KA head VS L20b head swap

[StewyN]

Hey guys, this is a bit of a follow up from my last post. I'm leaning towards maybe modifying the engine in my 4x4. Ive came across a few posts about head swaps, it has a blown head gasket so i figured if i gotta rip the head off, ill look at my options. So im wondering, for a 4x4, which head swap onto a Z24 is better? also what kind of work am i looking at to make either of those fit up?

[datzenmike]

Yeah a KA24E head will drop your compression to 7.47.

 

A KA24DE head will have a compression of 9.26 BUT the twin cam dual sprocket dual timing chain would be a nightmare.

 

Take note the KA heads have an oil drain back hole that would connect to a Z24 coolant hole in the block.

 

 

An L20B head would be 9.47 and a definite improvement in breathing. Multiple carbs would be a good idea for this larger displacement engine.

[StewyN]

So stay away from the KA's is what your saying. A L20 head would bolt right up no issues? Multiple carbs on on the L20 set up? What are you thinking, side drafts or..?

[captain720]

Mikunis.

[StewyN]

Mikunis.

 

 

 

Motorcycle carbs?

[datzenmike]

You have better chance of completing an L head swap without any issues. Lengthening the timing chain by 4 links will be the most interesting thing.  Try using 2 master links from a Mercedes-Benz timing chain (#000997-0598)  (and they say that the L series was never based on the Mercedes engine...)

 

 

 

 

Motorcycle carbs?

 

Yamaha R-1 carbs. http://community.ratsun.net/topic/7862-r1-carbs-lots-of-pics/

[Lockleaf]

Member HRH did a Z/KA hybrid. You can find that build somewhere on here. For how much effort it took, i agree with Mike. You are better off swapping an L head or swapping a complete ka.

[StewyN]

yea im leaning towards the L swap if any, so im wondering, ballparkish, how much of a benefit will that L head give me in terms of power (HP/torque)? 

[datzenmike]

A good question as it isn't done often and even less have run it on a dynomometer.  The Z series start to run out of breath above 4K due to their head design. The L head, even though having to flow 20% more, would still be superior above this point. I think a larger carb would also be in order here also. For the exhaust an L16 cast iron would flow better than either of the L20B designs.

[Stoffregen Motorsports]

Member HRH did a Z/KA hybrid. You can find that build somewhere on here. For how much effort it took, i agree with Mike. You are better off swapping an L head or swapping a complete ka.

I have done hybrids too, but they were built for racing classes that allowed only certain mods while other mods were illegal. In one case, multi valve heads were acceptable, but the displacement was limited to 2.0L.

 

Yes, it would be much cheaper in the long run to do a complete engine swap, unless you're a machinist/engine builder and have a bunch of spare parts laying around.