engine swap for fuel economy

[johntphipps]

Has anyone ever heard of someone wanting to put a smaller engine in a wagoneer? I used to have a cherokee pioneer with a 258 in it. It was so smooth and efficient I miss it. I have found out nice wagoneers with 6 cylinders are really rare . But I am thinking about getting one for a daily driver with fuel prices being what they are.

[indianafsj]

Has anyone ever heard of someone wanting to put a smaller engine in a wagoneer? I used to have a cherokee pioneer with a 258 in it. It was so smooth and efficient I miss it. I have found out nice wagoneers with 6 cylinders are really rare . But I am thinking about getting one for a daily driver with fuel prices being what they are.


I am not sure what kind of mileage the I6 gets in the wagoneers. I would get that by today's 6 cylinder standards, it wouldn't be great. It would still be alot of weight and such. My suggestion would be if you are looking for fuel efficiency, don't buy a wagoneer. But if you want a great, reliable and fun vehicle to own, go for it.:thumbsup:

[fulsizjeep]

My suggestion would be if you are looking for fuel efficiency, don't buy a wagoneer. But if you want a great, reliable and fun vehicle to own, go for it.:thumbsup:Yep...

I have owned two 258 powered FSJs over the years. They work great for torque but don't expect efficient highway performance.

[johntphipps]

Thanks for the advice. I am not looking for a prius. Just want something that uses less fuel than my '70 with the buick 350.

[addicted]

A 258 powered FSJ will do that, especially if it has a manual trans.

[RAMBLINFSJ]

If you don't mind a little work and wiring, a 4.0L would be the way to go.

[indianafsj]

what kind of mileage are you hoping for? My 83 has the 360, it does just as good as the new full size SUVs on the highway, I can usually stretch it to anywhere between 14 an 17 as long as i stay out of the left lane. The 360 is a great engine, and good gas and proper oil change intervals seem to help quite a bit.

[RAMBLINFSJ]

That's pretty darn good mileage out of a 360. Mine never got better than 8 mpg whether empty, loaded, uphill, downhill, or pulling a trailer. It was always 8 mpg.

[indianafsj]

really? only 8? mine doesn't have any off the line get up and go at all, but I can deal with that. I have seen videos of guys burning off their tires and stuff and can't imagine that out of my engine, but, I pretty good mileage out of it so I don't complain. We took a family trip this past summer and got 15mpg running the a/c!

[RAMBLINFSJ]

That's amazing. Yeah I could only get 8 mpg. Of course, it has almost 300,000 miles on it but it's not worn out at all. It will burn the tires off, well one tire anyway. I'm very happy with my motor except the mileage.

[johntphipps]

I used to have an 84 cherokee pioneer with the 6 in it. I was able to get almost 20mpg on the highway. I am down around 12 or so with my v8

[RAMBLINFSJ]

A 4.0L is diffinitely worth exploring. It only takes like 5 wires to run the fuel injection. Do a web search and there will be tons of info.

[addicted]

You could also do the 258 with 4.0 head and fuel injection. The torque of a 258 with the economy and top end power of a 4.0.

[joe]

An I6 will do better than a v8 mpg wise but not a great deal but the bottom line is that regardless of motor it's still a 4500lb rolling brick. If mpg's are important to you, enjoy the FSJ for what it is/does and buy an econobox to drive to work.

[mdill]

My 1977 J-10 258 I6 got ~16mpg (up hill, down hill, highway, city, it did not seem to matter much) 4.11 T-18 tranny
My 360 4V Cherokee gets ~14mpg highway, have not done long term measurments on average. 3.54 Th400 tranny

Mike D.

[Peter Matusov]

Thanks for the advice. I am not looking for a prius. Just want something that uses less fuel than my '70 with the buick 350.
Buick 350 is not much better or worse than any other carburetted V8 of similar displacement.
Low-rpm-stall, no-lockup, converter in a 3-speed TH400 is what costing your some gas mileage.
My 68 makes 10-12 mpg, up, down, in town, or on the highway (3.54 axle ratios, 31" tires). The torque converter locks up near 1500-1800 rpm, meaning I have to keep the right foot down even if I'm going down a steep grade.

My best mileage in an FSJ was in a 79 Cherokee with a 2-bbl 360 and 31" tires (3.54 axle ratios), and that was 14 mpg on the highway at 70-75 mph sustained. When the tires grew to 35", mileage went down to 8.5.

For comparison: the rovers (3.9 and 4.2 L V8, EFI) are all between 11 and 13 mpg in town, and 15 to 17 mpg on the highway. Same curb weight as a stock FSJ (~4500lb), 3.54 in axles, 1.2:1 underdrive in T-case high ratio, 29" tires (1.4:1 with 32" tires). 4-speed automatics with lockup torque converter.

[letank]

I used to get 15-17 with stock height.... almost low rider... and with a little lift 12-14.
Really if you want good mileage, get a four banger corolla or civic 35-40mpg.... even my 2 banger yamaha goes not get good mileage, but it if fun to drive and it was inexpensive at $1k to get 35 mpg, the old suzuki DR400 get almost 70 mpg on the road and 40 off road.... and I paid $120 for it:

http://picasaweb.google.com/jeepmr/DR400Adventures#5238661828584965170

yep, this is in Moab.... a little sunshine and warmth

[billyj7175]

I think the best I ever got was 11 mpg in town and 15 mpg on the highway, keeping it between 55-60 mph...and that was before the lift and 33's. I've never checked it since...

[RAMBLINFSJ]

I really think it's in the gearing. The folks above seem to be getting around 14 mpg with gearing around 3.50. My Wagon had the factory 2.29 or 2.79 whatever they are. That's more power being used up trying to get that spinning. A gear swap would probably help my mpg's. Less effort on the engine.

[Belteshazzar]

i would say give up on fuel economy. ya spend thousands to save hundreds. get a second car.

[CJ the noisemaker]

My L6 gets around 18-20 MPG as of now, but that when it's in good running condition. However, the comment about it's highway performance is true. It can't pass a car to save it's life.:p

[budojeepr]

Sorry to sound like a broken record, but think about swapping in a diesel. Religious wars - GM or Cummins - notwithstanding, you'll expect 20+ mpg AND you can tow AND burn the tires off.

[Bill Moore]

Sorry to sound like a broken record, but think about swapping in a diesel. Religious wars - GM or Cummins - notwithstanding, you'll expect 20+ mpg AND you can tow AND burn the tires off.

x2

[Mikel]

Sorry to sound like a broken record, but think about swapping in a diesel. Religious wars - GM or Cummins - notwithstanding, you'll expect 20+ mpg AND you can tow AND burn the tires off.

I get 23-25MPG in my 4BT-powered J300, driving like a maniac.

[SVO42]

An oddball idea I've had in the back of my mind is an engine looking for a project, sort of. I've considered it for an FSJ, obviously. I learned about it when I used to frequent TurboFord more often.

It's a marine engine, the Mercruiser 470. It's a 224 cid (3.7 L) I-4...basically half of a Ford 460. You can even use a performance 460 head on it. :eek: For easy swappability it also has a SBC bell pattern. I think one of these, nicely built, would have more power than a 4.2/4.0 (esp. with a Cobra Jet head on it). All things equal, a crossflow head (460) will outperform a uniside flow head (4.2/4.0). I'd either fuel inject it or use a Holley 470 CFM Truck Avenger. :drivin: Then put a 700R4 or a manual transmission and your choice of transfer case behind it and hit the road!

Pic:
http://img.photobucket.com/albums/v490/SVO42/mercruiser1.jpg

[CJ the noisemaker]

An oddball idea I've had in the back of my mind is an engine looking for a project, sort of. I've considered it for an FSJ, obviously. I learned about it when I used to frequent TurboFord more often.

It's a marine engine, the Mercruiser 470. It's a 224 cid (3.7 L) I-4...basically half of a Ford 460. You can even use a performance 460 head on it. :eek: For easy swappability it also has a SBC bell pattern. I think one of these, nicely built, would have more power than a 4.2/4.0 (esp. with a Cobra Jet head on it). All things equal, a crossflow head (460) will outperform a uniside flow head (4.2/4.0). I'd either fuel inject it or use a Holley 470 CFM Truck Avenger. :drivin: Then put a 700R4 or a manual transmission and your choice of transfer case behind it and hit the road!

Pic:
http://img.photobucket.com/albums/v490/SVO42/mercruiser1.jpgThat is a pretty sweet idea! I would like to put something like that in my GW, and even smaller cars. But this would be a real project, the motor mounts would have to be re-fabricated, an electric fan would be installed, and coolant lines need to be custom made for it. But go for it and see what happens!

[Serious Johnson]

Generally, just generally, the smallest engine that will move the vehicle adequately and maintain desired speed at wide-arse-open-trottle will return the best fuel efficiency. Whenever you let off the throttle you're carrying a less than ideally efficient engine. That's theory. In practice, a too-weak engine for commonly encountered tasks can have you turning a lot of revs just to keep the thing on boil, and that can burn more fuel than a larger engine spinning slowly. So the answer, like that to the "briefs or boxers" question, is "Depends".

Far and away the greatest waster of fuel, at least in rigs of this vintage, is a silly slushbox transmission.

S.J.

[SVO42]

Here's a Mercruiser 470 for sale right now on Ebay. I wouldn't have posted this except that it has more/better pics: http://cgi.ebay.com/ebaymotors/MERCRUISER-3-7L-470-165-170-190-MARINE-MOTOR-ENGINE_W0QQcmdZViewItemQQhashZitem2eab134a08QQitem Z200438663688QQptZBoatQ5fPartsQ5fAccessoriesQ5fGea r

Me want (after having said project to put it into. :o).

[Voodoochiled445]

What about a chevy 250? With an aftermarket intake and headers, Iv heard its easy to get 225HP with that combo. That should be plenty to scoot these huge jeeps with, heck the stock 360s make about 160HP right? My chevy 250 pushes 155HP and I get around 20mpg but that's in a camaro.

[budojeepr]

... So the answer, like that to the "briefs or boxers" question, is "Depends".
:D So, my mind wanders and comes up with "unfortunate choice of word."

Thanks for the guffaw!

[mcinfantry]

I get 23-25MPG in my 4BT-powered J300, driving like a maniac.
a buddy of mine is getting 21 in his driving and towing and flooring it. i mean REALLY treating it like crap.

[Logs0012]

Sorry to sound like a broken record, but think about swapping in a diesel. Religious wars - GM or Cummins - notwithstanding, you'll expect 20+ mpg AND you can tow AND burn the tires off.
X3

[madmikeX3]

Sorry to sound like a broken record, but think about swapping in a diesel. Religious wars - GM or Cummins - notwithstanding, you'll expect 20+ mpg AND you can tow AND burn the tires off.

X4