6.5l Detroit vs 7.3l IDI Turbo

FordGuy100

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As of right now, I think the 6.5's you can get a little more power out of them, and they do good on fuel economy. But if your going to be towing, I like the heavier platform Ford has, and Ford IDI's have a pretty good low torque to them.

I wouldnt mind driving a 6.5T 4x4 around, wouldnt bother me a bit. I actually like that 90's body style. Maybe one day I will own one ;Sweet
 

1994IDI

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The support for the 6.9/7.3 on this site alone is almost enough to make me stick with the Ford. I have not owned the chevy so I don't have much of opinion on that. But the 7.3 has been a very reliable motor that has pulled everything I've put behind it. 13 cty-16 hwy mpg's. Hope this helps.
 

turbonator

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Truck choices

We basically run GMC, a couple 6.2's and a couple 6.5's. We came across a 6.9 with a C6 out of a cubevan. Nice motor also, trying to talk a friend into putting it into a 93 Dodge 1500 (V6 gasser), backed up by a 14 bolt dually rear end. ;Sweet

So as many have stated both have there pros and cons. We like that the GMC platform bolts up to everything with no adapters.:thumbsup:
 

Fatback

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I have recent experience with a 6.5 turbo..... sunk thousands into it. new IP, new hi pop injectors, replaced the injector lines, new non waste gated turbo, 3" cross over and down pipe with a 4" exhaust. Heath GL4 chip (the only advantage with a DS4 is the ability to command more fuel and bigger injector lines) not to mention over $1100 in parts to freshen up the IFS front end, or the 4 hours it takes to change the starter because you can't get to it.

Driving home one day one of my Mylex tipped marine injectors failed open, flooded the cylinder with diesel fuel and hydrolocked the engine. Pulled the engine to disassemble and inspect for damage. one head was cracked (on the side opposite from the bad injector) and evidence of over heating (if the temp gauge on a 6.5 reads 260 then its too late, the heads are trashed). found a crack in the #8 cylinder wall (also not the failed injector) right below the fire deck. and a crack on the middle main web from the register to the cam journal. Ok so this engine was toast (200,160 miles). Did some research and found out that I had a 599 block (this is supposed to be the strongest GM produced block) I bought a 6.2L to do a quick rebuild on and drop in. The block was cracked on the same main web in the same way. I bought a military take out 6.2, it was also a 599 block and cracked in the same spot. long story short .... I looked at 6 blocks and they were all cracked.

I got most of my money for the engines back by selling the internals and heads, and recycling the blocks. I ended up taking off all my performance parts and scraping the truck (due to a hole in the frame)

for a 6.5. If you think the heads are cracked, they are.
if you think the head gaskets are blown, they are.
if you think an injector has gone bad, it has.
if you have not mounted the PMD on a heatsink and relocated it to the front bumper, you better.
Most DS4 problems can be fixed by cleaning the grounds.
If the engine has ever been over heated then the heads are junk.

a used oil analysis is very important on this engine.

other than that, its a good engine, mine was at 260 rwhp and 503 ft/lbs torque just buy doing injectors, a turbo, exhaust, and a custom tune. It would pull hard all the way to the point the computer defueled the engine which was fast enough to bury the speedometer and put down 15 psi boost. It could also smoke it's tires in 1st, 2nd, and 3rd with a 4L80e and 4.10 on stock size tires.

if i ever bought another I would buy a drop in P400 optimzer or build and engine from scratch with a new GEP block and heads.
 

HondaCowboy82

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my .02

I have had 4 trucks with the IDI, one Powerstroke, and rode in counteless 6.2/6.5L trucks (military).
Of course I am totally partial to the 7.3L/6.9L. Great torque. Bulletproof engines. Easy to change injectors, pumps, glow plugs. Everything is in the top of the motor. Simple with no electronics. Not alot of upgrades to a 7.3L or 6.9L besides marine injectors, turbo, or headers but they make 185hp or 195 horses from the factory in the NA department. Can free up some with A/C Delete and an electric fuel pump.
The GM diesels i have been around are junk. Of course the military uses them like slaves (for a better term) but constantly something. A few buddies had them growing up. Bad problems with overheating. Both heads cracked from overheating on seperate occasions, injection pump went out twice. Just bugging crap like that..
 

dracor85

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Having two 6.5's my self Id buy another one, the biggest thing is if your buying a used truck dont expect it to run like a new one. The fords are good to dont get me wrong. With the 94 and newer chevys the PMD's need relocated like fatback said (PMD Pump Mounted Driver, its a small computer like thing that mounts on the injection pump from the factory. It gets way to hot there and fails which is one of the bigest problems with the GM's. It just needs moved out of the engine bay and its as happy as a clam!)

Justin
 

Brimmstone

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I've worked on both and own nothing but IDIs now. What you have to remember is the 6.2 and 6.5 were based on a design that was basically a gas engine modified to be a diesel. The 6.9 was a diesel truck engine from the beginning. I'll admit the 6.9s and 7.3s have there issues. Early 6.9s are prone to cracking the block around the block heater, 7.3s are very prone to cavitation issues, and they are both known for burning valves. The 6.2 and 6.5 are infamous for cracking heads, breaking rockers, 6.5 turbos are good for killing wastegates and cracking exhaust manifolds, The later 6.5s are terrible for the PDM going out. They're bad enough I keep a complete relocate kit on hand in case it's needed. The pumps are also known for going bad on the later 6.5s.


What would I get?
A diesel Suburban would be a nice thing but I'm the type to take a crewcab and make my own centurion. As it is I have 3 Fords down here tight now. I'll probably stick with them as they almost always have a trailer hooked to them.
 

rjjp

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If you just want a truck for the 4x4 in the winter, or to look cool while driving around then get the Chevy, it's a light duty engine that will return good mileage right from the factory. If you're getting a truck to work it then get the Ford, the 6.9 and 7.3 IDIs were designed as industrial engines, and can be found in everything from pickup trucks to semi's (yes I did see an IH semi with a sleeper with a 6.9 IDI) and in large stand still applications.
If you're looking to work the truck a times and use it as a daily driver at others then I would suggest getting the ford and putting a brownie in, if you use the right one you could effectively all the towing power you need when you need it, and the ability to cruise down the freeway with the engine just humming along.
All makes and models have there downsides and there good sides.
Personally I will stick to my 7.3, it hasn't let me down yet. What ever you decide to get just read up on it and be ready for all the likely problems with that platform, and enjoy the diesel.
P.S. Towcat, with you're question to Mel, my truck is at 153,000 miles has had the glow plugs replaced 2 times (my father had auto-lights put in when I was in High school) only one has swelled up. And the valve covers are going to come off for the first time in a few weeks for valve cover gaskets (when you let an engine sit, leaks happen).
 

david85

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Well we have one of each in the family. My Dad has a 1993 K3500 srw and its not a bad truck but I wouldn't trust it like I trust my own.

For simply driving around, its more comfortable, and quieter at highway speeds. Turning circle for comparable wheelbase is much worse for the GM.

The 4wd thermal expansion actuator is crap and I disabled it after this expensive part failed a second time. Aftermarket mechanical actuators are available.

I'm at a loss to explain the high MPGs that others are reporting though. Ours struggles to stay above 16 MPG usually but its geared fairly low.

It is harder to service the injectors on the turbo side of the engine and removal of the turbo is required to get to all of them.

Access to the injectors on the other side of the engine is as easy as on the fords.

Fuel return lines are better on the GM. No O rings to dry out and the lines slip on with hose clamps directly to the injector body. Over all I would say the GM is less vulnerable to air intrusion.

The GM block is weaker - period. Less metal in the block and heads means that this engine will be more prone to cracking. Simply lifting a head off my dad's engine reminded me of the heads on my F150's 302 gasser. This is what makes the engine light enough to deploy in half ton trucks but it comes with a price.

The Glow plugs are harder to access on the driver's side and MUCH harder to access on the turbo side. If you are in the rust belt, the heat shields that are designed to protect the wiring harness for the plugs will fall apart eventually.

6.9/7.3s use built in coolant to oil cooler. 6.5s use an external oil to air cooler.

Fords have larger stock filters and can easily accept a huge powerstroke filter.

Fords also have a much larger oil capacity even before you add the larger filter.

Not positive, but I don't think the earlier 6.5s use piston oil squirters. All fords have these (heck, even the diesel ranger has them!).

Its also not what I would consider an engine that you can simply beat the crap out of. EGTs need to be monitored as does coolant temperature if you load them and work them hard.

Ours is a 1993 so that means no DS4 injection pump.

Ford is all gear driven timing set. GM uses a chain to connect the crank to the cam, then gears to connect the cam to the injection pump.

My opinion is the fords are a heavy duty engine while the 6.5 is a light duty diesel. Its lighter, smaller and holds less fluids. For a daily driver, I don't see much wrong with the 6.5 but I wouldn't use it in a work vehicle. Harder to service, parts are more expensive and its not over designed like the ford diesel.
 
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