Hey guys I have a high volume oil pump in my engine. I also have very high oil pressure. The gauge (stock, i know) is constantly pegged. I am using a quart of oil about every 200 miles, and i'm trying to determine the cause. Can the hv pump cause oil consumption? I whole intake including right up to the throttle blades is coated in oil. This is an L98 with TPI. I have about 4000 miles on my engine and it has been doing this since new, I am getting tired of adding a quart of oil at every fill up. I can provide any info on the engine if needed.

Thanks
John

 

do you have leaks, or smoke out of the exhaust? your pressure relief valve should (like it sounds) relieve pressure. you must have a leak if your whole intake is coated in oil.

 

I am burning a lot of oil (blue smoke out of the exhaust). The oil in the intake could be from an intake leak, pcv, ect... I'm trying to figure out which. The relief may be set higher than desireable. When I asked about my oil consumption on this board i did it in a more general sense, and i didn't get any answers that made sense. So now i'm trying again and i attacking each possible cause seperatly. So, can too high of oil pressure cause high oil consumption? For instance, maybe the extra pressure is allowing the pcv to suck up extra oil and deposite it in the intake. By the way the pcv and valve covers are stock. The pcv valve works.

Thanks
John

 

no, it should have no effect on consumtion. have you lloked around the base of your distributor? a lot of times oil will bubble out of there. has the motor recently been rebuilt?

 

Does that count as "recent"?

I'd start looking at PCV, intake gaskets, all the usual suspects. Since it has been consuming oil since the reassembly, that may indicate an assembly problem. Intake gaskets are a prime suspect. Were heads milled? Aftermarket heads? Altered/aftermarket intake base?

 

Here is the deal on the engine.

L98 bored .030"
10:1 compression
stock L98 iron heads milled .010", intake NOT milled to match
heads set up for cam
zz4 cam
high volume oil pump
stock intake manifold
heavy solid oil sludge on spark plugs
coating of wet oil on top of sludge on spark plugs
coating of oil of spark plug threads
coating of oil on inside of entire intake, right up to the throttle blades
small puddle of oil at the bottom of each runner
small puddle of oil on outside of intake, right below runners
Oil smoke out of the exhaust at start up and mid/high rpm
(new valve seals), not necessarily good ones

the rings were replaced after 2000 milesbecause of oil consumption, this did not help
however, i wouldn't doubt if my engine builders screwed up the rings twice

The intake gaskets were new with the rebuild and i've had 2 more sets on for the 2000 mile re-ring and various other problems. These are fel pro gaskets.

The pcv valve was replaced to no avail.

Any help would be greatly appreciated. Let me know if you need any more info.

Thanks
John

 

These are not external leaks. The oil is being burned. Yes, it was rebuilt about 4000 miles ago, with another set of rings 2000 miles ago.

 

bad valve guides maybe????

 

I don't believe that explains oil in the intake.

 

ok - TECHNICALLY the pressure reading on the guage is what the pump is providing - not the actual pressure in the system.(if there were actual pressure in the system you couldn't remove the oil cap or the dip stick with the car running, right?) So, no - your pressure isn't causing consuption. Blue smoke out exhaust, you are burning some, which should NOT (IMHO) happen on an engine with 4000 miles ( i've got one with 130,000 that doesn't smoke!) The L98 engines were NOTED for intake manifold leaks. Aluminum to steel can be a touchy proposition. So you may have multiple issues. I chased down leaks on mine for years, and found one that was TRULY bizzare. Used about 1 qt every 200 miles, but apparently ONLY if you were running below 3000ft altitude. (this saga is on the boards somewhere) It turns out, that the OIL FILTER was working itself loose. And would only leak when running! Now you'd think THAT would be pressure related, huh? It didn't seem to matter what brand filter, or who put it on, after a certain amount of time it would loosen up just enough to start leaking. Go figure.... Anyway, you are obviously burning some oil, and probably leaking some too. Steam clean that engine, and start nailing down the leaks.

 

If you have oil in the intake, your problem is most likely centered around the rings. Tear it back down and verify that the pistons and rods are facing the right way. Then check your oil rings. Before going through this hassle, do a compression check to see if any of your cylinder pressures are off. If this doesn't indicate a problem, then do a leak-down test using one of the dual gauge models. Your problem has to be coming from the pistons if your P.C.V. system is up to snuff. Your oil pump couldn't be the cause of this problem in my opinion. It could be responsible for oil starvation or aireation maybe, but not oil in the intake.

 

Thats what I'm afraid to hear. I had this engine out now twice, heads off once, and intake off twice since the rebuild and i'm getting very frustraded do it. This is why i'm spending extra time diaganosing the problem this time. I appreciate the input.

BTW I'm really not worried about external oil leaks. They are VERY minimal if at all. It is clear where the oil is going, out the exhaust.

 

I realize this, that is why i'm trying to fix it. The engine has seen 3 sets of felpro intake manifold gaskets in the last 4000 miles. The oil consumption hasn't changed with any set. My engne builder put 2 sets on, i put 1 set on. So i doubt we all did it wrong 3 times. Like i said the heads were milled 0.010" withouth the intake milled to match. However if this was the problem i would think i would have oil in the coolant and coolant in the oil.

 

You may end up removing the intake one more time. Perform some careful dimensional checks on the port locations when you remove the intake. Check both vertically and fore-and-aft positions. Draw them out with the dimensions. Compare the port runner locations with the intake manifold port locations.

If the heads and/or intake were ported, make sure nothing broke through to the top side or to the push rod guide side, or bottom side of the intake. Some castings can be frighteningly thin in those areas.

You'll also want to ascertain that the rocker studs didn't break through into the intake port roofs, or if they did, thread sealant was applied to the rocker studs before assembly (Some heads are designed to have the rocker studs intruding into the port roof).

Dry fit the intake back ontl the heads and check fitment with a feeler guage. Gaskets may only compensate for about 0.008" of difference in parallelism.

 

Vader,
I had problems with the stock rocker studs pulling out, which damaged 1 push rod slot. I had screw and studs and guide plates installed. To do this of course they had to drill out the pushrod holes. Any chance they screwed this up and went through into the intake side? I kinda doubt it though. The heads and intake have not been ported.

When you say dry fit the intake to the heads, do you mean with no gasket inbetween?

Basically you are saying make sure the intake exit matches up with the head inlet? right?

Thanks
John

 

It's certainly worth looking into. Something is causing the oil to mix with the air.

Precisely. Try to work around the ports with a feeler guage to check the contact patch. You might get some indication of this by closely inpecting the removed intake gaskets. It there is a heavy impression on one side and very little impression on th eother, the area is suspect.

Right. And also make sure the flanges are parallel and sealing together. Again, port runner placement and match might be indicated by the impressions on the removed intake gasket.