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Filling H2O ports on 4.0 head & Conversion Issues

510 Views 4 Replies 1 Participant Last post by  mindbender
I found a 4.0 head and exhaust manifold from 93 Wangler over the weekend. Tried finding folks to weld the ports, but told by two different folks who do much welding on heads, that they wouldn't touch this head because the ports are close to the sides of the head and probably would led to cracking. is JB Weld time. If you have JB Welded these closed, I'm interested in how you managed to get it to adhere to the small sides of the ports and how you held it into place. Was there any shrinkage? Does the filling in or blocking of these H2O ports create any problems related to overheating. There are 12 of these triagular ports that permit quite a bit of flow through the 4.0 head, but with them plugged the water flow would seem to be significantly reduced?

Also, I am aware that some of you have used the 4.0 head gasket and others have used the 4.2 head gasket. I purchased both head gaskets for comparison. The 4.0 head "value cylinder" is a bit wider than the 4.2 cylinders does this create a problem?

Appreciate your wisdom. Thanks, MindBender

If you've had the experience, I'm also interested in how well a exhaust manifold from the 93 Wangler will hook up to the 85 CJ exhaust system.

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I am in the same boat as you on the 4.0 head. I took it to a couple shops and one wouldn't touch it because the triangles were too close and one didn't have the equipment to weld on cast iron. I think after asking around I am going to give it a shot at not welding or JB welding anything and see how it goes. As far as which gasket to use, I have heard some people have used either one. Let me know if you find anything out about the gasket or anything else that might help us both out. I also found a used 93 wrangler head in a junkyard and just got it back from the machine shop, he did a valve job and checked it out for me. He's never heard of the 4.0 conversion so of course he thought I was nuts for wanting to weld up the H2O ports. Anyway, let me know how it goes and I'll let you know if I run into anything. Joel

Don't waste your time with welding or JB weld. I did the conversion and used just a stock 4.2 head gasket. No leaks after almost two years. You CAN NOT use a 4.0 head gasket, it will allow coolant to flow/leak/drain/pour out of the head. I know it is scary to put it together with the holes overhanging the block, I spent two weeks with the same issue. But it does work! Good luck!

Enjoying Montana's Big Sky (& rocks & rivers & mountians etc, You get the picture.)
Blocking off the small, triangular ports won't affect water flow. Those ports don't line up with anything on the 4.0L block either. If you can't get JB Weld to adhere to the sides of the ports, see if you can locate some high temp. epoxy like the racers use. A speed shop should have it, or be able to find it for you. I'm overdrawn at the memory bank so I can't remember the brand name of the stuff.


Thanks for the comments. I'll move ahead with the value job and NOT do the welding of the ports. Mindbender.

CJ7 258
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