N42 nismo pistons from a 280z??

Engine, Transmission and related drivetrain.
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Toybomber
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Joined: 12 Jan 2021 18:53
Location: Phoenix

N42 nismo pistons from a 280z??

Post by Toybomber »

I came across this CL posting and was wondering how good of an addition they would be on an L20 build? First.... has anyone seen these and second what the heck are they? Pros and Cons to adding em..... then whats a decent price for them?

https://phoenix.craigslist.org/nph/pts/ ... 62043.html
datzenmike
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Re: N42 nismo pistons from a 280z??

Post by datzenmike »

N42 is the block.

Yes I have seen these before.
Image

Those have a domes. Find out how many CC's the dome is. At a guess it's about 3/4 the diameter of the piston so about 32 sq cm area. If the dome is only 1/3 of a mm that's over 9cc*

If you had 86mm flattop pistons in an L20B with an open chamber head you would have a compression of 10.11 and those are 0.5mm wider and have a dome so compression would be out of sight high.*Plugging in the guesstimate above (which I think is conservative) I get 11.90 compression and again, this is for an 86mm not an 86.5mm wide piston.

This would not be a 'good' addition to any L20B.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
Toybomber
Posts: 14
Joined: 12 Jan 2021 18:53
Location: Phoenix

Re: N42 nismo pistons from a 280z??

Post by Toybomber »

Thanks Mike,

I really enjoy reading and learning from your post. Your technical knowledge is unmatched. What application would these pistons be good for then, aside from and other N42 block?
datzenmike
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Re: N42 nismo pistons from a 280z??

Post by datzenmike »

A fully modified L20B with head work, ported, gasket matched, oversize valves and a big cam. For induction, side drafts, for exhaust probably a header. For the block ARP rod bolts and head studs, crank scraper and windage tray and KA oil pump. Ignition a Nissan EI distributor and coil. This will never be street friendly
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
loungin112
Posts: 256
Joined: 05 Mar 2014 21:34
Location: Colorado

Re: N42 nismo pistons from a 280z??

Post by loungin112 »

I have these installed in my l20. My setup is an open chance head, aftermarket cam of done sort, dual 38mm SUs, and a Mallory distributor, Nismo head gasket for extra clearance. It is very streetable here, but my former engine builder ground some dimples in the domes to lower the compression ratio a bit.... Don't get me started. I always use 91 octane, the highest here, no detonation that I've detected. Would use octane booster at lower elevations. Dyno'd at 111hp and 130ft/lbs. It needs large carbs for the top end, but those are too much for my budget at the moment. Hope this helps.
Last edited by loungin112 on 25 Jan 2021 17:08, edited 1 time in total.
loungin112
Posts: 256
Joined: 05 Mar 2014 21:34
Location: Colorado

Re: N42 nismo pistons from a 280z??

Post by loungin112 »

Last quote I got for a set of 6 of these positions was $100 each without an option to buy 4.... So $600.
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