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Original Lister Cs Engines / Big funny piston rings
« on: March 28, 2020, 03:53:21 AM »
Hi guys
Our local machinist just failed Common Sense 101 (or at least his worker did)
I bought a 5slash6/1 recently with a long history of hard work on the farm. Bottom end started out as a 3/1 maybe in the late '30s . . .
When I tore it down it turned out to have a +40 thou alloy piston (kinda an 8/1 now i guess) and the top ring groove was pretty worn. I managed to buy some ring groove spacers in a suitable size as the 4&1/2 inch piston size was common in Bedford trucks & some other a half-century ago
So I calculated the clearance etc for the ring+spacer, WROTE IT ON THE PISTON WITH A PICTURE and gave it to the machinist we use at work. He as been bloody good up until now
For whatever reason, he left it to a worker to do who mistook the vertical dimension for a lateral dimension and machined what could only be called A Very Big Groove into the piston
By the time I got it back it was one of those "what's done is done" situations
His solution was to accept that the piston now has a very big ring groove and to get a Very Big Ring machined by a bloke who makes one-off piston rings . . .
See pics?
What do you guys reckon the implications are? I'd be interested to hear from some experienced folks
Cheers
Our local machinist just failed Common Sense 101 (or at least his worker did)
I bought a 5slash6/1 recently with a long history of hard work on the farm. Bottom end started out as a 3/1 maybe in the late '30s . . .
When I tore it down it turned out to have a +40 thou alloy piston (kinda an 8/1 now i guess) and the top ring groove was pretty worn. I managed to buy some ring groove spacers in a suitable size as the 4&1/2 inch piston size was common in Bedford trucks & some other a half-century ago
So I calculated the clearance etc for the ring+spacer, WROTE IT ON THE PISTON WITH A PICTURE and gave it to the machinist we use at work. He as been bloody good up until now
For whatever reason, he left it to a worker to do who mistook the vertical dimension for a lateral dimension and machined what could only be called A Very Big Groove into the piston
By the time I got it back it was one of those "what's done is done" situations
His solution was to accept that the piston now has a very big ring groove and to get a Very Big Ring machined by a bloke who makes one-off piston rings . . .
See pics?
What do you guys reckon the implications are? I'd be interested to hear from some experienced folks
Cheers