TheRealLefty

That funky water jacket galley place in the head gasket? Seems our steeds are double cursed. #2 loses rod bearings from oiling and #4 loses compression at corner of gasket. Will be interesting when you pull the head. I'll place a friendly nickel wager on a head gasket burn through at the #4 cylinder, albeit a big one Better that than harder parts, eh?

Chris White

OK, I am missing something here – does it run on just 3 cylinders? Make a kind of ‘chuffing’ noise while running? From your description it sounded like it was not running too badly (not possible with that low a compression on 1 cylinder).

Sounds like a valve – burnt, bent or just held open by a bunch of carbon….
This is a good thing as far as price to fix goes (compared to rings)!A burnt or bent valve will make a ‘chuffing’ noise as the air leaks past the valve back into the intake during the compression cycle.

BTW – nice guess on the head gasket – the problem with tat is he should have spit out a lot of antifreeze and also due to the resistance of the coolant he would still get a measurable compression at crank over rpm.

Chris White

PS - valves are pretty cheap!

Charlie944

Chris, it does run on 3 cylinders, and not all that horribly either. I know when I was driving home after the initial grey-black smoke show the car would still idle (although rougher) and accelerate under light boost. It does make a "chuffing" sound, and for a minute I though I sprung an exhaust leak where my muffler is attached. I do concur on the HG corner #4 being a nice guess. I have not gone through any coolant and I have found not traces of coolant/H2O in my oil either.

I much rather contend with valves than rings and re-boring/Alusil treatments, etc.

I could have the head off in a day easy, but what do you all think about upgrading the clutch/PP? Pull the engine and do the head (possibly more) and clutch, or leave engine in and do the head while yanking the clutch the traditional way? I have no A/C and manual steering.

Thank you all again for the insight and conern. I will keep you all updated!

Chris White

yep, its a burnt or slightly bent valve....take it apart.
Not worth pulling the whole engine, just the head.
Clutches are better done from the rear forward.

Chris White

Charlie944

I have the intake off now, and will proceed with the head here today. I am planning on installing a WFHG and some ARP studs. Where is a decent place to buy the studs from? Also, is it worth it to get a completely rebuilt head...I found one with all new components for $300.00. Plus I can still keep the existing head. What do you all think?
Again, thank you everyone for your help...I will keep you all updated and post some pics.

TheRealLefty

Good luck, Charlie! Keep us posted, pix expected

Charlie944

I have removed the head finally here to discover a hole in the #4 cylinder's exhaust valve. There was the leaker! All the bores looked great with no ridges. Pistons looked good as well, and I did not even clean them in the pics. The WFHG looked great as well, no burn spots or deformation, although the highest boost I ran was 1.0 bar over atmosphere. I was fortunate not to have any bolts or studs break or have to cut anything off. I tried to pull the head with the exhaust manifold and turbo still attached, but the turbo was hitting the body. Hence I had to unbolt the manifold and pull up on the head while the exhaust tilted downward. After the head was removed I then picked the manifold/turbo up and out. Hopefully, it will go back together a little more smoothly. When breaking the head nuts loose the upper stud by #1 came out to, do I need to use locktite when putting it back in, and are they tightened just finger tight? Also I have been researching on what head gasket to run, and I would love a MLS, but the coolant/oil leaking some folks are having is disconcerning. The head will be fresh, but I am not touching the block other than cleaning the mating surface. What do you all think? The highest I may go is 16 or 17 psi of boost with this turbo. An upgrade may be in the future if I can fit a larger one down there. I plan on reusing the stock head studs, but is there a need for getting new nuts and washers? I will clean up the orig washers up with some ScotchBrite real quick though. Unless there is a need to go with ARP's. Also, I was wanting to get the manifold heat coated by SwainTech.

Thank you all again for the help and insight. I will post more pics as the adventure continues.

Charlie944

A few more I just took:

Charlie944

one more of the other 3 combustion chambers:

Tom M'Guinn

Are those Alusil bores? They look so dark and shiny. Pistons are remarkably clean. Interesting exhaust/turbo set up. As for studs, the factory used red loctite. You should measure the height of the other studs, and install the loose one to that height. Good luck.

Chris White

Classic burnt valve. Take a close look at the hot side of the turbo to make sure that there was no damage from the molten metal flying through the exhaust.

Chris White

Charlie944

They are Alusil bores, and I was surprises as well how clean the pistons were! Would it be wise to replace the damaged valve, or to get the whole head refreshened? I will also inspect the hot side of turbo to see if the metal debris caused any damage.

Zero10

If you have a valve replaced, you need to re-seat the valve, which would usually involve at least lapping the valve seat. Not a bad idea to have the head gone over while you're in there. I forget, are you running a 951 head? If not, that's why you melted the exhaust valve.

hosrom_951

Charlie/Chris: I am interested in how that valve got to that condition.

Peckster

Right, you have to find out why that happened. I can't recall hearing of anything like that happening here. Possibly running too lean would do it.