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Discussion Starter · #1 ·
Hey guys. Since the motor was built, it's been consuming oil like crazy, an abnormal amount, maybe a full quart every 300 miles or so. Granted most of those miles are on the track, but that still seems a bit excessive to me. I can see it smoke through the tail pipe, it's pretty visible. I've had the motor checked out, and compression is still pretty decent (between 180-190 psi across all cylinders), leakdown is between 9-11%, and the motor still makes pretty solid power. Is it possible for all this to to be within spec, and still have a major oil consumption?
 

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Discussion Starter · #5 ·
That is excessive.
And you can see the oil being burned as evidence from the smoke out of the tailpipes.

3 things come to mind
1- valve stem seals/guides
2- pcv system
3- the rings have not sealed yet (unlikely)

Pull a few plugs and see if you have a buildup on any of them (or all)

Could also be a combination of the above along with an oil leak.
1. Valve stem seals have been replaced, with no effect.
2. PCV system was converted to an oil catch can at one point, and while the catch can did collect something, it certainly wasn't a quart, not even close.
3. I am starting to suspect the rings at this point, because it seems like I addressed pretty much everything. I've had oil leaks before, but they were mere drips, nothing that would form a puddle under the car.

pull the plugs and look at them, are they covered in oil?

what oil ring package did you use?

my guess would be valve guides and or oil rings, as compression rings dont really apply to oil control
I will check the plugs a little later today, but from what I remember, they did look a bit oily last time I pulled and replaced them. The rings are part of the Eagle Specialty Product bottom end kit, and they are Mahle Plasmamoly.
 

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Discussion Starter · #12 ·
You can pull your intake to see if lower intake gaskets are leaking aka 1262’s . A leak down value of more then 5-6% on a new motor is high.
I was planning on pulling the upper intake manifold to check and see if there is any oil on the intake ports in the heads (I think I can probably spot it with a flashlight. The heads are AFR 185CC Street Port and intake manifold is TrickFlow R Series. If the gaskets are leaking, which gasket set should I buy to replace them?
 

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Discussion Starter · #14 ·
Got a chance to pull a spark plug, just the easiest one to get to #4, and here is what it looks like. The plug itself is completely black, looks kinda greasy, and there is oil around the o-ring. I will pull and replace all plugs soon, and see if they all look like this. Next for me to is to pull the upper, and see if there is any oil in the runners, in order to eliminate the lower intake manifold gasket as a culprit.

 

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Discussion Starter · #15 ·
Ok, I've replaced all the spark plugs today. Here is the condition of the existing spark plugs, when I pulled them out, all numbered by the cylinder banks.





They all have a bit of what looks like oil fouling. The PVC has been reverted back to OEM setup, where as before I've had nothing, just venting into catch can. I still have to hook up the valve cover vent into the intake, because at the moment that vents into atmosphere as well. Looks like cylinder #1 and #3 are pretty bad, #3 being particularly oily. #1 plug was completely loose, I was able to take it out by hand, so it may be possible that #1 was external oil leak (valve cover leak) that leaked inside. Next up I will pull the upper intake manifold and inspect the lower ports to see if there is any oil build up in there, which would warrant the lower manifold gaskets to be replaced.

Any other thoughts?
 

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Discussion Starter · #17 ·
The valve cover “vent” line is not really a vent, it’s the fresh air inlet for the pcv system. It’s where fresh metered air enters the crankcase, and then circulates up through the pcv valve.

Without it, you are putting the crankcase under a vacuum, which is bad for gaskets and seals.
That's good to know. I will probably route it anyway, just to get it all hooked up.
 

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Discussion Starter · #19 ·
pull the lower

stick a boroscope into runner and look at top of valve, caked oil, your valve guides are out of spec, or you sucking in oil from the intake tract.
I've ordered a USB endoscope from Amazon, hopefully it will work with my phone. Once I get it I think just pulling the upper should be sufficient enough to get all the way by the valves.
 

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Discussion Starter · #21 ·
I finally got around to taking the upper off and taking a look inside. What I found was very light coating of oil on the intake ports in the cylinder head, definitely not a lot of oil to be found in there. The gasket between upper and lower had some oil on it as well, but there was no oil at all in the upper or lower intake manifold runners. One thing to keep in mind is that the car has been sitting without being started for about 5 weeks now, so whatever the oil might have been there could have leaked down by the valve. Looks like I will be pulling the lower intake off, and changing the gaskets in order to achieve better seals. I've got fresh plugs in the motor, so after another track day I will pull the plugs again and check to see if there is oil on them again. What's a little disappointing is that I was expecting #3 runner to be swimming in oil (since the spark plug was), and it looked same as the others, which leads me to believe that oil ring on that one is toast.
 

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Discussion Starter · #26 ·
I don't think PCV is an issue anymore. I reinstalled a stock PCV, because before it would just vent into a catch can. however one thing that I've noticed is that the amount of oil on the spark plugs is inconsistent between cylinders, #3 being completely covered in oil.

valve guides with excessive clearance, will not be seen in the runners
There was a bit of oil in the runners past the lower intake manifold gasket, but again, it wasn't much, probably because the car has been sitting for over a month. I will consider pulling the heads, since it's not that involving, but do you really think that valve guides could cause a cylinder to be swimming in oil?
 

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Discussion Starter · #28 ·
If it were a valve guide out of spec, what other telltale signs should I look out for, before I attempt to remove the cylinder heads? Would there be a pooling of oil somewhere, perhaps a build of of unburnt oil at the valve?
 

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Discussion Starter · #30 ·
Another thing worth mentioning. When I had it at the track last, whenever I would fire it up after a hard run session, it would shoot a lot of blue smoke out of the tail pipes, and eventually clear up. After a normal drive home though, I had to kill it and start it again when I was moving cars around, and upon a restart there was no smoke.
 

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Discussion Starter · #38 ·
Hey guys, since I've had the motor taken out and just taken apart the machine shop, I figure I'd update this thread. The cause of the oil consumption turned out to be 4 piston rings that were broken. The value guides were fine, the lower intake manifold gasket was good too. This is simply a result of either improper tune or overheating the engine at the track, causing detonation and thankfully only damaging the rings. The engine is still in the cleaning, I will know for sure what else got damaged, but this has been going on for years and years, so it's unlikely that it's recent. Hopefully the bore and pistons are OK, and it will be just a simple hone and rings/bearings job.
 

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Discussion Starter · #40 ·
I'll find out for sure, but the machine shop said both. I would have thought that would show up on compression test as well, which is rather odd. All the tests were performed by my mechanic, so maybe I gotta have a conversation with him about that. I am happy that the cause of oil consumption is that obvious and blatant, I won't have to do any further head scratching. It would have been really bizarre if the engine would be taken apart only not to find any faults at all.
 
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