Posts
423
Joined
3/8/2015
Location
GB
Edited Date/Time
6/14/2015 9:19am
After a bit of help/info, i have an 03 125 cylinder that has been bored to 57mm, it has been bored off centre so there is enough left on the exhaust bridge,
But It looks like they've used an 05-07 wiseco piston and machined it, cut an inlet window and machined the crown flat, my problem is the piston ring pin/locator is directly above the inlet window, so the ring ends aren't running in the bore, they're passing over the inlet port in the cylinder....
So my questions are,
1, is there a more appropriate 57mm piston i can use, something with the ring pin in the same location as the 03 ?
2, as the cylinder has been bored off centre, is it scrap now, or could i get the off centre half built back up with weld, and bored to a re-centred 56mm size, for ease of piston choice and modding headgaskets ?
But It looks like they've used an 05-07 wiseco piston and machined it, cut an inlet window and machined the crown flat, my problem is the piston ring pin/locator is directly above the inlet window, so the ring ends aren't running in the bore, they're passing over the inlet port in the cylinder....
So my questions are,
1, is there a more appropriate 57mm piston i can use, something with the ring pin in the same location as the 03 ?
2, as the cylinder has been bored off centre, is it scrap now, or could i get the off centre half built back up with weld, and bored to a re-centred 56mm size, for ease of piston choice and modding headgaskets ?
If you look on the inside of the piston there is raised lump where the ring stop pin is, there is also another identical raised lump next to it, so it looks to have provisions for the pin to be located in a different spot, i'm guessing this would meen wiseco make an identical piston but with the ring stop in a different position ?
How are the pins fitted in the piston, i'm guessing it's more than an interference fit, could I, or a machine shop change it to the other spot, or is it a waste of time ?
I have a brand new wiseco gp/racers choice 57mm piston here which has had the crown machined flat, and boost/inlet window cut out, my problem is where the ring locator pin sits, which is exactly opposite the exhaust bridge 180º, so the ring ends are running though the inlet/boost port of the cylinder, i was always led to believe this was a no no ?
Anywho, it's been bugging me so i've just pulled down my 03 134 motor which has a 56mm wiseco gp/racers choice piston in, this is the right piston as listed by wiseco, but this also has the ring locator pin 180º from the exhaust bridge, so subsequently the ring ends are running through the port, the standard size piston that was in before has the ring locator pin offset and runs through the bridge ?
Is then the wiseco gp/racers choice piston a crap design, or is it not seen as an issue having the ring ends running through a port ?
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