Hi Sat,
Sorry for taking so long to get on this thread! Now, lemme jump right in with my 0.02$ worth
Personally I would strongly recommend you steer clear of the engine transplant option! While the Isuzu engine never did give me any problems (besides repeatedly failing PUC tests), the various "creative solutions" we had to implement to get things going did - and often!! Another (and IMHO) a much better option, is to get a good mechanic to refine your existing petrol engine to give you better performance/ mileage. There are plenty of after market drop in parts available in USA for the CJ3B "Hurricane" engine and the early 1950's technology can be coaxed into much better performance with by replacing the original parts with some of these... A better carb is something to consider, next in line is changing the original condenser coil with a better one to give a stronger spark or better still take Mark's advice and change the CB point ignition system with an electronic one, but by far the best improvement in performance can be gained by changing the original intake and exhaust manifolds (especially the latter) along with fitting a freer flow exhaust system... If you are considering getting parts fabricated here, you may want to contact specialist shops that tune cars for rally's - they should be able to take care of all of the above mods quite easily.
In terms of reliability, the single biggest problem are the electrics... if you can replace these with a better system, maybe a custom made wiring set and better fuse box/ fuses etc.
From the safety point of view, do consider getting a diagonally split master cylinder to replace the original brake master cylinder. This was fitted as OEM in the later civvie models like the Mahindra Classic, and should prove to be easy to procure & fit. Taking it one step further you could replace the entire baking system with the much better front disk/ rear drums system used in the Mahindra classic, but this may be a tad expensive.
For economy, I would have recommend you get a gas kit - but since CNG/ LPG availability in your area is a question mark, I guess this option is out. No original Jeep has EVER sported a diesel engine... and honest to god, it just drives smoother and sounds a lot better with the gasoline option!
Having said the above - one of my (maternal) uncle's has had a lifelong obsession with converting every single one of his petrol vehicles into diesel, amongst the ones he's done - several Jeeps, a Jonga, an Esteem (don't even ask me why
), and finally a Gypsy... And I have yet to visit his place, without seeing him coming out of the garage with black greasy hands, shrugging and saying "car trouble - be with you in a minute"
Don't get me wrong - I love cars, engines and general mechanics... BUT when I walk out and turn the key in the ignition I do EXPECT the damn thing to work 99% of the time.... if you know what I am talking about... Incidentally, he finally caved in this time and bought himself a brand new diesel car (a Scorpio) in stead of buying yet another project... guess age catching up with him!
Is an army disposal vehicle worth the hassle? Well, if you are going in for a CJ3B, then most certainly.... the buggers had jacked up the prices for a short time (during the time I got mine)
but I believe the MLA/ MP rate is now back to 28k or so... Just keep a couple of things in mind when picking out the vehicle from the Central Vehicles Depot, Delhi (which is where I imagine you'll be getting it from) :-
a) "THE MAN" is that chap in dirty overalls who walks out with you while you "select" your vehicle! He KNOWS which one is a lemon and which one was an honest to god "Staff car"/ "Parade vehicle" - obviously a true blue forward base Jeep which has been rogered by one and all is something you would not want...
b) Be nice to him - it helps both in picking out a mechanically better vehicle as well as getting him to ensure that small bits and bobs of original kit are miraculously complete when you come to pick it up... in stead of being "lost in transit".
c) Avoid buying parts from Mayapuri unless it's absolutely imperative - they are almost always "duplicate" and can screw up your vehicle... Hunting through the automotive parts market next to Kashmiri gate, though painful, will ensure that you get the proper part... Those guys will almost always tell you before the sale if the part it a copy or the real Mc coy!
d) If you want to source an original CJ3B petrol engine to replace the current diesel one - besides Mayapuri also consider making a trip to Dabwali in Haryana. This is probably the single largest Jeep rebuilding/ reconditioning operation in the world. A large part of the town's economy is based around this trade and since almost everyone throws out the petrol engine and replace it with a diesel, these should be easy to source and pretty cheap to buy. Dabwali would also be a good source for procuring all types of original military issue Jeep "kit"... The single hardest part of kit to get these days of course are the original "gun mounts" that used to come on army Jeeps earlier...
HTH
Cheers!
Abhijeet