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Enginerd81

N42 Turbo Motor Build Questions

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Looking for some feedback on my plans.

 

Current setup:

F54/P90 280zx and turbo

Megasquirt 2 - 440cc injectors

Evo 8 intercooler

14psi

3" exhaust

Goals - 300-350HP 

Use - 95% street car, with 1 track day per year 

Due to too many car projects and minimal car space I need to minimize the non-driveable cars. In order to do this I wanted to use the spare block that came with car when I bought it. I had it cleaned and inspected.

It is an N42 block, the engine builder stated everything was in great shape except the rod journals that need .25mm to get back to in print clearances.

He has suggested re-using the pistons that came out of the block given their good condition and has given me the part number for some Hastings piston rings for the NA block as a recommendation.

Questions:

Is there an issue with using the dished NA N42 Pistons with NA piston rings for the horsepower I'm looking for?

 

 

Car seen here:

 

 

and

 

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Uhm n42 is not the block. Or engine. N42 would be a casting on the intake manifold. Im a bit confused by your question. F54 block dished pistons p90 head 14 psi intercooler and 3 inch exhaust. Sounds like that will be in the ballpark for the power u want.

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2 hours ago, MerloZ said:

Uhm n42 is not the block. Or engine. N42 would be a casting on the intake manifold. Im a bit confused by your question. F54 block dished pistons p90 head 14 psi intercooler and 3 inch exhaust. Sounds like that will be in the ballpark for the power u want.

There is a N42 block. Iirc it came on the 75/76 model years. 

 

 

IMG_0417.JPG

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I've been running a bone stock N42 bottom end coupled with a P90 and Holset HX35 at 18PSI for the last 4 years without any problems. Make sure you check the ring gaps / gap them on the large side to accommodate the extra thermal expansion of having a turbo feeding it.

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N42 is the early L28 (75-81ish), F54 the later. It can be a bit confusing considering there are also the N42 cylinder head and intake manifold (both paired with the N42 block the first few years)

 

As to the OPs question, I understand the N42 pistons, while they have approximately the same dish volume as the turbo version, don't have as strong of ring lands, so that's where you'll see failures if you have any detonation problems.

 

 

That said, lots of people have had plenty of success running the unmodified N42 bottom end in turbo applications, and I expect you will have the same if you keep detonation under control.

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