The V8 Owners Forum -

How think are they and how much is it safe to remove.

Thanks
Leigh

Are you on about the crowns or the bowls? you are limited on the crowns by the amount left above the top ring. Take too much off here and your ring will break out the top of the piston. No idea what's safe to be honest but I don't think it would be very much. If this is to shave the pistons as per your other post to reduce compression then I would have to do the calcs but I don't think you would get much as its not that large an area so quite a lot would need removed. Your other problem would be you would screw up the balance so an engine balance would be needed.

No this is metal to be remove from the inside to get all the pistons the same weight.

Ah sorry put 2 and 2 together and got 6 lol. All the pistons I have seen done have had the bottom of the small end lightly drilled, kinda like dimples. You should never really have to remove much to balance pistons.

some of mine have had upto 2mm valley cut under the small end.

but seemed a bit excessive.

see pic

I wouldnt mess around with taking any metal from the crown area if you want good reliable power from TVR pistons. I assume you have cast pistons with valve cutouts?

The cutouts make them weak enough as I just found to my displeasure. They may be ok for NASP use, but they cant handle the cylinder pressures on gas.

No prob with taking some metal from the skirts as per pics though. You can even skim a bit from the inside as well.

Take some weight from the ends of the pins if you can. Also, I'd remove weight from the flat pad area under the pins and from the inside of the skirts. How much variation in weight have you got and what are you weighing them on? I use scales accurate to 1/10th gram, kitchen scales are no good.

Boosted LS1 wrote:Take some weight from the ends of the pins if you can. Also, I'd remove weight from the flat pad area under the pins and from the inside of the skirts. How much variation in weight have you got and what are you weighing them on? I use scales accurate to 1/10th gram, kitchen scales are no good.

The scales I have measure in 0.1g's accurate to 0.2g

I think there was 2g difference from lightest to heaviest.

But the work shown was done by the balance company. but look a bit extreme. as some was upto 2mm.

I don't have cut outs and will not be running NOS but by run a supercharger next year.