Engine stud, what type to buy + shims

[Jimmy]

Folks

Currently undertaking an engine rebuild, have machined the case where the barrels sit as they weren't flat. The studs removed (retaining the cylinders in-place) have seen better days so am replacing these. Looking at the standard Porsche studs, are these recommended?

Having machined 0.007" off the case, are shims required (effectively replacing the 0.007" removed) to get the clearance needed between TDC and the valves. If so, are the shims available and from where?

Car 1968 911 (changing from T spec to S pistons / cylinders with an E spec cam)

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Jimmy

[Jimmy]

Any thoughts on whether I have to add a shim to each cylinder?


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Jimmy

[MikeB]

You will fit a copper gasket between the base of the cylinder barrel and the case, the smallest thickness is 10 thou (0.25 mm) you can use these in various combinations to adjust the height of the barrels. In your case, as you are fitting different pistons, you need to do a test build to see how many you need to fit to give the required clearance.

https://www.rosepassion.com/en/cat/pors ... 79/P116582

You get a set of 6 in a gasket set

[Jimmy]

Perfect - thanks Mike

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Jimmy

[MikeB]

Jimmy

If you haven't got it, this is THE book you need

https://www.abebooks.co.uk/book-search/ ... 760310878/

[acclassics]

+ 1 on mike,

dont guess on the shims, you need to measure deck height, and piston to valve clearance, then decide what size shims you need, especially with the S/E specs your going for. You will do trial build of top end, then final build with sealants

Another good book is by Cole Scrogham, he talks in detail about the piston to valve clearance

https://www.abebooks.co.uk/servlet/Book ... 6an%3Dcole

Waynes is really good (the link in mikes post), but it does have errors, especially on some of the torque settings, so you need to also follow his website he put together which lists the corrections (see below). A really good read for sure.

http://www.101projects.com/911-Rebuild/corrections.htm

Others also disagree with everything that is written so always consult more than one source, including the genuine porsche workshop manual, that should always be the first point of reference, other books after such as Bruce Andersons(performance manual), Cole Scogham, Wayne Dempsey, Haynes, Etc :

[Jimmy]

Many thanks - 'Porsche 911 Engine Assembly Guide' now ordered.


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Jimmy