Anybody like the Z24?

[gryffinwings]

I'm curious to know if anyone likes the Z24? If so why?

 

[wayno]

It's a great engine for what it is, it has lots of torque, and if you re-torque the head every tune-up, it will last for 300+ thousand miles if driven normally.

It's not a performance engine, that is why you don't see Z24 builds, it's a great engine for what it is.

[ggzilla]

I love it for the mid range HP (you don't have to rev it over 5000 rpm to make maximum power) and for the good fuel economy. No way I would swap out a good Z24.

[datzenmike]

I agree I like them too. Had one in my 620. 2.4 liters, same bearings as the L20B... so bulletproof bottom end. Makes it's 135 ft lbs of torque @ 2,800 RPMs and great for pulling a heavy truck around.

[DaveZilla]

I agree as well, very strong bottom ends in these engines and the power is right where it's needed for a small 4x4 truck where it would be pointless to try to rev to 6k rpms just to get any power out of it. It's peak torque also sits right at highway speeds which is really nice.

These engines weren't built for performance, but they can definitely withstand some serious power if one decides to do a head swap or add a turbo etc..

[Sealik]

There are some Z24s producing some good numbers.

Members from Guam (and other locales) swear by them....turbo charged of course.

[_chiefjt]

If I read this correctly, This z24 ran a 14.87 where I live. I like the z24 because you don't need to do much to make it reliable and dependable. And if you want a little more horsepower get a Weber 32/36 or a 38/38 but if you want more, you'd go with a dual side draft setup which is about all it'll take seeing as a turbo setup blows the head gaskets. 

 

http://www.youtube.com/watch?v=JUv9tt0x-78

[dr.feltersnatch]

I loved it in my 720 4x4 lots of low end torque. Perfect for wheelin. It falls on its face on the top end though so it wasn't much fun on the street. It wouldn't be my first choice for a street only vehicle but I wouldn't pass on a nice truck because of it.

[720_DRIFT]

I'm new to this forum but not new to the datsun/nissan game. I have to say the Z24 is by far underestimated. I've personally built my Z24 for "racing", I drift my 720 on the daily, not professional but just love doing it, and while out driving I tend to hurt peoples feeling when the can't keep up with the single cammer. Not trying to boast but the topic was on the Z24 and I think its a beast.

[bryant2482]

In my opinion these are one of the best built engines, especially of its time! I still have the original z24 in my 720, no major issues what so ever! Practically bullet proof! I've ran this thing into the ground and it still start first crank and has lots of power! So yes this is probably the toughest little 4 cylinder ever built!

[720warpony]

the Z24 is a good motor Iam hard on my truck it still runs strongs at 216 on it use no oil and never get hot and I let a lot of hondaS see my tail lights

[harlow426@msn.com]

I swear by the Z22-z24's. I just parted out my 82 with a z motor in favor of my "new" 80kc. I replaced the bad L20b with a good one and it runs like it should. I miss the bottom end grunt the z motors have....and the top speed. My 82 could stuff the speedo on the H(MPH) just leaving 4th(95mph approx) and still have 5th 2 go(55+second gear). Running light I think it would almost do 110mph, and yea it's fun to "drift" her sideways when jumping onto the freeway! I gotta twist the shit outta the l20b in third and fourth just to get 85+ outta it, have 2 downshift on hills. Same gear ratios, tire sizes, carb, exhaust. I know a lot of people "poo-poo" the idea of the z head but it is a better design(cross flow). All the car manufacturers dropped the L head design in favor of cross flow. Increased compression can b achieved by milling the head and block. I have not done it yet but I am going to put a machined z head on a long rod l18 @ some point. I may have to cut cheeks in the pistons to clear the valves at full lift but I know it will breathe better than any L head. The Z head has big valves but could use port/polish, 3 angle valve job, and header just like any other  head.  In fact I think a long rod L18 with a z22-24 head it will spank any l20b and most lz2.2s. U can keep the intake cooler thus have a more condensed fuel charge w/o the exhaust under it. The lighter weight l18 pistons (less reciprocating mass)and improved rod ratio will allow 4 faster accel/decell(easier on rods/pistons)....engine should come ALIVE in mid mpm range regardless of the application. Remember the destroked chev 302s that screamed in 69-70? I would drop a Z motor in my 80 if it wasn't a low mile factory A/C rig. I am gonna put the z-22 outta my "departed" 82 into my 74 620 along with a propane conversion. I was able 2 get 30mpg outta it with a webber, 2 1/8 exhaust, and premium Chevron fuel when it was in my 82.....12-14mpg if I flogged it. I found I had to block off 75% of the radiator in order 2 get enough "heat" in the z motors(82-86 std 720's). Even with the correct fan/thermostat/pully size etc they all seem to run cold. They perk up when u get em hot enough and the fuel economy goes up. I ran a 298000mile z24 w/o a radiator fan with no heat issues while driving(at idle would heat up after awile) pulling a 14' flatbed trailer, 90deg weather and total gvw 10,000lbs(truck 3300lbs). If u try and push the ign timing more advanced than 3btdc u get detonation.....less than 3 sluggish. I also ran a 4" x 14" air cleaner on my webber(just barely touch hood on HARD launches) and ditched the noisy multi-blade clutchfan 4 standard 4 blade non clutch. I don't know how many times I've moved the impossible w/ z powered 720....just keep her floored and stab the clutch enuf to grab the next gear(hard on tranny mounts!). I don't know how 2 kill one and I've tried.....more than once! :thumbup:

[ggzilla]

Yep, 2.4 liters beats 2.0 liters.

[datzenmike]

The Z heads do not flow better than the L heads. If they did why do people swap L heads onto Z22 and Z24??????

 

To it credit the Z has cross flow, hemi head and dual plugs... all are advantageous, but the ports are too low and have to bend sharply at the valve seat. Works great below 4,500 but restricts flow above. You can only add a small amount of cam lift, or the valves hit each other. Because of the tilt on the valves, the larger intakes are too close to the piston tops. (another reason for no cam lift)

 

Because of the three things above the Z head is perfect for use with a turbo!!!!! If you put on an L18, think about a turbo.

[harlow426@msn.com]

Unless on the track is it prudent to want to make HP above 4500? A flatter midrange(1500-4500) torque curve is best in most applications. Valve timing is more critical than total lift. I am still a "newbee" in the Ratsun world but I think with the right machine-work and part selection the Z head is the way to go....unless u r building a track car. Going in a semi-straight line seems better than a U-turn. Maybe next winter I'll fire up the Bridgeport and go to town on a z head(port polish/3angle seats/ full length guides/flycut to get comp ratio). If all said and done I'm wrong....I'll let u-all know. BTW how much boost can u put to a z motor b-4 it blows?

[datzenmike]

No one does this that I know...just saying the cross flow/hemi/dual plugs is the best design for low detonation. If it there why not turbo it?

 

But for boost, I would run a copper head gasket and have the block O ringed. Then there is no limit.

 

Working on a copper HG for my 2.3 engine build...

 

[TheEddie]

...go to town on a z head(port polish/3angle seats/ full length guides/flycut to get comp ratio...

Correct me if I'm wrong (and we WILL, there, Noob--Moderator), but last night I was studying the 1984 Nissan 720 service manual, and the specified valve and seat angles were indeed in three angles...from the factory!  (Gasp!)

 

Eddie

[izzo]

I like the Z24.  Tends to run OK.  I've had a handful of them too :rofl:

 

Just remember how the brackets for the power steering go back on, in the right order. Otherwise you will be playing jig saw puzzle, ask me how i learned lol......  The head does require re-torques... But whatever, it's not that bad of a deal.  Adjusting the valves to spec is pretty easy, hell they really aren't a bad motor. Just known for no top end, non performance motors.  You can haul a ton of shit with them.  I'd rock another napz motor any day.

[ggzilla]

Yes above 4500 rpm is better.

 

Unless on the track is it prudent to want to make HP above 4500? A flatter midrange(1500-4500) torque curve is best in most applications.

Most engines made in the last 15 years have a power band of 1500-6000 rpm. More power can be made at high RPMs, but these engines also pull from low RPMs. Best of both worlds.

 

Many Datsun engines have a power band of 2000-6000 rpm and can handle moderate acceleration from 1000 rpm. These engines are immensely streetable.

 

Lower power bands used to be a side effect of a poor engine design (e.g. poor breathing or long strokes), but now it is about fuel economy. MPG skyrockets at lower RPMs hence engines are still made that don't rev high.

 

The Z-series engine was designed as a compromise of economy/emissions vs power. And it succeeded very well. Nothing bettered it until 16-valve designs came out - namely the KA24 and CA18 engines.

[datzenmike]

Correct me if I'm wrong (and we WILL, there, Noob--Moderator), but last night I was studying the 1984 Nissan 720 service manual, and the specified valve and seat angles were indeed in three angles...from the factory!  (Gasp!)

 

Eddie

.

 

Z24 valves are 45 degrees. Seats are 45 on the face and 60.

 

The Z20 mileage option motor has a 30 / 45 / 60 seat angle.

[ggzilla]

I thought all Datsuns had a 3-angle valve job. You got more for your money with Datsun.

[datzenmike]

The seat is three

[Matt Chappus]

Any advice on building a Z24 for my 510 would be appreciated .

[datzenmike]

I would use L series engine brackets to position the block to fit the 510 transmission and the 510's oil pan and pickup. Then put a U67 L20B head and manifolds on it to make a 2.4 liter 'stroker' L series engine. Technically, using Nissan nomenclature, it would be an L24B as there already is an L24 six cylinder just like the L20 six cylinder forced the new 2 liter 4 cylinder to be called the L20B. 

 

The head now sits on 89mm cylinders so the combustion chamber can be hogged out to remove the shrouding around the valves. Compression is around 9.5 but slightly lower with the shrouding removed. Use a Z24 head gasket and add two links to the L20B timing chain. The L head will actually fit the Z24 timing chain cover so no need to use the L20B timing cover and weld a 2cm extension on the top.

 

 

Small fillet of JB Weld to help seal L head against the Z24 timing cover.

 

 

Cam is for mock up only

 

Used old L series gasket to mark an additional hole to be drilled in Z24 block.

 

 

Again a small fillet of JB on this coolant hole just to help the seal so near the outer edge of the block

 

[Lockleaf]

If you install it without making it a "stroker" L series, you will still need the L series engine mount brackets.  Put passenger bracket on driver side and driver bracket on passenger side.  You will have to wire up the second coil, or get a 4 plug distributor.

 

See my thread "half pint".  I have a z22 in my 510 wagon and the install is in there.