chb280z

I was wondering if the dished pistons in my N42 are the same as the ones in the F54 turbo? Also has anyone had any expierences w/ knock off/Ebay turbos Good or Bad? Thanks in advance!

entropy31

BAAAAAAAAAAAAAAAAAAAAAAAAAAD. search around here a bit and you will find PLENTY of posts to support that.

duowing

I've been reading alot of info on hybridz, and from what I can tell is that the dished pistons in the N42 are different from the F54, but no one seems to be 100% sure as no one has directly compared them.

chb280z

Yeah i know i have this L series engine builder program and when i select the normal dished pistons and the turbo ones the CR stays the same and i am wondering if there is maybe just a difference in material, so i am thinking maybe i can us the ones i have and just use better rings. Any sugestions on rings?

snwbrderphat540

i doubt theres a material difference, back then in the day they really didn't use different manufacturing techniques on stock engine builds. besides, as far as pistons go, they are either forged, or not forged, and ill tell you now forged pistons were not used on stock engines as fas as my knowledge goes until the 1990's.

chb280z

So as for rings should i just get the turbo rings or is there a difference. Also will all of the other internals and the N42 block handle the turbo as long as i get a P90 head?

snwbrderphat540

don't even need the P90 head though its a good idea cause it flows better. i turbo'd a 82 NA motor worked freaking GREAT once i worked out the wiring bugs. they came back though once the car was sold off to a fellow in Florida though. lol. and use the rings assigned to that year motor not worth the risk.

chb280z

Well i have the N42 head that came on the motor but i took it to the machine shop to be pressure tested and bead blasted and when they got in to it the noticed that there were a few little crscks between the intake and exhaust valves on 2,3,4 and 5 and said that it passed the pressure test and it would be fine for an N/A engine but they think if I put boost to it it will drop a seat and screw everything up. So maybe i shout get it out and test an Ebay turbo so if it drops a seat it will go flying through the cheap turbo? (Just thinking out loud) Anyways i need a P90 if anyone has one laying arround. Let me know! Would I be ok using a P79 because they are a dime a dozen i know they have the sleves but other than that i believe thay are the same. Correct? Also for berrings and gaskets is there any one place that is better than another to get them? I was thinking Black Dragon or one of those Rebuild Kits from Auto Zone? any sugestions?

duowing

You could use a P79, as it's pretty similar to the P90, the only difference is the exhaust ports, and the P90 is said to be better flowing. Although With a P79 head on dished pistons you will see a drop in compression I believe to about what the normal turbo compression is. This will be good though as it will allow for alot more boost to be run.

Someone mentioned it's up to you, but as you go to higher compression you begin to limit the amount of boost you can run. You get better low end, but with lower compression you can always add more boost and probably outdo the higher compression engine. Although you sacrifice low end.

chb280z

So maybe if i used the P79 w/ a 1mm head gasket taking the CR to about7.6:1 that would be fine and still be able to run 14psi, Right? And i am not building a full out race engine here so really how restrictive are the sleves? I mean i am trying to stay as cheep as posible. I am getting free 440cc supra injectors so i guess i need to find a o-ring fuel rail any sugestions?