Too Diesel or Not

[Knucklehead]

Recent discussion here has got me thinking (a dangerous activity) about going to a 6.2 or 6.5 GM diesel in my Cherokee. Currently it has a t-18/d-20 with 3.54 D44s with a 360 up front. I want to retain the transmission/transfer and axel set up. Is this realistic? I think that I can get an adapter to mate the T-18 up to a chevy bell-housing. And, I think that the 6.2 and 6.5, both, use a standard chevy bell-housing. Is this true?

Also, what about the flywheel/clutch set up? does anyone here have any experience with this sort of swap.

How good is the 6.2? Really????

[waggin'ear]

By no means an expert, but hopefully will be soon with the 6.2 in the M1008.

The 6.2 is a dog! Without upgrades, such as a banks kit or something, it is not a performance upgrade over a gasser.

Even with the 4.56 gears the thing is slow off the line and at top speed. Don't get me wrong, I like it the way it is and it will stay that way, but I am in no hurry to get anywhere.

My 360's with 3.54 or 2.72 gears could easily outrun the CUCV off the line and be in another state at top speed. It does seem to need a little less coaxing to get up hills though.

The plus side is that I got about 18mpg with the 6.2 so far.

Hopefully it will last for a LONG time, but the 6.2 doesn't have the reputation for longevity of say the Cummins.

Overall, I don't think that it would be a worthwhile swap unless you have it already and your AMC V8 is dead. If I was going to swap diesel, it would be a Cummins.

[Knucklehead]

Someone here, said that by ugrading the injection pump, they got a substantial power increase.

Would a higher gear ratio give better gas mileage?

How many miles is the bottom end usually good for?

[Mikel]

After I'm done with my M715 (by 2057 or so), my next project will be an old J-truck with a 6BT and a NV4500. I think I'll use a 70-78 truck with the razor grille, as I think I can do substantial cutting in the rad support, to move the rad forward, and to hopefully fit an intercooler and an A/C condenser, side by side in front of the rad, and it would still be hidden from view by the grille.

[ January 12, 2005, 03:58 PM: Message edited by: Mikel ]

[FSJeeper]

I have about 8 years experience with the GM 6.2/6.5. Lots of road miles and several different CUCV trucks and Blazers and engine swaps into FSJ's.

For the record, the Cummins 6BT, or the 4BT for that matter, are superior engines to the GM diesels but are heavier, and much, much more expensive to buy and adapt.

In a CUCV truck with 4.56 gearing, and as stated earlier, the 6.2 is a dog when it comes to performance. However, just by tweaking the injection pum and bumping it up 10%, the performance increase is incredible and you can actually burn rubber after it is done. But it still is no big time performer. A banks turbo kit will wake up the 6.2 bigtime. The 6.5 turbo engine is OK in terms of power, but not really impressive.

I have a GM diesel built up with every mod available except propane injection. Custom injection pump, ported heads, seriouse blueprinting wasy beyaond the call of duty, aluminum rods, pennisular 18 to 1 pistons, BD gear drive, etc. etc. This engine cranks out a true 300HP and about 480 ft lbs at 1900 rpms. Gets about 20 MPG when it was in a heavy M715. I am putting it in a Chevy 1 ton dually with a Jeep cab and M715 sheetmetal soon for a work truck.

The several thousand dollars investment in the motor bumped up the performance to great levels, but if I had it to do over again, I just would have gone 6BT.

If you can live with mediocre performance, and want great gas mileage and a durable engine, the 6.2 or 6.5 would be a good choice.

[Nightshade]

I have been looking into this a bit as well and as soon as I kill off my 360 I am thinking the diesel swap is a likely choice.

Is there a slightly lighter diesel engine worth looking at?

Keep in mind on road performance is not a factor at all since this is an ORV and sees no street duty at all.

I was thinking of hitting a Dodge Cummins Turbo Diesel because I have heard great things but I do want to keep it somewhere close to the same weight as the 360 that is in it (+/- 100-200 pounds)

Any suggestions?

[FSJeeper]

The GM diesel is about the same weight as the big block Chevy. It is the lightest of the diesels in its range, even lighter than the Cummins 4BT 4 cylinder engine. It would not be more than 200 lbs heavier than an AMC V-8.

Swapping the GM diesel is fairly straightforward. Novak, AA, and Transdapt motor mounts. They use the same mounnts as the small and large block Chevy.

Novak and AA make Bell housing adapters.

[waggin'ear]

Pascal,

My 62-65 membership hasn't cleared yet. So I am going to waste your time and pick your brain if you don't mind.

When you say tweaking the injection pump, is this something that I can adjust myself. If so, is this something you could explain over the net?

Thanks

[FSJeeper]

Originally posted by waggin'ear:
Pascal,

My 62-65 membership hasn't cleared yet. So I am going to waste your time and pick your brain if you don't mind.

When you say tweaking the injection pump, is this something that I can adjust myself. If so, is this something you could explain over the net?

Thanks

The Stanadyne pump is adjustable. Can't explain it here, but lots of infomation on the net and the 6.2/6.5 sight. It is not a big project to do.
However, there are a number of modifications that can be used to blueprint the Standayn pump as well as bumping up the fuel injection. There is a FI shop in Waco, Texas that rebuilt, blueprinted, did the upgrade mods, and bumped up the injector pump 10% for about $300, 1 day service and fed-exed the pump back to me. I absolutely could not believe the performance after I installed it. Instant throttle response, no smoke, and 20 MPG. I drove the truck for 3 years stock, except the pump and it was not a bad ride at all. Not a powerhouse, but acceptable performance for sure. 10% seems to be the agreed bump for stock military CUCV's and Hummers.

The injection pump in my built motor was bumped 25% but I would not go more than 10% on a stock engine.

I like the Standyne injection system. Only problem is that when a military vehicle sits for a long time without running, the seals dry out. Common problem on military vehicles with the 6.2. I normally just swap out the injection pump on new CUCV purchases for the performance and I know sooner or later, it will start leaking. Several CUCV's I bought ran perfect, then started leaking diesel out of the injection pump, had to swap injection pumps. Some of my surplus cucv buddies have had the same problem.

So when I get a new one, I set aside a day, and just swap out the pump. Well worth the time just for the performance increase.

[FSJeeper]

I wasn't clear.

Bumping up the injection pump is a 2 to 3 hour job and you can do it in your driveway easy. Some guys keep bumping it till it smokes, then back off, but for me, a 10% increase was perfect and has been for other cucv guys I know. I don't have that much spare time to experiment and tearing things apart several times to get it perfect.

Having the injection pump upgraded with the latest mods, and bumped professionally, is well worth the money if you plan on keeping and driving the truck, and judging the condition or your truck, it is a keeper.

[FSJeeper]

And the Bosch glow plug upgrade, and eliminating the glow plug panel and wiring it in direct with a push button switch, holding it down 10 seconds for starting, is an absolute must.

[waggin'ear]

YOU ARE THE MAN!

Thanks for the advice. I already have a push button glowplug system which is very nice. I was thinking about using the AC 60G plugs that aren't supposed to swell, but I will certainly take a look at the Bosch plugs.

Thanks for the advice on injection pump.

What about fuel filter replacement. The CUCV one looks nothing like the civy ones. Are they available?

Thanks again your insight and experience are awsome

[FSJeeper]

Originally posted by waggin'ear:
What about fuel filter replacement. The CUCV one looks nothing like the civy ones. Are they available?

Every CUCV I have owned, like 12 or so, had a stock Chevy diesel fuel filter/water filter/fuel heater setup like the civy models do. It is mounted on the passenger side firewall next to the wiring terminal. If you have something else, it is not stock.

The stock fuel filter setup is excellent. Easy to change. Take the old filter off, put the new one in, open the bleed screw, take the green wire off the injection pump and turn the engine over unitl fuel comes out of the bleed port. Close the bleed screw, hood the green wire back up, and fire the baby up. Outstanding setup.

[FSJeeper]

And you can get a CUCV fuel filter at any parts store, very common.

[mtnbikerman]

I have a 94 Chevy diesel suburban. I've been through a flexplate and Oil Pressure Switches and 1 lift pump. The glow plug button is a must with the timed plugs not sure which ones I put in I got them from Peninsular. I like to jumper the lift pump to fill the fuel filter up instead of wearing out the starter. I think you can get just about any adapter you want to mate up to the 6.5 or the 4BT. My choice is the 4BT I haven't found any negatives about it. The 6.5 on the other hand you have to know what year block it is cause the newer ones from 97 to 99 had a coolant line that leaked into the #8 cylinder So you have to watch for that. Even the newer blocks from GEP are having problems. Then you have the webbings that crack and have to be filled in and polished. The electronic pump on the 94's and up can be problematic but I've had good luck but I think it was replaced in 2001. The manual injection pump from 93 and down has fuel starvation problems too. The engine is not very powerful stock but with $5,000 for the Peninsular pistons, cooling mods and you name it the 6.5 will run. Like I said I haven't been able to find anything wrong with the 4bt and the 6bt uses the same parts. You can find plenty of 6.5s but you gotta be careful if you go that route call Jamie @ Diesel Depot he can provide you with either engine and will not sell you a bad 6.5.
The 4bt on the other hand has become a hot commodity these days and everyone knows it. Check ebay all auctions for "diesel" stepvans start at $2500 with 150K miles. Jamie quoted me a couple weeks ago @ $2500. You can contact Frito Lay in your area they have them all the time and thats where Jamie gets his. He also get them from Bread Companies. You can buy the 4BT new also that one is about $5000 I believe with a $1,000 core. Sorry to run on but this is can be an in depth subject