NAPS Z 2.4L BLOCK WITH L20B HEAD?

[Spades]

if you want the least complicated route, find a naps z20, overbore it and stick z24 pistons in it, buy the timing chain kit, timing cover, and l20 head. it will still involve machining, but the actual swap won't be that bad(or so I am told). The deck height of the Z24 is taller as people mentioned earlier in this thread, so a timing cover would need to be welded then machined if you wanted to use your z24 block.

 

I would advise against using the stock fuel pump, because most of the downdraft and side draft carburetors you would put on a l20 head need more around 3-7 PSI, and most electronic fuel injection systems need a feed of 40+ PSI, that means you would need a very good fuel pressure regulator with a return line built in, and would cost $100+, and would be allot less reliable and way more money than the nissan mechanical fuel pump and modifying the fuel tank pick up or fuel line on the frame rail(not sure if the pump was in the tank, on the rail, or both on nissan pickups).

 

 

Perhaps you are overlooking the easiest and least expensive way to make power with your truck. If you rebuild the motor with forged parts(like I did with my NAPS), you can use a power adder. Over boring it or stroking the motor, decking/porting/polishing the head, a mild camshaft, ect. like I did on mine will add more horsepower, and if you use forged parts, you can add a turbocharger...so you would be using your stock fuel injection system.

 

almost all fuel injection systems can accommodate 5PSI of boost from a turbo, and if you found a garret t3/t4 hybrid with a "wicked wheel", a type of compressor wheel that allows for faster spool up, you could add a fair amount of power from 2k RPMs to redline.

 

P.S. to fit the z24 in my 72 datsun 510 wagon, I am using a reversed crossmember and front sump oil pan, and one mount out of a naps powered 1980 nissan 510(stanza) on the passenger side, and one modified mount from a z24 powered 1986 nissan pickup. As far as clearance I don't think it will be an issue if he runs a Z20S motor bored over with a L head, cause the casting for the mounting points are almost identical(at least the were on my blocks), and would be easy to accommodate for. A downdraft weber might stick through the hood of the pickup like it did on my wagon, but either it would be hoodscoop time or sidedraft time.

[datzenmike]

if you want the least complicated route, find a naps z20, overbore it and stick z24 pistons in it

 

This will only work with the Z20S motor. but it seems it will work. 2.1 liter 8.6 compression.

[ZXR]

This will only work with the Z20S motor. but it seems it will work. 2.1 liter 8.6 compression.

 

 

Sounds great, but back to what you had said earlier in the post. I would have to mod the engine pretty heavily, on a smaller engine, to get what I already have stock with what I've got. That's why after more research and talking with you Mike, I've decided to go with a VG30E with a www.VG30.com intake manifold and Holley 500cfm carb. Just that engine alone produced 153 hp and 182 ft·lbft of torque. It's already made for a Hardbody and just by doing what you have indicated in my other post (changing out the bell housing from the NAPS to VG30), it should bolt directly up to what I have. These engines themselves have been known to last well over 300K. I had a 1985 300ZX N/A with 336K on it when I sold it and it never smoked a day in its life. Also, the VG30E is less expensive then a KA24E from any wrecking yard and modifying it would definitely produce more HP gains. 100 HP isn't quite enough for this heavy hardbody, but just a stock VG30E should bring me up closer to what I am looking for, without modding it. If anything, I could add the ZEX nitrous plate to the carb and gain (cheater hp) that way, but I'm not looking to drag this 4X4 anyway. Just need more power to be able to pass someone without being scared that I'm not going to make it around them in time.

 

The alternative engine as explained, I'm sure would be great in an older 720, 510 or lighter body vehicle. I bet one would scream. It just sounds like it could become an expensive build. Again, great idea for a smaller, lighter vehicle.

 

By no means am I asking for advice and not using it. All of your knowledge, I have considered in making the right choice. I do appreciate that guys. You all obviously spent endless hours in, under or around vehicles to know what you know to help the next guy out for FREE.Thank you all for your feedback! :)

 

I'm sure this post will greatly help out the next guy who is looking to do what I was looking to do in the beginning of my search for modifications and engine alternatives.

 

I love both of my datsuns and I wouldn't ever consider going to a hybrid american engine for power. I'd rather take a loss in quick american power gain, to build a Datsun engine for longevity.

[sinner720st]

well that sounds like a logical choice, and congrats on making it.... im just a little upset because i was hoping to see a good naps engine build... but you have made very good points about the vg30 pick, my nissan 720 is pretty quick, but its a two wheel drive and i have about 800 bucks and countless hours with a die grinder into it.