Mag vs Al Upper Valve Covers

[tom1394racing]

When did Porsche switch from Mag to Al on the upper valve covers? The PET shows only one part number for the upper covers (p/n 901.105.115.03). How do you tell the difference between the two?

[Jim Williams]

Tom,

On the top covers, the aluminum ones are a little heavier. For the part numbers, the top mags are 901.105.115.0R (casting numbers) and the aluminum ones are 901.105.115.2R. Part numbers are often different from the casting numbers. It may be that the part number you have is the one for the newer aluminum ones which would replace the earlier ones as well as fit the later cars. I would guess that the mag ones are NLA as a new part.

I could weigh the ones I have if you need to know what the weight difference is.

Oh, and I think the year of change was from '77 to '78.

[davidppp]

hello, Tom.

The SC marked the change.

Kind regards
David

[Henry Schmidt]

In the middle of the '77 production year many of the parts previously made of mag were replaced with aluminum.
Although the parts were intended for the SC model, Porsche
substituted valve covers, chain boxes, chain box covers and breather covers on some '77 engines.

[davidppp]

Once again, Henry's input is definitive!

Porsches have sooo many such undocumented mods intrayear...

Part of the fun..

Kind regards
David

[Eagledriver]

The mag covers are much darker, they don't look much like aluminum. The aluminum covers look like...well...aluminum.

-Andy

[Wayne 962]

The tops almost never leak - the bottom ones are the ones you need to replace with the Turbo ones, as they get heated and warped by the exhaust...

-Wayne