916 Crank Cases - Painted Or Bare?

Correct factory finish is paint that falls off

 

The whole engine is painted except for mating/gasket surfaces. When repainting, all loose paint should be removed and etch primer applied before the silver

 

I'd paint the lot mate it will look so much better here's my 996 engine I painted

 

When I refurbished my 1999 748 last year I removed the crankcase covers and all the cam & rocker covers, stripped the old flaky paint off and resprayed them. The closest colour match I found was Zinc Phosphate which is actually a primer, this then had a lacquer applied on top to give it solvent ie petrol/oil resilience. For the crankcases themselves I removed the old paint and used ‘aluminium engine enamel’ which I picked up in Halfords; only had to do the left side where the engine number is and the rear, the rest, including cylinders & heads was ok.

 

After corrosion has crept under it

 

I used this

https://www.eastwood.com/ew-zinc-phosphate-aerosol-12-oz.html

but got it from a car detailer/restorer in Cork; I’m guessing if you search on Amazon UK or eBay you’ll find some.

I learned the hard way it’s not petrol proof so subsequently applied this over the top


The side of the crankcases and the rear were sprayed with this



on checking I didn’t get them from Halfords but from my local motor factor.

Oh, and I just used Frost’s Paint Stripper on the crankcase & cam covers.

 

How did you persuade the sight glasses out of the covers without damage?

 

I didn’t. I masked it. I put some tape over and then carefully cut it to fit with a scalpel/modelling knife.

 

Personally, I like the bare alli finish on my 998.

 

@Sev just wire brush mate then went over it with wire wool.

 

Agree, the bare sandcast finish looks better and stays looking good.
The sight glass pushes out from the inside. A new one is only a few quid from the dealers.

 

Can’t see them getting oxidisation. As long as kept dry...

 

Not sure weather the sand cast cases have some sort of protective coating on them but can’t see anything on there.

 

I’d try a soft brass brush first Sev. Just to avoid scoring the cases...

 

But Sev, Ian has a 998S which has sandcast cases, nowt else does. Would it be the same if they’re just the regular old die cast painted cases?

 

They're sand cast so have a natural rough finish, ive not seen any corrosion whatsoever.

 

What paint did you use?