Massive carbon(?) buildup in #2 exhaust port

preston_brown · preston_brown's Garage

Guys,

I've just removed my heat exchangers (no broken studs! Yay MAPP gas!) in order to remove the hard oil line that goes to the case and complete my engine resealing project (I messed up this oil line so I need to replace it). Most of the exhaust ports seem to have a fair amount of carbon in them, but this is the #2 exhaust port and it is the WORST of the bunch. Do I need to be worried about this? Do I need to do anything about it?

Car felt like it was running fine before pulling the motor.

911pcars · 03-18-2007, 12:30 PM

Typically, worn valve guides. Sometimes, worn valve guide seal. I think your MY engine may have valve guide issues.

Sherwood

DUK · 03-18-2007, 12:33 PM

My 3.2l had the same thing and I found a cracked intake gasket on the same cylinder. May be why it's shows lean on that cylinder also. Just my .02.

preston_brown · preston_brown's Garage

Well should I freak out and deal with this now? I really just wanted to button it back up and keep driving. Can I clean it up and live with it? The motor isn't burning much oil and isn't smoking. I am replacing all the intake gaskets.

zbph10 · 03-18-2007, 09:32 PM

My heads looked like a lot better than that and I still sent them off to get redone by Henry. Unlike you though I had to take the heads off anyway to fix broken head studs.

For me it was a piece of mind issue.

You've gone this far, I'd do the guides. (Easy for me to say)
Taking the cams and towers off wasn't a huge deal, putting it back together and timing is a little tougher.

Once you do the guides then you'll think to yourself "Maybe I should replace the rings since I have it this far" and "Are those Dilavar heads studs?" "I'd better replace those too"

We've warned you about this
Good luck

Brian

randywebb · 03-18-2007, 09:45 PM

You've gone this far....

john walker's workshop · 03-18-2007, 09:45 PM

chip it out carefully and run it until a problem arises. obviously it's using oil in that cylinder, most likely down the valve guide(s). a fouled plug should follow soon enough. it's not like you really have to tear it down right now.

Rot 911 · 03-19-2007, 05:19 AM

John W definitely knows what he is talking about. On the other hand you might want to do a leak down test on the engine. I had a very strong 3.2 engine that when I did a leak down test was showing 80% leakdown in one cylinder. Turns out I had a burnt valve that was so bad it had major cracks in it. Don't want to sound like an alarmist, but a leakdown test is cheap insurance.

By the way after I discovered the bad leakdown I rebuilt the engine. All my head work was done by John W. I live in Missouri, but I trusted him enough to ship my heads all the way to Washington state to do the work.

notfarnow · 03-19-2007, 05:36 AM

OK, help me understand:

JW says if it's running fine, just clean it up and drive it... but watch for fouling plugs.

A leakdown test would only show a problem if the valve was so loose it wasn't seating, or if it was cracked. Correct?

john walker's workshop · 03-19-2007, 07:09 AM

you can get a high leakdown reading for anything from carbon between the valve and seat to a hole in a piston. anything that causes the incoming air pressure to leak out, not just a valve problem.

preston_brown · preston_brown's Garage

I'm going to chip it out and run it, thanks for the reassurance John. I know the solution isn't 100% ideal, but I want to get the car back on the road. If smoking starts to get bad or oil consumption goes up any higher, at least I'll know what's going on.

I'll keep an eye on this.

JeremyD · JeremyD's Garage

Well, I posted to this but if did not go through. I'd button it back up and drive it as JW recommended.

I would also keep a close eye on oil consumption - and the plugs at every 2-3000 miles.

I would also start an engine rebuild fund and start collecting parts and $$.

preston_brown · preston_brown's Garage

Here are pictures of the plugs from that side of the engine:

The right side bank (from left to right, #1, #2, and #3):

#2 plug:

What do you think? Clearly a bit crusty and oily, but fouled?

Rot 911 · 03-19-2007, 05:35 PM

How much oil you burning?

preston_brown · preston_brown's Garage

Hmm, like a quart every 1000 miles? Maybe a little more, like 800 miles?

Any other pictures of areas I can offer up in order to diagnose my current state of affairs?

scottb · 06:00 PM

What about chipping off as much of the carbon as possible, and then giving the engine a Sea Foam treatment in an effort to clean it out more?

Sea Foam Web Page

john walker's workshop · 03-19-2007, 06:18 PM

often the plug will look like the port, given enough oil flow. it crusts up thick and eventually closes the gap.

Early_S_Man · 06:59 PM

3.2s are often known to have worn intake valve guides, and oil from that source would end up being burnt in the combustion chamber and building up on the spark plug. But, if the exhaust valve guide is what is worn, and the source of the buildup in that port ... then it would never get into the combustion chamber to be burnt -- it would buildup on the underside of the valve, just like this pic.

I suggest trying to determine play/wear of the exhaust valve in the guide at 10 mm lift ... you don't want to let it go until the head of the exhaust valve breaks off and destroys the engine!

sjf911 · sjf911's Garage

Why not disassemble the #2 head and inspect the valve guides/stems for wear? You are already 95% of the way there. I would think the risk of dropping a valve later on is not insignificant if there is major wear that is not detected.

DanielDudley · 03-20-2007, 02:54 PM

See all the black stuff on the valve stem ? I'll bet that if you do a compression test it will test out fine. Some of the strongest engines I have run ran oil out the exhaust guides. If you have good compression, bolt it back up and start saving your pennies.

I'll bet the PO would fire that puppy up and hammer on it as soon as he got out of the drive.