I have read that the L24 makes 151hp, while the L26 makes only around 130hp and the L28 isn't much better. Is this true, and if so wouldn't it be more logical to keep a L24 in a 240z and work on it? Does the extra displacement really make much difference?

 

If you are modifying an engine, the old saying, "There's no replacement for displacement." is very true. People pay thousands of dillars to build stroker L6s (3.2L and more).



John Coffey
johnc@betamotorsports.com

 

Can you remove the emission controls from these engines? I am not sure about laws like this in Australia, but I think it would probably be legal. How much would this improve the engine preformance? At all? Did nissan specifically not tune them up to the performance of the 240z? Thanks.

 

If you measure H.P. under S.A.E, conditions ( as with the 260 and 280Z ) you would find the 240Z only produced around 120 H.P.

REDZED

 

Alan,

Relax... stop relying on factory published (or anyone else's) horsepower numbers. You'll find as you learn more about this stuff that horsepower numbers are like a man bragging about the length of his *****, as long as you don't have to prove it, either can be as big as you want.


John Coffey
johnc@betamotorsports.com

 

Alan I believe that the 260z & 280z engines L26 & L28 were less powerful compared with the l24 when all 3 are stock because the l26 had a bad set of carbies to comply with emission controls and the L28 had the first form of fuel injection. The injection however was better than the 260z carbs I believe. Anyway currently I am tearing down a 240z and I was thinking of putting an L28 turbo engine in but I have recently descided against that and want to work the l24 and turbo charge it because they are the same block I will use L28 parts but I wanted to keep it an original engine just incase later on in life I want to revert it back to factory standards to have a full on original classic 240z.


-=240z=-

 

What do you mean by stroker L6's do you mean the l26 engine with a 3.1ltr bore I still don't understand alot about engines.

-=240z=-

 

So if the carbs are replaced on a L26 it would preform better? That would be good for me as there are an abundance of 260z's in adelaide, so sourcing an engine would not be too difficult. What are the emission controls? Just carbs? or are they something electronic that can be removed? thanks.

 

Well L28 would be even better. I have a 260z 2+2 which has an L28 engine with British Su's which are off a 72 240z I believe. Anyway I don't think you'd have to worry about emission controls if you have a 240z because they had none when they came out. The 260z was the first Z to employ emission contorls and thus performance lacked. The only thing to be worried about would be when getting a Road Worthy but who's gonna know the difference between an L28 and L24 engine.

-=240z=-

 

We don't get 280z's in australia, only 280zx

 

Alan,

Depends on what head you have! If you have a e33 you are in great shape. I recommend you ditch the L24 BLOCK for a L28 BLOCK. If you have a e88 chance are pretty good you have the newer hatachi carbs, not so good. Then you are better off looking at your engine options.

The newer e88 head have more flow restriced round intakes, where as the e33 is pre-emmissioned square intakes(better flow). e33 head were put on from 1969-1971 oct.. You can find the markings on the head below and between the 1 and 2 spark plug wires.

Good luck in you decision, hope I helped.

 

I have done the L28 swap in my 240Z using the original SU carbs that came with my L24 engine and found a very noticeable increase in horsepower and torque. Some of the heads on the 280ZX have square exhaust ports and are also drilled to accept the L24 intake manifold.(N42/P90) however, I agree with the suggestion to keep the E33 head if that is what you have.

 

I am sorry for the typo. the older head is not a e33 it is a e31. E31 is the correct head model #. Sorry

 

Also a very important factor early 240s had E3100's.

 

I have a 70' 240 with stock L24 motor and E31 head. I don't quite understand E3100 as in 3100cc's, or something else why is that important , I already know that is the most desireable head. I was going to put a L28 block in mine cause I found a nice one for cheap, I just have to swap heads and put it in. Why does the compression go down if you put the E31 on a L28 from 9.15/1 to 8.79/1 I beleive is what my engine builder program says. (thanks David 1TUFFZ) I like having my hi revs on the stock 240 with the head swap will that bring the revs back some on the L28 block, or will I still have the lower revs like on the stock L28. Thanks for the help.

What turns? There all straight to my Z