It depends on what you intend to use the car for - Street, track, daily driver, show? It also depends on you budget and your mechanical expertise. If you want to simply drop-in a new engine, then stick with the straight six and find an original 2.4 liter from a 240Z or a 2.8 liter from a 280Z or 280ZX. If you go with a 2.8 liter then do some research because, while the block is the same on all 2.8 liters engines, heads and intake manifolds are not and they have an effect on horsepower.
The easiest approach would be to go back with a 2.4 liter from a 240Z but they might be hard to find. Your 240 is already wired and piped for that engine so this would be the quickest solution.
The next best approach would be to drop in a 2.8 liter. However, these engines are fuel injected and require a fuel management computer which your 240Z does not have. So, when you purchase the engine also purchase the computer and wiring harness. I recall that there are also issues with the ignition and cooling systems.
V8's require modified motor mounts, tranny mounts, and a custom built drive shaft. A weak point is the rear diff and half shafts. You can get by with the stock rear differential and half shafts but they WILL eventually fail under the additional V8 horsepower. The V8 conversion is expensive and a bit complicated. The 240 frame rails cannot hold up to the torque of a V8 and you will eventually have trouble with the frame rails. Bottom line, the 240 chassis was not build for the torgue of a V8.
There are many Z club websites and many of them have articles covering this topic so I'd suggest you read all the articles you can find and then decide.
If you are going to truely restore your 240 then go back with original otherwise it will not be considered a restoration and at car shows you will compete in a modified category. Also, true ZCar enthusiasts/puresists frown on V8 conversions.
I restored my 1977 280Z and I decided to go back with a well built 10.5:1 compression fuel injected 2.8 Liter engine with a mild street cam, competition clutch. I built the engine myself and had a lot of fun doing it! It is as much fun to drive as my 01 Corvette Coupe and it will light up the tires and it will put you back in the seat.
You can get a lot of performance and HP out of those straight 6 engines.
Good Luck!
Last edited by Trudge : Nov 24th, 2005 at 09:18 AM.
It depends on what you intend to use the car for - Street, track, daily driver, show? It also depends on you budget and your mechanical expertise. If you want to simply drop-in a new engine, then stick with the straight six and find an original 2.4 liter from a 240Z or a 2.8 liter from a 280Z or 280ZX. If you go with a 2.8 liter then do some research because, while the block is the same on all 2.8 liters engines, heads and intake manifolds are not and they have an effect on horsepower.
The easiest approach would be to go back with a 2.4 liter from a 240Z but they might be hard to find. Your 240 is already wired and piped for that engine so this would be the quickest solution.
The next best approach would be to drop in a 2.8 liter. However, these engines are fuel injected and require a fuel management computer which your 240Z does not have. So, when you purchase the engine also purchase the computer and wiring harness. I recall that there are also issues with the ignition and cooling systems.
V8's require modified motor mounts, tranny mounts, and a custom built drive shaft. A weak point is the rear diff and half shafts. You can get by with the stock rear differential and half shafts but they WILL eventually fail under the additional V8 horsepower. The V8 conversion is expensive and a bit complicated. The 240 frame rails cannot hold up to the torque of a V8 and you will eventually have trouble with the frame rails. Bottom line, the 240 chassis was not build for the torgue of a V8.
There are many Z club websites and many of them have articles covering this topic so I'd suggest you read all the articles you can find and then decide.
If you are going to truely restore your 240 then go back with original otherwise it will not be considered a restoration and at car shows you will compete in a modified category. Also, true ZCar enthusiasts/puresists frown on V8 conversions.
I restored my 1977 280Z and I decided to go back with a well built 10.5:1 compression fuel injected 2.8 Liter engine with a mild street cam, competition clutch. I built the engine myself and had a lot of fun doing it! It is as much fun to drive as my 01 Corvette Coupe and it will light up the tires and it will put you back in the seat.
You can get a lot of performance and HP out of those straight 6 engines.
Good Luck!
What cam do you have? I was probably gonna go with a .270in/.280ex duration 460*lift on mine. Also, what kind of supporting mods are needed to go along, besides the obvious valves/springs/rocker arms/lashings/etc? I'm not trying to hijack the thread or anything, just curious.
What cam do you have? I was probably gonna go with a .270in/.280ex duration 460*lift on mine. Also, what kind of supporting mods are needed to go along, besides the obvious valves/springs/rocker arms/lashings/etc? I'm not trying to hijack the thread or anything, just curious.
I don't know yet cause I havent got the car. I think it doesnt even have an engine!
Actually, I was asking Trudge, lol. Sorry for the mixup.
I would try and find a n/a 81-83 L28 (2.8 liter motor). I'm pretty sure you can mount some 240z carbs up to it no problem. They will have to be re-tuned for the bigger displacement. You should be able to get at least as much hp out of it as the 240 originally had. 240's had 150 hp gross, which is probably like 130 net or something. A fuel injected L28 had 145 hp max net. In a car as light as a 240, it should feel pretty peppy. There are tons of stuff you can do to the L28 with parts swapping and stuff. One important thing to note is that the later L28's cannot be equiped with a mechanical fuel pump, but this is not problem as an electrical one can be hooked up easily. If you switch to fuel injection, there are a host of things that will have to be addressed. It is not that hard to do, but you should do some research on zcar.com. It is a great site, lots of history and a good search engine.
The most popular swap for the 1stgen Zs is the L28ET swap. This swap gives you the most power for your money. As Trudge said, the L28s are fuel injected so make sure you get the computer and wire harness. There are a few other things that you will need as well. If you aren't familiar with these sites, zcar.com and hybridz.org, check them out. They have a wealth of information about these swaps.
My personal favorite engine swap for these cars is an RB25 or RB26 swap from a Skyline. They aren't cheap and would require custom mounts, but the exotic factor is very high and even though they have gobs of HP, they aren't torque monsters, so you wouldn't have to worry about them twisting up your unibody like a SBC V8 would, until you started building them for over 400HP.
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God must love stupid people; he made so many of them.
Imolog , I took the engine, 5-spd and differential from a wrecked 280zx 2+2 and put them in my '72 240 back in the mid '80s. Used the stock 240 intake manifold, carbs and linkage. and the electronic ignition for a 260Z. Dumped all emissions junk except for pcv valve. I think I used a 280 z down pipe for the exhaust, I dont remember the pipe size , but my local muffler shop put me a nice quiet free flow system together. Used the zx mags with 225/60 14 Michelins all around. Also put the zx fuel tank in the car. The entire project was cheap and easy to do.
Why 280 zx 2+2 parts? Bigger flywheel, larger heavier duty clutch, hefty 5spd, bigger differential with 3:55 to 1 gear, and all the parts bolt right in to a 240Z with no cutting, fitting probs or irreversible stuff in case you realise that the 240 has vintage value.
What did I gain? 30+ mpg at freeway speeds in 5th. Extended highway range from the extra fuel capacity. good torque and acceleration increase through all the lower gears ( 2+2 3.55 to 1 rr) ,and outrageous top end. Now I also had a 4:11 rr end and another l28 with 10.5to1 compression, crower cam, and triple DCOE 40s on a Cannon manifold, with Cannon header and a 2 1/4" freeflow system which I ran in the same car. That setup was Porsche 911 humiliator territory. Unfortunately that engine eventually wiped a cam lobe and dropped a valve .
My wife has made me promise to never build another street Z like that one because it was just to scary to ride in! Light the tires? Just like the drifters on TV!
So for what it's worth my opinion would be stay Z, keep your 240 stuf in case you need to put the car back to original.
All the best with your project, enjoy it, and don't drive like a madman!
You must be an N/A guy. Because if you have done that much work on Z's, you know the power potential of the L28ET. But I would have liked to have seen your 10:1 CR L28E. That sounds like a fire breather.
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God must love stupid people; he made so many of them.
Hey Pathfinder:
It was! I'ts also the reason my wife won't let me build another "built up" Z !
Lest everyone gets the wrong impression,i am not a great engine builder. I used to be a minor partner in a sports car shop on the extreme eastern edge of Columbus Ohio, my partner John turned me on to using 2+2 ZX running gear. I bought the built up L28 (with blown head gasket), and the 4.11 rr end from the manager of another local shop. Our mechanic Jack was a highly respected Porsche competition engine builder, and my fiddling with the reassembly of that L28 drove him crazy. So much so that he took my engine away from me and would not give it back until it was assembled! We installed the engine, tuned it, took the Z and Jacks 944t to a closed road, and promptly trounced the 944t. Boy was Jack upset! Anyway that setup was marginally drivable in traffic, but the stock l28 was a dream in that 72Z.
Sadly Jack died of a heart attack, but John is still in business repairing jag's and Bimmers.
I'm currently amusing myself with the rebuilding of an '84 N-12 Pulsar.
Keep at it Imolog, my next project will be another Z, SHHH ! Don't let my wife know!
Rich.
Never did mess with the l28 turbo engines, I felt that the N/A engines were already pushing the limits of controllability, at least for me. Had some friends in Ft lauderdale who had some 350hp monster 28t Z's running around though. They reckoned 400 hp was possible.
I almost forgot to pass this on. If you are having carb trouble, find a pair of 175 Strombergs ala TR-6 vintage, they bolt right up to a 240/260 manifold, and work very well. Great for keeping your car drivable while searching for early Z SU style carbs.
Gotta go ,all the best. Rich
So many choices. As you've read, these are all very good swaps. Very easy to deal with for the most part. The information is there. It has been done. With the "tuners" its become popular to do the all-powerful rb26 hybrid w rb25 5 spd trans. but thats $$$$$. also people often throw in a 25. I have seen 4 different SR powered 240z's. Interesting, as they are basically mid engine (sits far enough back). Light-weight, fun, easy to get parts for, and people make the mounts. Check on hybridz.org also you may want to look on zcar.com 2 good places for everything Z related. As these knowledgable builders here know, the info is out there, search is your friend.
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s30 72 l24 powered 240z.
Working on 89 Mk1 Mr2
Built CA18 powered S12
In the past, Built 490HP Sr powered s14
In the past, built 740HP 2JZ Powered Soarer (SC)
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