[Cloud9...68]

Drat! I already tossed my broken maple ones (I think...), seeing as we already have plenty of firewood <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" />

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[mbardeen]

Two years later, I've finally gotten around to pulling the head to replace the head gasket on my car.



I saw no definitive evidence of a blown head gasket, though to my unpracticed eye, it looks like it has seen better days. I'm posting the photos here (clicking on them will take you to Flickr where you can see a higher resolution version) in the hopes that someone with more experience eye will look them over and let me know if they see anything unusual.











P.S.

And since I evidently can't put more than one image in a post (WTF is up with that?)...

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[mbardeen]

As I'm comparing the two gaskets, I note that the old gasket has many more holes than the new one, and these holes are where water jackets are on the block. I'm 90% sure this is a "casera" gasket -- one made by a chilean gasket shop. So I wonder if those holes would signficantly affect up the coolant flow through the engine?

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[MB968]

If the new head gasket doesn't have holes that line up with all the holes in the head, I wouldn't use it. I don't know for a fact, but one can assume all those extra small holes are coolant flow holes. You wouldn't want to block them.

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[mbardeen]

I've checked images of other 968 gaskets online, they don't have those extra holes either.



p.s. new head gasket is from a Victor Reinz cylinder head gasket set.

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[flash]

are we sure that's a 968 head, and not a 928 head?

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[flash]

this is what the head should look like



   

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[mbardeen]

Part number cast on the head is 944.104.414.1R..



This PDF seems to indicate that it's an original or remanufactured head for the 968 -- http://www.texas912.org/912E%20Tech%20Da...ts912E.pdf

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[banditsc]

Does the head also have the holes drilled around the cylinders like the gasket?

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[flash]

part number should be 944.104.054.00

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[mbardeen]

Ok, here's the shot of the cylinder head stripped of the gasket. Flickr has the original high-res image if you need more detail. As best I can tell it seems to match up with Flash's image.





Cylinder head bottom by mbardeen, on Flickr

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[banditsc]

Ok, so it seems you had the wrong head gasket in there, which was actually blocking off water jackets, which was probably why you were seeing issues. And actually by having those extra holes drilled in it, it was opening up coolant flow to areas it shouldn't have been, which would probably explain the white smoke. It would make sense if they didn't have the proper head gasket and decided to break out the drill to alleviate that issue that they would drill into all the areas that had an opening on the head. They should have used the old gasket as a model and not the head.

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[banditsc]

Also looking at the head without the gasket it does look like coolant was making it in between the cylinders, right down the center line of the head. The valves looks to clean to not have been steam cleaned, or had the head off early and refreshed.

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[mbardeen]

The head has definitely been off at some point in the car's past. There's spanish writing on the underside and the intake and exhaust gaskets were dubious at best (grey RTV for the intake, red RTV for the exhaust). Also, the head was relatively clean while the block was pretty grungy.



How recently this occured is anyone's guess.



The clean part of the head is just where there was the steel ring of the gasket and no actual gasket material, so nothing stuck to it. There's no coolant passages between the cylinders in that area.There is a small black burnt mark on one of the steel rings, that definitely looks like a potential leak candidate, but that is in between the cylinders too.

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[94'968]

valves look different to me... my head is off right now and the valves do not have those concave centers on them. mine look identical to the ones in flash's picture.

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[mbardeen]

Damn.. you're right. All the photos I can find online show the flat valves.



Where's that emoticon for banging your head against a brick wall?

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[Cloud9...68]

My valves look like the ones in Flash's picture as well. How strange...



Oh, and ask and ye shall receive:

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[mbardeen]

Indeed, those are surely some generic valves dropped in after some <acronym title='previous owner'>PO</acronym>(S) neglected the timing belt and realized how much genuine P-valves cost. So now I'm wrestling with the choice: do it right or bolt it all back up, forget I saw them, and sell the car before I remember?



The cost of doing it right is $300 for the valves and another $++ for guides and whatever else needs to be done. On the other hand, the car was running with the current valves.





I've thankfully confirmed that the pistons are correct, so it seems the chilean mechanics didn't get that far down in the engine.

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[banditsc]

Ya, not sure what those valves are, they don't look like stock 968 valve. The 16v Euro 928 heads had dished valves like that, but I think those are the wrong size.

The dished valves would lower the compression some, not much though, doubt it would be noticed. Might help with the hotter climate and lower octane you might see down there.

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[mbardeen]

I picked up a cheap spring compressor today so I could get the valves out and give them a good inspection. The good news is that the shaft size is spot on, in fact, it looks like they've been machined down to the correct size.



The bad news is that the worn seal area for the intake valves is less than 1mm wide. For the exhaust valves it's a bit larger, around 1.5mm.



I'm going to go ahead and get replacement valves all around. Should I take the opportunity to refresh the springs at the same time? Supposedly the car has 68K miles on it, but I don't really believe it. If I had to guess, I'd say it was 100K+ mile car.

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