Arias pistons tech question

[Florida240sx]

For those who have built your engine I need to know if my block is done or not. With arias pistons the spec sheet that comes with it says to have .004 clearance. so therefore you'd bore your engine .024 over to match the pistons specs. isn't .004 too much clearance? Or is this common with turbo engines. I know the pistons heat up and expand...... My machinist asked me.I told him to go by the spec sheet that came with it. I think it said to bore the engine to 3.574 IIRC. They are non-coated pistons (for coated it said for clearance to be .002)

[9sec240]

The clearance is actually built into the piston... You bore the motor .020 over and your good to go... The reason for the spec is to check to make sure everything is golden...

[wild_maxx]

quick Q about the arias pistson. When installing them, the star on the bottom of the pistons need to face toward the front of the motor correct?

[j-z]

the bigger valve relief cut is for the bigger intake valves. so just make sure the bigger cutouts are on the intake side. and damn arent those wrist pin clips a *****. it took me a while to figure out how to get the first one in, but after the first one it was cake. kinda tore my fingas up though.

[Chezedik]

Normally, yes. But just face them all the same way, to the front if the option exists.

[9sec240]

Yes, star to front... Double check that the larger valve reliefs are on the intake side...

[wild_maxx]

will do. Thanx for the info guys.

[Florida240sx]

So therefore my engine might be ruined...... I beleive he bored my motor .024 over.....Anything I can do??? I believe he has already reassembeled the bottom end.My eninge still had factory crosshatch at 184k. What do I need to do. I called and was told to go by the spec sheet. Do I need to stop him from going any further??? Any measurement I can check to see if I'm safe? Like 3.574/3.578"????

[Florida240sx]

What you mena the pistons have it built in? So the pistons are only .016 over? Think my engine is f***ed once again.

[wild_maxx]

i am not sure if the pistons are .016" over... but if the bore is .004" over bore i don't think it would cause a terrible problem.. but i am no machinist. FYI: a human hair is about .003" thick

[Florida240sx]

As it is right now my engine would have .008 clearance which is twice the recommended. Will this be safe or will my rings blow quickly or will I not even be able to get them to seal????

[Chezedik]

You may be able to get larger rings.

[jollygreen]

i've got an extra drivetrain in my garage i'll let go for cheap, i live in panama city shoot me an e-mail if you're interested [email protected]

[j-z]

LOL dang man you truly do have some shlt luck

[Florida240sx]

Think I'm just going to keep them and then order some 30bore pistons.......use these in my vert when it gets rebuilt. Unless someone wants to buy them..........

[9sec240]

There is a piston spec sheet that is in the box with the Arias pistons... It gives you finished bore size for the pistons...

There is also a piston installation guide sheet in the box with the pistons... Section 2 of this guide is all about finished bore size... It clearly states "finished bore size is indicated on the printed customer specification sheet provided. Any variation of the finished bore diameter will affect the assembled piston to cylinder wall clearance....... Arias engineers determine proper piston to wall clearance and incoperate this into the manufacturing process. This clearance is based on sevral variables: Bore size, alloy used, fuel used, power enhancements (supercharged, turbocharged, nitrous, etc)

Piston clerance is given in the spec sheet at .004" This spec is just so you can check clearance after your motor is bored / honed...

I would check with your machine shop and make sure they bored the motor too large... I cant imagine a reputable machine shop making this mistake.. ALL pistons are sized this way and incorperate the clearance in the piston so you can bore the motor to nominal sizes.... If you find your machine shop bored the motor incorrectly, we can get you custom pistons to fit your bore or shelf pistons at .040" over and you can have the machine shop bore the motor again...

[Florida240sx]

What is the price on the .040??? This guy is good, but he deals with domestics mainly. I'll found out on Monday...