Oil bypass mod, how do you tell?

[cstreit]

Other than the different style pistons, how can you tell if the case was modified for the oil bypass modification?

(All references mention "case modification" but don't suggest what actually is done...)

Thanks,

Chris

[cstreit]

It's a conspiracy I tell you! This is some great Porsche secret handed down to only to those who know the special handshake and bear the mark of the priviledged few. No case modification information other than to say that "It is done" shall pass the hallowed doors of the machinist?

Can you see that we are being oppressed? Strike a blow for open source knowledge friends and tell me the answer! Do it for the children for gods sake!

*pant, pant*

[Tim Walsh]

As an open source user, here is what I've found/observed. There is a hole in the case by the 2 oil plugs that is about 6-8 mm across. If this hole is plugged then it's had the oil bypass mod done. If it's open then it does. I could be wrong but that's what I've seen. Unfortunetly the hole is inside the case so it has to be split in order to find out.

[cstreit]

I'm not sure what you mean "by the two oil plugs".. Can you point it out on this picture?

If it's what I THINK it is, it would be in the opposite case half, lower right of this picture yes?

[Steve@Rennsport]

Chris:

The oil bypass mod only affects the early 2.0 aluminum & mag cases used before 1976.

The case in your picture (above) doesn't need that,.....

You can install any oil pump you want,.....(I'd suggest either 930 or GT-3).

[Tim Walsh]

Chris,
Exactly what Steve said but in early mag cases there is a hole in the lower right hand corner of that picture that would be plugged. I'll try and get a picture in just a min.

[Tim Walsh]

There is a brass looking plug in this picture. THat is where the bypass plug is supposed to go.

[cstreit]

Thanks guys.

Steve - Thanks.. I just had that case picture laying around, it was a 3.0L, but just using it as a reference for location... Glad to see you are bandying about the board!

Tim, thanks too.. So the mod (aside from the pistons and springs) is just plugging that hole? Huh!


Oh, and sorry everyone for the conspiracy theory wackiness. Guiness before dinner had me feeling ornery.

[HawgRyder]

Chris....the mod is also drilling a passage (hole) down through that hole just above and to the right of Tim's brass plug.
The new hole extends down through that hole and meets up with the passage that you are plugging with the brass plug.
According to other pelicans...the new hole is about 12mm in size.
Drilling should be done on a mill....and de-burring in the original passage would be necessary.
Bob

[Peterfrans]

More info and a clear pic can be found in this thread: