Kaiser Supersonic head on a CJ3A engine??

Jordan · Post by **Jordan** » Thu Apr 05, 2012 10:21 pm

Guys:

I have a '52 M-38 (civilinized) which I've been restoring/renovating for almost a decade. When I bought it, the owner would not sell me the M-38 engine that came with the jeep (I later learned the M-38 had a gear drive valve train which makes it a little more desirable than the chain drive version---I think!?). Anyhoo, the original owner did sell me an engine that I think is a CJ3A engine. I've had it over-hauled and it is fine fitment wise.

But, an issue has arisen:

I've scored a nice Kaiser Supersonic head which I want to install, but I notice on the front of the head on my engine, there is a small boss with a water hose inlet and then a small water hose feeding water to the head directly from the top of the water pump into the head. (This is not the thermostat housing/hose oulet on top of the head.) The supersonic head does not have this boss with inlet in the front that is on the original head. I assume the head is cooled with water coming from holes in the top of the block and circulating into the head.

Can I still use the supersonic head even though it does not have this water hole in the front of the head? I assume I can simply plug the outlet in the top of the water pump. The other altnerative would be to drill and tap the head, but again, there is no boss for that purpose and that is a mod that makes me very nervous.

So, can I use this Kaiser supersonic head or not?

Thanks,

Jordan

Post by **wesk** » Thu Apr 05, 2012 10:43 pm

Yes. The purpose of the bypass is to allow for a quicker warmup of the engine and it helps with the heater plumbing. Expect to run longer warmups with the choke pulled and no hot water heater capability.

You can mill the stock head and get the same compression ratio and keep the bypass and use a heater.

Jordan · Post by **Jordan** » Thu Apr 05, 2012 11:10 pm

Thank you Wes. The wealth of knowledge on this board is phenomenal---now if one of you guys would just fly out to Kalifornia and finish this project for me!

Jordan · Post by **Jordan** » Thu Apr 05, 2012 11:19 pm

Wes,

How much would I have to mill the original head to get the same compression as the Kaiser Supersonic, if you know?

Thanks,

Jordan

Post by **wesk** » Fri Apr 06, 2012 11:51 am

The auto machinist will be the one to ask that question of. If you cc the volume of the combustion chamber in your head and do the math you can compute the amount of chamber size reduction to reach the desired change in compression. Your machinist will also be able to determine if there is adequate material remaining on your head to allow the cut.