Topic: weisco pistons

[BPellerine]

any one install these weiscos before?


are they installed with the arrow facing forward?this puts the largest valve pocket on the ex side is this right?bill

[Big Jay]

That is correct. I helped develop those pistons, they were a copy of the cast pistons we made.  Using a wide exhaust pocket was so it could be used in any hole. Didn't need two different pistons.

Those might be the F2 pistons

[Sam Green Racing]

As pistons go, one would expect the bigger valve cut out to be for the inlet valve but as Jay says, it's not true in the case of these pistons.
I had my doubts when I first saw a set and wondered if the arrows had been stamped the wrong way but you can also tell from the off set of the piston pin.

Sam.

[MRieck]

That's an old Wiseco box for sure.

[BPellerine]

many thanks guys ,after an ill fated attempt at finding an rc cast piston to match my 3 nos ones,a member helped me out with these so thank you you know who you are!the part no is the same as the modern 4016  but any install pages are kind of generic and show small valve pockets at the ex.and you are right they will fit any hole unlike the rc pistons..0025 clearance right.by the way they are nos!bill

[Big Jay]

You can run those at .0015" They are very high silicone.

That box is 20+ years old. Check and make sure they are XC rings.

[BPellerine]

yes big jay I checked with weisco Canada and the part no for the rings is 2559xc same as later ones .I guess they make 2 types of rings?but the rep sent me the onfo on the rings for these.do the present day pistons look any diff other than the info on the top of the piston?bill

[Big Jay]

Thew present day 836s have a lond part number etched into the top.

In my 1990 catalog,  the rings were XC, so you are OK.

[BPellerine]

thanks for the info big jay these will be going in a motor along with a few of your parts the boxes will make a nice display.bill