Cam tower rocker pin damage

[1974phil]

Hi Everyone,

I have torn my 2.2 engine down.

Among the bad surprises, a rocker pin bore is severely damaged.

As the rocker towers are original to the car, I would prefer to keep them. Do you think I could use a type of aluminium epoxy to fill the damage and then use a flexhone to polish the bore? Other than ensuring that there is no leak, I suppose that once tightened, the pin should not rotate and there is no pressure or pulling on that spot in this area. Temperature is also a limiting factor of epoxy, I see that they are usually ok til 200 Celsius which should be fine.

I know it would be preferable to use another cam tower but find a good one from 1971 might be difficult.

I was thinking of using RSR rocker pin seals to limit leaks.

Thanks for your help,

Phil

[edmayo]

I've never tried it, but I suppose the hole could be cut oversize and a bushing press fit into place and honed to fit. It would be an expensive fix.

[1974phil]

Hi Ed,

If it was not for the sake of keeping the car as original as possible, I would not hesitate to change the cam towers. I have read that there are different aluminium alloys. it seems that 7075 is stronger than 6061 which is stronger than 5052.

What aluminium alloy are the cam towers made of, do you know ? Perhaps bushings could be done in bronze same as for the piston wristpin bushings in the rods..

[1QuickS]

The cam towers are cast aluminum, typically A356, and no, not a Porsche. The three aluminum alloys you identified are compositions used for extrusions or rolled aluminum shapes.

Here is link discussing worn rocker bores:

https://www.google.com/search?q=pors...qQIaoUJEo,st:0

[tom1394racing]

I might have a late '70 or early '71 cam tower should you decide to replace yours. PM me to follow up.

[dho]

If Tom Butler has the correct part, I recommend replacing it. I’ve bought several parts from Tom-reasonable prices and excellent communication.

dho

[1974phil]

Hi Dho,

Yes, I wrote him a PM to see what he has available and the condition.

We'll see..

[NorthernThrux]

You could get it Al welded and then honed, or milled out and press fit the right size bushing. Not super expensive, but not as cheap as aluminium epoxy.

Ravi

[1974phil]

Aluminium epoxy would be the easiest and then sand the high points.

I am just wondering if the successive heating and cooling cycles of the camshaft housing could cause the epoxy to become brittle and detach from the camshaft housing..

[stephers]

I saw on a hot rod site where they were using a special epoxy for the floors of the port called Goodsons Wonder if that would work?

Thanks, Rick