ShApE

O-ringed is when a machinist cuts a groove around the top of your cylinders, and installs steel or copper O-ring in the head around the combustion chamber that protrudes enough to fit into the groove that was cut into the cylinder. Yours block was definitely O-ringed if you look at the top of your cylinders you will see a groove cut out.

ShApE

And there is somewhat of an argument about if a MLS headgasket can be used with an O-ringed head/block. Some people say they have done it with no problems, others say its not a good idea and wont seal well.

333pg333

Well spotted.

951_RS

First rodeo or not cowboy, your block was definitely o-ringed
Did you get to see how high a spike in psi you saw before the HG blew

Josh B

I could be wrong but I am pretty sure the headgasket in those pictures is not a widefire one? The metal ring doesn't look any wider than stock?

rlm328

You mentioned that you over boosted, do you know what your final boost number was? Usually when the vacuum line to the waste gate breaks or gets a hole in it the maximum pressure it will boost to is the spring rating, which in most of our cases is around 11 psi.

The number 4 piston where your gasket blew has a steam lock issue in the cooling jacket, which may be the actual culprit. While you have the head off you may want to look at putting in Lindsey's Steam Vent Line. This will drastically improve your cooling efficiency as it helps eliminate the cooling lock issues. You also don't have to worry about bleeding the system as it is self bleeding after installation.

Since this is your first Porsche rebuild get very friendly with www.clarks-garage.com as they have pretty good instructions on everything you are about to do. The heads in particular need to be torqued in a certain sequence and if you do not do them in the designated fashion you do so at your own peril.

As for being o-ringed, that looks like gasket debris to me.

JohnKoaWood

That was his block, not his head, but I am sure that was what. you meant..

And yes. It was o-ringed at some point.

951_RS

Well, if he had it in dual port configuration and the side port came off the pressure would be pretty high on both sides of the piston. Whatever exhaust pressure he produced would be on the exhaust side of course, and on the top he'd have intake pressure plus spring pressure. That could make for some really high boost if his turbo is efficient enough to have a halfway decent intake to exhaust pressure ratio.

JohnKoaWood

Who is arguing?

From http://www.cometic.com/faq.aspx#q3

"Can MLS head gaskets be used with motors setup with o-rings or receiver grooves around the cylinder bores?
No. MLS head gaskets require smooth, flat and true head and deck surfaces to seal. Most of the time with o-ring setups the wire and groove fall where our gasket’s combustion seal is located; therefore, the wire will hold the gasket and not allow proper compression while the receiver grooves allow combustion gases to escape."

They make the gaskets, so they should know if it is OK to use with O-ring grooves.

951_RS

Look, just cuz Im' a drunk doesn't mean you gotta follow my every post and make me look stupid!
If you're not careful I'll start typing like gt37vgt

JohnKoaWood

Sad part is I posted that from my Driod while looking out the window...

951_RS

Youch, well, I could pretend I posted it on my iphone with a cracked screen while doing a keg stand, but you'd see right through that, wouldn't you

reno808

john lol

fast951

What is the history on the head, was it O-ringed. Or a O-ringed head was ever used on this engine?
The groove on top of the cylinders look a bit too wide and too shallow for a O-ring, however it looks like a matching groove for a O-ringed head (tongue and groove setup).
If the block is not O-ringed but has a groove. It's best to O-ring the head to match the groove. When a O-ring is used, it's best to use a WF gasket. The HG failing might have saved the bottom end.

Before installing the head, turn the engine a few times, make sure all the pistons are traveling the same distance. At least eliminate any possibility of a bent rod before assembling the engine.

Some sort of overboost protection would have helped the engine. When upgrading the turbo, you need to address the tuning side as well. Let me know if you have any questions.

DDP

If you can, post some pictures of the head and the turbo that is currently on the car. That will help us help you.

Why not just rebuild the current turbo you have? If it makes the power you're interested in, I would stick with it. This is going be more money then you're expecting, I can tell you that much. And I would stray away from the GT35 idea, it's probably a bit more then you're willing to take on right now. If you're interested in why, you can do a quick search on it.

A good place to look for gaskets and seals is www.paragon-products.com. I wouldn't change the headstuds, they're more then fine to reuse. Depending on what the situation is with your o-ringed head/block, you're probably going to want a widefire headgasket. It has a thicker compression ring that works well with an o-ringed head or block.

Also, before you get crazy with upgrading the turbo and what not, you should look into a good boost controller, cat-less exhaust, wastegate, injectors, etc. and most importantly a good tune. The tune will make or break your car.

Good luck.