Oil in Intake Runners

[Garry Sharp]

After my overheating session at Road Atlanta, I got back and started the engine. It seemed to be running on 3 cylinders. I did another leak down test-good results, a compression test-135 to 140 psi on all cylinders, spark plugs are firing, timing is right, valve lash-.006 on all valves. I started it again and read the exhaust header flanges with laser thermometer. After a minute or so, #3 & #4 read about 230 degrees but #1 & #2 only 115 degrees. I then took off the intake manifold on #1 & #2 head and the intake runners are full of oil. I'm sure somebody knows exactly what this is, but I don't- I got a feeling I'm done for another year though.

Thanks for any help,
Garry

[Daryl DeArman]

I am no VW expert, or engine expert for that matter, but I'd bet you are looking at something simple such as valve guides and/or seals.

Certainly not a season-ending deal.

It's the only thing that comes to mind immediately that wouldn't show up in either a compression test or leak-down

[BLS]

I then took off the intake manifold on #1 & #2 head and the intake runners are full of oil.

Gary, can you elaborate a bit? "Full of oil" sounds like oil that runs out when you disconnect, but that seems unlikely. Is it just that they are oily on the inside of the runners and head? Or literally full of oil?

The only thing that comes to mind are valve guide issues.

[rgu]

Gary

I seen something like this two times before although it may not be whats causing your issue. The fact that your problem was associated with running heads super hot makes it worth considering.

Dual port heads have much thinner walls where the ports come down to the intakes valves. Engine builders sometimes are overzealous about porting can easily go too far. Thus when the head gets hot a hole develops and oil from the rocker box gets in the mixture. As you said compression is still good and you have spark. If the motor sat for a long time oil can run from the tank and fill the rocker box exacerbating the problem.

I agree with the with the conclusion this is not a "season ender". Best case the crack can be repaired. Worst case the head is replaced.

Check this theory out.

[Garry Sharp]

OK so I took off the other manifold and it's the same. Pools of oil under the valve guides, pretty much the same amount on both sides but that's where it would collect no matter where it as coming from I think. I was thinking a cracked head on the side that wasn't running right, but maybe it is the guides. The weird thing is there was a lot of oil on the mating surfaces of the head and the metal intake gasket and the manifold and the gasket. Again, the same on both sides. I don't see how it could get in there unless the tank oil literally filled up almost the entire engine. Is that stock metal gasket what everybody is using?

Still working on it,
Garry

[BLS]

Gary,

Maybe somebody smarter than me will chime in, but I cannot see oil in that location coming from anywhere but the guides. And I cannot imagine it is pooling up while running with the velocity of air through there. I would guess you have quite a bit of oil in the valve covers when you shut it down, which then runs through the guides to pool up as you see it. Is there any reason to suspect the oil is not draining back through the pushrod tubes properly?

This issue may not be related to your engine running problem, or a symptom of it. Why do you think it is running on 3 cylinders? I read the heads were getting too hot, but is there another problem?

[Garry Sharp]

I'm not going to worry about the oil right now since it is the same everywhere. and might not be related to the rough running as BLS said. I took out the #1 spark plug and it looks like it is not firing when in the cylinder, even though it fires when laying on the head. It is clean, with gas on it and not like the other 3. Could the Pertronix ignition be intermittent in relation to the RPM? By the way, can I get the model or part # of that module FST uses?

Thanks for the advice,
Garry

[Hardingfv32]

Oil can be drawn past the rings and into the intake port by the intake flow reversion. Chance are that the over heating upset the ring pack to cylinder relationship. Might not be a permeant issue at this point.

Brian

[Daryl DeArman]

Oil can be drawn past the rings and into the intake port by the intake flow reversion. Chance are that the over heating upset the ring pack to cylinder relationship. Might not be a permeant issue at this point.

Brian

Leak down and compression numbers are good per original post which tells me that everything with the ring pack cylinder tolerances is normal at this point. Cylinder head combustion chamber cracks too.

If heat caused rings to lose tension/shape drawing oil into the intake ports, wouldn't it have burned off in short order once things returned to normal?

[BLS]

Gary,

The petronix cannot know which cylinder is firing and fail only on that one. I suppose if one lobe on the distributor cam was worn down you might have an issue, very unlikely. If you have an issue with that cyl firing, change the plug and the dist cap as those items are the ones that could effect just the one cylinder. I have seen bad dist caps (not VW) that would cause a problem on one cyl. The rotor button is unlikely to cause a single cyl issue, but I recall a situation where the combination of a defective rotor button and dist cap gap caused a problem.

Last thought, somewhere I recall reading an issue related to the spark plug grounding. It must ground in the threads/seat to fire properly. It seems there have been anti - sieze compounds that were insulators and caused an issue.

If you actually have a single cyl misfiring, it is probably not a fuel/carb/manifold issue which narrows it down to cyl issues or ignition as noted above. Since you did a leakdown and it was OK, I would bet on plug/cap issue.

One more last thought, if your cam lobe(s) was worn out you would have an issue on that cyl. Make sure the valves are opening and closing.

Regards,
Barry

[sracing]

The Pertronix ignitor is 1847A or 91847A. (The 91847A has a dwell extension in it. Overkill for a <8000 RPM 4 Cyl engine.

Yes, most are using the stock metal gasket. But there are other options: Aftermarket fiber gaskets, or NO gasket at all, just some permatex. If the engine idles decently you don't have an intake sealing leak. I have always been surprised at how well the stock setup works. (multiple time better than the old 1200 seals) While idling, spray some brake cleaner, carb cleaner, etc at the mating surfaces. If the engine responds quickly by speeding up or slowing down you have a leak..

Put the engine back together. You have no problem. You overheated. Your leakdown and compression is fine you said. You have a fouled plug at worse. A flat VW motor will throw oil (and fuel) all over the place in weird situations. Like Brian has pointed out and for other reasons. Don't borrow trouble. You are fine.

Re: Number one plug. A plug will fire with 3 or 4 thousand volts with no compression. When under even slight compression it will take 8K. The plug is fouled or the wire is bad. I seriously doubt the Pertronix is bad. It fires 2 times per crank rotation and 4 per distributor. It has no idea WHAT cylinder it is firing.

Barry beat my post. Yes, COULD be cap, etc. Do check the valve lift, but the cam would have to be almost totally flat to keep a cylinder from firing at all.

[rave motorsports]

In tearing down several motors now built by others we have noticed that the Total Seal ring is being put in the top piston groove frequently. We had always only put it in the second groove. Being new to building motors specifically for FST we questioned ourselves first so we called Total Seal. Their Tech told us it is to always be put in the second groove and not doing so can result in premature failure. Makes me wonder if that's not your oiling issue. When I get back to the shop we will discuss the misfiring issue and I will post our humble opinion.

[sracing]

In tearing down several motors now built by others we have noticed that the Total Seal ring is being put in the top piston groove frequently.

WRONG! Total seal makes at least 3 rings sets for the AC/VW 1600.

Part Number T1876 - This has the gapless ring in the 2nd groove. (Noted in Total Seal Instructions with !!!! marks)
Part Number M1876 - This has the gapless ring in the Top groove. (Noted in Total Seal Instructions with !!! marks)
Part Number CUSM-04XXX This is a special custom set that we have made. It also uses the top gapless, but has a different spacer and oil ring set.

The reason you typically want the gapless ring in one or the other (not both) is to supposedly eliminate pressure build up between ring sets. On a ACVW with low CR and a large land from the top ring to the top of the piston I would use the TOP gapless ring set. (M1876) This is what we have used most often.

[killerken53]

An old trick my dad showed me on these engines is to pull the offending plug wire at the distributor cap and just let it sit on the hole, not pushed in. The spark will jump from the cap to the wire and fire a fouled plug. Admittedly this was on an engine still running points, but it was a simple diagnostic tool.

[BLS]

What Jim said, I missed the possibility of a bad wire...

And, as the expert reported, a bad plug/other ignition problem will fire without compression pressure but not fire when compression is there.

Brian and Jim make good points, if you have a misfire other issues may result leading to a somewhat faulty diagnosis.

I'm betting it is something very simple.

[HayesCages]

...Part Number M1876 - This has the topless ring in the Top groove....

Oh yeah baby, topless rings!!

[sracing]

Oh yeah baby, topless rings!!

Typo, maybe Fruedian? GAPLESS

[HayesCages]

Maybe.
Have a friend that had the same problem (the oiling issue!) in an FV, it was from unnamed builder that went a little too far with port grinding.

[Steve Davis]

Garry,
Carefully inspect the backside (inside the valve cover) of the intake port. At our MO race a few weeks ago, a freshly rebuilt engine was POURING SMOKE and raw OIL out the exhaust. After 2 lost sessions, a tiny pinhole was found between the intake port and the valve cover resulting in exactly what you are reporting. Darken the area and shine a flashlight all over the backside of the port (in the valve area) while looking into the port itself. MO was the first time I had seen that in so many years .. LOTS, but obviously, it CAN happen.

If you DO find something like that, it should be a quick J/B weld fix I would think .. after cleaning the area around the hole, stick it on the valve side and it should stay - maybe rough it up with some coarse sand paper.

[Garry Sharp]

Wow, thanks for all the help. I now believe it can be solved. When I saw all that oil in places there should not be any, I thought it HAD to be terminal. Thank goodness there is so much experience out there to prove me wrong. I am going to replace cap, rotor, plug wires, and intake gaskets (all cheap) and start it up!

What's the best place that isn't on the west coast to get all that stuff?

Thanks for everything,
Garry

[Steve Davis]

Cap, rotor and plug wires should be available at your local auto parts place. Intake gaskets are another issue, but I'm confident that they are NOT part of the 'messy oil' situation - fix the oiling first and THEN worry about intake gaskets.

[GregSmith]

Is there good (your normal) oil pressure? If so, that much oil in the engine, assuming a dry sump, would make me wonder if there was some kind of restriction in either the return line or possibly a venting issue...

[Garry Sharp]

So I got it running right- #1&#2 were cross-sparking because of the way I had the wires routed. Now has nice 1K RPM idle and really takes off on the cam. I cleaned up all the oil everywhere, put in new intake gaskets and ran it for about a minute or so. Took it back apart-oil all over the intake gasket and down it the ports. I did the test Steve suggested and there was no light leakage from the back side of the head into the ports. It has to be the guides. The thing is, during the running in the shop, there hasn't been any blue smoke. Just so I'll know, how is oil supplied to the valve stems/guides? I was trying to make it to the Open Wheel TT at Barber next weekend for further shakedown, could I run it with this problem? There is a depression right below the guides for the oil to collect in. I'm afraid after enough running these little pools would overflow and start draining directly into the cylinder. One last question, is there a chance this situation could dissipate some when a normal operating temperature was reached?

Thanks for the help,
Garry

[BLS]

Gary,

All the oil that lubricates the rocker arms and valves is pumped through the pushrods to the topend, then drains back to the sump through the pushrod tubes. The valve guides/valve stems get lubricated by this oil supply just up there splashing around.

Barry

[sracing]

It has to be the guides. The thing is, during the running in the shop, there hasn't been any blue smoke. Garry

As Barry described that is how the valve train gets its lubrication.

Something is missing here. 1/2 teaspoon of oil will smoke for several minutes. You say you are getting it all down the intakes? It would HAVE to be sucked into the cylinders on the intake stroke. It would HAVE to then burn and smoke. LOTS.
It COULD be guides, but again you would get lots of smoke. Especially as you raced the throttle up and down a bit. (at least based upon the amounts you say you are getting into the intakes.

Are you SURE this is oil and not fuel from a carb float issue? OR....... I GOT IT !!!!

The oil sump tank level is high compared to the engine level. The oil in the sump tank will drain through the oil pump and try to find it's own level in the engine case. This COULD be ABOVE the cylinder holes. Thus., oil will get into the cylinder before you even start the engine. This oil will be blown through the guides and into EVERYTHING.

I SUSPECT this is the issue. It happens on many of the ACVW's with dry sump. But after the engine runs a few secs/minutes, the oil is scavenged from the case and goes back into the sump tank and the intakes get sucked clean. The bigger scavenge sump gears keeps it in equilibrium after that. EVERYONE probably has this same problem, but no one knows it, since no one ever bothered to take it apart just to look right after running it a few secs. You were anal enough to do it.

Again, based upon the fact that you have good compression, leakdown, 4 cylinders firing
and no intake leaks.... drive it. ...

[rgu]

Bring it to the Glen in 3 weeks.

[Garry Sharp]

How about this also, if the crankcase pressure was not vented enough (this engine is in need of a rebuild) could the valve covers get so pressurized that the only outlet is through the valve guides blowing oil with it?

[Steve Davis]

Garry,
I think you've missed Jim's point. Fact is, you should EXPECT to have oil in the valve covers on initial start (along with accordant smoke) .. however, after it runs a minute or so at speed, it should clear out. Running it at (near) idle for only a minute or so is NOT enough to overcome the amount of oil that has "leaked" (when NOT running) into the valve covers due to the TANK being higher than the sump.

Since I don't have a dry sump configuration I never see it .. and if your tank was low enough (almost impossible for a Vee .. even an FST ), it would not be an issue.

If you have a driveway or street where you can run the car at least into decent RPM's in second gear, you should be able to clear everything and confirm his diagnosis in about 100 yards or so. If it runs OK, it'll probably be fine. The more, faster, further, you can run it, the better the test. In my case, I am fortunate enough to have a nearly 1/4 mile long driveway that I can test on. It's certainly not a mile long straight entered at 60 MPH, but it's a LOT better than nothing. I have discovered more than a couple of issues there.

The really sad thing is that, if you DON'T have such a test area, you CAN likely find out less than half way through your FIRST LAP on track at your next event. Hopefully, you'll find out something positive.

[sracing]

Not idling. Maybe under load at WOT at 5000+ RPM. Your not smoking, so blowby can't be all that bad. I assume you have at least a 3/8 NPT+ vent at the oil filler and probably more? I have two 3/8" NPT vents on my engines. No oil blowing around. (Of course I have never looked in my intake runners right after a short run. . ) Might be oil in there for a few seconds after startup, but I am not going to look.

You say the engine is in "need of a rebuild". Based upon what? Oil pressure?. Your leakdown and compression sure don't indicate that.

And Steven is correct. But typically you will get the sump tank full (and the engine case just about empty) by running at 2000 RPM or so for a couple minutes. I still think that is your only issue. IE. The case is filling with oil.

What often happens is the case sits for a week (or an hour) and the owner opens the sump tank to look at the oil level. It's LOW. (The oil has simply run back into the case.) Now the owner adds another quart or two. Looks good. But, lots of oil is now in the cylinders) Then it gets started and blows oil everywhere. The scavenge gear takes oil out of the case and adds an extra quart or two to the sump tank.

Procedure is to start the engine watching the OP. Run it for 20 secs or so at a high idle. Shut it down. Immediately look in the sump tank. It should be just below the top windage tray. or screen, de-foamer, etc. That is it. DO NOT LOOK in the intake runners. I don't know what might be there.

[Garry Sharp]

OK. I'm putting it back together and not looking in there again.

Thanks for all the replies, I learned a lot.

Garry

[BLS]

Thanks for all the replies, I learned a lot.

Just got in and read the latest. I learned something new as well, never even considered a dry sump level draining back. Seems very plausible. Thanks Jim!

Barry

[sracing]

On my Porsche, if you park on a hill just right, it does the same thing. Smokes for about 2 or 3 seconds.