low91rex

Well I just got everything back from the machine shop and I'm in the process of putting everything back together. I ordered the wiseco 81.5mm pistons and got the block bored over. Now my machinist kept asking me how much boost, how much boost are you gonna run. I told him about 15psi on a 60 trim. So he said he will take care of the clearances. Before doing my ring end gap I wanted to test fit the piston in the bore and it seems like there is a TON of space between the piston and the wall. took a video so you guys could tell me what you think.


http://www.youtube.com/watch?v=C3UCO...Q&feature=plcp


Is that too much? I have to measure and check the ptw clearance. Last thing I want is some piston slap.

racebum

you're rocking the piston the wrong way and it's not even set in. having it half in and rocking the short side will of course do that.

ask the machine shop what they were set it. will solve all questions

W!d3b0dYr3X

^agree. always check intake-exhaust since they are the major and minor thrust surfaces, and not side to side. if your unsure you could always contact wiseco and see what gap they recommend for your setup, and rent a dial bore gauge and make sure it is within spec.

cibao2ner

its probably fine...piston slap is only at idle on cold starts...unless its way too loose...

low91rex

When I picked up the motor I asked what the P2W would be and he said "350" I'm guessing he meant .0035". I will call him up Monday to double check. He had the pistons and block so I trust he knows what hes doing. Its just when I did my all motor build the piston had a much tighter fit and you couldn't necessarily move the piston around in the bore like this. I know when you boost your supposed to have more clearance I just don't want the motor to have a loud piston slap.

cibao2ner

yea he probably meant .0035....im running .0040 on my allmotor and its has a lil piston slap when warming up..but after its warm no more slap...

Turbo-LS

iTrader: (4)

.0040 on an all motor???? why

blackeg

my boost engine is at .0045 and it can hear it until i get 130-140 degrees of oil temp.

.0035 is fine for your boost and power level, but it should be measured about halfway down the bore. ring gaps too. when you gap them, make sure they are about halfway down the bore and then measure gap with the feeler gauge. for me i usually flip the piston upside down and use it to push the ring down until the bottom of the piston sideskirt is flush with the deck surface

sleepencivic

Looks a little excessive to me, get a dial bore gauge (jegs) and a outside micrometer (jegs)and measure for yourself! It looks like you doing the build yourself just spend the funds to get the right tools you will thank me later.

Not all machine shops are accurate thats why you need to double check before final assembly! I allways bring my bore gauge/ mics to the machine shop when I pick my motors up!

The spec sheet for the pistons should say where to measure on the piston below the pin. Measure each piston and write the number down. Then measure the bore and do the math for each cyllinder. Try to make the PTW cleareances as close as you can by moving the pistons around if need be. A good machine shop would of done this and marked the pistons for each cylinder.I know CP pistons are all the same size but most others vary that why they have to be measured.

Turbo-LS

iTrader: (4)

But he isnt rocking the piston the correct way nor is it far enough down the bore to actually tell

H22AFerio

It might seem loose when its cold and with no rings on the piston.that piston will heat up and expand and fill that gap up... like everyone said you will hear some piston slap on start up thats to be expected with forged pistons but the slap goes away real quick when those bad boys heat up so gap the rings right slap them in there and have fun

Thomascivicsi

.0035 should be jst fine... but jst like they said you should double check it anyways before final assembly... GL