[Bearhawke]

I just sold my Studebaker and may wind up getting a different project car in the near future.

Contemplating swapping in a late 2000's Jeep 3.8L with matching auto tranny into a 1963-66 Dart or Valiant SW.

I'm quite happy with the 3.3L V6 in my 1994 Caravan and at least the 3.8L (same engine family) was available in a longitudinal configuration.

Any ideas, thoughts, brickbats, etc. here? I'm mostly concerned about oil pan and possibly tranny clearance issues; everything else i.e. motor mounts, exhaust, fuel system, computer etc. should be (relatively) easy to sort out.

 

[TWX]

Interesting, I didn't know that the 3.8L was ever used longitudinally...

There was also the 3.5L OHC H.O. aluminum block in some of the LH cars, and while the transmission wasn't longitudinal, the engine mounting was, and if it uses the same bellhousing as the 3.8 then that might also have some potential...

 

[TWX]

I used the wrong terminology. I got transverse mount and FWD confused.

 

[kzooman83]

I imagine this swap is doable (anything is doable with enough money and time) if you have your heart set on the 3.8L, but FWI the 3.9L V6 from the '90s dodge trucks would be almost a direct replacement for an A body, since it is essentially a 318 V8 minus two cylinders. Not saying not to go with the 3.8L, just throwing that out there.

 

[JTE]

If you want an engineering project and not just a repower, I would install it transverse using a caravan (or any other dimensionally suitable FWD) powertrain & front suspension, a tape measure and cocktail napkin is the first step. Bobs N-S / AWD idea sounds fun too, but you can tell by our ideas we were 90 degrees apart back in the 80's. A friend did his Dakota with a 2.2 fwd and it was quite unique. If however the base vehicle is a 63 Dart you have no choice, Max Wedge.

 

[Dave Z]

I think the reason for the 3.8 is, well, it was a much better engine than the 3.9 -- better gas mileage, much more power, less vibration.

I often think about repowering my Valiant, but really, I like it as it is... well, I wouldn't say no to a 318. A 340 would be pushing it. I used to think about putting in a 2.2 Turbo 3 but that would be a waste of an engine that would be much more fun in a Reliant. (There's a project I have to love -- in concept at least.)

 

[TWX]

If I had a bodily messed up 4cyl Dakota, a bodily messed up Spirit RT, and an A-body with a bad motor I'd consider something...

 

[Bearhawke]

I think the reason for the 3.8 is, well, it was a much better engine than the 3.9 -- better gas mileage, much more power, less vibration.

I often think about repowering my Valiant, but really, I like it as it is... well, I wouldn't say no to a 318. A 340 would be pushing it. I used to think about putting in a 2.2 Turbo 3 but that would be a waste of an engine that would be much more fun in a Reliant. (There's a project I have to love -- in concept at least.)

Another thought may be a later model multi speed AT adapted to your 225 Slant Six: better MPG and more performance. Maybe an 8 spd out of an LY car?

 

[AC TC]

pentastar...eight speed.
They should start to show up at junkyrds any day now.
To bad mother doesent sell em as crate units with standalone electronics

 

[Bearhawke]

pentastar...eight speed.
They should start to show up at junkyrds any day now.
To bad mother doesent sell em as crate units with standalone electronics

Standalone controllers will become available (more likely aftermarket) IMHO since I'll bet the farm that many swappers/rodders will be interested in those 8 spd trannys.

 

[dana44]

Definitely the 3,8 Jeep engine would be the way to go, and being an aluminum oil pan, should be easy to refabricate to clear the K member. If you do happen to get the 3.8 and transmission and don't want it, I would really love to do that in my TR4 over the 2.5 5spd I have, but I can still have fun with either. A full donor vehicle is definitely the way to go to get everything to work properly.

 

[Lt. Dan]

If you're going to go through the trouble of rigging up a drive by wire setup, mounts, and everything else to put a 3.8 in, why not just call AEV and get a take-out Pentastar instead?

 

[Bearhawke]

If you're going to go through the trouble of rigging up a drive by wire setup, mounts, and everything else to put a 3.8 in, why not just call AEV and get a take-out Pentastar instead?

Question: are you the same 'Lt Dan' who had a 1972 VaSP Ply Fury I 440 some years ago?

 

[minivanin]

For years ive said I wanted to do a 3.8 jeep take out swap into a 72 dart...or even better...my favorite a 3.3. I think it would be neat. Lose weight compared to a slant sickness gain power and move the weight futher back for enhanced handling

 

[Rick Anderson]

Interesting, I didn't know that the 3.8L was ever used longitudinally...

There was also the 3.5L OHC H.O. aluminum block in some of the LH cars, and while the transmission wasn't longitudinal, the engine mounting was, and if it uses the same bellhousing as the 3.8 then that might also have some potential...

I used the wrong terminology. I got transverse mount and FWD confused.

Yea, unless I'm confusing the LH platform with another, the trans was mounted logitudinally like the motor, it was FWD because the trans was a funky adaption that included a differential in the front of it with driveshaft take off's on either side of the front of the trans. Sorta like the old Rear Engine Porsche 911 and Volkswagen Beatles, except turned around to the front of the car.

 

[Rick Anderson]

Any ideas, thoughts, brickbats, etc. here? I'm mostly concerned about oil pan and possibly tranny clearance issues; everything else i.e. motor mounts, exhaust, fuel system, computer etc. should be (relatively) easy to sort out.

I'm thinking motor mounts might NOT be so easy to sort out. If you're unlucky the K-member mounts will be too close together and you'll have a to cut them off and do a ton of fabrication, if you're lucky, the k-member mounts will be far enough apart and you'll just have to fabricate an adapter between the two, which is far easier said then done. Whose to say the trans mount might NOT be way off either and you'd have to relocate the crossover piece for the trans mount.

Oil pan, look at moroso's catalogue, maybe they have alternate oil pans for the 3.8L, as well, many aftermarket off-road/lift places for Jeep's might have alternate oil pans to clear aftermarket lifts/steering equipment. That way you can avoid having to fabricate you're own oil pan, or at least a moroso pan might be easier to cut up and reweld than the OEM diecast aluminum pan.

If you can't find drawings of the motor/trans comination with dimensions, maybe you could find a Jeep JK that you could crawl around and measure yourself. I'd measure everything from the engine/trans mounts as the reference, i.e. where is the back of the engine from the engine mount, top/bottom of the engine motor mount. Beginning and end of oil pan sump from the motor mounts, etc. The top of the bellhousing from the trans mount, the top of the trans body from the trans mount, the longitidunal distance of the bellhousing (from engine to trans body) from the motor mounts.

Does the Jeep trans have a slip yoke for the driveshaft? Or you would have to adapt the Jeep driveshaft to the 60's Dart, those aluminum Driveshafts are NOT exactly cheap or easy to cut and reweld, let alone stick an extender in them.

At the same time, if the only problem you have is the trans won't fit the trans tunnel of the 60's Dart, if you're able to do this project, than cutting out the existing trans tunnel and rolling and welding in new sheet metal to expand the trans tunnel should be easy for you as well.

 

[55Plaza]

I think the reason for the 3.8 is, well, it was a much better engine than the 3.9 -- better gas mileage, much more power, less vibration.

Is the 3.8L Jeep V6 a different engine than the 3.8L V6 in my 2008 GC? The 3.8L that was in my 2008 GC may have been more powerful than the 3.9L in my Dakota, but gas mileage was at least 10% worse.

 

[valiant67]

The 3.8 in the Jeep is the minivan engine, for all practical purposes except maybe for different mounting bosses machined on the block.

 

[Rick Anderson]

Mileage is a function of vehicle weight, gearing, and a bunch of other factors including driver habits, etc.... NOT the least of which is the tuning of the motor and the transmission mated to it.

But as a general rule, to make more power you need to burn more fuel, so it shouldn't be surprising that a motor that produces more power also gets worse mileage. Better technology could produce a motor that makes more power and still get as good as mileage as a less powerful motor, but comparing two different engine in two totally different classes of vehicles, with different transmissions, is like comparing apples and oranges, I wouldn't be surprised if a 3.8L in a Dakota would get better mileage and power than a 3.9L, it might be the mini-van and all the factors that go with it that made for the worse mileage.

 

[Dave Z]

We generally get 18 city, 24 highway in the van. Not great, not terrible. We could do better by staying at 55. The 3.8 should be more efficient, all other variables held constant. I believe in the Dakota it had a traditional Chrysler RWD automatic which was probably more efficient. Dakota is smaller and possibly lighter.