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Tolerance For Pistons & Pins 86mm Rebore Zetec

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Old 16-06-2011, 09:26 AM
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4eyes
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Default Tolerance For Pistons & Pins 86mm Rebore Zetec

Hi,

Can anyone who has fitted c20let pistons to a blacktop zetec help me out?

Been to my machine shop this morning to enquire on the cost for some work to be done, including the rebore from the standard size, up to the 86mm required to fit a set of forged c20let vauxhall pistons, and also the pins on the rods.

I was told the rebore is no issue, however what tolerance is advised for them, as if they are too tight they could cause overheating, and too much would cause piston slap?

Also with regards to the pins, then need opening out, however are they to be fitted as a floating fit, and any idea on their tolerance?

Common sense would be to follow the let set up from the vauxhall, however the machine shop wanted this information prior to the work

Any help would be great, even if its in the way of pointing me to a forum that can help!
Old 16-06-2011, 10:16 AM
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Chip
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The pin is fully floating on the vauxhall in both the piston and the rod.

All the info you could ever want about LET pistons is here mate:
http://www.vauxhall-sport-forum.com/...let-t3546.html


Including:

Gudgeon pin diameter.............21mm
Gudgeon pin fit in piston........Clearance 0,004/0,010mm
Gudgeon pin fit in con rod.......Clearance 0,015/0,030mm


And:

Piston Clearance in bore.........0,05/0,07mm

If you are likely to be working it quite hard, be at the top end of that piston to bore clearance range, it still wont slap.
Old 16-06-2011, 10:27 AM
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4eyes
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Originally Posted by Chip
The pin is fully floating on the vauxhall in both the piston and the rod.

All the info you could ever want about LET pistons is here mate:
http://www.vauxhall-sport-forum.com/...let-t3546.html


Including:

Gudgeon pin diameter.............21mm
Gudgeon pin fit in piston........Clearance 0,004/0,010mm
Gudgeon pin fit in con rod.......Clearance 0,015/0,030mm


And:

Piston Clearance in bore.........0,05/0,07mm

If you are likely to be working it quite hard, be at the top end of that piston to bore clearance range, it still wont slap.
Spot on, very helpful!! Cheers
Old 16-06-2011, 10:45 AM
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Chip
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No problem mate, that's what we are all here for
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