NAPS Z 2.4L BLOCK WITH L20B HEAD?

[ZXR]

I have a 1987 Hardbody with the NAPS Z 2.4L engine. I spoke to Devin at the Blue Lake show yesterday about converting an L20B Head directly onto my 2.4L Block. Is this doable? What other parts would I need to make it work, if any? I am new to this modification. Also, if it were to work, what year L20B head is the best to use? I appreciate the information.

[izzo]

LoL, yes its doable. This has been ran over 1400 times, tho i still can't remember what all is involved. I know for a fact you have to extend the l20 timing cover (a few mm, so be prepared to hire a welder unless you can do aluminum), something to do with the crank getting re-ground, blah blah lol.

 

 

Check this thread out man

 

http://community.ratsun.net/topic/996-jason-grey-info/

[datzenmike]

Any L head will fit but one from a 'larger' L20B would be best. U-67 with square exhaust ports or W58 with round. The L head has a combustion chamber that is about 12 cc smaller and this will really jump the compression ratio on a 2.4 liter engine. I worked it out... 9.47

 

Your motor is actually a Z24i with TBI so the fuel pump pressure will be 10 times too high for a carburetor.

[izzo]

Any L head will fit but one from a 'larger' L20B would be best. U-67 with square exhaust ports or W58 with round. The L head has a combustion chamber that is about 12 cc smaller and this will really jump the compression ratio on a 2.4 liter engine. I worked it out... 9.47

 

Your motor is actually a Z24i with TBI so the fuel pump pressure will be 10 times too high for a carburetor.

 

 

To solve that just use an L series fuel pump on the L head :D

[datzenmike]

Ah, it's the simple things in life.

[ZXR]

]I understand that this has been talked over prob way too much. This is just new to me. So if you know of any links to reference, I can just go there as well. I appreciate your feedback. I am a welder for the Boilermakers, so It wouldn't be a problem welding it up. If the later year would be better, as you have suggested, I will go with that. Will that head (say a W58) half to be modified as well to fit the timing cover?

In regard to the fuel pump.....The TBI is going down the road. Prob go with the Weber 32/36. Unless you have another suggestion? I will just run a Holley regulated fuel pump instead.

Also, do both run the dual timing chains? and would you know if the NAPS Z Hooker Header bolt up to the L20B? Again, I appreciate the info. At this time, I only happen to know just about everything about the Z car end of engines and am very interested in learning more about these conversions. I read on Wiki about the LZ22 conversion. I believe it was L22 block, Crank and L20B head? I just need to be able to still run my stock tranny with whatever conversion is best. I just want to be able to get more power than this gutless POS engine I have now. Just need to know what's best to do on both the cylinder head and block. Cause it's gonna be a monster when I'm done with it.

[izzo]

I posted the link to the z24 l20b shit, check it and read, if for some reason your finger can click the link, ill paste it here or something...

[datzenmike]

The L head won't need modifying to fit. A Z engine exhaust will not fit an L head. L and Z engines both use the double row timing chain. To use an L head it will need to be modified for length.

[Z-train]

To solve that just use an L series fuel pump on the L head :D

Actually,keep the existing pump and reg it down will keep better pressure and recirculate fuel.

[ZXR]

Thank you very much! I just finished reading all the information resources that you have given me. You guys know your shit. At this point, it basically sounds like a major headache to go with a Z24 block conversion. Sounds like a pain in the neck. You know what post I would like to see, is one of all of your guy's opinions on a perfect build. That could be interesting. And not make it an arguement, but just one's opinion on what he would prefer for a high compression engine build with maximum output (H.P and Torque) and whether it would work in a 4X4 scenario or not.

 

LMFAO......There are way too many combo's to go by. I noticed that there isn't much in the way of flat-top pistons.

 

You either have;

 

Z20E------------------ 31.75 / approx 13cc dish / 85mm bore (Ive also seen flattop Z20E pistons). or

 

L28 (late)------------ 38.1mm /0.0cc Flatop in '81-'83 ZX / 86mm bore

 

Why couldn't one use the F54 block, L28 Flatop's in say the Z20S Head? With either Z20E rods or L20B rods and ??? crank

(Please excuse my lack of knowledge. I don't want to even start to mention that I know anything about any of these mods, as I only know about the conversions from L24 to L28 mostly and which mods are best within the Zcar years) I'm just curious if one could build a flat-top high compression conversion and what it would take, if it were possible without having the whole NAPS Z build issues. Please keep in mind, that I will be using this in my 1987 Hardbody 4X4. I was told that the L20B would bolt up to my tranny, but would a Z20S per say?

 

Here's my scenario. I want high output (H.P. and Torque) for my 4X4. I don't want to just drop in a L20B conversion and have it the same power as what I have now with the NAPS Z, but I don't want a pain in the ass build either. Like the L20B Head to NAPS Z 2.4L block conversion and I want it to be able to bold directly up to my current drivetrain (transmission).

[hang_510]

would you know if the NAPS Z Hooker Header bolt up to the L20B?

 

I just need to be able to still run my stock tranny with whatever conversion is best.

yes, it will NOT!

 

the LZ24 uses the same Z24 tranny, as youre only changing the top end.

 

 

youll also need a nice set of carbs (i have some 40PHH, but if your looking for top end, theyre too small)

 

 

i have a modded cover & chain avail(w/ matched pulleys)

 

 

 

if i find a cheap Z24 block local, i will be rebuilding mine :)

 

 

 

You know what post I would like to see, is one of all of your guy's opinions on a perfect build.

38-26-36

[MicroMachinery]

I've heard that the tilt of a NapsZ motor towards the driver's side allows fuel to flow out of the throat of a side draft carb if used with an L Series head. I haven't experienced that firsthand, but I'm using L series mounts in my LZ along w/ an L series bellhousing on an NapsZ tranny..

[datzenmike]

You're going to have a hard time equaling your Z24i motor. It has tons of bottom and mid torque essential for a 4X4. If you aren't going with an ZL24 then you have to settle for a smaller LZ22 with an L head. The LZ22 might equal a stock Z24 or a bit more for hp depending if you change to a bigger cam and carbs. The thing is, the smaller you go the more you have to build it up to simply just equal the stock motor. I would look at a KA24E or DE swap. It will fit your FS5W71C tranny just fine. A bit more torque and way more hp. Lots of bolt on after market parts and support too.

 

 

[datzenmike]

You're going to have a hard time equaling your Z24i motor. It has tons of bottom and mid torque essential for a 4X4. If you aren't going with an ZL24 then you have to settle for a smaller LZ22 with an L head. The LZ22 might equal a stock Z24 or a bit more for hp depending if you change to a bigger cam and carbs. The thing is, the smaller you go the more you have to build it up to simply just equal the stock motor. I would look at a KA24E or DE swap. It will fit your FS5W71C tranny just fine. A bit more torque and way more hp. Lots of bolt on after market parts and support too.

 

Lunch time ran out.

 

To continue: Your 4X4 is never going to be crazy fast. They are heavy trucks that will soak up power like a sponge. KA24E and DEs came in the D21 and there should be lots of them laying about. Want even more go? Swap a VG30i in or VG30E.

[ZXR]

***I would look at a KA24E or DE swap. It will fit your FS5W71C tranny just fine. A bit more torque and way more hp. Lots of bolt on after market parts and support too.

 

datzenmike you have been extremely helpful. I appreciate your knowledge. I had heard that the KA24E Conversion would bolt directly up, but I wasn't sure about the KA24DE swap. There was one other conversion that is also possible and they make a kit for it to bolt up and that is the Buick Grand National 3.8L Supercharged Conversion. However, I'm not into swapping bulletproof foreign engines for American made junk. That's why whatever swap I went with, even if it were a smaller block/head conversion, I know I would have to really modify it to equal or surpass what I already have now. You basically summed it up for me, when you indicated that "it would only equal" what I have now. So then, I have to decide what's next. I'm not biased to the KA24DE swap and would actually be willing to go that way. Especially since there are many aftermarket parts for it. However, I'm not too stoked about the KA24E, since I owned a 1989 Nissan 240SX with the KA24E and had many problems with that engine and ended up selling that car after spending nearly the same amount in repair cost as what I bought the car for. So basically, what I am saying is that I already have my own biased opinion about it and I'm pretty sure you have had trouble with sertain things that have also made you biased at some point toward ever using that product again as well.

 

 

***To continue: Your 4X4 is never going to be crazy fast. They are heavy trucks that will soak up power like a sponge. KA24E and DEs came in the D21 and there should be lots of them laying about. Want even more go? Swap a VG30i in or VG30E.

 

Not really looking for crazy fast. Just more then what I am experiencing now. I guess more torque, per say. So basically, if I don't go with a KA24E or even maybe add a turbo to that engine, I'm pretty much at a loss, unless I decided to the Z24 block and L20B Head conversion. Sounds like the only two options without changing out the transmission.

Because isn't it true that the KA24DE, VG30i and the VG30E all take a different transmission? And if so, would that transmission bolt up to my transfer case or would I half to change that out as well? Because I was ultimately thinking of going with the VG30E with a carb manifold (there is a guy in Seattle, Wa that fabricates a carb intake manifold for these engines). I could build the shit out of one of those and get what I want. My best friend has the 1988 Pathfinder with the VG30i with 348,000 miles. He is able to smoke the tires at a stand still. It has more than enough power for what it is, but not exactly the dream engine because of the injected carb, but I could still convert over to a Weber.

Anyway, those are my thoughts. Again, I appreciate and respect you taking the time for reading and your input.

[hang_510]

that is the Buick Grand National 3.8L Supercharged

do you have???

 

i want one!!! :frantics:

 

 

my neighbor has one in his morris minor

[Sealik]

do you have???

 

i want one!!! :frantics:

 

 

my neighbor has one in his morris minor

 

 

A friend of mine has that engine and the car to boot..(86-87?)...just the stock turbo though..... ;)

Very quick car.

[ZXR]

You're going to have a hard time equaling your Z24i motor. It has tons of bottom and mid torque essential for a 4X4. If you aren't going with an ZL24 then you have to settle for a smaller LZ22 with an L head. The LZ22 might equal a stock Z24 or a bit more for hp depending if you change to a bigger cam and carbs. The thing is, the smaller you go the more you have to build it up to simply just equal the stock motor. I would look at a KA24E or DE swap. It will fit your FS5W71C tranny just fine. A bit more torque and way more hp. Lots of bolt on after market parts and support too.

 

 

 

 

So a KA24DE would bolt up? Since my last post on this Mike, I still am not exactly sure what I am going to go with? I've been looking into the VG30E as suggested prior. I heard that there was someone on here that sells a conversion plate to bolt a VG30 to a 4 cylinder tranny (NAP-Z?). I figure that if I have to build an engine, I may as well goto a V6. Because, as you've said, if I go smaller, then I will have to add more mods to get the same amount of power as stock. You're right and I considered that, but if I goto a V6, then I will have more power stock and gain in top-end with the gearing I have now in the rearend. There doesn't seem to be any simple conversion, that will give me anymore HP than what I already have. So I may as well goto a V6 build. I did find out that a 1994 Hardbody 2wd has a KA24E with TBI. Thought about that conversion, but replacing the TBI with a Weber 038 and running headers. There is a guy named Roman (Idk his last name), here in Vancouver, Wa., that is a whiz with the Z31 and Z32 engines. My dad takes his Z32 to him to work on. I was able to meet Roman the other night and he really is a whiz. I figured that if I goto the VG30E conversion, I will talk to Roman about what mods are best. The only problem will be is with a clutch and flywheel going from the V6 to NAP-Z tranny. I have appreciated everyone's help on this topic. I have learned so much since I started my research. Thanks again.

[ZXR]

yes, it will NOT!

 

the LZ24 uses the same Z24 tranny, as youre only changing the top end.

 

-Thanks for the info.

 

youll also need a nice set of carbs (i have some 40PHH, but if your looking for top end, theyre too small)

 

*If I go that way, I was considering using a Weber 038. Since I would be adding headers.

 

 

i have a modded cover & chain avail(w/ matched pulleys)

 

*I will definitely keep you in mind, if I decide to go that way. It's just as what Mike had said, I would have to modfiy the L20B to get the same HP out of a stock Z24. So I am looking into other mods as well. Thanks

.

 

 

if i find a cheap Z24 block local, i will be rebuilding mine :)

 

**If I decide on something completely different to go with, I wil let you have my block.

 

38-26-36

[ZXR]

LoL, yes its doable. This has been ran over 1400 times, tho i still can't remember what all is involved. I know for a fact you have to extend the l20 timing cover (a few mm, so be prepared to hire a welder unless you can do aluminum), something to do with the crank getting re-ground, blah blah lol.

 

 

Check this thread out man

 

http://community.rat...ason-grey-info/

 

 

Thanks for the info. I'm sure it's been run over many times before, but to try and find the info again is almost impossible in a short amount of time. lol

[datzenmike]

the LZ24 uses the same Z24 tranny, as youre only changing the top end.

 

You could run the Z24 transmission but the L head is designed to sit on a motor that is tilted over to the pass side by 12 degrees. Placing the L head on a Z block will tilt the intake and exhaust down and towards to the driver's side. On top of this, the L intake and exhaust take up a lot of space on the driver's side and will be very close to the master cylinder. LZ motors are typically installed on L series cars which already have clearance for this. The only difference is the Z block is 3/4" taller.

 

Hang has an L series timing cover that is already welded and is 3/4" taller to fit the Z block. Get it.

[ZXR]

You could run the Z24 transmission but the L head is designed to sit on a motor that is tilted over to the pass side by 12 degrees. Placing the L head on a Z block will tilt the intake and exhaust down and towards to the driver's side. On top of this, the L intake and exhaust take up a lot of space on the driver's side and will be very close to the master cylinder. LZ motors are typically installed on L series cars which already have clearance for this. The only difference is the Z block is 3/4" taller.

 

Hang has an L series timing cover that is already welded and is 3/4" taller to fit the Z block. Get it.

 

 

I see. Makes sense. So how do the guys that do these conversions on the trucks get around the intake and exhaust manifolds not hitting the master cylinder? Or has anyone not this to know?

[datzenmike]

It might clear the master, I'm going by the 720 and the Hardbody may be different and have more room. The air cleaner would be the problem. Just something to look into if you go that route. The carb would be on a slight tilt.

 

Some other things:

 

The fuel pump in the tank is a high pressure unit so you would have to use the mechanical one on the L head.

 

You will need an L dizzy and drive spindle as the one you have is a CAS crank angle sensor.

[hang_510]

LZ motors are typically installed on L series cars which already have clearance for this.

didnt think about it goin in a truck :huh:

 

would changing the mounts(not the rubber) to a L series help the angle?

the Z22 mounts are different than the L

[datzenmike]

Changing to L mounts on the engine would twist it over to the pass side but would also twist the tranny as well. The rubber mount won't survive it long.