Citroen XM Forum

White Exec wrote: Tue May 25, 2021 3:08 pm
I was just very concerned about the finish on some of these seriously precious alloy wheels, not so much a one-off clean-up of a cylinder head.

I believe the only cleaning chemicals that are not either acid, or alkali, are detergents.
Acids are good for oxide removal, alkali (caustic) good for grease removal.

I think any ionic surfactant will be caustic.

As far as destruction of aluminium goes...ones skin would be adversely affected before the metal, but long term exposure would dissolve aluminium.

Stickfinger wrote: Wed May 26, 2021 4:38 pm Moving on....
20210526_165641[1].jpg

Looks very nice...no envy here...

Dieselman wrote: Thu May 27, 2021 7:16 am

Stickfinger wrote: Wed May 26, 2021 4:38 pm Moving on....
20210526_165641[1].jpg

Looks very nice...no envy here...

Stunning ain't it..

Regarding the mechanicals. Did the engine workshop do any work to the valve guides, or was the sticking purely a result of the bent valve stems?

I'm sure alasdair said it was litterally a slightly bent valve and the guide is perfectly fine..

Correct, bent at the top when the camshaft stopped dead. I am with Jim E today, we concur that it was the rockers that bent the top of the valve stems (x3) ZERO marks on the Valve heads or the Pistons. There is no movement of the valves in the guides and they all drop free with WD40 and slowly with 20/50 oil. The replacement valves in 1/8/12 fit fine as well (which is lucky).

The Cam belt did NOT break remember, it all jammed up solid with the Aux belt wrapping around the cam sprocket and the pump sprocket

Sounding good, and in some of the best hands in the game.
Take care of our Jim.

Super work alasdair. Be like a new engine..

I have not broken him ........ YET

I didn't know the belt didn't snap at all, so the auxiliary belt wound round it and caused the cam timing to slip causing multiple sets of valves to meet the pistons of doom.

It should all be back together this weekend.