Second Gas Tank in an MJ?

[johnj92131]

Wondering if anyone has put a second gas tank in the MJ, perhaps in place of the spare tire? If so, how was it done and what did you do with the spare?

 

Thought about using a stock Cherokee tank in place of the spare and trying to fill both tanks from the existing filler.

 

My truck is a 91 long bed.

 

Also, still have not given up the idea of finding a Comanche with a diesel engine. Anyone have a lead for me on a diesel?

[Pete M]

Some have thought about it, but I don't think anyone has actually done it yet. :hmm:

[DirtyComanche]

I toyed with the idea of putting a second stock tank on the other side. But, no dice, at least not with the rearend I had. The driveshaft was offset just a bit too far.

 

I don't think the XJ tank would fit worth anything... I think that big ol' X-brace in the rear gets in the way. Maybe not though, I've never tried.

[BLHTAZ]

Maybe a smaller 15 gallon tank from an old CJ would work better with it's square/rectangular shape to fit in the spare tire area. :idea:

[Jerry]

Maybe look at getting a prefabricated one from companies making fuel tanks for other stuff?

Here's a company making tanks for boats:

http://www.coastline-tanks.com/bellytanks.html

I'm not sure about cost though, might be pricey!

[carnuck]

The option for the spare is leave it off or throw it in the bed. I thought about redoing the exhaust and putting a tank on the other side.

 

 

As for diesel, the Renault engine these came with is getting nearly impo$$ible to get parts for. I would do a VW diesel (grab a '79 DJ-5G with 2.0L like the one I have for sale http://www.comancheclub.com/forums/viewtopic.php?f=3&t=12684&hilit=+postal+jeep&start=45 to get a RWD 904 auto trans or a '77-79 Gremlin for std trans which I think is an SR4?) or Toyota 2LT (they ran a similar AX-15 and a close version of the AW4)

 

Other option is a Nissan SD33 (SD33t is faster!) which came in CJ10s and Scouts with a 727 trans. (It's adapted to a Mopar big block trans)

[summerinmaine]

The option for the spare is leave it off or throw it in the bed. I thought about redoing the exhaust and putting a tank on the other side.

 

On my old 4WD, I had a hood-mounted spare, kind of like the old Land Rover, as well as the rear mount.

 

 

Don't know if you could get away with it these days. :dunno:

[johnj92131]

Frankly, I wondered about getting a rear bumper mounted, swing away tire carrier. Saw a few at local junk yards that "might" be able to work.

 

Do want to get a front mounted hitch so I can carry the Honda Trail 90 with me at the same time I take the HiLo camping trailer.

 

Nice picture of the Land Rover!!!

[90eliminator]

This is more toward the Diesel question.....

I have 1 of about 5 or 6 that I know about a 2.5 VMI diesel that was in a 1996 cherokee.. This engine is very popular in England and Ireland and stuff... A couple slipped into the country mine was right hand drive.....and was in an accident... but the drivetrain behind the 2.5 VMI is an AX-5 and a 231.... You could find one of these and it would be a drop in for a 4 cylinder comanche.... Do a search on ebay europe for cherokee.'s Good luck...

[johnj92131]

Is that VMI 2.5 diesel a relative of the 2.8 CRD used in the 2005-7 Liberty?

[JeepcoMJ]

Wondering if anyone has put a second gas tank in the MJ, perhaps in place of the spare tire? If so, how was it done and what did you do with the spare?

 

Thought about using a stock Cherokee tank in place of the spare and trying to fill both tanks from the existing filler.

 

My truck is a 91 long bed.

 

Also, still have not given up the idea of finding a Comanche with a diesel engine. Anyone have a lead for me on a diesel?

 

a cherokee tank would work, but you'd have to rework the bracing a bit, and make bracketry for the straps. this idea would SUCK in a longbed if you were going to wheel it...you'd leak gas everywhere, even with a skid :ack: . you would also need to add a second filler neck...no one in their right mind would trust 6 or more feet of rubber to send gas to a tank :doh:

 

as for the diesel...there is a diesel MJ sitting in my dad's shop right now. if you have questions about them, ask away. it's not for sale, and you'll have little luck finding one...there are somewhere between 13 and 17 diesel MJ's in the states that I can find. British Ontario is the best bet to locate one, but the next best bet is to get a 4 cylinder MJ, and find a 2.1 litre TD xj from the 85-88 vintage, and swap the parts over. those are rare, but not impossible to find.

 

also, I second the statement on expensive parts...a head is $1200 used in good shape, $1900 new IF you can find one. Winnebago Lesharo's used the same motor with a smaller turbo, so that's your best bet for parts. the block is aluminum with a cast drop-in sleeve, and a gasket set for it is upwards of $400, and there are several variances so you need to be correct on gaskets or you'll detonate.

 

common problems are starter failure (leading to destroyed ring gear), cracked cylinders, cracked precups, and stuck wastegates. we have 250k on ours, and lucked out finding a BRAND NEW motor for it for $75 sitting on a guy's trailer (he gave up trying to use it on a log splitter right after purchasing it in 1987)...it just needs new gaskets, as we tore it down to inspect it.

 

:cheers:

 

-Pat

[johnj92131]

JeepcoMJ wrote: "a cherokee tank would work, but you'd have to rework the bracing a bit, and make bracketry for the straps. this idea would SUCK in a longbed if you were going to wheel it...you'd leak gas everywhere, even with a skid you would also need to add a second filler neck...no one in their right mind would trust 6 or more feet of rubber to send gas to a tank"

 

Yes, that big X brace popped my balloon when I finally looked at it. I "thought/assumed" I had a real simple idea. Oh Well!

 

I am not into wheeling, so that is not an issue for me. And the truck is 2 wheel drive. Frankly, I would never use rubber hose to feed a second gas tank. I would use metal tubing for most of the run. And I would want to avoid adding a second filler neck. Good venting of both tanks would help assure a full load of either gas or Diesel from a single filler. Take a look at how the Mk. 4 and 5 Sunbeam Alpine and some Jag sedans used dual tanks with one filler. The Alpine used a rubber hose at the bottom to suck gas from both tanks at the same time. Not sure about the Jag.

 

And If you don't think a Sunbeam Alpine was ever cool, take a look at the very first James Bond movie, "Dr. No" - Bond drove a Sunbeam Alpine long before he "moved up" to Aston Martin

 

The 2.8 litre CRD engine from a Liberty would be a good choice, if I could find one for a reasonable price. My second choice would be a VW TDI engine. Lot's of them around, strong as all get out. Lots of well known power enhancements. 250 plus lbs/ft of torque in not hard to get. Acme Adaptor to Toyota transmission is well worked out. I can see getting mid 30's mpg around town, even with a 3400 lbs truck. (I own a 96 Passat TDI, so I know a little bit about the engine).

 

The 3 litere V6 diesel for the 2009 Audi Q7 sounds great. 221 hp. and 406 lbs-ft of torque!!! Can you imagine pulling a fully loaded Comanche over the continental divide via the Eisenhower tunnel at an average altitude of 11,100 ft.?

 

Know there was a fellow on the club in New Orleans who put a 5 cyl. 3 litre MB engine in his Comanche. Think he lost the truck to Katrina.

 

Still, the idea of putting my trail bike on the front of the Comanche, hooking up a camping traile on the back, running a fuel efficient diesel engine, with dual fuel tanks and hitting the Alaska Highway really appeals to me. I have wanted to travel the Alaska Highway ever since I was 19 years old - I will be 61 in March!!! Still dream like a kid.

 

Last year I found a Diesel MJ on Vancouver Island, just was not quick enough. I was second in line to buy it. Agree with you that the Renault Diesel is way too expensive - hence my interest in the VW TDI.

 

Still, the 2.8 VM Common Rail Diesel might be the best choice for a diesel conversion.

 

Appreciate all the input so far.

 

On the other hand, a 2010 Mahindra pickup sounds like what I might want and it could be cheaper than modifying the Comanche. Not to mention that the better half would "feel" much better taking the trip in a "new" truck.

[gogetemturbo]

I spent some time laying under my long bed rig and measured things out a little while ago. A factory MJ 16gal tank would work (on mine at least) if you mirror the stock tank. If you play with the filler hose turns and so forth, you can theoretically get the filler out into the wheel well to deal with the fuel filler issue. You'd have to build custom mounts, and shorten the exhaust but I think it would work.

 

I need to lay underneath my short bed and see if it will work there too. I would most likely cut the hole and put the fuel filler into the side of the body so it looks like a factory option. Just because the California smog devil is temper mental and I don't want to give them a reason to complain.

 

I'm sure I'll do it sooner or later, so I'll post up how it goes.

[lil_loco]

I am also interested in a 2nd tank, but on my 86 longbox... would the longbox without spare tire underneath work easier?

[Pete M]

I think you guys are putting too much thought into it. I've got 2 military gas cans hanging on the back of my truck. That's 10 gallons and all I needed was to fab up a mount for them.

 

Cost me $10 each

 

 

And I think they look sweet. :D

[gogetemturbo]

lil_loco - You certainly could, but I think it would require a custom tank to do it so it's not hanging down too much.

 

 

Pete - Of course we are over analyzing it! LoL You gotta admit, it would be cool to just flip a switch instead of getting out and dumping more fuel in. Not to mention if you want to do a really long trip you could fill both tanks AND have a couple of jerry cans.

 

Besides, it's fun to have something different, even though we are all already different just because we have MJs.

[Pete M]

It's a lot of weight to drag around everywhere you go. I don't even keep gas in the cans anymore. I've never needed them and so I just used the gas in them one day and never filled them up again. They're just there for looks now. :roll:

[1990 Pioneer 4x4]

How much gas do you really need to carry? Why not upgrade to the 25 gallon tank?

[gogetemturbo]

Both statements are very true. Everyone has their preference...I get tired of only having a roughly 175 mile range around town. Granted that was the old truck and this one may be better but we'll see.

 

The 25 gallon tank would be an option. But I would still want 2 just to keep the truck even. :yes:

[lil_loco]

a second tank would rock for long distance travel... say cross-country. No reason to keep it 'full' all the time, could just alternate tanks and think of those long lineups at the pumps where the only available pump is on the 'wrong' side... not anymore! :clapping: