Right now my 73 240Z has a beater L28, I don't trust it. I would like to rebuild the original engine so I have matching numbers. The valve and piston hit on the original engine, this apearently released some built up carbon deposits and that scared the cylinder wall. The woodruff key on the crank also wore into the crank making the original crank useless. So i at least need: new pistons, a new crank, maching work and a rebuilt head. I also would like more power around 200 at the crank would be enough for now.

My thinking is that I should bore it .020 over (1mm). Then put in an l28 crank and rods. I will rebuild the E88 head and use SU carbs. My real concerns are these:

Should I get larger valves?

Should I get forged or cast pistons?

What cam should I get?

What machine work should be done to the crank, rods, and block?

What is a good header? (mine is leaky)

In the distant future I may desire to turbo this engine. I wouldn't desire to make much more then 200hp at the wheels with the turbo. I would put a whole new topend on the motor for this (p90, efi, etc.) With flat top pistons the E88 would be under 10:1 CR and the P90 would be under 9:1 CR.

Any input will be appreciated. Thanks.

How much $$$ do you want to spend? I'd suggest boring out 0.120 (86mm) and using 280 pistons, rod and crank. That turns your 2.4 to a 2.8, but looks numbers matching on the outside. I think that's what Rebello does with his motors--see this thread:

http://www.classiczcars.com/forums/showthread.php?t=18641&highlight=rebello+dyno

And,

http://rebelloracing.com/eng_info.htm

End result is a CR of around 10 (premium fuel only), with HP varying on degree of headwork and tuning you do. Cam selection depends on headwork and airflow characteristics...

Forged? Probably not necessary unless you turbo with high boost.

Steve

I was actually trying to figure out how much money I will need. I would only like to spend as much as I have to at this time. I would like to build a shortblock capable of around 250hp at the flywheel and, for the time being, do the minimal amount of work to the head. Once I have the money I will do further upgrades.

My first thought would be to not do all this to your matching-number block. For the kind of power you'd like to have eventually, I'd start with the late ZX F-54 block with the extra internal stiffening. Lacking that, there are lots of L-series blocks out available for free, or nearly. (Shoot, I don't know where you live, but I've got a surplus L24 block out of a '73 myself. And I'll have an F-54 block and crank available in a few weeks.)

After all, if you end up building the bejeebers out of it and blow it up, you don't want to throw a rod through the side of your original block.

machine work will be the cheap part, just make sure you find a reputable shop to do the work. The most expensive shop won't necessarily do the best job. I was quoted over $300 to prep my block for a rebuild by one shop, but I know of another shop that quite a few mechanics have recommended. They quoted me about $100 to micropolish the crank, hone the cylinders, and measure the crank for correct bearing clearances.

I'm planning on rebuilding my original numbers matching engine (I have a post here somewhere about it), and I'm swapping in another crank and rods, but reusing the stock pistons, and replacing all bearings and rings. From what I understand, it's alright to swap the crank and rods, but you really don't want to swap pistons between blocks.

Thanks for all the help so far. I thought that 200hp at the wheels wouldn't stress the stock block too much. That Rebello engine is pushing 219 hp with the stock block and no header. I am sure it could push 250hp with no trouble and that should get me to 200hp at the wheels. In fact it may be best not to turbo it in the distant future if these numbers are achievable NA. I am not aiming to build a 400hp turbo L-series monster. I want a daily driver with a little pep in its step.