Oil from spark plug hole, smoke at startup only

[bajcsi]

Hello all,

I'm having a frustrating problem and I wanted to get some opinions. I've searched quite a bit but haven't found anything that either I haven't tried or was relevant. That back story: I have a built 3.1L stroker (not done on the cheap) with E31 head running somewhere north of 11:1 compression. The most runs well with good compression across all cylinders. The head has had a sigfnificant amount of work done. Another piece of infromation is that it has a timesert in sparkplug hole number 3 due to an issue with the head that predates me. I'm running triple webers and Electromotive HPX ignition.

I AM running PCV, as using advice from Tony D I created a vacuum log with a restrictor on one end for the PCV valve (mounted to a grommet which is mounted where the pipe once was all pressure fit). So I THINK I'm exacuating pressure from the crankcase. I have no other leaks that I know of.

Engine mileage is 1200.

Onto the issue:

Symptom #1: On cylinder number 3, I have a small amount of oil coming out of the spark plug hole while the engine runs. As I drive, it slowly works it's way down the side of the block and makes a mess of things.

Symptom #2: When the engine starts after sitting for more than a few hours, I get a greyish smoke while I idle. Once I drive off into the sunset, the smoke dies off and doesn't reappear until the car has been off for several hours.

Things I have checked:

• Valve Cover Gasket - it doesn't leak and the oil clearly originates from the spark plug hole.
  
• Spark Plug Torque: It's well torqued, but even it if it wasn't, you would expect something other than oil to escape.
  
• Valve Seals - I replaced them last night and the problem persists.
  
• Ignition - the plug is firing correctly, so I wouldn't think it's unspent fuel coming out.
  
• I'm not running overly rich either, 12.5 at idle. 13ish -.13.8 at WOT on the idle/progression circuits and 13.0ish on the main circuit.
  

And now on to what's left for my theories:

• Head cracked - Lord, I hope not.
  
• Oil passage nicked - Along the above lines, do the oil passages run anywhere close to the spark plug holes that a timesert may have affected.
  
• Oil passage nicked - I assume there is way too much metal in the combustion chamber that the machine shop doing the head work could have gotten close to oil passages?
  
• Bad oil control rings - If I had a bad oil control ring, would I not be BURNING oil consistently rather than for a few moments at startup (aka like when you have bad valve stem seals)? Also, would it be possible for oil to find it's way all the way up the cylinder wall and out a spark plug hole?
  
• Bad head gasket - I have an HKS 1mm head gasket on now. The problem existed with an HKS 2mm head gasket as well. Using ARP studs torqued to spec.
  

Of all those, I would prefer one of the last two to be the case even though I don't relish pulling the engine anytime soon. The oil comes out clean with no antifreeze or anything else in it when drained. The antifreeze looks good.

Thanks,

Brett

[Mark Maras]

Hi bajcsi

I'm not familiar with the item called a timesert. Assuming that it is a thread insert. I'm guessing that the insert is leaking between the insert and the head. If #3 is leaking and #3 was repaired, I think you will have to redo the thread repair or replace the head.

Anyone else with an idea?

Mark in Portland

[EuroDat]

A spark plug shouldn't be leaking like that past the threads.

Have you done a compression test? You could also try a leak down test. Its easy to do yourself if you have a compressor and a fitting for the spark plug hole.

I made a fitting for my engine by punching the guts out of a used spark plug and screwing a hose quick connect fitting into the back of the spark plug body.

To do the test: Rotate the engine to TDC on that cylinder, put the car in 4th or 5th with handbrake on.

Use the compressor to pressurize the cylinder and check (listen) for leaks at the filler cap, exhaust pipe and inlet manifold.

Check a good cylinder first to have a reference what it should sound like, you will hear some leakage, but thats normal.

That could help you find something.

Chas

[Zed Head]

Seems like you're not really sure that the oil is coming out of the "hole". More that the spark plug well is filling up and overflowing.

If the oil is coming from inside the cylinder you would expect the spark plug to be fouled or dirtier than the others. Have you pulled the plug and compared?

The only oil passage in that area is the one straight passage from the block up to the cam shaft towers. It's drilled so it's straight and I think that you can see the outline of it's location on the outside of the block. It runs between 3 and 4. If a large timesert was used maybe it is possible that they nicked the passage. You might be able to pull the timesert and replace it with another but with better sealing.

If the oil was coming from the passage between the block and head the spark plug well would not fill up. It's not uncommon for the head gasket to leak there.

BUT, the simplest thought is that the timesert is standing "proud" of the head, with a poor sealing surface for the spark plug base, and you have a compression leak. Fuel and oil vapors, and combustion byproducts are leaking out and condensing, filling the well and dripping down the block. Pull the plug and check the plug sealing surface of the head.

[gnosez]

Or oil is really leaking from the valve cover gasket and into the well.

[ajmcforester]

Pull the plugs, if the oil is getting in the cylinder will see it on the plug. You can tell a lot by looking at the plug, maybe post pictures of the plug. If the plug is dirty then do a pressure test. My concern is the plug repair nicked the oil gallery. The good thing is were dealing with a aluminum head so if cracked it could be repaired

[bajcsi]

Hey guys,

I did check the plugs, and they don't appear oily. I'll have to pull again tonight and take a picture. Regarding the thread repair, I farmed it out to a second machine shop port matching my intake to my head. Per the suggestions, I'll see if I can determine if it appears to be more of a thread/plug sealing issue which I imagine I could check by seeing of the ID of the timesert shows signs of the same substance as is leaking. If not, then I guess that means it's coming from the OD where it seals to the head.

See the below attached photo. I'm very confident it's not coming from my head gasket. My engine is pretty clean (other than this issue) and I would have noticed that... probably... maybe.

I built the engine with a 1mm headgasket in mind, but did the initial tuning with the 2mm in place. I have done compression tests although not since installing the 1mm gasket, I'll do another to make sure nothing has changed. But my last numbers when I still had the 2MM headgasket on it were:

#1 230

#2 230

#3 215

#4 240

#5 240

#6 230

I had to dig those up and looking at those it does support Zed Head's thought that I have a small compression leak, and given the cylinder and symptoms probably due to the thread repair. Does the oily substance look like oil to you guys or just general combustion byproduct/unburned gass/etc?

I appreciate everyone's input on this. I wasn't able to dig into this last night - I have twin 1 year olds, my time is tight! But I should be able to dig in and start checking everything. I'll redo the compression test and do a leakdown test as well.

Thanks,

Brett

A spark plug shouldn't be leaking like that past the threads.

Have you done a compression test? You could also try a leak down test. Its easy to do yourself if you have a compressor and a fitting for the spark plug hole.

I made a fitting for my engine by punching the guts out of a used spark plug and screwing a hose quick connect fitting into the back of the spark plug body.

To do the test: Rotate the engine to TDC on that cylinder, put the car in 4th or 5th with handbrake on.

Use the compressor to pressurize the cylinder and check (listen) for leaks at the filler cap, exhaust pipe and inlet manifold.

Check a good cylinder first to have a reference what it should sound like, you will hear some leakage, but thats normal.

That could help you find something.

Chas

[bajcsi]

Oh, there is usually a bit more. I had wiped it the other night and didn't run the motor this morning before taking a photo.

[ajmcforester]

When you pull the plug is the oil on the threads going into the head and if so how far? If the oil is coming from the cylinder you should find oil on all the threads if not then it something with the head.

The compression should read within 10% of average your a 6.5% to 8.5% depending how you take the average. The high side is a little high, but is what is considered accessible. EuroDat was recommending a leak down test this might not be a bad idea exspecialy if you find oil on all the threads. Basically it gives you an idea of how much the cylinder chamber seals up.

Also I was looking at your picture. It does not look like the repair method I like. Please take picture of the hole when the plug is out. I hope they did not use a heli-coil (sp?), that would explain a lot.

Lets hope it is the threads. The good thing is their are some kits for repairing threads and even putting in thread seats without removing the head or the engine. The kits use a die that and drilling bits that slide into the plug hole the screw out to keep things from falling into the engine. I've help or installed about 4-5 plugs and used dies to repair about 15-20 holes.

Also I recommend using anti-seize on the threads, especially with aluminum heads this will help in keeping the threads from getting damaged so you don't need to make repairs like you had to with this block.

[bajcsi]

Howdy AJ,

I'll be able to dig into the motor a bit tonight. I'll get the additional pics, run the leak down, etc. As for the repair, it's not a helicoil. I BELIEVE it's a timesert (++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair,) but can't say for sure without checking with the machine shop again. Regardless, I'll get the pics, check the threads, etc. Thanks for all the good feedback and suggestions.

Brett

When you pull the plug is the oil on the threads going into the head and if so how far? If the oil is coming from the cylinder you should find oil on all the threads if not then it something with the head.

The compression should read within 10% of average your a 6.5% to 8.5% depending how you take the average. The high side is a little high, but is what is considered accessible. EuroDat was recommending a leak down test this might not be a bad idea exspecialy if you find oil on all the threads. Basically it gives you an idea of how much the cylinder chamber seals up.

Also I was looking at your picture. It does not look like the repair method I like. Please take picture of the hole when the plug is out. I hope they did not use a heli-coil (sp?), that would explain a lot.

Lets hope it is the threads. The good thing is their are some kits for repairing threads and even putting in thread seats without removing the head or the engine. The kits use a die that and drilling bits that slide into the plug hole the screw out to keep things from falling into the engine. I've help or installed about 4-5 plugs and used dies to repair about 15-20 holes.

Also I recommend using anti-seize on the threads, especially with aluminum heads this will help in keeping the threads from getting damaged so you don't need to make repairs like you had to with this block.

[tlorber]

I definitely concur with the leak down test. This should tell whether you are leaking past rings vs. valves. I had once had a car that burned oil only on startup, and it turned out to be the valve guide seals. However is sounds as if you have already replaced them.

While the threads may be seeping oil (in which case I'd think you would hear exhaust gas escaping on compression) that still would not explain how oil is getting INTO the combustion chamber. Please keep us informed.

[ajmcforester]

OK that what they call them. I have heard the mechanics at work complain about them. That is why they like to run the spark-plug down to nothing to avoid risk of damaging the Triton heads. I asked what the problem they have with them. They told me that if the new threads that the sert threads into the block are not perfect it would leak or blow the spark-plug out all together destroying the head (we are talking about triton V8 heads not E31 heads so I don't think were going to blow up a head). They also stated they are a pain to get out unless the plug rips through the head.

Well I guess I should not make you worry anymore until we get more picture and testing done. Honestly I'm hoping it is the sert, because that can be fixed without taking the engine apart.