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post #1 of (permalink) Old 02-24-2008, 09:39 PM Thread Starter
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258 rebuild questions

Hello again,

Well I've decided to actually work on the Jeep and stop putting it off. heh
The block out of the 89 Wrangler is shot. I believe the timing chain was so stretched that the #3 piston was slapping the valve until the piston shattered and killed the block.
Now the head on that engine supposedly had a valve job 2 years before said incident. (Too bad they didn't do a timing chain. :/)
I have another block from I think an 80's CJ that I want to use with the 89 head.
I don't really want to go too deep in maby new bearings and rings...
The casting # on the older block is 008C14 and on the block from the 89 it's maby 909C27 (Hard to tell thru the grease and paint) both blocks bare the # EF3235444.
The never block has 5 big frost plugs on the side and the older one has 3 big and 2 small frost plugs on the side.
What about the crank and cam shafts are they interchangeable? Which should I use?
Am I going to run into problems? I have already bought the timing chain and gasket set for an 89. :/

Thanks for any input!

Troy

It's not the thing you fling, It's the fling itself!

Last edited by Sasquatch; 02-24-2008 at 10:08 PM.
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post #2 of (permalink) Old 02-24-2008, 11:19 PM
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Except for some minor casting changes....just about all 4.2L blocks are the same....the biggest potential difference is the bolt size for the head. I had two blocks and they both had different size bolts....same location...but different...1/2" vs 7/16" I belive.

A little advice on the rebuild....don't try to save money by taking short cuts....the little money you save will be quickly lost if you miss something. One of the most common mistakes is to just hone out the cylinders...in many cases the wear is more than people realize....pretty soon you are getting piston slap and excessive blow by.....so, do it right....if you have to buy new pistons....do it....you can get a set of 6 from Summit for about $10 ea....new cam and lifters...about $100....

AKA DDawg16
84 CJ7, SOA, 5.7LTBI, 4L60E, 35"x12.5, 4.10 gears, F/Det, R/ARB, Full Roll Cage,
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post #3 of (permalink) Old 02-25-2008, 08:20 AM
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Just some things I'd do:
  • Get the heads checked,
  • the block decked and
  • the facing edges on intake and exhaust faced,
  • the exhaust and intake manifold faces trued and
  • faced
While your doing this check out the cylinder for runout and plastiguage the main bearings and replace the front and rear main seals. This is a good time to get to know your machinist.
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post #4 of (permalink) Old 02-25-2008, 08:02 PM
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I have an 87 that needed a block a few years ago. I ended up buying a 75 motor from Will and had it rebuilt as the other was shot. I used the 87 head on it and the 75 crankshaft in it. I think either crank would have worked, but the machine shop recommended using the one that came in the block. It was about twice as heavy as the newer one. The head bolts were the same size for me, but some time in the early 80s they did use a different size head bolt. I can't remember exactly when, but a friend ran into that issue on his. I ordered the camshaft according to the code on the block I used. The machine shop decked the block and checked the head, as well as boring it .030. When I can keep my tranny together, it runs fine with no problems.
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post #5 of (permalink) Old 02-25-2008, 10:09 PM Thread Starter
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Thank you guys!

I will do everything suggested!
I'll try and do some pics and followup.

Be prepared for further requests for help.

Troy

It's not the thing you fling, It's the fling itself!
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post #6 of (permalink) Old 03-03-2008, 07:52 PM Thread Starter
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Ok,

So I have the head bolt size issue. :/
Is the only option to use the old head with the old block or is there a way around this?

ie: Anyone heard of the old block being tapped to 1/2" ?
I would think since the holes were tapped the first time as long as it's a decent Machinest than should be no problem???
Am I mistaken?

BTW: The Head bolts on the 1980 are 7/16"X6" and on the 89 are 1/2"X5"

Thanks Again

Troy

It's not the thing you fling, It's the fling itself!

Last edited by Sasquatch; 03-03-2008 at 10:03 PM.
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post #7 of (permalink) Old 03-03-2008, 11:20 PM
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I actually reamed out the extra head I had that had the 7/16" bolts...worked fine.

But if I understand you correctly....you want to take your older head with the 7/16 bolt and use it on the 89 block with 1/2"

Personally, unless the head on the 89 is in bad shape, have it redone. If you don't have the 89 head, then yes, ream out the head bolts.

AKA DDawg16
84 CJ7, SOA, 5.7LTBI, 4L60E, 35"x12.5, 4.10 gears, F/Det, R/ARB, Full Roll Cage,
D44 Flat top in progress...
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post #8 of (permalink) Old 03-04-2008, 09:21 AM Thread Starter
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Actually I want to use the 89 head on the 80 block so I was thinking of tapping the block to 1/2".

It's not the thing you fling, It's the fling itself!
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post #9 of (permalink) Old 03-04-2008, 05:05 PM
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That I would NOT do....when you inlarge the holes, you may end up going into a water passage. There is a good chance that they modified the block casting to allow for larger bolts....

AKA DDawg16
84 CJ7, SOA, 5.7LTBI, 4L60E, 35"x12.5, 4.10 gears, F/Det, R/ARB, Full Roll Cage,
D44 Flat top in progress...
Link to my Frame up Restore
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post #10 of (permalink) Old 03-04-2008, 06:32 PM
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The cranks are different depending on serpentine or v belt. Spacers are now available at Summit Racing that allow 7/16" head bolts to be used with 1/2" heads. Having a machinest install threaded bushings is also an option. I ran into the crankshaft and head issue in a rebuild (don't ask. long story ). I had success by ensuring the (1/2" bolt) head was on straight using the dowel pins and just securing the head using the correct (7/16") bolts for the block. But, I do not recommend it.

The spacers are available at Summit Racing - High Performance Car and Truck Parts | 800-230-3030

The 7/16" block and 1/2" block problem has been covered in the many 4.0 head swap articles on the internet. A lot of good info was here as well as Pirate4x4.Com - The largest off roading website in the world..

Good luck and let us know what solution you use and how it works.

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