short stroke engine

[toletero]

Does anyone knows what will be the setup for a short stroke z engine , Im been reading that the setup will be a long 280 block with a 240z crank and 240z rods , now my question is what is the Pro and con of a engine like this . I know that the power band will be at high RPM rev , but because Im going to build my engine with a 560 lift and a 300 duration cam , I would say that an engine like this will rev and operate better , but because I have never done this I want to know if someone have done it or if someone have any info on this setup , thanks for any info . Take care ...

[2ManyZs]

Well it has been done. A lot depends on what you are going to use the car for. Daily driving only or are you going to race it once in a while. With a 280 block and 240 crank and rods you will be around 2600cc's but the powerband is going to be in the 4500-7000rpm range, which would require re-gearing to use it to the fullest extent. It will have a much narrower powerband than if you used a straight L-28 swap and the torque curve is going to be less linear than the L28.

There is an article in the Nov/Dec 1997 issue of the old Z-car magazine about this swap. One thing the author did say is that below 3,000 rpm the engine was pretty weak so in stop and go traffic it is a bit hard to deal with. It would almost be the same as the new Honda S2000 where you have to run the car to the upper ends of the rpm range to use any of the available power.

IMHO for a street driven car it would be better to use a straight L-28 swap and gain the torque down lower in the rpm range and you will also gain a bit in displacement.

[toletero]

Well I was thinking to use this car not every day but once and a while , just to drive it to the club here in Miami or to events , but like you said , it is going be too week in low RPM than is not what Im looking for , I think Im going be using the L28 block anyways with the normal setup . What do you think about using the 560 lift and 300 duration cam , I know it's a wild cam but I like the overlap sound of the valve in the engine , and I olso planing to put a aluminun flywheel , what do you think ?

[2ManyZs]

The aluminum flywheel sounds like a good idea but remember that most times they recommend a better clutch such as a Centerforce with a higher clamping force to get the most out of the flywheel. Not sure how a stock clutch would hold up, but it might allow too much slippage and not last very long.

The cam choice is OK but a lot of how it will work will be in what head and carb set-up you use, and what pistons you are going to use. The cam might be a little too wild for stock SU's, you might need to think about Webers/Mikuni triples to get the most out of the cam. Another thing to think about would be how much vacuum you will be getting with this cam.

I'm not an engine builder so I can't really give you a definate opinion on your ideas, I only base my opinions on what I have read. You might want to consult with someone like Rebello racing engines on your final choices. Your cam choice is going to affect many other areas so you need to talk to someone that knows what works as I have no experience with this cam.

Piston choice, head, and induction system are going to be critical in how this works, so you may want to do some research on this from the pro's before you start gathering parts.

My guess would be an E-31 head (or a P-79 or P-90) with the larger 280 valves and flat top pistons to come up with a final compression ratio in the 10 to 10.5 to 1 range, with a set of triple Mikuni's.

[byunique]

Regarding the cam, I used to have a 304 duration, .525 lift cam. Because the motor was not high compression, that was a huge mistake (installed by my mechanic). At the time it was just a basic 240 block with E88 head with triple webers. Also, the power range is really weak below 4500 rpm. Once you hit 4500, it takes off wildly, but figure you have to build the engine to pull past 7000 rpm if you want a decent powerband. Su carbs will also not flow well at that rate, so triple carbs will be inevitable. Yes, it is a big cam, and with a light flywheel, it is going to idle very rough.