Correct lower valve covers for ‘72 MY

[matteo68]

Can anyone advise what is correct for ‘72 MY please? I think they should be magnesium but I’ve discovered my S has later turbo ones fitted and I’d like to replace them but I understand the mag ones are prone to warping and leaking and that the later aluminium SC ones are better and can be cerakoted to look correct?

Any advice please?

[Lightweight_911]

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Original fitment would have been magnesium - which, as you rightly state, are subject to warping/distortion - hence why many people replace them with 'Turbo' covers since that was the Factory's solution ...

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[RobFrost]

I believe the issue is threefold.

The cam towers are aluminium, so if you use the magnesium covers, they expand and contract at a different rate to the aluminium, making them leak over time. If you want it correct then in theory a thicker, softer, flexible gasket would be sufficient to allow the two to expand differently. Some people swear by reusable silicone gaskets, other people have used them and hated them.

Next, the magnesium ones get out of flat so the gasket face needs flattening with abrasive on a flat surface.

Finally, the rocker shafts leak. You can add a little rubber seal to the splits on the rocker shafts, which reduces or eliminates leakage along the rocker shafts.

I noticed my 1970 911T has later covers added, while the 2.2E engine I'm rebuilding has the original magnesium ones. In their defence, they are nice and light.

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[matteo68]

Thanks both. Maybe I should just live with the turbo ones but my OCD will struggle with that!

[stretch]

Matt.... Do you wear 72 period pants when you drive it.

[anglophone1]

Of course he will- ask me how I know?

[matteo68]

Matt.... Do you wear 72 period pants when you drive it.

Yup got it in one Dave!

[RobFrost]

This is one of the rocker shaft solutions, although there are cheaper and simpler ones. But I think your engine is built already.

https://www.neilbainbridge.com/Products ... ealing-Kit

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[matteo68]

Yes built already Rob, but thanks and I may mention this to Sam next time I see him anyway

[Gary71]

Thanks both. Maybe I should just live with the turbo ones but my OCD will struggle with that!

It will struggle more when they leak oil everywhere… my ‘72 magnesium originals were warped, and even after being machined flat again they still leaked.

[matteo68]

Am I right in thinking the later alu SC ones look the same as the mag ones?

[Lightweight_911]

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Yes, the diecast aluminium valve covers look the same ...

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[matteo68]

Ok, thanks Andy! In that case does anyone have a couple of pairs please?!

[RobFrost]

These are the ones I'd say. Based on them looking the same as my mag ones.

https://www.ebay.co.uk/itm/385032586904

But I assume yours need drilling for the twin plugging?

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[hot66]

I have my mag ones in storage as they had a mild warp .. even after flattening and rubber gaskets they leaked. I’ve got later alloys ones fitted these days .