Looking to build a z24 to rev high in 2 gear for Circle Track

[Hyser387]

I am looking to build my Z24 to have more compression and to rev at high RPMs in 2nd gear looking at putting a z22 or z20 head on a Z24 block with 40 over Pistons and obviously some cam work can anybody give me any info or where to find good quality parts

[datzenmike]

Z22 and Z20E and Z20S heads are the same size combustion chambers and besides, the intake ports are round and slightly smaller so I would pass on that. 

 

Engines are air pumps, the more air you can move through it the more power the engine makes. You may not know it, but the Z head is not a very good breathing head and there isn't much you can do to improve this. The Z series engines are part of the NAPS engine series. It's primary goal is lowered emissions, not making high revving power and certainly there was never any room built into it for improvement. Cam lift is limited by the two valves hitting each other. Intake and exhaust ports are low and close to the head gasket surface forcing incoming air to make a bend at the valve to enter the combustion chamber. It's the same with the exhaust getting out. Above 4K there is restriction in and out.  The thing is the Z series is perfect for what it is and can do which is pull a truck or car around with lots of torque and make few emissions. It was never intended to rev much over what it would normally do on the highway which is 3-4K RPM. Valve springs do not have to work above 6K because it isn't going there. It doesn't have to breath well above 4K because it isn't going there. Again... what it can do it does very well.

 

It's not a total loss. You can tweak some more torque out of it. The Z24 tends to have too small a carb.Good for mileage and emissions, but a bit more air won't hurt. A Weber 32/36 is a nice improvement but full out a Weber 36/36 Outlaw gives more. Choose your cam carefully as most I've seen are barely more than the stock one. Stock lift is 0.413" and duration 248 so go from there. If for racing only replace with 0.040" KA24E pistons. They only have 2cc of dish and would raise the compression to 9.78 with 0.40" over.

 

The Z24 is a torque monster with 130 ft lbs at only 2,800 RPMs so rather than revving the shit out of it, why not run 4.375 gears in it and use second and third gears. If you have a Z24 and 2wd it probably has nothing higher than 3.889 gears very possibly less. There is an engine tag on the inner passenger fender under the hood hinge that gives your differential ratio. Check it and see. Differentials can be from free to maybe $100 and a couple of hours to swap. Best bang for the buck there ever was. It allows you more power without increasing the strain on the engine.

 

 

Are you allowed to use heads from different engines??? An L series and a few mods will put a vastly better breathing head on your Z24. Just the head alone with it's smaller combustion chambers will raise the compression to 9.63

[wayno]

You are the second guy on here talking about circle track racing a Z24 block recently, but I cannot find the thread, he had a head issue.

I believe he lived in South Dakota.

[Stoffregen Motorsports]

Two major issues with that engine: rotating assembly balance and clashing valves.

 

The crank is only partially counter weighted, so if rules allow, weld additional counter weights onto the crank and knife edge them.

 

The opposing valves tend to be a problem at high speeds so keeping valve float under control is a must.

 

What kind of parts are you in need of?

 

Good Luck!

[datzenmike]

 If L heads are not allowed you can boost your compression by swapping in 0.040" over KA24E pistons. The KA pistons have almost no dish so the compression goes up to about 9.7. They have the same pin height and are the same diameter of the Z24. Make sure the Z24 small rod end has adequate side to side clearance on the KA piston pin. I believe the Z24 rod small ends are slightly wider than the KA rods so clearance is tight.

 

 

Three things that are to your advantage on the Z24 are cross flow design. Hot exhaust ports are not near the intake ports, allowing them to run cooler. The combustion chamber design is pretty close to the ideal efficient HEMI shape. The Z series run dual plugs which shortens the burn time and allows much less ignition advance. Less time for pre ignition.

[scooter]

if you have to run the Z head, if your allowed to port anything then attack the head with the die grinder. maybe put KA pistons in it to get the squeeze up, They DO make cams for the z motors, even though they are not much bigger than stock, I think you can get 1mm overside valves too. basically lots of money for small gains.

anything will help. depending on your rules you may be able to run a holley 500 if this is a mini stock or outlaw type of class.

 

its still not gonna make power above 6 grand so i dont think you need to weld on counterweights, but it would be a good idea to make sure your whole rotating assembly is balanced very accurately.

 

if you can, get a race prepped L head and a hogged out w58 intake with a holley 500 flange welded on it. assuming that's what your rules are.

Theres big bore 2.3's and 2.4 l series motors that run outlaw compact in Washington that do fairly well. they have to race against mustangs with esslinger crate motors, Hondas and shit.

 

If this is more of a Hornet car class, drop a ka24E on it with all the EFI and call the truck a hardbody