AMC Eagle Den Forum

The Mighty 258 => The Engine => Topic started by: vj318 on October 08, 2013, 08:38:10 PM

Title: 4.0 head swap
Post by: vj318 on October 08, 2013, 08:38:10 PM
I have an 88 waggon that broke the oil pump drive about a year ago. I want to get started on rebuilding the motor. and doing a 4.0 head swap. plan on using intake manifold with after market carb. from other posts it appears that a 91 thru 95 head is the best. the question i have is. will a 96 work and what is the difference. also does anyone know what cam i can use that will be simular to a 4.0 but will still be able to use the stock fuel pump.
Title: Re: 4.0 head swap
Post by: vj318 on October 08, 2013, 11:36:24 PM
after doing a little more seaching i found something fro amc evolution by tougeagle, in which he says the 96&97 are the same but without the coolant temp sensor port. this means finding an alternative way of wiring in your temp sensor gauge. has anyone had to do this and how is it done.
Title: Re: 4.0 head swap
Post by: 1985amceagle on October 09, 2013, 12:38:23 AM
I believe Casper on amc evolution, and vangremlin has done the head swap. Maybe van will come out of lurking? Don't know so much about if Casper will.
Title: Re: 4.0 head swap
Post by: IowaEagle on October 09, 2013, 09:44:02 AM
Didn't Jeep stick the sensor onto the water pump later on?
Title: Re: 4.0 head swap
Post by: eaglefreek on October 09, 2013, 11:56:04 AM
Quote from: IowaEagle on October 09, 2013, 09:44:02 AM
Didn't Jeep stick the sensor onto the water pump later on?
There was a sensor in the water neck on 4.0L's but that was for the computer and don't see why it wouldn't work for the gauge. The 96 head should work fine as long as you match valve cover and valve train parts. Here's a good selection of cams, but you will have to figure out which one has a fuel pump lobe. You definitely need to replace the cam to take advantage of the new head. Others who have changed the head a left the stock cam, didn't notice much difference.
http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm
Title: Re: 4.0 head swap
Post by: vangremlin on October 09, 2013, 09:43:16 PM
Quote from: 1985amceagle on October 09, 2013, 12:38:23 AM
I believe Casper on amc evolution, and vangremlin has done the head swap. Maybe van will come out of lurking? Don't know so much about if Casper will.

I did have the head swap done earlier this summer.  Most of the work is covered in this thread:

http://forums.amceaglesden.com/index.php?topic=42319.0

I'm very pleased with the results.  A lot more power, the engine doesn't have to work as hard at highway speeds, and acceleration at higher speeds is much better.  I used a comp cam, the part number is also in the thread.

Have you found a replacement oil pump?  When I did an engine swap, none of the new pumps that were available matched up with the original Eagle pump. I bought one, but the pickup was different, and the old pickup wouldn't work with the new pump. I'd be interested to hear what you found.

Good luck!
Title: Re: 4.0 head swap
Post by: mudkicker715 on October 09, 2013, 10:25:39 PM
my old pickup worked fine. so i am interested in why yours did not
Title: Re: 4.0 head swap
Post by: vangremlin on October 09, 2013, 11:18:55 PM
Quote from: mudkicker715 on October 09, 2013, 10:25:39 PM
my old pickup worked fine. so i am interested in why yours did not

If I remember correctly, the "snout" on the new pump where the pickup joined to it was short, but the part of the old pickup that was supposed to go in that hole was long.  This made it impossible for the bracket that was on the pickup to be screwed onto the pump.  There might have been a way to work around it, but the old pump was still good, so we put it back together and slapped in on the engine we were swapping in. 
Title: Re: 4.0 head swap
Post by: mudkicker715 on October 10, 2013, 01:18:42 AM
interesting. i wonder if there was a burr or somthing holding it from seating properly.
Title: Re: 4.0 head swap
Post by: vangremlin on October 10, 2013, 08:26:57 AM
Quote from: mudkicker715 on October 10, 2013, 01:18:42 AM
interesting. i wonder if there was a burr or somthing holding it from seating properly.

No they definitely weren't made for each other lol.
Title: Re: 4.0 head swap
Post by: Amc1320 on October 10, 2013, 09:33:51 PM
I'm in the process of putting a 4.0 in our Gremlin, in swapping the car oil pan on the jeep engine I swapped the pickup, the 258 pickup fits ok but the hole on the hold down tab does not line up correctly. I just drilled a new hole kinda next to the old hole and it fits perfect now.
Title: Re: 4.0 head swap
Post by: vj318 on February 21, 2014, 01:59:10 AM
does anyone out there have a copy of tim weavers write up on the 4.0 head conversion. it is supposed to be on monsterslayer, but is no longer there. i have not been able to find it anywhere else. it is supposed to be quite detailed. where can i find it?
Title: Re: 4.0 head swap
Post by: vj318 on February 21, 2014, 02:06:24 AM
when doing the 4.0 head swap can i use the 4.2 head gasket or do i need a 4.0 head gasket.
Title: Re: 4.0 head swap
Post by: vangremlin on February 21, 2014, 08:23:17 AM
Quote from: vj318 on February 21, 2014, 01:59:10 AM
does anyone out there have a copy of tim weavers write up on the 4.0 head conversion. it is supposed to be on monsterslayer, but is no longer there. i have not been able to find it anywhere else. it is supposed to be quite detailed. where can i find it?

Yes, it disappeared several months ago....right before I was going to do my swap!!!

I searched the web for other write-ups, and found this one to be really good.  Heavy on very helpful pictures!  Good luck!

https://picasaweb.google.com/85YellowCJ7/40HeadSwap#5301796730947263378
Title: Re: 4.0 head swap
Post by: Draekon on February 21, 2014, 08:07:08 PM
Tim Weaver's write up:
http://web.archive.org/web/20060902231446/http://www.monsterslayer.com/jeep/40Head/40Head.htm
Title: Re: 4.0 head swap
Post by: vangremlin on February 21, 2014, 09:24:46 PM
Quote from: Draekon on February 21, 2014, 08:07:08 PM
Tim Weaver's write up:
http://web.archive.org/web/20060902231446/http://www.monsterslayer.com/jeep/40Head/40Head.htm

Thanks for posting that link.  Thumbs up!
Title: Re: 4.0 head swap
Post by: vj318 on February 22, 2014, 12:28:32 AM
thanks draekon very much. just printed it up tonight. cant wait to read thru it. this should make it alot easyer for my son to do this at school.