L24 crank and rod into L28 block

[jbuenviaje]

Does anybody done a rebuild using a 1973 L24 crank and rod into L28 block..Please let me know whats was the result???

[jbuenviaje]

Of course using L28 flat piston

[sblake01]

L24 crank and rods with L28 flat top pistons? The pistons would be a little over 5 mm short of where they should be at TDC unless I'm missing something here..........

[jbuenviaje]

I was thinking about a L28 block and pistons with the L24 crank and rods for a high revving engine with more displacement than the stock L24.I will run with larger L28 valves P90 head..also be running Ztheraphy SUs..Please tell me what you think and give suggestions.

[Diseazd]

The L28 P79 and P90 head has a larger combustion chamber than the L24 head. The stock compression ratio with the f54 block and P79 or P90 head and flat-tops is just south of 8.5 to 1. The pin height of the L28 is lower which means your piston would come up short of your block deck (5mm?). Your C/R in that engine would seem to me to be awfully low.......It may work with a turbo, but I've never heard of anyone doing it. There must be a reason. All IMO.

[jbuenviaje]

I was thinking make it big-bore with short stroke

[sblake01]

You'd have to have pistons made for that combination. The L28's deck is higher that the L24's.

Edited March 22, 2010 by sblake01

[Diseazd]

Boring out the L24 .060 TO .080 over would be a better solution (IMO).

[jbuenviaje]

Please help on L28 Performance engine buildup suggestions???as much as i want to maintain high revving engine..

Currently I gathered all these parts:

N42 short block

P90 head, 3 to 2

headers,

Z theraphy SUs, and

stage 2 schneider cam

N33 intake manilfold

280ZX dizzy..

[Diseazd]

H.P. is built in the head......You can take the P90 head to someone who knows Datsun heads. Shave the head .090, shim the towers and valve springs up .080 , install early longer L28 valves (they are .080 longer) and you will have approximately 10 to 1 C/R. Next, choose your camshaft (going stock is cheaper) but performance is more H.P. If you have a cam reground, you'll have to install the proper springs and lash pads to attain proper valve train geometry. The stock L28 cam will give you 10 degrees more duration than the L24 cam and more lift....plus it's a lot easier than going with the springs, lash pad and retainer route. You should get a nice boost in H.P. by just shaving the head and running the stock L28 camshaft. Remember....you can't use the L24 cam in an L28 P90 head, but you can run an L28 self-oiling cam in the L24.

[ozconnection]

Does anybody done a rebuild using a 1973 L24 crank and rod into L28 block..Please let me know whats was the result???

Ummmm, I just read the posts here and the information given to you is not correct.

Deck heights were quoted when piston pin heights were supposed to be quoted.....the pin height of the L24 and L28 piston is the same at 1.5 inches or 38.1mms. L24 and L28 blocks are identical except for bore size (The L24E Maxima block has different main journal sizes and the crank and rods are light duty) and have the same deck heights of 207.85mm's (page 54 Datsun rebuild book, Tom Monroe).

As for camshaft interchangeability, check to see what type of oiling setup the cam uses. Some cams (early) use an external spray bar for lobe lubrication, others (late) use a camshaft that is self oiled via a series of passageways internal in the cam. For a full explanation, the book I mention for you to buy has it all in plain English. Get it mate.

Page 4 and 26 of Honsowetz's book is where I'm quoting from for the piston and part interchangeability. I strongly suggest you get this book as well and read it yourself. The information there will help you build the engine your after with accuracy.

Good luck with your project.

Ps I'm toying with the idea of running an L20A crank in my spare L28 block for even more of the same. R/S ratio is something like 1.9 :classic:

Edited March 27, 2010 by ozconnection

[Diseazd]

Sorry,sorry,sorry......You're right it's the rod that is different not the the pin height. The rod on the L28 is 130.2 mm vs. 133.0mm on the L24. Could you indeed build this combo of an L24 crank and rods in an L28 with L28 pistons?

Edited March 27, 2010 by Diseazd