Head Gasket - leaking

Howdy y'all - Thought I would pick a few brains (lol). 73 911E - ran a compression test with the following results:
#1 200, #2 145, #3 195, #4 210 #5 180, #6 195
Obviously #2 has a bit of a problem: leaky head cylinder (evident "cough" on hard accelleration and rough running - even after my recent tune up) The question is:
Should I bother having the head tightened as a temporary mend? or should I wait (budgetary constraints) and have the engine taken out and new gasket put in (obviously a few more hours of expensive NY - Porsche technician labor)? Also - do I run the risk of damaging anything if I continue to run it as is until the fall?

Regards as always,

Bruno

The leaking cylinder may be the result of something much worse than just a 'loose' nut! It could be from a pulled or broken stud ... even 2.4 engines can have broken studs from corrosion, or pulled from excessive heat damage to crankcase! Rat, mouse, or insect nests can cause extreme cylinder overheating because of blocked airflow!

If you look in Bruce Anderson's 'Porsche 911 Performance Handbook' you will find pictures illustrating damage to cylinders and heads caused by continued operation with broken/pulled studs. Under NO CIRCUNSTANCES continue to drive normally until the fall!!! I seriously doubt if your engine will survive the summer, unless you confine your driving to short trips of 20 minutes or less!

Your #2 cylinder head may already be damaged, as flame cutting can occur very rapidly after the head audibly starts 'slapping' against the cylinder! Minor damage can be repaired by milling the head sealing surface, but that will not be possible if you drive it all summer, I assure you. Good luck.

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Warren Hall
1973 911S Targa

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 05-05-2000).]

73 911E - ran a compression test with the following results:
#1 200, #2 145, #3 195, #4 210 #5 180, #6 195
Obviously #2 has a bit of a problem: leaky head cylinder (evident "cough" on hard accelleration and rough running - even after my recent tune up) The question is:

If you did a compression test and NOT a leak down test your heads maybe fine, BUT you may have a problem with the rings? piston? or cylinder?

What you need to do is drop some oil in the cylinder and see if the compression rises, if it does you got a problem, if it does not rise then do a leak down to test the heads to see if the head studs have pulled.

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Yes, it can be a broken ring gland or ring and if the piston comes apart which is aluminum JUST think of all that metal floating around YIKES!
or
If it is a pulled head studs the cylinder is boucing into the heads and the case because it is loose and it will damage the faces including if it is really bad make the piston skirt angle and can break a skirt more $$$$

No matter what have it checked, but one main question how many miles on this motor?????

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Bruno>>

Anytime Bruno

Roy at http://www.motormeister.com

Roy - thanks for the input - the motor was rebuilt in 1997 by a fellow porsche fan (he races and is a visible member of the CVR porsche club) it has approx 20k miles since rebuilt. I have to assume new head studs and I know he put new pistons and rings as well.
One thing as well - he upped the cr to 9.5:1. I don't know if this helps (sometimes i feel silly knowing so little)

Bruno

Oh and it was just a compression test (not a leakdown)

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Low miles

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The head studs will not be a problem, you have Birol or cast iron cylinders that do not have the expansion rate like the 2.7s-3.6s, BUT, you WILL pull head studs if the case was not time serted correctly and spigots where not machined correctly

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Did he fly cut the heads to get this type of compression?

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The leak down is the key of pulled head studs or problems with heads, compression is the main test for problems with P/L or rings

Roy at http://www.motormeister.com

If I EVER take the heads off my engine, it WILL get Dilivar studs and probably timecert inserts. Even though mine's a 3-liter. It seems silly to not do this at rebuild time.

It sounds like your motor should come apart soon, even if it's just for head gaskets. I think Warren is warning you that the heat passing between your heads and cylinders will cut them like a torch. it should get the upgraded studs and inserts and (if necessary) valve and ring job.

Finally, it is REALLY good advice to have the tests performed which will give a better idea of the problem BEFORE you take the engine out (leakdown). Sometimes problems are simpler than you might fear. Regrettably, the CT results would suggest a head gasket problem instead of the (much easier to fix) exhaust manifold leak.

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'83 SC