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Rockridge 4WD IS Taking Zone Offroad Suspension Lift Kits BLACK FRIDAY SPECIALS!! You asked, we deliver!Rough Country Lift Kits and Parts!

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Unread 01-22-2006, 04:35 PM   #1
paulhumphries
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GM V8 diesels

I've just bought a CJ5 to restore.
In the UK such a vehicle is rare so I'm going to have to adapt rather than just go to the local dealers for a lot of parts.
The engine is missing and I want a diesel unit - preferably with autobox.
It's been suggested that I use the old GM 6.2, 6.5 or 6.7 diesel V8 as they are a common engine and easilly avaliable out of vans. They are used in Range Rover conversions (although the torque destroyed gearboxes ) which means better spares avalibilty that a lot of US engines over here.
I've been trying to find out a little about them and came across a discussion forum which basically said they weren't very good and why do the British fit them !

What is this list opinion of this engine and suitabilty (with autobox) for a CJ5.

Thanks.

Paul Humphries,
Stoke-on-trent,
Staffs.,
UK.

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Unread 01-22-2006, 11:32 PM   #2
jeepdaddy2000
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Weight is always an issue with diesel conversions. I have the feeling that the GM unit is going to be a bit much in that department. Most diesel conversions for CJ's consist of four bangers. Americans running diesels, as a whole have not been impressed with the GM 6.2 and 6.5 motors. With the Ford and Dodge offerings far out powering them, most buyers overlooked them when making a choice for a power plant. Auto transplants in 5's are always a dicey project, especially in pre 71 units due to the drive trains overall length. Careful measurements of the proposed drive train need to be taken, or you will wind up with a extremely short rear driveline.
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Unread 01-23-2006, 12:14 AM   #3
Bgeddes
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Americans running diesels, as a whole have not been impressed with the GM 6.2
I drove GMC Suburban 6.2 for 125,000 miles. In a vehicle whos gasoline counterpart would get 15mpg at best, I routinely made 30mpg. I was far from fast, but, far from powerful. I regualrly towed cars on trailers behind the truck, in that capacity, it excelled. As Jeepdaddy said, the GM diesels are heavy, very heavy. They are also huge, and to get the power to the ground, the drivetrain must match. I can't think of a capable auto trans that would give you any acceptable driveline angle. Fullsize trucks in the States are long, and so is thier drivetrain. Good luck.
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Unread 01-23-2006, 03:15 AM   #4
paulhumphries
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Thanks for replys.
I think I'll forget that idea then !
I've got a 2.5 VM diesel of the same type fitted to Cherokee so will try and adapt that and stick with manual gearbox.
I've a "bad" left leg and although I can, and do, drive manuals I prefer autos.
What I have got, sitting unused in a box, is an auto clutch conversion. I bought it for my Land Rover Discovery but it'll now pobably end up on the Jeep.
I assume you have them in the US but for those who don't know what they are it's a device that operates the clutch dependant on engine speed, road speed, whether braking etc so you don't need to touch the clutch pedal. You still change gear manualy but other than that a small control unit feeds the clutch in and out. You have a button on the gear knob to operate it manualy if the auto operation isn't fast etc enough.

Paul Humphries,
Stoke-on-Trent,
Staffs.,
UK.
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Unread 01-23-2006, 06:56 AM   #5
jeepdaddy2000
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Paul, application is everything. With a mild lift and no real expectation of flogging it off road, an auto can be done. Other tricks are to space the engine further forward in the engine bay. Just remember that length is an issue, and needs to be addressed early on. By the way, what year is it? Seems that there are a few folks transplanting Diesels into Jeeps on the earlycj5.com forum, as well as the binder bulletin(IH's). While your swap might entail different powerplants, you might want see if they have any advice on adapters and bellhousing patterns.
For some reason Americans have been late to embrace diesels. The new units being offered by various manufactures in light trucks are in most cases, better in every way when compared to their gas counterparts. My wifes Ford F350 4x4 crew with the powerstroke will outdo it's gas cousin in every way.
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Unread 01-23-2006, 11:40 AM   #6
Bgeddes
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That 2.5VM diesel would fit into a CJ5, even and early one. They come with an auto (5sp) here in the states, that option might be easier than converting the clutch. I own a Diesel Liberty (Cherokee on your side of the pond) and I thnk that motor would EXCELL in a CJ. The KJs weigh in at 4000lbs plus, so the CJ should really fly with the diesel. Even better, at 300lb-ft of torque, drive line issues should be easier to address. Remeber to take lots of pictures, keep a detailed parts list, and post progress here!!! Thanks.
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Unread 01-23-2006, 12:26 PM   #7
Fullsize_CJ5
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The big thing about GM diesel v-8 engines is the fact they were actually gasoline engines converted to run on diesel. The had many issues. Nothing on the engine was actually heavy duty enuff to hold up to the abuse a diesel engine sees even under "normal" conditions. A diesel engine has much higher compression, and needs bigger stronger parts through out. The gas conversions just never held up.
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Unread 01-23-2006, 04:59 PM   #8
Bgeddes
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The big thing about GM diesel v-8 engines is the fact they were actually gasoline engines converted to run on diesel.
This is only true for the very early ones. Oldsmobile was guilty of this also. When I owned my 6.2 I also owned BB & SB Chevys and none of the accesory brackets etc would bolt onto the Diesel. The block and heads were different. It was my understanding the 6.2 is a Detriot. I didn't wear the 6.2 out in 225,000 miles, the last 80K spent dragging a loaded car trailer around. I am certain any gasoline engine would have been done long before 200,000, especially worked like dog pulling the trailer.
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Unread 01-23-2006, 06:37 PM   #9
jeepdaddy2000
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Quote:
Originally Posted by Full size_CJ5
The big thing about GM diesel v-8 engines is the fact they were actually gasoline engines converted to run on diesel. The had many issues. Nothing on the engine was actually heavy duty enuff to hold up to the abuse a diesel engine sees even under "normal" conditions. A diesel engine has much higher compression, and needs bigger stronger parts through out. The gas conversions just never held up.
The engine you speak of is the 5.7 used in auto's. The 6 liter engine family is a different engine altogether. GM always seemed to be behind with their diesel technology till they offered the duramax. Because of this, their sales of diesel equipped full sized trucks always lagged.
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Unread 01-27-2006, 01:44 AM   #10
violatedppl
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mybe the duramax is so good because its not really a gm deisle. If I remember right its a mitsubishy ( I know its spelled wrong) engine, When my dad was looking at a gm or ford he told me about it. Also I have heard alot of problems with the early duramax engines so....
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Unread 01-28-2006, 05:02 PM   #11
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The dmax is a joint venture with Isuzu.
Most of the 'rumored' problems never occured with the dmax. The early ones did have injector issues but GM extended the warranty to 200K on those. Want to talk about problems, bring up the Ford 6.0L. Ford went public and stated a $500million warranty cost to that line along with many buybacks.

The 6.2/6.5 was also intended for 1/2 ton trucks, something the IH/Cummins never was.
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