Jump to content


Photo

L28-P90 Head Piston Question


  • Please log in to reply
7 replies to this topic

#1 MATTY

MATTY

    Advanced Member

  • Members
  • PipPipPip
  • 373 posts
  • Location:Toowoomba
  • Tagline:https://www.facebook.com/thezedshed/

Posted 22 March 2017 - 07:39 PM

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

#2 dat2kman

dat2kman

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 4,061 posts
  • Location:Newport Waters Qld
  • Tagline:going sailing, see ya later!

Posted 22 March 2017 - 08:33 PM

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.

#3 MATTY

MATTY

    Advanced Member

  • Members
  • PipPipPip
  • 373 posts
  • Location:Toowoomba
  • Tagline:https://www.facebook.com/thezedshed/

Posted 22 March 2017 - 08:38 PM

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.

#4 dat2kman

dat2kman

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 4,061 posts
  • Location:Newport Waters Qld
  • Tagline:going sailing, see ya later!

Posted 22 March 2017 - 08:44 PM

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?

#5 MATTY

MATTY

    Advanced Member

  • Members
  • PipPipPip
  • 373 posts
  • Location:Toowoomba
  • Tagline:https://www.facebook.com/thezedshed/

Posted 22 March 2017 - 08:48 PM

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 👍🏻

#6 Neuby

Neuby

    Advanced Member

  • Members
  • PipPipPip
  • 290 posts
  • Location:Bundaberg, QLD

Posted 22 March 2017 - 09:56 PM

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.precision...=1363&EID=12684

 

snip.PNG



#7 MATTY

MATTY

    Advanced Member

  • Members
  • PipPipPip
  • 373 posts
  • Location:Toowoomba
  • Tagline:https://www.facebook.com/thezedshed/

Posted 22 March 2017 - 10:02 PM

Yeah mate more or less.

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

#8 600Z

600Z

    Advanced Member

  • Members
  • PipPipPip
  • 266 posts
  • Location:Tasmania

Posted 23 March 2017 - 12:17 AM

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 by 600Z, 23 March 2017 - 12:22 AM.





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users