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I had an idea that I was playing around with and wanted to see the viability of it before continuing any further. I have a 4G63 block, crank, and head sitting in the shop. I also have a 4G64 block and crank. I'm planning on doing a 2.3L stroker with the 63 block and head with the 64 crank. I'm also planning on doing a 2.1L de-stroker with the 64 block and the 63 crank. I do not have a cylinder head for that engine.
Bearing that in mind, I came across a post today on Facebook where someone was selling G4JS Kia Optima heads on an Evo group. He said they're interchangeable with the 4G63 cylinder head, save for a few things that are different. They include a different valve cover, no oil feed for the turbo, a different water hose housing, and a larger combustion chamber (+13cc iirc). Obviously the internals from that head are also different. There were a couple of other things I read elsewhere saying that there'd be an issue with the cam angle sensor working properly.
The reason I'm here in the first place is that my tuner doesn't believe that the oil galleries and coolant passages in the G4JS head line up perfectly with the 4G63/64 blocks. I also am unsure of whether the height of the camshaft centerline is different than that of the 4G63 head, since if it is it would affect the timing. I know that with a 4G64 block I'm going to have to have at least one adjustable cam gear, but I want to know if I'll need two or not.
I read a few posts about this swap on 3gclub, but couldn't really find anything conclusive on the questions I have. I felt it would be a waste of time and money to go to a pull yard and grab one of these heads out of a car, so I decided to come here and ask other Evo owners instead. My hope is that the info here will help other people build/rebuild their cars for pennies on the dollar. Thanks in advance!
TL;DR - Does a G4JS head fit on a 4G63/64 block? Is the information I have actually correct? Do the passages/galleries line up? Is there a difference in cam placement that would affect timing?
You haven't looked that well in the 3gclub forum cause most of the guys except a few of us that's doing or done the swap are using the evo heads. Most of them used the Kia head. You have to really research it in our group. I was going to use the kia head, but decided to go with the evo 8 head to my 4g64 block. Although it does work evo 8 head or kia head. Also there's a pdf where you can see what parts you need for the kia head vs the evo 8/9 heads.
I did the swap and am currently running it hard. G4js head with thermostat housing and all. Internals are drop in from an evo. I'm running evo 8 ferrea valves, gsc springs, evo 8 cams, gsc lifters, and adjustable gears. Everything bolts in like it should. The oil passage crap that your tuner is stuck on is for the 2g eclipse 4g64. There's like ten legitimate threads on club3g with all of the info you need. Hell, even a parts list.
May 17, 2016, 05:25 PM
