Performance mods for a z-24i engine

[Minibeast]

Hey guys, I'm new to this site and I noticed there are no forums for my type of engine. So I thought I would just give it a shot and ask if anybody knew what performance mods I can do to my Z-24i engine that I have in my 87 Nissan Hardbody? Any help is appreciated. Thanks

Here is a list of mods that I have done:

Complete Engine Rebuild KitComp Cam High Energy Camshaftport and polished head, intake manifoldpistons bored .20 over standardcustom made cold air intake w/K&N filter8 mm. sparkplug wiresbosch platinum 4 sparkplugshi-flow cat. convertorFlowmaster mufflerDoug Thorley headerExedy Clutch Kitcustom short throw shifter

[nismopu]

you could see about turboing it. the z18et's came with turbos over in other countries but you can still find parts for them. everything will bolt up too!

[robertwb70]

you could put KA-24E pistons in it for more compression and a weber 38 DGS would probably allow more power than the factory EFI but there are trade offs in that you might not want to make-the Z motor really doesn't have much potential you're probably getting most of what it has to offer already

if you really want better performance the best option is a complete KA-24E swap-maybe even a hybrid with a DE head on it-that's what I'm working on next for my truck

[vvaffle]

Don't know much at all about the z24 at all but from what I have heard, bosch plugs aren't great in nissan engines, platinum plugs aren't great in older engines, and multi tipped spark plugs aren't great in older engines.

If I was you, I would try to find out who the OEM manufacturer of plugs for the engine is (most likely NGK) and get their copper or iridium version of a single tip spark plug. Don't trust me on this though, just what I have heard.

[pregmantis]

itb's/dual sidedrafts would be good. What are the specs for your cam?

[deviousKA]

Sounds like you have covered most of your bases. If you would like to keep the upgrades you have done to your valvetrain (cam) you may want to look into the Z20 head/Z20e intake manifold. This is the best Z series, straight shot round port and can be upgraded to 2.4l valve size. Z22/Z24 designed mainly for truck use have protrusions in the ports to aid in intake swirl, good for torque bad for top end.

Your best bet would be to upgrade to sohc KA head and valvetrain, it is direct bolt on, allowing you to use your original timing chain configuration (better than ka24e). Only hitch is you must use an external thermostat housing.

[Bigvinnie]

Your best bet would be to upgrade to sohc KA head and valvetrain, it is direct bolt on, allowing you to use your original timing chain configuration (better than ka24e). Only hitch is you must use an external thermostat housing.

You failed to mention that switching to MPI he will also need the wiring harness, and ecu. Well atleast that is if he decides to go carbed, it says that he is z24(I)....Biggest performance gainers with the NAPS-z is high compression pistons.Also advancing the timing. If you can get your hands on an adjustable timing gear you are good to go. Rebello racing can fab you an adjustable timing gear. Alot of the guys still using the naps-z usually use the z20 head (to bump compression), and switch from the DPI, to the MPI using the 200sx MPI from 1981-83. Cheapest way to go and the ecu uses 4 wires, it's really easy to install.
Modified by Bigvinnie at 2:20 PM 10/29/2005

[pregmantis]

devious, I have seen some some z24 engines with single and mostly double timing chains. I vaguely remember trying the to bolt the double timing gear to my kae cam and it not compatible. Did I forget my memory? or does both the z24 single timing and double timing gear bolt directly to the kae camshaft?

[deviousKA]

I did fail to mention induction system, variety of ways to go.

pregmantis, the late 88 and 89 model of the z24i does have a single row chain OEM. The earlier version dual chain kit is directly compatible. From all of my part suppliers, the dual row chain kit supercedes all other part numbers.

The Z series upper gears will mount directly onto a ka24e camshaft. These gears cannot be used without a full Z series timing chain system due to a difference in gear tooth count. The lower Z series gear cannot be transferred to ka24 crankshaft, crank snout is smaller diameter.

The Z series has 3 position cam timing adjustment upper gear in original form. The best aftermarket adjustable gears can be purchased from Arizona Z car in the US, or from kameari in japan.

http://arizonazcar.com/sprock.html

[Bigvinnie]

the late 88 and 89 model of the z24i does have a single row chain OEM. The earlier version dual chain kit is directly compatible. From all of my part suppliers, the dual row chain kit supercedes all other part numbers.

I have an 88 with a dual row timing chain, production of the truck was in later 87.Man I miss driving the naps-z it was a fun engine too mess with but alas I have no time to fix it right now, it sits in my drive way from hydrostatic locking of ALL pistons, from coolant leaking into the oil pan, due to the timing chain....... Check out the cob webs....LOL

[deviousKA]

Yeah, the Z timing system can still wear holes in the timing cover if the other components fail, but overall the system is superior to the ka24e. I do not know why they changed this really.

I think it may have something to do with the unnecessary large diameter of the Z series crank snout. When designing the KA this diameter was cut down, and so was the tooth count of the lower gear for part simplicity. The Z was over built.

Pull that Z24 and build yourself a nice KAE/Z Vinnie

Oh, and you will hear about the Z24 being crack-prone. These are only superficial cracks on the deck surface and cause no harm, but always get the block decked.

[Bigvinnie]

Pull that Z24 and build yourself a nice KAE/Z Vinnie

Yeah, I always wanted to do the KAE head, but I have this grind from a non ground. Got the cam for $40, tito's machine shop did the specific spec I asked for, for only $90.00. Claim to power improvement is 30CHP above stock. I'm kinda of curious to see the results, and the drop in torque.Planning on the z22head with a valve enlargement of .40, and minor intake porting and polished exhaust ports, especially since there is no valve curtain, (lack of valves compared to the KAE).