Ordering custom pistons HELLLP, I feel im over my head!!

[Evan Purple240zt]

Hey guys heres the deal. I have to order another set of pistons from ross. NO biggie, but the problem is if i screw up a parameter is my bag and im SOL. Has anyone ordered custom pistons before?????

 

They want;

 

Stroke

bore size (88mm)

head CC

Deck height (what is this?)

rod length and pin diameter

Valve diameter

head casting number

 

I THINK this is all they need, if you have something to add to this list that I need fill me in! I dont know the answeres to the parameters, if anyone can help that would be so badass of ya.

 

Thanks all!- Evan

 

PS 82zxt motor with stock rods and no milling of head or deck!

[TimZ]

Evan - I just posted a response to this over on zcar.com (so sue me... I was having connectivity problems here again, so I went there first... ).

 

One other thing - if you don't intend to spring for custom rods, you might want to consider going with 240 rods (only the ones with the 9mm rod bolts, though). Those rods are longer than the 280 rods, and you'll have to get a non-standard piston pin height, but this is simple when they are making them for you, anyway.

 

The longer rods basically reduce the maximum angle that the rod needs to have with the piston, and also increases the dwell time at TDC and BDC. This will make you less sensitive to cam timing errors. I believe that it's also supposed to be better for high RPM operation, due to the reduced side loading on the piston pin/rod bearing.

 

Actually, I've heard of people using the L20 rods, which are even longer, but I'm not sure if you need to do anything funky with the pin location to get this to work, though.

 

Anyway - one more thing to think about...

 

[This message has been edited by TimZ (edited April 10, 2001).]

[Evan Purple240zt]

I saw that tim, thanks alot. Good info you have provided. I have considered the 240 rod but i have ONE minor problem. My L28t rods have been pressed with ARP bolts, sized and balanced. I really freaking wish i could get my money back out of them to do 240 rods but money is excessively tight right now. Ill consider it once again though. The side load thing is a major plus for me though.

 

Thanks- Evan

 

PS anyone got rods fer cheap

[Dan Baldwin]

Diesel or L28 crank? Go to http://www.zcluboftexas.org/ , click on "about the Z", then "L28 Bore & Stroke Combinations" for a lot of good info, incl. stroke, head cc, pin heights, deck heights, etc. Unfortunately piston data is for Z22, Z24, and KA24 pistons, not L-series. BTW, deck height is the dimension from crank centerline to the block's deck (what the head gasket and head sit on). Pin height is the distance from the wrist pin to the top of the piston. Anyway, this page should get you started on what you want for piston spec. Let me/us know what you come up with before you order to double-check that it'll work, clearance- and compression ratio-wise.

 

I'd reconsider using L24 rods, too. If you're going to this much trouble, you may as well do it right. Another benefit to longer rods Tim didn't mention is reduced peak piston acceleration, which varies linearly with stroke, with the square of rpm, and linearly with 1 plus the ratio of stroke to rod length.

 

I assume you're getting forged pistons so you can up the boost and or redline?

 

Dan Baldwin

'71 240Z 3.1

COMSCC #7 SPB