Head Gasket Part III: the plot thickens

[NoTheOtherMikey]

As detailed in Part I and Part II, I overheated my '84 944 and blew a head gasket. I put a rebuilt head on (thanks Bennington Motorsports) and tried to start it. No start; no compression in cylinder 4.

Just pulled it back apart. Much quicker the second time.

I found that each cylinder had some water in it but that cylinder 4 was chock full. The car HAD NOT STARTED and it fired only a few times in an effort to start. The head gasket was intact.

Is is possible/probable that the water got into the cylinders from the water jacket when I pulled it apart? I drained the radiator before starting this but of course there was still plenty of water in the jacket. There's no other evidence of damage to cylinder 4 or to any other cylinder for that matter. Bores are smooth.

Back to the no compression problem, looks like the exhaust valve on cylinder 4 is not seating properly. Could be bent or could just be misseated.

I'll fix the valve and put this back together, but I'm wondering if I'm just doing something wrong or if there's some problem with the block. I have been following Clark's Garage instructions to a T.

Frickin' water cooled Porsches.

[Techno Duck]

How badly did the car over heat? Check the block mating surface for flatness. Some water in the cylinders from pulling the head is normal, but not more than a few teaspoons worth if you drained via the radiator.

Are you sure you had the timing marks on the cam / flywheel set correctly the first time?

[NoTheOtherMikey]

It overheated pretty good. Just checked the block with a straightedge. Didn't see any obvious signs of warping checking multiple directions. Would it be more likely to cup (lower in the middle) or bow out (higher in the middle)?

Timing was correct when assembled. Torque on head was correct and done in stages, etc.

Any further tips on checking the block for warping?

[Techno Duck]

I would use a combination of a high powered flashlight and a piece of notebook paper to check for gaps. Check to see if any light makes it past the straight edge, or use the paper to try and get it between the block / straight edge. I forgot what the accepted value in the book is but its probably something like .01mm, can use a feeler gauge also.

The longer the straight edge the better. Its honestly not a great test on the 944 block due to the open deck.. more suitable to an engine with a closed deck. But if done carefully should be enough to tell.

[NoTheOtherMikey]

I think the block is warped. So I guess I'm going to get to learn how to pull/rebuild the motor. More than I bargained for but it'll be a good project.

Guess I'll need an engine hoist and stand. Harbor Freight, here I come.

I should remove all accessories before unbolting motor and pulling it out? Or is there a shortcut here?

Thanks for all the tips.

[NoTheOtherMikey]

While I have it out I'll rebuild the bottom end, do rings, etc. I should also baffle the oil pan? Anything else while I'm in there? Don't want to spend more than I need to but then again I don't want to have to do this again.

[NoTheOtherMikey]

One more question: how much of the pollution control stuff can I strip? Want to keep it legal for Spec 944 racing.

[nynor]

Originally Posted by NoTheOtherMikey

I think the block is warped. So I guess I'm going to get to learn how to pull/rebuild the motor. More than I bargained for but it'll be a good project.

Guess I'll need an engine hoist and stand. Harbor Freight, here I come.

I should remove all accessories before unbolting motor and pulling it out? Or is there a shortcut here?

Thanks for all the tips.

how is rebuilding going to resolve a warped block?

[Dean924s]

Originally Posted by nor

how is rebuilding going to resolve a warped block?

During the machining process you have the block decked / skimmed. It may be better / cheaper to look for a good used block. I would even consider looking for a complete used long block. In the long run it will probably be cheaper and easier / faster. IF you then want to rebuild your motor for future use go for it!!!