F54 Block and N42 Head

[OZ001]

i am so gonna get killed for this...

 

 

did the F54 come with a N42 head?? i cant seem to find the P90 head anywhere. also what kind of power does this put out??? roughly..

[Zedman240®]

The F54 Blocks came with both N42 and P90 heads. Some had dished pistons (with the N42) and the F54's with the P90 heads had flat top pistons. With standard internals and head, power output (with 240Z carbs and elec igntion) yeilds around 90-95ish rwKw's. Add more with good mods.

[OZ001]

cheers thanks zedman240 trying to source a LD28 over in japan now $2100 landed

[hunterzed]

You can get away with using the N42 head on a stroker. Has better flow and larger valves as well. You just need to use the dished pistons and maybe a larger head gasket. You'll have a compression ratio of around 10:1

[OZ001]

You can get away with using the N42 head on a stroker. Has better flow and larger valves as well. You just need to use the dished pistons and maybe a larger head gasket. You'll have a compression ratio of around 10:1

 

i thought the P90 head had better flow :S or is the P90 just better for turbo setups?

[hunterzed]

P90 will drop you compression so you have a larger range of pistons available to fine tune your compression but the N42 head has the largest vavles out of the 2 and is a lot easier and cheaper to modify and get a hold of. To get the same gains out of each head the P90 will cost you more. Most people go for the P90 head to leave them with more options such as a turbo later on. N42 is a better option in my opinion anyway. But everyone has an opinion. Just to qualify my thoughts. I haven't used a P90 head. This info is from some of the other members here, such as PZG302, (his comments found here http://www.viczcar.com/forum/index.php/topic,5835.0.html) that have used both and are now sticking with the N42 head. So take this info for what its worth.

[Zedman240®]

I got great results using a N42/N42 combo.. If your F54 bottom end has the dished pistons, stick with the n42 head. But if your block has the flat top pistons and you install a N42 head, unless you run avgas/premium, be prepared for some knocking.

[hunterzed]

If you run L28 block bored .120 with Ld28 crank, L24 rods, KA24 pistons, N42 head and 1mm head gasket you'll have a compression ratio of 11.33:1 and with a 2mm gasket you'll get 10.14:1 with a 3098cc displacement. Thats straight off the engine calculator. With P90 head you can expect around 1.58 drop in compression. As I said though, straight off the calculator.

[OZ001]

with the KA24 pistons wheere am i likely to find some? and out of which motor? KA24E or DE or they just both the same and im making myself look stupid?

[OZ001]

KA24 off a U13 bluebird right???!!!

[hunterzed]

240sx. Or you can checke out kameari in the states for their stroker kits. They do the whole lot with either an LD28 crank or if you're going to race it then you might be more interested in the fully counterbalanced crank or even the 85mm crank for an L32.

[OZ001]

is there any other car i can get the pistons from with out looking for a 240sx?

 

[PZG302]

Try JP Pistons in South Aus, they can custom make the pistons you want/need. Won't be cheap, but will be right. If you're looking at building a stroker DON'T skimp on anything.

 

I'm only running a stroker because one fell into my lap at the very right price of not a lot. I will be keeping it for as long as I can, but if it goes bang and the bottom end is damaged beyond salvaging at a resonable cost, then I will go back to a standard bottom end and big bore to go to L29 as per a previous motor spec I raced with faiorly good results, ie 150hp at the wheels and plenty of torque, not quite as much as the stroker but still plenty.

 

Personally for a good strong motor that will be liveable on the street and quite handy on the track and relatively cheap, here is what I would do.

 

N42/F54 block, whichever you have. Get tested to determine safest over bore possible, be very happy if you can get a 89 or 90mm bore, it will be a good torquey motor.

 

N42 head, clean up the ports and combustion chambers. The amount of work depends on budget. In reality not a lot is needed. Get the head serviced and new valves and valve springs as minimum, as well as seats. No real need to port the head, just clean up and don't polish, you want some turbulent flow.

 

Cam, depends on what you want. I run the Nissan motor sports 76 degree grind in the race motor with injection and I could live with it on the street in this set up. It pulls from about 3500 to 6800 and I rev the motor to a max of 7200. Idles at about 800 - 1200 when warm.

 

A more suitable grind for the street would be around the 72 degree grind, or I have used a 65-25 grind with good results for a streetable motor.

 

Personally, I would run EFI, but get the right manifold. Do not use a L24E manifold, too small. If you can, run a NAPS manifold, or a 280ZX manifold. The 280ZX should have twin butterflies, this will work, but there are better. The N40, I think this is the right cast marking is a single 63mm butterfly and has slightly longer runners and better ploenum shape. Dat2Kman can give you a very thorough tutorial on the logs.

 

The ultimate would be ITB, but only if the injectors are placed in the standard location at the head. The L series doesn't rev fast enough or pull enough air to really make the most of the injectors being away from  the head as most aftermarket set ups are.

 

The standard L28 injectors are fine for most NA applications. I run the standard injectors with a Haltech F9 computer and electronic dizzy. Other aftermarket computers will work just as well, and the standard L28 computer is quite goos and there are some tricks to be used with that one as well. My personal preference would be for Haltech or Motech, more exxy than some of the others but that's what I prefer.

 

If you don't want injection, then triples or a good set of 2 to 2.5 inch Su's will work. Triples will be the most fun, but be prepared to spend money on them, my preference would be webers or Mikunis and buy new. Get the best linkages you can find and pay someone to set them and tune them right. This will see you only having to get them tuned every 12 months or so if you don't play with them, or worse yet let someone else play with them.

 

Exhaust, a good set of extractors, if you can afford it get some made by someone who knows L series motors, not the bloke down the road who says he can, and then if it's a road motor, a good 2 1/2" system.

 

This is only my personal opinion based on 20 years of racing L series motors in 4 and six cylinder form, using standard carbies, webbers and injection, for categories like Production Street Sedans, Improved production and Marque and Production Sports cars, plus being able to spend time around some of whom I believe to be the best people to play with L series motors over the last 30 to 40 years.

 

 

[hunterzed]

Thanks heaps for that. Not trying to hijack the thread but this helps me out heaps too. Some good savings to be made by getting the right stuff the first time round. 

[OZ001]

^+1 agreed very useful information, im still gonna run triple carbs

[Timwell]

Yeah what a great post.

 

Just to take this on a slight tangent.

 

With a stroker what are the best conrods? I have been reading FJ20 conrods and L14 conrods......is it worth the hassel?

 

 

regards,

 

Tim

[sexual_sushi]

Great post PZG302.

 

Oz001, Bajcsi over on zcar.com had some custom pistons made from JE in replace of the the ka24 pistons...

 

"I had mine built by JE. I can provide you or anyone the full spec/reorder sheet for them. They cost $800. Not cheap, but, they are custom for the car not KA24 pistons surfaced or with .6 deck height to deal with. The are forged and actually have proper valve reliefs, etc so you can run a 1mm head gasket with an e31 and get around 12:1"

 

 

He was nice enough to give me the order sheet for them. I can upload it if you are interested. I might email him first and make sure he's alright with me posting the file. Note the scan is a bit hard to read, I'll try clean it up in photoshop a bit first.

[hunterzed]

I'm sure people have seen this floating around on the forums before. This version was made by one of the guys on the Sydney Z car club forum. I'm not sure who exactly otherwise I'd credit them directly. Either way it is a good little program that makes things very easy to calculate for different set ups.

 

http://www.zshop.net.au/Photos/Parts/specials.htm

 

 

[PZG302]

Yeah what a great post.

 

Just to take this on a slight tangent.

 

With a stroker what are the best conrods? I have been reading FJ20 conrods and L14 conrods......is it worth the hassel?

 

 

regards,

 

Tim

 

For mine,

 

The best con rods are custom made ones to get everything right.

 

When you use existing new or second hand production rods there will always be compromises.

 

From what I have read and been told, the best production rods are the L14, but from memory you have to get the correct L14 rods to use, and I believe they are getting rarer than rocking horse poo.

 

As I stated above, if I didn't have a stroker fall into my lap, I wouldn't be bothering in building one. I would use a good L28, either N42 or F54, out to 89 or 90mm, depending on condition, using the standard L28 rods and oversize flat top pistons to suit. And get another N42 head prepped the way mine has been and run standard injection with Haltech computer.

 

The L series bottom end doesn't any work as the factory tolerences were brilliant compared to the old red motors and 250's Holden and Ford threw together in the '70's, so they don't need the work that these anchors need to hold together at anything over 5500rpm. The stock bottom end will handle 7000rpm all day everyday if not abused.

 

[electronics]

Noted with interest all the  comments and rhetoric about F54, P90  and N42.

On the ONEZ website in 2004-2005 all the techncial information you needed was there but websites come and websites go.

Then you read next G people re-inventing the wheel and talking all sorts of stuff about what fits with what.

In our wrecking yard over past few years we have crushed up P90 after P90 and F54.

I pulled one and  had the opportunity to build one up in 2004 using all original Nissan parts.

I thought at the time the $2000 bill was excessive but we started and ran the engine on LPG only.

It handled the flat tops just fine.

 

The car is still around rego is ZX2802.

Engine is strong, runs a Crowe gas cam and despite all the hoo hah about what head to run I found N42 was just fine.

The F54 was a real high serial number.

Flat tops worked just fine.

The car was at the Nats in Goulburn in 2004 then I sold it, wonder where it is now?