best diesel engine to swap into early-model CJ5?

[jesusgatos]

Have spent the last few years building this monstrosity of a motorhome, and now that it's almost finished, it's time to start putting together a little Jeep to go with it. Have a fresh Buick 225 V6 and an SM465 and Dana 18 transfercase with a Warn overdrive (25%). But I just put a brand new LDS465 multifuel engine in my motorhome, and I'll have the ability to process fuel onboard, using this system that Racor helped me put together. So it would make a lot of sense to use some kind of a little diesel engine in this Jeep.



Mercedes OM617 would have been a good option, but it's too big to fit in the short-hood early model CJ5. The 4-cylinder OM616 fits, but what I read about this guy's swap was not particularly encouraging.

My Grandpa had a Jeep with a Perkins 4-cylinder diesel in it, but they didn't make very many of them and it doesn't seem worth the trouble to go find one.

Yesterday I found a practically brand new Isuzu C240 engine that off some kind of military genset, so did a little bit of research and found out that Jeep actually installed that engine in some CJ7's from 80-82 for the international market (here). So I looked up the specs and it makes a bit more torque than the OM616. That spec-sheet made me wish I'd found a 4JG1T though...

So what do you guys think? Is this little Isuzu engine a good candidate? What other engines should I consider? TDI might be an option? Looks like OTT makes an adapter that would allow me to use the SM465 with that engine.


EDIT - here's the list of engines up for consideration so far:

Kubota V2003 MT / V2203 / V2403
Onana L423 / Cummins A-series
Cummins B3.3T
VW 1.9L TDI
Isuzu C240
Isuzu 4JG1T
Perkins 4.108

 

[ODdave]

What about a L423 Onan? (cummins A series)

 

[Cycletek]

Subscribed.......opcorn:

 

[jesusgatos]

What about a L423 Onan? (cummins A series)

Don't know anything about those engines, and google didn't turn-up much. Found this post, and a few more that suggested they might have been used in some military Jeeps? What are these engines all about?

EDIT: found a lot more info when I searched for 'Cummins A2300'

 

[Floridianson]

Cummins 4bt

 

[ODdave]

Google search of 2.3 cummins has some good info. They are not super common but they came in 3,4&6 cylinder versions. 1.7,2.3&3.4 L

 

[ODdave]

4bt is WAY bigger than the om616 and I Belive bigger than the om617, I can mesure them if any one wants.

 

[jesusgatos]

4BT is way too big and heavy. The A2300 looks interesting though. What kind of money are those Onan L423 engines selling for through surplus?

 

[patracy]

I've longed after a CJ-8 with a 4BT, NV4500, twin sticked NP205, on D60's....

 

[rickf]

What do they use in the CJ-10 tugs? That might be an option. I know there is a guy, Steve, that goes to the Virginia rally who has one.

 

[ODdave]

Not sure on the surplus price but if you happen upon a ip for one in your travels my 5in water pump is in need.

 

[natem]

I would go with the Isuzu. Back in the day I had a GMC S15 with the 4 cyl Isuzu, 40+mpg and very dependable.

 

[jesusgatos]

Onan / Cummins A2300T looks pretty interesting.

TDI might be an option? Looks like OTT makes an adapter that would allow me to use the SM465 with that engine using a Toyota bellhousing.

Someone on pirate4x4 pointed me to this discussion about Kubota V2003 MT /V2203 DI/ V2403 engines.

 

[patracy]

I'll have to warn you, as a Samurai Diesel owner. Get as powerful engine as possible in the jeep as possible. My 1.6 is an upgrade over stock. But it's a real slouch honestly.

A 4BT will fit in a jeep.

 

[trukhead]

I would go with the Isuzu. Back in the day I had a GMC S15 with the 4 cyl Isuzu, 40+mpg and very dependable.

If you go with this engine make sure you keep the valve lash clearances in spec. Out of spec clearances will rattle the valve train and break the rocker stands and replacement parts for this engine are not stocked or available.
I made one engine out of two and reused the head gasket. It worked fine. clean both sealing surfaces without any abrasions and clean the gasket shiny and use hitac on the gasket. also a friend said to soak it in water to reswell it. I don't remember if I did that or not. engine didn't leak and it ran perfect.
Internal hard parts were not available 10 years ago. The valves have lash caps that can break as well if lash gets sloppy. engine is peppy. about 50 horse power.
I was thinking about installing one in a Pietenpol aircamper but didn't happen.

 

[Mack Attack]

Get an Isuzu 4BD1T ! It'll make cummins power without all the weight, Are you opposed to running the Nissan SD33T which came in CJ's ? That would be a bolt in bolt up OEM serviceable unit. For Jeeps I always use the Isuzu's over Cummins same power less weight due to they were designed for lighter duty vehicles than the Cummins. Sure ya find them in 3/4 and 1 ton RAMs but they were designed for 5-7 series trucks 1.5-2.5T. The AM715/720a2 exports AM General built '81-'83 had 6BD Isuzu diesels later they got re-man'd and updated to the 6BD1T turbo charged version. A few of the exported AM7's aka CJ-7s had the NA and Turbo Izzy 4

 

[jesusgatos]

I'll have to warn you, as a Samurai Diesel owner. Get as powerful engine as possible in the jeep as possible. My 1.6 is an upgrade over stock. But it's a real slouch honestly.

A 4BT will fit in a jeep.

Don't want to argue the point with you, but I've looked at the specs and the 4BT is a bad fit for an early model CJ5 (length, height, weight). This is just a little runaround Jeep. Only concerned about power to the extent that I want to enough torque to pull gears and keep up with traffic. Beyond that, more concerned about fuel economy.

If you go with this engine make sure you keep the valve lash clearances in spec. Out of spec clearances will rattle the valve train and break the rocker stands and replacement parts for this engine are not stocked or available.
I made one engine out of two and reused the head gasket. It worked fine. clean both sealing surfaces without any abrasions and clean the gasket shiny and use hitac on the gasket. also a friend said to soak it in water to reswell it. I don't remember if I did that or not. engine didn't leak and it ran perfect.
Internal hard parts were not available 10 years ago. The valves have lash caps that can break as well if lash gets sloppy. engine is peppy. about 50 horse power.
I was thinking about installing one in a Pietenpol aircamper but didn't happen.

Oh, that's a bummer. Lack of parts availability is a deal-breaker. No way I'm going to engineer a custom swap based on something I won't be able to fix if/when it breaks. Thanks for the heads-up.

EDIT: just to be clear, which model Isuzu engine are we talking about here?

 

[jesusgatos]

Get an Isuzu 4BD1T !

770lbs!?! Way too big/heavy.

Are you opposed to running the Nissan SD33T which came in CJ's ?

No room for that inline six in the early CJ5 (shorter hood than the later-model CJ's).

 

[diesel583]

If my memory works right the pre 72 CJ is about 6 inches shorter under the hood than the newer ones.

 

[Mack Attack]

770lbs ? ! They put that thing in Wranglers on the time I had no idea it was still that bloody heavy.I wasn't sure on SD33T I just knew some CJ's had them. Learned something new today.