The aneroid is a diaphragm that uses pressure differential to modify fuel delivery over the operating range. One side of the diaphragm is connected to the intake manifold for the turbo boost signal, and in the case of our diesel ranger (same make of injector pump) the other side is connected to a vacuum source. The bigger the pressure differential, the more fuel is available under your boot. Some call it the smoke screw, because thats what it is designed to prevent. Another nice thing about about the dodge diesels is the EXTERNAL fuel screw. More info here:

http://dodgeram.org/tech/dsl/more_power/Power_ve.htm

Cavitation is an effect of high pressure applied to water on the metal surface. Heavy container ships need to have their props specially tested to prevent the very same thing from happening (prop can be eaten away), since there is a safe limit to how much horse power a single prop can transmit. In the case of diesel engines, the flexibility of the cylinder wall plays a big role to how vulnerable the engine may be to developing the condition. This is why the 7.3 IDI is so prone to having problems, not only is there less metal to eat through, but the rate of erosion is also higher.

I think this why 6.9s don't seem to have the problem, the cylinder wall is over 1/4" thick from the factory, I don't know what the cummins is. SCAs can prevent the condition, and considering the risk, it should be in any diesel coolant.

 

CheaperJeeper,

I think you're exactly right about the GM diesels they never really got a fair shake and GM didn't help things. A diesel is not a gasser and people didn't know that, they were just supposed to gat better gas mileage and don't forget as a side benefit diesel was way cheaper than gas back then. I think you'll have a cool rig, I LOVE Cherokees and if mine was a fuel efficient diesel I'd be in HOG heaven. I love my improved 4.0L (over the previous 4.0L and all the crappy GM v-6s) but the fuel mileage around town sucks.
But those short trips are one of the things that hurt the early diesels anyway and gave them a bad name.
I know where RCrawler is coming from, you have to draw the line somewhere or you'll have a whole herd of VW Bunny diesels around. It sounds like his line is drawn just above the GM mills. I can respect that! Mine line used to be a cicle around Cummins, nothing else exited, but I'm starting to really like 6.9Ls.

 

David85,

Everytime I think of a Duramax the aluminum head thing pops into my ..uh..head. I always think of VW NA Bunny and Bunny pick'em-up truck diesels. There was agreat rig: front wheel drive, aluminum headed, naturally aspirated diesel..CCCOOOOOOLLL.
They did finally get there act together, they made a really great motor (1.9L TDI) to put in Suzuki Sammys so you can build a really capable, street legal oversized quad/fourwheeler.

 

I'm going to gues the sylinder wall problem is between 88 an 92 for the 7.3, if it isn't then my family was graced with some stout 7.3. i think we used tap water and mixed it with antifreeze. and we had one 7.3 that lasted to 325000 miles. I just figured my brother turned the fuel up to much but it could be that corrosion finally ate through it did have a crack in the block. can we order old idi crates from ford? I just got to get that old 93 f250 rollin again.

 

A 7.3 is a 6.9 bored 110 thousandths.
The cavitation issue is a diesel problem, all of the engines from all manufacturers have the same problem.
What is different is how bad the problem is in some of the engines.
SCA's were developed to counteract the cavitation.

All of the diesels Ford has used are Navistar engines, even the 6.4 they are using now.

 

My post about the 5.7 diesels was a bit tongue in cheek. GM missed the mark big time on their early diesel program with the 5.7, 6.2, 6.5. Ford and Dodge went out and sourced medium duty engines which turned out to be a great move.
And I agree with Cheaper Jeeper on the general public's acceptance and understanding on how to drive a diesel. Even today when a lot of people are driving diesel pickups as family cars, it is much the same. I was reading on a Cummins forum about a guy wanting an idle timer so his wife wouldn't have to let the truck idle for a couple of minutes after running hard. Said she didn't have time. All I could think of when I read that is maybe they don't have a need for a diesel anyways and they would be suited better with a gasser. Bought a diesel pickup to "keep up with the Joneses". Makes me laugh when I see a newer diesel pickup with a pristine bed and no signs of a receiver ever being in the hitch. What's the point???

Jason

 

I agree with you there! So many people buy a diesel just because everyone else, or their best friend, or whoever, got one. And then they'll have a lifted Suburban for their wife as a short trip/ take the four kids to school.....oops I'm talking about myself and starting to realise how dumb some of my "rigs" are. Well It's too late to change now.

 

Oh yeah, I hear ya!

Was chatting with a mechanic/machinist that did some of the work on my 6.9L block and he echoed your views. Folks buy new diesels for the prestige and not for what they were built for and in some cases end up glazing up a brand new diesel. Use a $80 000 2007 Dmax for driving to starbucks and back, and they can't figure out why its using 1 qt of oil every month.

 

I remember a post probably over a year ago that went something like this.

I have an F350 dually and it rides terrible.
Is there anything I can do to make it ride better?

I suggested he put about a ton of something in the large hole behind the cab and it would ride fine.

People that use one ton trucks for commuters and expect it to ride like a Lincoln Town car are sure making it hard on people that expect to be able to work with a truck.

I know I spent several thousand dollars getting mine to ride, off road and haul like a truck.
Looking at the newer ones, I would not even want to try converting one of them back into a truck.

 

A freakin' men!

I am sick of people arguing over which HD truck rides better, I guess it makes since if they are all comparable in capability but I personally don't drive one tons to race or for the ride quality and handling. CAR magazines that review TRUCKS and pick the Honda Ridgeline as truck of the year are operating out of their area of expertise!

 

Ridgeline is a rebodied minivan. Same V6 gasser, same front wheel drive based drivetrain. Calling it a truck is an insult on many levels......AND YOU HAVE TO EMPLY THE BED TO ACCESS THE COMPACT SPARE TIRE

 

They also made a big deal out of the "cooler/storage bin" that's UNDER THE BED FLOOR! I think they realise their bed is useless for any think but granola bars and mountain bikes and one is light and the other has wheels so they're easy to move off of the lid. Stinkin' yuppies don't know anyth........................................

 

Damn right Dave. And the IDIs are one tough engine, I have first hand experience with my 84 F250. I have been plowing snow with this truck all winter with a blown head gasket (leak was slowed with the help of pepper in the rad.) and a sick and ailing C6 tranny. This truck has not let me down once. I can remember a couple times when my delivery truck (05 GMC Duramax 5500 16 ft box truck) got stuck in the loading dock in a foot and a half of snow... the ol 6.9 came to the rescue every time. I have dealt with many 6.2 and 6.5 GM diesels when I was in the service (USMC 2002 to 2006) the 6.2s were gutless turds... always popping rear main seals and headgaskets. Damn things couldn't pull an empty mule cart downhill with a tail wind. My 84 F150 with a 300 six/ 4 spd had more pulling power! The 6.5s weren't too bad, they had decent power but would still pop a head gasket if you ran it too hard. The Cummins motors imo have always been a good... other than the fact that they aren't wet sleeve blocks. Naturally being an inline six they make killer torque on the the bottom end. I do believe GM was the first to offer a diesel in their pickup trucks (1981 or 82), but it was that gutless 5.7 POS. I know a few people who pulled their 5.7s and 6.2s and replaced them with gassers. But it was Ford who was first to offer a good diesel in their trucks that people actually could pull something heavy with. The first year for Dodge was 88 with the 5.9 Cummins I6 turbo nonintercooled... those were good motors.

 

I learned about the IDI on the old 7.3 NA working for U-haul. Now I have a 87 with a 6.9 that when I get the chance it's coming down for a rebuild and a turbo upgrade along with a overdrive unit. It wasn't bought for looks but to work. Just want to get there a little faster and little less fuel. It's a proven engine that's dependable as long as you keep it fed and watered well. This was also the replacement for my 89 350 with the 7.5 gas.

 

Actually the first Dodges were '89 although they were probably available for sale in '88.
Just splitting hairs here.
Also, good to hear about your experiences with the 6.2 GMs that's the next engine I'm going to "educate" myself on, but I doubt I'll ever own one.