p90 on a na

[naplesZ]

My n42 head that I have been waiting on for near a month as fallen through and now I need a find a new fast. I gotten a line on a p90.My question is other then lowering my compression are there any other side effects? Would I require any different parts to make it work? If anybody has a head let me know.

Thanks

[Pyro]

The head will work just fine on a NA engine. However, I wouldn't install a P90 or P79 head on a engine with dished pistons (75 to 80 L28). If you put that head on a dished piston engine then the compression will be 7.4:1 (stock turbo compression) and that will kill power over the entire rpm range. In one of my Z's (NA 78 280Z), I'm using a P90 head on a L28 block with flat top pistons which makes 8.8:1 cr (stock 81 to 83 cr).

 

If you are using a round port exhaust manifold it might be a good idea to grind the end of the manifold ports to fit the gasket. Just grind the last 1/4 inch of the port. Should take just a few minutes.

[fl327]

p90 head on a flatop motor is torquey.

junkyard run 14s maybe faster combo (240z) with stock parts of different years is:

 

p90 head, n42 head bumps compression a little higher and works well too.

flatop f54

81-3 zx trans

3.9 -4.1 r200 (if you want maximum short gearing- 75-8 5 speed trans)

z31 ignition coil

zx or maxima distributor with e12-80 module

 

rework the su's a bit, grose jets and some porting

use a square port header, its worth the 100 or so for a new header to match the square port head.

 

sad part about all the junkyard parts is that it skews your notions of how much things should cost, and when you look to upgrade the cam it costs as much sometimes more than all thejunkyard parts listed above!

 

good luck.

[naplesZ]

My main issue is finding a head.I going to try and find out if I can return my pistons for flat tops.There still in the box from victorybritish.I would like to find a n42 head but so far no luck.If anyone knows of a good place let me know please.Time is somewhat of a issue.

Thanks

[fl327]

Here in California, especially where I live, it seems like they are almost giving away L parts, so we have a skewed concept of what we can get at the junkyards really quick.

[JMortensen]

I think the P90 is the best head to use, and I like the way this guy did it:

http://geocities.com/zgarage2001/p90.html

 

That way you get the best of all worlds. Straightest runners, best quench area, runs on pump gas, don't need to change lash pads or any of that.

 

Jon

[evildky]

you can also shave the p90 to run on the na motor, you would then need to shim the cam tovers to compensate for cam timing and add thicker lashpads to maintain valve geometry but you could then run it with dishtops, you might be able to adjust the cam enough with one of the other 2 possible cam position but I've never tried that

[JMortensen]

evil, check the link I put up before. You can just swap valves with a 280Z head then you don't even need to mess with the valve geometry. Just add shims under the cam towers and you're done.

[naplesZ]

The main problem I have is lack of knowledge on my part.I only drove my car twice before I realized it had a blown head. I am currently living in Italy and I don't speak Italian. If I try and rebuild or modify the head and screw up I am screwed. So finding a head shop that know about nissans and understands what I want is pretty much out of the question. If one knows of a head shop or someone who has one please help .

[(goldfish)]

if you put a P90 on an N/A, would you, should you change out the cam?