Cylinder ID help

[Tom '74 911]

Hi -
Is it possible to tell w/the photos below what cylinders I have? The engine is a '77 911S that's has been rebuilt at least once (by PO).

Thanks for the help,
Tom

[MBEngineering]

HI Tom I would say thay are mahle from the markings and matching up with the ones I have in the shop, so nikasil cylinders, if you have the top off the engine, make is on the side of the cylinders, you should just see it with a torch. The po has had some engine prob' in the past looking at the size of the cylinder base gasket, prob' snapped/pulled studs and blown head joints??, with head and cylinder re-face.

regards mike

[Tom '74 911]

Originally posted by MBEngineering
HI Tom I would say thay are mahle from the markings and matching up with the ones I have in the shop, so nikasil cylinders, if you have the top off the engine, make is on the side of the cylinders, you should just see it with a torch. The po has had some engine prob' in the past looking at the size of the cylinder base gasket, prob' snapped/pulled studs and blown head joints??, with head and cylinder re-face.

regards mike

Mike -
Thanks for the ID help. Just so I'm understanding you correctly - to you it looks like the base of the cylinder and probably the case mating surface was machined down some due to a prior bad event(s) - and the difference has been made up w/a thicker gasket? I'm new to all this and know just enough to cause trouble for myself!

Also, from Wayne's book - mahle/nikasil is a good thing rather than alusil right? At least as far as the possibility of reusing the cylinders w/new (higher comp.) pistons?

Thanks,
Tom

[MBEngineering]

HI Tom the cylinder base gasket is usually .25mm thick and yours looks like 1-1.5 mm thick which indicates that some machining has gone on , ither to the heads or the cylinders to repair poss' damaged faces. If you are pulling the engine apart you will have to make some checks/measurements to the heads and cylinders to find out why the base gasket is so thick.

regards mike

[Tom '74 911]

Thanks for the help Mike.

Tom