Heads and L28 Blocks

[CoastGuardZ]

HMMMM,

Looking for info...

I will probably be building an engine before I get a Z do to the fact that I have pretty much decided to go with a 2.8. I MUST have a 240... but do to the power i want I feel it will be better to go with the L28.

Now falling back on my shadetree small block Chevy days my thought process is... no replacement for displacement, and make her squeeze tight (10.5:1) slight overbore on the block ~.030, Shave the head a bit ~.030ish, Flat top pistons.

I used that handy dandy lil' program from our Aussie friends (damn that's cool) and what I gather the L28 came with the N47 head, dished pistons, and about 8.3:1. So I start adjusting and get L28 block, crank, rods, N47, FELPRO gasket, .060 over and Flat tops with 10.4:1. Which is where I want to be, I think.

Now on the chevys .060 could start to be a culprit of high running temps. Is that true here also? Where does one get .060 flat tops from? Is the chamber big enough on the N47 to run 10.5:1 with large twin carbs or even triples? I plan on going mild to aggressive cam, plenty of carb, and headers. I'd like to have 200-225hp. When it's all said and done it'll have a 5spd, LSD, and hopefully pull high 12's if not better. What do you guys think? Am I on the right track?

Aren't there multiple L28's out there? I assume the turbo blocks were different. Are they better for building?

How about heads? N47 E31 E88 P79 P90 What's the deal?

Biggest quetion is Am I on the right track?

Whats worked for ya'll?

Thanks,

Nate:cross-eye

[seerex]

this was in a thread I post about building a f54 and 31 combo I hope it helps http://www.classiczcars.com/forums/showthread.php?s=&threadid=1292&highlight=L+engine+calculator

good luck

[ZmeFly]

Id go with the later ZX block F54 designation, already has flat tops, and this you will get a lot of replies on which head is the best but I would say the N42 or the P90. Couple that with a new cam kit, 460 lift 270-280 duration cam, Ztherapy SU's or injection, your choice, a good equal length tube header, 2.5 inch exhaust, 79 5 speed and a 3.9 or 4.11 rear and your cooking with gas.

[CoastGuardZ]

Thanks guys.

It's always good to hear from you Zmefly!

How's things up in PA? Drinking plenty of the Yuengling to stay warm?

Alright so hear it goes... again.

Did all ZX's, turbo or NA, have the F54?

And how about heads?

Am I correct in assuming that the P90 was a turbo head? So wouldn't it be a lower compression head? Personally I'm subscribing to the idea of squeezing it as tight as possible to make power... as of yet I'm not wanting to boost...yet.

Was the N47 the stock 75-78 L28 head?

Was the N42 the L26 head?

Does anyone have any links that may give the whole breakdown on this?

Thanks

Nate the Confused:stupid:

[1975yellowBSPZ]

http://www.geocities.com/zgarage2001/engine.html

this should have most of your answers, didn't know if you'd seen it, figured you hadn't.

[texasz]

Certainly read the zgarage site, it is packed with info!!

Now some things that may or may not be on that site (a summary if you will) all of which is from my research not personal experience:

F54 block was in the '81(or '80)-'83 240ZX, the turbo model has dished pistons, the non-turbo has flat top pistons

the P90 is a turbo head and to get good results from it I have found that you must shave it, shim the cam towers, etc.

the N42 head will give you about the same results as the worked over P90 just by putting it on an F54 block with flat top pistons, results being about a 10:1 CR

I agree with the 3.9 or 4.11 diff completely!

on the tranny I am going with the '77 5-speed (which I believe to be the same as the '78 and '79), here's a site with a nifty calculator to help you decide: http://www.geocities.com/z_design_studio/

header and larger exhaust yes, either a 2.25 or 2.5 (there is some debate on which is better)

carb or injection, your choice (I'm staying with SUs)

HAVE FUN!!!

[mwz]

The N42 was the 75-76 head

The N47 was the 77-78 head.

I'd stay away from the N47 head, IMO. They have a tendency to crack, and they're not that great for performance. It's hard to find one that's not cracked

Chloe

[sblake01]

How did the N47 get such a bad rap? I have two of them now. One on my 78 Z and one on my 79 810. They're both fine. I have seen cracked N47's but I have also seen many of the others cracked. I wouldn't necessarily single out the N47 because I've always had good luck with them.

[CoastGuardZ]

You guys are great! Thanks for all the input. Right now I'm having problems loading the Z garage, but I do rember seeing it before and noting the amount of info kept there.

Let's talk rods.

Were all L28 Rods '75 all the way to the turbo ZX's the same? Were any heftier or were they all the same? Is the L28 known for any bottom end problems? It's alway nice to keep rotating mass down so if there were lighter stock l28 rods that can put up with the abuse of a hefty right foot and 225-275 HP I'm sure that would be the way to go.

Thanks again!

Nate

[280zx Fever]

N42 Head P54 Block Flat tops makes around 10:1 compression..

Now this is where the fun begins...

N42 with Dish Pistons and L24 rods... 10:1 comp

P90 with flat tops and L24 Rods 10:1 comp

N42 Flat tops L24 Rods 15:1

N42 Dished Pistons and L20E rods = 11:1

have fun

[texasz]

Originally posted by 280zx Fever

...N42 Flat tops L24 Rods 15:1 ...

Good lord!! What kind of fuel do you have to run in that monster? Jet fuel??

[MAX]

Has anyone had any experiences with an L28 block and E31 head. I've heard that makes a good combo for a 240.?