Diesel crank???

[red_dog007]

I hear a lot about a diesel crank for N/A motors and it increasing the engines displacement. Is this thing just for L28 n/a motors, or could I look into this for a L24 motor?

Also, even if just for the L28 motor, other then displacement increase (any noticable HP gains?), what are the other added benefits of a diesel crank?

[RIP260Z]

You can put a LD28 crank into a L24 motor, as the journals are the same size. I think the displacement goes to around 2.7 liter. The main gain is more torque, as the diesel crank, but with both you would have to have different pistons/con rods to bring the piston top down to the block deck height.

Ian

[ezzzzzzz]

There is extensive talk of the LD28 crank over at www.hybridz.org. Just do a search over there on diesel crankshaft or LD28. I'm building a 2.9 using a

LD28 block and crankshaft, L20b connecting rods, and custom pistons.

[Mike]

Isn't this modification called a "stroker engine?"

[Arne]

Isn't this modification called a "stroker engine?"

Yup. The basics are the diesel crank, 240Z rods (generally the later rods with 9 mm bolts), and pistons (often modified) from non-L-series engines. Properly over-bored you can get 3.1 to almost 3.2 liters.

[red_dog007]

I think that I searched their forums really good, but I only found L28's with a diesel crank. Found nothing on L24's getting a diesel crank.

Where would I be able to buy a LD28 diesel crank and then new pistons and con rods?

I recently found a guy who lives 5 minutes from my house that does EVERYTHING zcar, so I might ask him to see if he has want I am looking for and maybe even a 5-speed tranny.

[Pir0San]

people choose to put the LD28 crank in the later 280Z blocks because of the siamesed cylinder walls, which have better cooling passages, if I remember correctly. I believe the block code was f54. Here's a good site on what to look for when building a 3.1 stroker: click here.

[brushie1320022]

Arne is right propperly done you can get a 3.2 liter out of it. I may be able to get you one. It is NEW..Private message me and let me know what you want..

[ezzzzzzz]

You can stroke the 2.4 it you want to. The dimensions are the same from L24 to L28. Most do use the later blocks, N42 or F54, because they offer stiffing between cylinders. I have everything but pistons to build a stroker. I decided to go with the LD28 block because I can fit L20b rods (145.9mm) into it. It isn't a cut and paste project but is very doable. Instead of punching out the cylinders to fit alternate OEM pistons (89mm) I am going to have some made. The cost isn't effective but I can keep the bore smaller achieving a 2.9 liter. This will allow another rebuild and eliminate thin cylinders walls sometimes created in excessive overbore. That amounts to reliability. With an Eaton M62 supercharger it should run it's arse off in my little 240Z.

[ktm]

I would not use an LD28 crank in a L24 block. Using the engine design utility, you get a deck clearance of -4.75mm. That is, the pistons stick 4.75mm ABOVE the block. Even using a 2mm gasket means that you have 2.75mm you need to address.

This was using L24 rods, L24 block, E31 head, and L24 cam. The compression ratio was a whopping 20.5:1!

Now, if you went with a 2mm gasket and L28 rods, you will solve the clearance issue. However, your static compression ratio is still 11.5:1.

The displacement is 2.69 L.

[ezzzzzzz]

I wouldn't discount the L24 block for these reasons. I would look to the L28 block for strength when compared to the L24 block though. The E31 is a great head but has small valves. The E88 or a later head would be more viable. The 240Z rod provides less rod angle and sustained piston hang at TDC. Lastly, most everyone wants to use a readily available piston. While that is a reasonable desire it may not acheive a harmonious balance. That is why I will have custom 86mm pistons with 40mm compression height made for my 2.9 stroker.

[ktm]

You would not discount the L24 block because the pistons stick 4.75 mm above the deck or that it yields a 20.5:1 (18.7:1 using an E88 head) compression ratio using L24 rods? Or that it yields an 12.5:1 - I mistyped the last one (12:1 using an E88 head) using L28 rods? A 12:1 compression ratio would require an aggressive cam and race gas.

Why bother putting an LD28 crank into an L24 and only getting 2.7L of displacement. LD28 cranks typically run $300. For $300 you can get a complete L28 N42 or F54 and N42 head setup.