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I Need To Know If This Engine Combo Will Work...


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hey all i need t oknow if this engien combo will work ? and if not let me know what will be needed to get it to work ook?

billet aluminum flywheel+stock 7'1 L24 engine+L28d crank+E-31 head+40mm tripple webber carbs+77 280 z 5 speed+perfromance clutch. the part im not sure about is the desil crank? what do i have to do to get the crank to run in my engien what parts am i going to need to build around that and the parts that i have said will they work with the crank? or will i have to start with a l28 engine or can i just bore the l24 to the apropriate bore. plz lemi know thnx what will be needed to do this.

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It will work if you have a couple thousand dollars for machine work to keep it from self-destruction. There is so much machine work to be done to the diesel crank to lighten it and balance it it is my opinion you are asking for more trouble than it is worth.

A much better alternative would be to use an F-54 block with the flat top pistons with the parts you have and save yourself a lot of time, money and aggravation. You will gain quite a bit of displacement by going to the L-28 Zx block, this will cost you about half what it would cost to modify the diesel crank.

If you want a good street engine don't bother with the diesel crank unless you have at least 3-5 thousand dollars to do the job right. If it isn't done right, you will end up with a very expensive conversation piece sitting in the corner of your garage.

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FYI, last time I talked to Rebello they felt that 40mm carbs are only good for show on a stock motor. They recommended triple 44's or 45's minimum for a modified Z motor.

I am not familiar with the diesel crank setup but I do think with whatever crank you deside to use the F54 280ZX L28 block that 2manyZ's recommended is a good choice.

Given the choice I also prefer the ZX 5-speed because I feel the ratios better compliment each other.

Have fun!

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yes but who has the block for sale i mean like just the block+the pistons = the power of the stroker crank? how much more displacement will it have over the stroker? 2.4L-3.6L? =)

im hopeing to get the same amount of tourqe as my friend 84 300zx which is stock but loads of tourqe i want that but in my datsun which wieghs much much less

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you can easily match your friends 300zx with the proper mods to you car...the diesel crank "stroker kit" just isnt worth the amount of time and effort. Stick with and L28 with flat-top pistons and maybe a higher compression head (i.e. E31, E88). Stick a nice cam on it...tripple delorttos/webbers/mikunis, whichever you prefer, a nice 2 1/2" exhaust with headers, EI,....i mean, theres just so many things you can do, its all up to what you decide. But like most other ppl here....i feel that the stroker motor is a waste of time and money.

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grantman240z,

I was looking through some documentation last night and was suprised to see that the L6 engines produced more HP while the V6 Z31 engines produced more torgue. I understand that it was needed due to the extra weight they had to drag around but I have always thought the L6 would be the torque monsters.

71datsun240z,

There are lots of places to find a good F54 L28 block with flattop pistons. In fact I would think it would be much cheaper and much easier to find than a L28d crank. I bet if you told us where on the planet you lived someone might be able to chime in with their favorite junk yard are engine source that would be close to you.

If you use a stock F54 L28 N/A block, which came with flattop pistons, with a stock early head- E31, E88, N42 or N47(has different exhaust ports.) you will greatly increase your compression (just over 10:1 I believe) over stock which gives you the potential for more torque/HP. The change itself may not help a lot until you make other changes to take advantage of this increase in compression. Going from memory here so don't remember if it is necessary to cut into piston or block to allow for valves to open completely. A higher compression engine responds better to other modifications- bigger , larger valves, more aggressive cam, exhaust.and ignition.

On the other hand I am pretty sure if you want to go with the L28D crank with a stock L24 bore you will end up somewhere in the same 2.8l area. If you bore the block out to it's max I think the combo will give you approx. 3.2l. I am going from memory and haven't done the math recently so corrections are welcome. But you will not be able to use both your stock L24 rods and pistons or the increased stroke will try to run your pistons through the head. Again, this engine setup alone will not give you tons more torque/HP but will respond better than a stock L24 to other modifications.

I apologise that most of this is information regurgitated from my fussy memory. Hopefully someone else can fill in with details, or I'll try to come back with more factual numbers after doing some research.

Maybe John Coffee can give us some of the specifications- bore, stroke, block, head, compression, etc of his 305HP Sunbelt L6 engine!? :)

Hope it helps!

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I don't understand the comments regarding strokers. Machine work required on the crank? No, mine was installed as-is. Expensive/hard to find? They show up on Zcar.com for $250 all the time. I don't think there's an easy way to get it to work in an L24, however. In an L28, you need L24 rods and KA24E pistons (240SX/hardbody truck), and a .120" overbore. Works like a charm. 3.1 liters, 10+:1 compression ratio with the right head (N42 on mine). I ran it with stock 240Z carbs for a long time, with stock 280Z cam. Torque monster! Then I put in a cam and 2" Jag SU carbs and it pulled to 7000 rpm, no problem. I've got about 30,000 miles and ~40 track days on my 3.1 liter, and have had no reliability issues. It's a great setup, and you can build on it as much as you want (cam, head, carbs, turbo, etc.).

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Oops, sorry John I misspelled your last name! John Coffey is a contributor here and on other Z discussion groups. Here recently mentioned his 305HP motor for his 240Z on the IZCC group and I thought maybe I could get him to let us know more about the engine design for his hot rod Datsun L6. Don't know if he will want to tell all his performance secrets or how much he paid for his motor but I am willing to guess it doesn't involve a diesel crank and was more than 10K for the block and head alone.

Are you watching this conversation John?

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I *think* John's class limits him to 3 liters, so no diesel crank. That's gotta be one of the baddest NA L6s ever built. Sunbelt in Atlanta built it. Twernt cheap, I'm sure! I just spent some dough there on cylinder head/cam. Went 5 seconds quicker at Watkins Glen compared to two years ago! 2:22.? to 2:17.0. Sure, my driving improved, but 5 seconds?! My speed at the back straight increased ~5mph. 150 indicated! Oh, but that's close to 130 actual.

Anyway, I still say a diesel stroker is a good idea. I'd sooner recommend that than throwing carbs/cam/headwork at a 2.4 or 2.8. Start with as much displacement as you can get, then add high-rpm capability on a pay-as-you-go basis. The stroker motor doesn't have to be as pricey as some seem to think.

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Dan,

How much did the pistons cost? Do you know how much rear wheel HP/torque your motor puts out?

I certainly don't have anything against the stroker setup, I was just thinking of building the motor the other way around. Build the top end first because a good top end will make any L6 a lot better and then go after the bottom end. Regardless of whether the bottom end is a stock L24, a 10:1 compression stroker L28 with custom pistons or a 10:1 stock crank/flattop piston L28 it will really sing with modifications to head and exhaust. Since a F54 L28 could be bought for about $100 it wouldn't be very much more to upgrade there. But if the budget is more open up front then I could see how it would probably save money(cam choice, etc.) in the long run to start with the bottom end and then build the top end from there. I love my family but they sure have cut into the Z budget! ;-)

Have fun!

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Way back in '94 the pistons cost me $36.38 per (list at $50.53/ea). Rear wheel torque measured last year was 189 lb-ft. rwhp was 177 BUT I had a busted spark plug causing the engine to cut out above 5000 rpm. It was headed to 190 for sure. Can't wait to get back to the dyno to see what the cylinder head work has gotten me! Then I'll swap the 2" jag carbs for the 45mm OER 3x2s I've got and see what that does.

A flat-top L28 is certainly a great bottom-end to build on as well. A diesel crank is by no means a necessity. But if you're rebuilding a bottom-end anyway, it's the perfect time to inch up!

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