Head to Cylinder leak in a 2.0 911E

[EarlySport]

I've recently purchased a 1969 911E with an engine problem.

The middle cylinder on the right hand bank has a combustion leak between the cylinder and head. I can feel the puffing leak with my fingers when the car is idling. It becomes quite loud when driving, occasionally emanating a squeaking sound.

The engine was rebuilt some 8000 miles ago. According to the PO, the head studs are not pulled and are all at correct torque settings. I need to check this is true.

My aim is to gather what are the most likely parts required to repair this before I pull the engine down.

Is it sensible to source a used 911E head, and potentially a single cylinder? Will I have issues with cylinder heights ( or anything else ? )

Does anyone have any feedback ( purely opinion ) on what is likely to have failed?

There are no other problems with the engine, so I'd like to fix this with as limited dissasembly and as simply as possible.

Thanks all,

[304065]

Craig,

My guess is the head studs have pulled on that cylinder causing the head to float off the cylinder top on combustion. Query just HOW the PO determined they were at the correct torque-- probably by removing valve covers and re-torquing them. The problem is that once they've pulled, that technique just exacerbates the problem.

Any mag case engine is prone to head studs pulling. Worst case you can expect damage to the head sealing surface and the top of the Biral 80mm cylinder. But of course, if head studs have pulled, you need to go the whole case-saver route and have other required maintenance to a 2R case performed, such as a resize and line-bore, as these have a tendency to warp when disassembled. While you are in there I would do the oil bypass mod and squirters and cut for an SC oil pump just for grins.

Cylinder heights should be OK, but you should determine that once you've torn it down. Cylinders can be surface ground to true them up so it's not a big deal. The head, if not too buggered, can be machined along with the other heads to true up the sealing surface-- if the same amount isn't taken off all the heads, the cam will bind, so you want the cam box sealing surface to cylinder sealing surface to be identical on all the heads-- a fairly simple task for a machinist or enthusiastic DIYer.

My 02, hope this helps. The fewer hours before teardown the better. Good luck!

[YTNUKLR]

the mag cases are prone to warping in the middle, cylinders #2 and #5, lowering these cylinders and increasing the head/cylinder gap. it's not often i've seen pulled studs in pre-2.7s (though it happens). i would be willing to bet it's your case needing some machine work (deck the spigots). who knows what you'll find-i'd venture a guess your head and cylinder will be basically ok (may need a .005" resurfacing, but that's minor)

[Grady Clay]

I agree that the head studs need to be checked and that a warped case may be an issue.

Another possibility is the builder didn’t have the head gasket properly in place. While this is more common with the CE gaskets, I have seen it with a 2.0 gasket.

Best,
Grady

[Henry Schmidt]

Another possibility is that the heads were machined incorrectly.
Simply stated, the machinist cut the sealing surface but not the gasket surface.
When head studs were not the issue, incorrect machine work has (in my experience) been the problem.

[EarlySport]

Thanks all for your feedback. The engine rebuild invoice from the PO wasn't as high as I would expect, so I think there is a definite possibility corners were cut.

Just to clarify though - I was under the impression that a 69 2.0E motor had no head gaskets? Am I wrong?