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'71 240Z

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I am currently stripping my '71 240Z, and have it mounted on a rotisserie where I am media blasting the car as best I can. In the meantime, I have been researching more and more into what I'd like to do with the engine. It is the original engine, matching numbers, E31 head, P30 block etc. 
When the time comes I will be taking it to a local machine shop and getting their advice and guidance, however, I am looking for some second opinions for future reference and pointers in case there is any new information I've missed on the forums. 

-  Cylinder head ported and polished, larger L28 valve seats fitted

- Camshaft undecided, but will be upgraded (possibly Schneider?)
- Valves, DSI big valves
- Jenvey ITB L28 kit, to run with megasquirt COP setup

- L24 conrods

- LD28 crank


- Custom L24 pistons, pin height lowered from 38.1mm to 33.4mm

I am looking for a 10:1 CR or higher, using the OZDAT calculator (with 1mm HG) the above setup came to 10.420:1 CR, and 2.694L . I am aware of how difficult and expensive LD28 cranks are to track down, and the cost associated with custom pistons.
I know this will cost a lot of money, and that going with an L28 would be a better choice, however, I am not so...

Simply my questions are:
- Would this setup work? (pretty sure it would from my research)
- Live in the UK so will run on 97 or higher, would this cause issues?



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56 minutes ago, turbogrill said:

Sounds great! But point less getting the ld28 if you are not going l28?


Isky has cams as well. Race car or DD?

Will daily drive it mainly but it will see a good few track days as well. Since I posted this I've had a rethink and will either stick with the L24 crank or find an L28 crank and use L26/28 conrods. L28 crank, L24 pistons and L26/28 rods (130.2mm) would give a 9.86:1 CR. I've drawn up some custom conrods on CAD (130.35mm) only a small difference, but that would give a 10.021:1 CR. In short, I've decided to build an L26 haha. 
The LD28 crank is too rare and expensive, rather put the money elsewhere on the build. My power target is between 200hp, anything over that is a bonus, not 100% what that would translate to in RWHP, but that's the aim. 

Other plans for the build, CD009 6-speed transmission, with the Hoke Performance 6-speed adaptor kit to match, along with their crank sensor. Got a Nismo 4:1 2-way VLSD from an S13 downstairs which will eventually make its way into the car as well. All suspension components will be from T3. Lots of work to be done, and lots of ideas to test and implement! 

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4 hours ago, HuD 91gt said:

CD009 is way overkill.  Search for a 240sx transmission, or if your dying for a 6speed, a SR20 is probably similar in adaptation.  


Pretty set on the CD009 as the kit from Hoke Performance I've only seen and heard good things about, and the cost is good considering what's provided, in my opinion. Lots of development work has gone into it and it'll save me a lot of custom fabrication and machine work. I've found a supplier for a CD00A, so it'll be a fresh gearbox, no synchro issues and paired with the adaptor kit it should be a real clean setup. 

Maybe overkill, but that means I'll have no worries of it failing on me... Fingers crossed. 


2 hours ago, turbogrill said:

Just build a l28....or are you limited to bore somehow?


Also, cam selection is very important. 10000 different strategies.

I'm sticking with the L24 as I'd prefer to keep what I've got, I see no reason to get rid of it. It's the original engine, it worked and ran last I checked and seems in pretty decent condition so why get rid of it when I'm not looking for big power. If it turns out that the head and/or block are no good, then I'll look into an L28... But finding parts in the UK isn't always the easiest of tasks. Plus I don't have the space to keep a spare engine lying around, and selling it is just hassle I'd rather save myself from. 

But yes, swapping to an L28 would make sense. But if I bought a car to make sense I wouldn't have got a project car, let alone a 47-year-old one haha!

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