1948 Willys CJ2A - 4.1 transplant

D

dmcquillan

Member
Joined
Feb 5, 2010
Charlie....I figured I may as well just start another thread here. :biggrin:

Hi all,
I'm a Jeep guy from Alberta,Canada (next door to the Olympics). I have a 1948 Willys CJ2A that blew a 3.8 Buick, and I just got a 4.1 V6 to implant.

I pulled the 4.1 V6 from a pink Mary Kay Caddy yesterday, and now I'm sitting around trying to figure out what to do. (plus I'm sore, plus I have beer, plus the Olympics are on next to the Nincomweb :biggrin:)

I HAD a Buick 3.8 in the Willys. So the mounts and everything will fit. It was mated to an sm420, but threw a rod or something (with the noise, guys were asking if she was an old diesel :redface:).

I would like to keep the manual, and I did some searching on here about tossing a manual behind a turbo 4.1 jut for fun. I don't have the turbo, just the non-aspirated version, but I did see that to do this in front of a manual tranny, a different flywheel will be needed. I have the flywheel from a 79 Monza Spyder, the same engine that dies on me.....would this work?

Plus, if you haven't gotten up yet for another beer while reading, I lucked onto a "crated" 4.1 V6. I'm trading a Chev 4.3 for it. So I have the Caddy engine, and now a crated block (no oil pan, heads, etc).

I guess the first place to start is to clean the 4.1 I have. OMG, the vacuum lines and wiring on that sucker! Climate control, overdrive tranny, sensor after sensor....etc. What is the MINIMUM wiring and vacuum that I need to run this is the Willys?

And how about hooking the engine up to the manual tranny? Anything special there I need for the non-turbo, or the turbo (if I ever get around to going that way)?

Thanks for any and all help you can give. Charlie speaks very highly of you people. :cool:
 
LOL I told you this was the location you would want to post in Darcy.:biggrin:

As far as using the flywheel on the 4.1 you'll need to take everything apart and have the rotating assembly balanced. The 4.1 is a little different balance than the 3.8 because of the bigger bore on it. This will also let you do some upgrades like cam ect. Vating the block would be a good idea as well as Earls timing cover mods (general section sticky on other board) for better oil pressure. You could also port the heads and get a good valve job while you're at it.

Some of the other guys will be on later to put their .02 cents in I'm sure so keep an eye on the thread.
 
I'm torn between tearing into this one, and building the crated block for later. I'm a teacher and I am heading to the East Coast this summer for the month of July (parent's 50th).

As I'm a self-taught noob mechanic (6 years ago I could change my oil, now I'm pulling and replacing engines) I'm a little leary at getting into "building" an engine. I don't want to screw up.

If I'm contradicting myself, it's probably because I change directions every 5 minutes in my head. :biggrin:
 
Tear into it so you can make sure there are no issues with it. Fresh bearings will help it to stay a live. Everything you've done so far will help you fix it up. If you take your time and pay attention to what you're doing you won't screw it up. Plus you have a whole forum here to look at and ask questions. We really do help each other out on the board. Do some searching in the engine section and I'm sure you'll be more confident about tearing into it.
 
So is it better to tear into this one, or start rebuilding the crate motor with components from the Caddy 4.1?
 
Power wise you'll make more with the 4.1, but it will be more expensive. For what you want though you'll be happier. The 4.1 will produce more torque which is what you want for a crawler.
 
charlief1 said:
Power wise you'll make more with the 4.1, but it will be more expensive. For what you want though you'll be happier. The 4.1 will produce more torque which is what you want for a crawler.
Click to expand...


Uhmmm....they're BOTH 4.1's. The Caddy motor, and the crated block.
 
If there both 4.1's then I'd use the crate engine but you'll still need to have the rotating assembly balanced to the manual flywheel.
 
So instead of a quick replacement, it looks like I have myself into a full rebuild? Scared? How about crapping my pants? lol

Can you suggest some good rebuild manuals for a first-timer? Step by step guides, what do I do first, etc?

Thanks.
 
So instead of a quick replacement, it looks like I have myself into a full rebuild? Scared? How about crapping my pants? lol

Can you suggest some good rebuild manuals for a first-timer? Step by step guides, what do I do first, etc?

Thanks.
 
Do a little reading in the engine section Darcy. It really isn't that hard if you know what to do. Making sure everything is good is very easy if you do some reading on what to look for. Since you have a crate engine you shouldn't have to replace to much. But you have to remember the last of the 4.1 crate engines were produced over 20 years ago so I'd at leat take it apart to make sure everything is good.
 
I am doing reading, trust me. Being a teacher, I like researching and do trust that I can teach myself things (it's how I got this far). But as I have taught myself everything, I'm just not sure what to be reading yet.:redface:

I'll keep looking....thanks for the encouragement! :cool:
 
LOL I was like you 20 plus years ago. The internet wasn't out there so I had to do a Lot of reading on the subject of the Buick V6. See if you can find The Buick Power Source and V6 Performance on Amazon. I've got several books on the Buick V6 and still have to look at them to make sure I've got the info I need.
 
if its a stock NA 4.1 motor and the 3.8 was a stock NA motor, the flywheel should swap over with out issue.... no reblancing needed. factory tolerance is plenty of room for a margin of safety.

other than that, should be a straight across swap.

welcome to the looney bin.... ha! looney.... i was a canadian myself for a short time... lived in victoria. nice place.

Anyways... welcome and feel free to ask us questions.

:biggrin:A.j.
 
dr_frankenstein said:
welcome to the looney bin.... ha! looney.... i was a canadian myself for a short time... lived in victoria. nice place.

Anyways... welcome and feel free to ask us questions.

:biggrin:A.j.
Click to expand...

A.J.....thanks for the warm welcome. I visited Victoria in `93 before sailing up the coast to the end of the Alaskan Panhandle to gillnet salmon for a summer.....great little city.

if its a stock NA 4.1 motor and the 3.8 was a stock NA motor, the flywheel should swap over with out issue.... no reblancing needed. factory tolerance is plenty of room for a margin of safety.

other than that, should be a straight across swap.
Click to expand...

Okay, so it should swap straight across, and it should not need rebalancing. Is there anyway that you can confirm this? These blocks are hard to find up here, so I'd hate to ruin one by missing something here....it's not that I don't believe you...I just want to be sure.

If the flywheel is fine, then I can start on other things. I'm off for a 3 day Wilderness First Aid Course this weekend, and forms to get ready for tomorrow at work, so no Buick playtime for me until next week. :frown:
 
Sorry!

I made a copy of it, 33 pages in length, w/lots of pics. I copied it on 1/14/06. It really should be a sticky on the board in the "how to's" section. Any ideas?:confused:
 
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