Hi folks. I have this unknown piston and rings that came with some WM20 parts. I was hoping someone might be able to identify it for me? I think its a B33 but really I'm just guessing. diameter is a shade under 85mm and the rings look unused. I would appreciate any help - pictures below:
The B33 and the Goldie share the same bore. The 'normal' B33 piston is flat but there is also a higher compression version...Not as domed as your example though which, as I say looks Goldie...
I'm not sure if I have all the part numbers for the Goldie pistons but I'll take a look...Perhaps someone else will confirm it...Ian
The piston certainly looks serviceable and the marks on the crown, although unsightly, won't affect its function (though probably will affect the price...)...Ian
That's what I thought, Ken, hence the tongue-in-cheek '3 valve' comment. I was trying to imagine a scenario whereby some idiot might have removed a barrel and head and tried in some way to check clearance...but I can't.
If a valve head had detached or a valve dropped in then the damage would have been far, far worse.
It's too big a radius to have been caused by careless use of a timing tool.
Rik, Someone spent a while wondering where that last 1/2 inch washer had got to?
.....it was here just before I put the head on....
I realised it was tongue in cheek, but now I am more delighted with the notion we are taking rivet counting to a new level, by musing on what caused this damage......
The source of this piston is also amusing (I think). Some time ago I bought a replacement barrel on Ebay (My original one had a bunch of fins missing). The piston came with the barrel which had been machined to accept it. So, I now need a new sleeve. Maybe I'm missing something but I can not see how a domed piston would make for an improved WM20, and how it might be damaged by a valve in a flathead engine.