4.1 vs. '77 odd fire 3.8 vs. dauntless 225

I'm having issues figuring this out.

My '66 cj-6a's original 225 is a bit tired (low oil pressure, lower compression), and is in need of a freshening up. She runs great and fires up every time, but is not as "perky" as she used to be. While roaming a local junk yard for other parts, two buick engines caught my attention - one an 80-something 252, the other a '77 odd fire. They are a phenomenally low price (under 100 w/o accessories - which I can't use anyway).

I do know the later engines have lower performance ratings because of increased emissions regulations (and more honest hp ratings?) - the 77 3.8 has something around 110 hp vs. the 150-something of the 225 (I'm finding 125hp for the 4.1). BUT - I've read about increased strength of the "late & great" odd fire and more cubic inches sounds very tempting.

Time for the inevitable question - in your opinion should I rebuild/freshen up the original 225, or grab one the others, rebuild, and swap?

If it is pertinent - my jeep is mainly used for running trails/exploring/prospecting during weekends in southern AZ (low speed, low RPMs, low range). Heat is also an issue - I don't hide from the triple digit temps, and we all know that early cj's have tiny radiators.

(BTW - I have no intention to start a war over which is better, just looking for personal experiences/opinions of the various engines)

 

I feel that your CJ will retain much more of its value if you rebuild the original D225.

 

The HP rating system was changed, so you can't compare HP across model years. I doubt you would notice much "seat of the pants" difference between a Dauntless and a later model V6.

Resale value in modified jeeps has virtually nothing to do with keeping original drivetrains intact. I would go so far as to say that transplanting later model engines can actually add resale value.

Among your choices listed, I would just go with whatever option is going to give you the most reliable and efficient driveability.

 

If the oddfire 231 is ready to run I'd put that in as a user until you can rebuild the 225. Personally I like the 252 but in this case I agree with Oldtime and feel the Jeep would be cooler and hold better value with the 225. I chose the Oddfire 231 because you can use the 225 flywheel without having balance issues. Would be a virtual bolt in to get you by.


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FWIW, I'm in the middle of a 252 rebuild right now for my 47 CJ2A project. I also have an even fire 231 on a stand in the shop. One thing I'm discovering about the 252 is that there doesn't seem to be a lot of aftermarket pistons offered for this particular engine so I'll be going with the stock 8 to 1 which is fine for what I'm gonna use it for. It also comes with a factory aluminum intake and a rolled fillet crank that was used in the turbo V6's. The 252 is really just a 231 with a bigger bore. Your 225 is rated for more HP as others have pointed out and has a much higher coolness factor IMHO. And there's nothing like the sound of a sweet running odd fire. My .02 centavos...

Mike

 

Yes and no. All depends on whether the Jeep is completely stock or already has some modifications. I, for one, would likely pay more for a desirable (can be a bit subjective) swap engine in a non-stock jeep, but that would also depend on the quality of the other non-stock pieces and their installation. I think the most valuable Jeeps remain, and will remain, the completely stock versions if they are in good condition.

 

Well it looks like I'm going to head over to the junk yard tomorrow morning. I'm pretty sure that I'll be grabbing the 231 odd fire, mainly for the simplicity of pulling my engine out and dropping that one in (not quite that easily - I know).

 

Correct me if I am wrong someone but for me the big advantage is the 231 has the hardened valve seats & guides for today's unleaded fuel where as the 225 if from the leaded fuel era.

rocmoc n AZ/Mexico

 

Depends on the year of the 231. Not all had induction hardened valve seats (very early production) although most did.
Really not an issue with modern fuels anyway.


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