taylor76zharris

I was given a l28et motor with out either intake or exhaust manifold, basically just the block with the ET internals. Now, i already have a running l28et in my 280 so i don’t really need another one. I really want to build an l28 carb motor. Can i just use the flat top pistons to raise the compression ratio and put carbs on? I just want to convert an l28et to an l28. I know that seems crazy being most people seem to want to do the opposite

PredatorZ

A turbo swap can be done to an NA motor, but just getting a turbo block wont help you much, if your looking to do a turbo swap I would recommend getting a turbo donor car, just the block alone w/o turbo and ecu and all the additional parts wont do you much good. If all you want to do is add Carbs to your engine, no need to use the turbo block, it is a lower compression and wont work as well as your current motor. Fuel injection is much better than carbs, but having it as you like is your choice, you will most likely spend a lot more time fussing with a carb setup, get worse mileage and have more cold starting issues. I could be wrong, and trust me if I am, one of the Guru's will be quick to correct me, but I don't think having an ET block will help you much. What type of carburetor setup were you looking to add on ?

zero

That is astounding reading comprehension. Anyway, to answer your question- Yes. The f54 block is used for turbos with dished pistons the and same block for 82-83 naturally aspirated cars using flat top pistons. The difference in heads is there too. Find the L engine calculator by searching and compare compression ratios for flat top pistons and whichever turbo head you have to a P79, N42, e88 or N47 etc. and see what you get/think. Any injection head you will have to weld up the injector ports.

hoov100

I had a turbo long block with 280z EFI on it and it ran just fine.

zero

And do research away from this website.

zero

Because you had dished pistons in your old block and a head designed for it! He is trying to RAISE compression for more power using flat tops! He is not building a get-by EFI slug. Geeeze.

ThaPimpShrimp

I have no idea what these other guys are on about (aside from Hoov) but from what I have read it is definitely possible. I have also read that the Turbo block is stronger so it is better to start with. It won't have a lower compression, the lower compression is due to the pistons and head. The engine is under boost so it actually goes through more than the n/a block..

Most of the people that build a stroker engine prefer to start with a Turbo block, and I plan to do the same on my build some day.

NismoPick

^^^ To clarify, the F54 is not "only" a turbo block (Datsun L-series ZCAR engine modifications). It was for all 81-83 L28E's and L28ET's.

The L28ET has a 7.4:1 CR (dished P90 pistons), the L28E has a 8.3:1 CR (flat top pistons). I believe the L24 (240Z motor) has a CR of ~9.1:1.

Running SU or triple carbs meant for 9:1 CR on a motor with 7.4:1 will probably be a tuning nightmare.

zero

What exactly would be a tuning nightmare? I have a l26 bored to 2.8 with e88 head, 10:1 cr, and early 240z Hitachi carbs, and Its been in tune since I dropped the motor in over a year ago. I run 93 octane.

ThaPimpShrimp

What I was getting at was this, "The block of choice for the 3.1 stroker is the F54. Although some people have used the N42, the F54 block has webbing built in between the cylinders for extra rigidity."

Datsun 240Z 3.1 Stroker

NismoPick

Said I.

zero

Why can none of you read? He wants to use flat top pistons and is NOT using EFI. So quit bringing up EFI and dished piston scenarios.

zero

You're talking about a combination of parts he is not going to use! On top of that there wouldnt be a tuning "issue" or problem with it anyway! You are talking about a nonexistant issue on a motor he is not building. Go put on the dunce cap and sit in the corner.

zero

With flat top pistons and the turbo head you are looking at 8.4:1 CR. Not fantastic. Sell/keep the p90 and find a N47 head to get 9.6:1 or even closer to 10:1 with a 1mm head gasket. That is a good combination.

69-GnoseZ

Or he could shave the P90 80 thousand to bring the compression ratio up past 8.4:1 (F54 block + flat top pistons + shaved P90).

zenzee

Zero, you must be old school where the original wisdom comes from to be able to di-sect simple information that becomes otherwise contrary to what is being said. Must say i like it, though others might take offence. Thanks Zero.