Re: [Amc-list] Concord Engine Question - 4.0 EFi Six -

[Frank Swygert <farna@xxxxxxx>]

I see your reasoning, but still wouldn't discount a 91-95 4.0L for a daily driver. I don't think the differences in the block are really that detrimental. I dod know a couple people who got good deals on Cherokees with a little piston noise because the owners were afraid something was going in them, but they put well over 150K miles on them, just made a little ticking noise at idle. 

If you plan on putting in a bigger cam then maybe a Renix system would be better, unless you plan on going to a programmable computer like the GM or any number of aftermarket units (like the MegaSquirt). I don't have a problem with the Renix system, but it is harder to find someone who can/will work with it. You have to have an expensive code reader and it doesn't store codes. Modern "technicians" don't like that, a REAL mechanic will do the trouble shooting and figure it out without help from the computer, but it takes longer and costs more. 

The best thing might be to use a 87-90 Renix block (or 96-06 block, since it is stiffer than 91-95) with the later 91-95 electronics. 96+ electronics are harder to use only because they have those theft deterrents built in. Don't get the key and switch with it and you're out of luck! I wouldn't attempt to use a 96+ engine unless I had the entire Jeep just so I could make sure I had everything needed to make it run. Some have hidden the Jeep switch with key in it under the dash then wired the factory Jeep/car switch into the system, just leave the 96+ switch and key tied in place. Would make a good theft deterrent if the second key switch was accessible though. 

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Date: Sun, 08 Mar 2009 15:30:22 -0500
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From: Wrambler <wrambler242@xxxxxxxxxxx>

Looking at your reply Brien it looks like you are saying nah to using the 91-95 4.0L for the swap?

Since those are my preference years for 4.0L swaps I would like to know why you say nah?

Those years of the OBD efi are most swappable, easiest to do and wire, less sensors and hoops to get working than a 96 up OBD II system.  The 91-95 is what Chrysler based the swap harness and efi on. I have a 91 Wrangler system in my American and it has been performing flawlessly since install.
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From: Brien Tourville <hh7x@xxxxxxxxxxxxx>

Correct_ah_Mundo - :]

 Because ..  IMO and Others  .. the Renix engines were designed & built really well - the blocks - can't speak to the Ni-Si  contents in these years but have read the Kudos from builders on their impressions while machining them - and unlike the '91 - '95 blocks - they like 'em.

Chrysler removed material from the engine blocks - to lighten them and to save money in the '91 thru 95 engines .  

I believe materials used at the Foundries were of a lower cost as well from the machining comments I've read - kinda the difference between a richly dense quality & one that is drier & less dense.

In keeping with your premise that 'less is more' applied to EFI engine management - I disagree  .

Chrysler did a 're_rethink' like AMC did with their 258 block - so much so they had to add a Main Stud Girdle to stiffen the blocks.. and kept adding back block material casting run after casting run - which led to the NHV Blocks - Noise Harmonic Vibration - with lettering NVH cast right into the blocks of latter years  .

Cash strapped Chrysler would not have done any of this - if there weren't obvious problems that would cost them in service complaints & ratings.

There were problems with the '91 - 95 engines - wear problems - noise problems - flex problems.

Might just as well get the quality version as pricing is the same.


-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
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