Exhaust gasket, head

4sd911 · 01-06-2011, 01:14 PM

Engine, '74 2.7 CIS:
The exhaust port on the head measures at 36mm as does the gaskets that were removed. I ordered new gaskets for the 74-77 year and the new gaskets are 39mm ID. While they fit, will the uncovered surface portion on the head be damaged from the bigger gasket? I first bought a set of these from a different supplier that were aluminum with the 39mm opening, I plan on returning them for the correct size but to speed up the repair I bought more from pelican for the 74-77 year that came with the same 39mm opening although they are paper / asbestos type. Should I be concerned?

cgarr · cgarr's Garage

I think the later heads used a short blow proof pipe which extended into the head which size is 39mm If it were me I would rather use a gasket closer to the head port size. Here is a 76 head top and 74 head bottom.

Flat6pac · 01-06-2011, 02:29 PM

The top head is typical of a 77 with thermal reactors. The thermal reactor used inserts inserting into the head. Thats the recess cut and the narrow centered 8mm studs. This exhaust used a thermal gasket that is mainly metal threads and looks like asbestos and dark grey in color, although I believe there is no asbestos.
The 74 would use the copper colored early style gaskets with the white insulator between the copper sheets. These look like the muffler gaskets for the pre 75 but smaller.
Bruce

4sd911 · 01-07-2011, 05:02 PM

Thanks, a local parts house had them. Part no. 901-111-195 if you search that no. here at pelican you get two lines of superseded no.s and one line with that part no. The part no. with the 39mm ID under 74-77 cars is a 911 part no.

RC924 · 06-18-2012, 10:32 AM

Hi guys. Stumbled across this thread searching the site for an answer to a similar question I posted on the 4cyl water cooled forum relating to a 931 (924 turbo) gasket.

They also utilize an inner fire tube that protrudes into the manifold fitted with a larger 39mm ID metal composition gasket. OE gasket is a 930 part #. As I`m running with a supercharger, do not use the OE manifold but have 1.5" tube headers and need a quality gasket with a rolled metal inner edge.

Can someone please confirm that the OE-901-111-195 gasket (from our host here) has the 36mm ID and what the stud spacing is on your heads? Hopefully for me it will be 66mm (between centers).

TIA.