L28-P90 Head Piston Question

[MATTY]

Hey guys

 

I've had a bit of a hunt around and I'll be neededing flat top pistons for my NA L28 with P90 head. Now my question is has any one ever used NA VG30DE (1989) Pistons before? Only reason I ask the question is I have a set sitting here in a spare motor that I could use. Obviously the block will need a bore out to accommodate the larger pistons but still unsure of using second hand internals even though I'll still be using my factory crank.

 

Any advice would be great if it means saving some coin when it comes to getting the motor built( even thought saving money or cutting corners as such on a new built motor is a sone what of a oxymoron, I'm just trying to best utilise what I have on hand)

 

Cheers

Matty

[dat2kman]

You need to cofirm bottom end specs, ie stroke, rod length, piston pin to crown height.

A bit of a bore some new rings, if numbers work out, why not!

Depending on piston crown height, you can quite easily knock a fair bit off their tops,, but check thickness at center of the crown.

[MATTY]

Thanks mate. We were trying to find the specs but all that information believe it or not we couldn't find. I might just pull the motor down and get some measurements of the VG gear on the weekend after all the motors literally sitting doing nothing.

[dat2kman]

Google up info on the std specs on that piston, should be something somewhere.

Stroke at 79, slock L28 rod at 130mm, subtract that from stock deck height, to give you piston height

Cant recall exact numbers, but, if you throw in a set of 133 mm rods from a L24, you can run a piston 3mm shorter than stock,

Reckon that the modern VG and others will have shorter height pistons?

[MATTY]

Gives us basic info but nothing specific I might even suss out my old 300zx tech manual and see if it's listed. Thanks again for that given the calculations it should give me an idea if it will work. Yeah not too sure on the piston heights but I'll find out soon enough ??

[Aaron Neubauer]

Is this what we were talking about on the weekend?

 

When it comes to comp height I use precision international's website.  9 times out of 10 they have comp height, nice picture etc. AND you can search by engine 

 

If I have the motor correct, 32mm +1.5mm dome.  Considering the flycut valves there'd be some meat in the top.

 

http://www.precisionintl.com/Engine.aspx?ID=1363&EID=12684

 

[MATTY]

Yeah mate more or less.

 

Shit yeah that's the go man. Looks to be a handy website too ??

[600Z]

Neuby has it right at 32mm compression height but also the gudgen pin is 22mm not a big deal but the compression height is compared to 38.1mm standard.

 

VW Pistons are a easy fit, just have to have a engine shop bore out the small end of your rod 1mm and then turn off 0.9mm and you have standard compression height or more or less if you want to play with compression.

Edited March 22, 2017 by 600Z