1/2" exhaust through Dynomax SS Race Magnum Straight Through muffers, and the N-25 bumper 3-1/2" tips. The motor does not smoke at all, back in 1995 I pulled the motor down to up the compression, and found the intake valves to be in the same condition (oil deposits). At that time we found the valve guides to be out of limit after one season. We replaced guides, valves, under warranty, then valve job, and PC seals. I do remember having a few plug fouling issues then, but its way worse now. I stopped racing in 1997 so everthing just stayed as it was. In 2009 when I decided to bring it back, I replaced the valve stem seals with the Manley viton #2403-16. The lifters seem to be a question in my mind because of some of the archived threads stating how much oil was being fed to the top end with those. I should mention, since I am running a Dominator, I have no PCV system in place, though that carb has a brass plug I could remove to put a PCV into use. I do have 4 Offenhauser valve cover breathers installed since 1992. I did just order, and received new replacement filter foams and screens for them, as the old ones were in pretty sad shape over the years. I do drive the car on the street more than on the strip, but have about 100-1/4 mile passes and 1000 miles on this 1996 set-up. The intake gaskets are sealing, and of the composite type with no valley pan. Its probably time to freshen up anyway, but this car always ran so well before going to a solid cam that I wanted to just weld the hood closed and have fun. I have not removed the headers yet to look at the exhaust valves, though i don't expect to see much in the way of oil there,

[462 Chevelle]

retainers arent hitting the valve seals are they? have you checked valve train geometry? could that put load on the valve guides if its off?

[Jim Rodgers]

Larry,

Its good to see you getting the car back out. Thats an old GSE setup if there ever was one. Bring it to BG this year.

In my opinion, YOU NEED A PCV SYSTEM! That engine makes crankcase pressure and you need to get rid of it.

Get a valley pan from Mike at AMP and put the intake back on with the valley pan. Then check the cylinder head torque and retorque if necessary. Then plug up all but one of the crankcase breathers and install a PCV valve, or better yet plug up all but the front two breathers and install a crankcase evac system like I designed back about 1993 in the GSXtra that plumbs into the header collectors. Make sure the idle RPM is sufficient to hold steady crankcase vac thru the PCV or the evac system ie 700-800 may be too low. Or even better yet but more expensive will be a vac pump at about 8-10 inches which will give you about 10-15 hp at the crank.

Also, make sure you have sufficient oil drain out of the top of the cylinder heads. I'm sure you do but it would be good to make sure.

PS if you put seals on the exhaust valve stems I would take them back off, they need oil on the stem to protect the guide from the heat.

Hope this helps. I wouldnt tear it down tho.

[Bluzilla]

Hey Jim, good to hear from you. I may be at BG this year. I'm leaning more toward the pan-evac than the vacuum pump. Steve Johnson at AMS Racing Engines here in town was telling how the vac pumps actually can lower oil pressure, or the effect there of. He advised me to re-think using a vac-pump since I see more street than strip these days. I'll try to look back through my issues to find your set-up. The car idles at 1100 in drive so a pan-evac should work. Thanks for the heads up on the exhaust seals. I had heard of that years ago, but since the heads came from T/A with them installed on the exhaust, I just replaced them. On the Chevys I remove the top tension ring on the exhaust seals, I may do that on the Buick. I'm going to pull the valve springs off on Monday and re-check geometry, and see if intakes are too loose in guides. What do you think about those leak down numbers, and the old style chevy lifters with oil band placement? Take care, Larry

[462 Chevelle]

when your saying lbs on your leakdown are you talking about %??

[Bluzilla]

What I was saying is that I put 90lbs. of air pressure into the cyl. as in the first gauge reading. The second gauge reading is the lbs. of air pressure that cyl. held. To calculate the actual percentage of leak-down, you simply multiply the difference of the two readings by (1.1), #1=5.5%, #2=5.5%, #3=5.5%, #4=9.9%, #5=11%, #6=11%, #7=9.9%, #8=8.25% of leak-down. Hope that clears up any confusion I may have caused. Larry

[462 Chevelle]

ahhh.. my leakdown tester has 0-100 psi on the first guage and 100%-0% leakdown on the second guage

[Jim Rodgers]

Larry,

Those percentages dont look bad to me at all considering the engine was dead cold. I wouldnt tear it down if it were mine as long as the oil filter was clean.

As long as you have good oil pressure and the oil press gauge isnt bouncing around, the lifters should be fine. The prob with some of the Chevy lifters in a Buick is the oil hole is too low and comes out of the lifter bore and bleeds off oil pressure. So if your oil pressure is good I wouldnt sweat it.

A vac pump will be fine as long as you dont carry more than 15"-18" for an extended period of time. On my old GSE engine 8-12" would give 15-18 hp all the way up with NO effect on oil pressure. I kept a vac gauge mounted on the A pillar. If I were you I would go with the pan evac system. My article was in the GSXtra sometime in 1993 I think. Since my article, Summitt and others have come out with a pan evac kit to make a simple install. This system will help in my opinion.

You can call Mike at AMP about the valley pan. If nothing else it will keep the bottom of your intake cooler and if you decide to use a PCV valve then you will definitly need it.

[TORQUED455]

Don't confuse cylinder leak down testing with oil fouling spark plugs. You can have good compression rings and still have problems with oil rings. I would advise against a vacuum pump on anything but a trailered race car. Either use an intake splash shield and PCV valve or header evacuation system. I disagree with dumping the exhaust valve seals. I think we need to know what guides are in there first. I would DEFINATELY check the guides and seals before a complete teardown.

[Bluzilla]

You know, I was scrambling around today to try and find the part # of the Piston rings I installed back in 95 (bottom end together since 95, top end serviced in 96), and found it was speed-pro #R9278 .035. That was a LOW TENSION oil control ring package. I'm not too sure, but that may have been all that was available at the time. Now I have been looking at the R9798 .035 set. S/P states this to have a Standard Tension oil control ring package. This could be my problem, trying to run low tension oil control rings for street use. I have close to 1000 miles on this set up, and I am aware there are sacrifices to be considered when attempting to place a 10:51 et., 3770lb car into street driving conditions. I would like to hear from you as far as this ring issue exists. That seems to jive with what Bob just posted about having good compression and still have problems with oil control rings. Bronze guides are from T/A, replaced under warranty in 96. Larry

[carmantx]

We run a pan evac system on our street car, without a PVC. You need something to pull the pressure down.

Also, what type of oil do you run? I run Valvoline racing oil, and always have, and I have not had an oil fouled plug issue. Even when I had a old chevy that used 6 quarts of oil in a 100 mile road trip. I believe it is designed to burn in the chamber for engines passing oil through.

Good luck. Glad you are getting use from the car. Sounds like a nice ride.

[Bluzilla]

Well-well, I finally got time to pull the valve stem seals (Manley #24046) today. They fit like over-cooked noodles. I installed them back in 2009 when this all started. The area of seal contact is no more than 1/16" at the top of the seal. If you take a valve in hand, slide one of these seals on the stem, and hold the seal, the valve drops to the floor. Thats happening cold, I wonder how loose they are hot? They also seemed to be the loosest just when I removed them from the guide, as if the slight stretch to hold them onto the guide made the fit even looser. I installed a teflon lined rubber seal, and a replacement all rubber seal, and they are both tight. So much for the TRICK VITON Manley seals. At least I know where the oil was entering the combustion chamber from. I have another source for viton seals I'm checking into which looks like they have about a 1/8th' to 3/16' contact area with internal ribs. Combine those old style lifters with the (wider-lower oil-band) and these loose valve stem seals, no wonder I'm fouling plugs. I also just got in a set of the #9798-35 with the standard tension oil rings today. So it looks like I'm going to pull the motor and do an inspection-freshen up. I'm thinking about taking it to Bowling Green this Year for the first time since 1997, so there may be a few updates and mods I will be doing to try to be more competitive. Thanks again to all who chimmed in. Larry100_3180.jpg