Next time the Stroke guy looks at it, tell him it is his Strokes great grandfather.

Now show it some respect like all elders should get.
6.9 was generation one.
7.3 was generation two.
7.3 IDI turbo was generation three
94-97 Power Stroke was generation four
99-03 7.3 Power Stroke was generation five
04 thru _ _ 6.0 Power Stroke was generation six
And I guess the 6.4 is now generation seven

And just like families, the new engines look nothing like the parents did and don't act like them either.

 

C'mon Dave, we gotta give most of the credit to the great and reliable converted GM 350 diesels in the 70's

So, speaking of modified IDI's, have you had a chance to dyno yours yet?

Jason

 

i have a freind with an idi 7.3 non turbo van, and it would defently get a big jump on my psd off the line and would probably beat me in acceleration. of course its an auto and mine is a stick, a big clunky 3/4 ton truck stick at that with a long throw so no gear jamming super fast shifts plus i loose some spool on my shifts. but you put a identical trailer behind both of them ill take my psd any day. id like to have an idi for just normal stuff running around town and light loads, besides the idi van is getting slightly better millage 23mpg compaired to about 18 in my psd

 

Actually those GMs were mostly in the 80's. Very limited production in 78 & a little more in 79. They built them up through 85 though, and 81-84 were the high production years from what I've read.

They weren't just 5.7 liters/350s either. They also built a 4.3 liter/262 c.i.d. in both V8 and V6 configurations. The V8 was used in RWD applications only and bolts to a Turbo 350 tranny. I have one of the FWD 4.3 V6 engines that came out of an 82 Cutlass, and I plan on swapping into an 86 Cherokee in place of the 2.8 V6 it came with.

The FWD 4.3 V6 diesel has the same bellhousing bolt pattern as the RWD 2.8 V6 gasser, so I'm going to use the stock automatic tranny and transfer case that is already in the Cherokee, and just transplant the 4.3 diesel mill this summer.

I'm thinking that it ought to work out pretty well since the 2.8 gasser and the 4.3 diesel have about the same HP ratings, the diesel just has more torque. The gearing in the tranny and axles may be a little slow, since the gasser is designed to make its power at higher RPMs, but if so, I can just put a little taller than stock wheels & tires on it to compensate - so that I'm not having to turn high RPMs to get it up to freeway speed.

The 4.3 got close to 30 mpg in the boat of an Oldsmobile it came out of, so if it even does 80% as well pushin' the Jeep it will still be more economical to drive than even the most economy model Cherokee - wich had the 2.5 liter 4 cylinder. They only get about 19-21 MPG in stock form.

Should be a pretty interesting project....

 

I agree with you guys that the 6.9L is the most overlooked P/U diesel ever. If Ford or IH/Navistar would have ever put a Turbo on it, like they did the 7.3L, it would have been a real Jewel. I've been learning everything I can about diesels in my price range, the more I learn the more I like 6.9s and the more I love my Cummins 12V. I don't think I can ever take the Chevys seriously, they're too light duty for my tastes, I mean jeez they even put them in half-tons and Blazers!
I started paying attention to the Duramax after they started running with, and occasionally beating, the Cummins in the mega-power arena. The problem is they cost a ton of money to build and when they break it's BIG-TIME! They don't just blow head gaskets, intercooler hoses bend a valve here and there, they break rods and cranks and real 'spensive stuff.
Everytime a Powerstroke or Duramax owner tells me they can blow my '91.5 12V's a## off the road I just have to agree with them and say "yeah but I OWN mine, I haven't put much money into mod's OR REPAIRS and I've about 6-800,000 miles to go before I do.
As 94F250TD has noticed the first generation Cummins, like mine, are not fast or extremely powerful because of their large non-wastegated turbo housing,they are only 160HP/400 ft.lbs. but I get really good mileage and virtually no smoke (probably goes hand in hand) and there's still a TON of stuff I COULD do.
Now, let's not get the word out about the 6.9Ls! Keep it quiet! I'm trying to find a donor truck right now and I don't need the prices going up. Let's all just keep it under our hats, don't let any new members in and get some kind of encryption going on this sight. Then as the older owners of these trucks start dying off we can get their trucks real cheap. We can all have a couple-three "runners" and a few parts trucks around for peanuts as nobody else will know anything about them. They'll just lump them into the old 5.7/6.2 catagory, it's all good!
Plus I've been a member for a whole week now so I'm grandfathered in...RIGHT???

 

What you have to remember is that the Dmax has aluminum heads. If they blow a head gasket, it will more than likely warp the head as well. Probably warms up faster though. Heavan help you if you have problems with ANY new diesel after the warranty runs out. They are all too expencive and complex to be worth keeping.

I think the cummins 12v also had a fuel aneroid from day one, so that helps smoke, emissions and MPG. Hypermax makes on for the IDI navistars, but its pricy.

Unfortunately, the word seems to be getting out about how long the 6.9s can last. Well kept trucks are going for well over the market value in my neck of the woods. The 6.9 powered trucks seem to have bottomed out in value and are slowly getting more expencive, especially the decent ones.

What I have yet to hear is of some one ever actually succeeded in breaking a 6.9 or 7.3 IDI that was built right. Never heard of the bottom end failing. Have heard of cracked blocks, but those cases were not related to how much power the engine was putting out. I wonder where the structural limit really is??

 

I agree with almost everything you said there Dodge/Cummins.

The only exception is the part about Ford & IH never putting turbos on them. Unless I am mistaken they did - all the 7.3 turbo Fords up through at least 97 are Navstars - aren't they?

I'm not sure but I've always been of the impression that even the 7.3 PSDs are based on the Navstar block and major internals - just with different heads, intakes, exhausts, injectors, and pump.

Someone correct me if I'm wrong.

 

All of the diesel V8s that ford used in light E and F series trucks starting in 1983 were navistar engines. The only thing I remember that was really ford's idea was the hydraulic injectors that went on the 7.3 and 6.0 powerstrokes, but that was hear say so may have been BS.

The 6.9 never had a turbo for two reasons. It was already the most powerful diesel available, and it would have been too expencive. As I recall, ford was the last to use a turbo on their diesels trucks.

 

I meant the 6.9Ls were never turbo'd, you'll see in the first couple of lines I said "like the 7.3s." To me the 6.9L and the 7.3s are two differnt engines. I know the two are HUGELY similar and hardly anything is different but I've a bad taste in my mouth from the 7.3L's elecrolysis/pitting/cavitating what ever you want to cal it. I've never heard of it happening to a 6.9L but of course that doesn't mean it hasn't. If I bought a 7.3L I'd drive it home and the cylinder wall would fall aprt! That's my luck!
I read an article by a very P.O.d writer in an RV magazine who had it happen to his PowerStroke in his motorhome, yeah it was right after the warranty ran out. He was mad because he felt it was a problem Ford and IH/Navistar knew about and swept under the rug. He claims he had the reciepts to prove he ran the recommended antifreeze/coolant too.

David85,
You make a good point. I don't think I've ever seen ,or heard of, a bottom end problem in these motors that wasn't just normal wear or water ingestion. And you got me on this fuel aneroid thing, I don't even know what the heck it is! That's why I never claim to know something I don't, I've spent over 10 years fartin' around with Cummins and I've never even heard of that.
David85,

 

That was pretty much what I thought - from the 83 6.9 right on up through at least the 2003 7.3 they are all IH Navstars, just with different heads, etc.

So are you saying even the newer 6.0 and 6.4 are based on an IH engine too? I know that Ford and IH had a falling out and Ford stopped using their engines sometime in the last few years, I just didn (still don't) know when they stopped.

 

Funny, but I look at it exactly the opposite. The 7.3 is just a bored 6.9 (same block and bottom end) and drilled for bigger head bolts. The reason the 6.9s don't cavitate is that the cylinder walls haven't been bored out until they are paper thin.

You guys are both right on that. In about a year and a half of hanging out on these boards and reading everything I can find on the Navstar, I have yet to see anyone with a bottom end problem unless a blown head gasket dumped coolant into the crankcase or hydrolocked a cylinder.

And I'm also very curious about what an aneriod is too - never even heard the term.

 

Ford and Navistar had worked together on all of their previos powerplants but when the 6.0L was in development Ford just kin of saved their own resources and let IH/Navistar desighn and build it with out much of their input.
They had so much revenue out put on warranty issues that Ford wanted them to foot (some or more of ,I'm not sure) the costs.
Then with the 6.4L Ford got ticked at IH/Navistar because they raised their cost of the motor so much it was rediculous. IH said fine we won't sell you anymore, Ford had no diesel trucks to sell so they took IH to court. IH countersued for the detriment to their brand by Ford bad mouthing them AND Ford was working on doing their next gen. diesels on their own w/o Navistar. The judge said "you will pay the price for the engines, then you will have trucks to sel and we'll sort it all out later.
I don't know what happened from there but they seemed to have kissed and made-up!

 

You might be right about the thin cylinder wall thing, I really don't know, but I hope you're wrong because I have convinced myself in my own feeble mind that my future 6.9L won't have that problem. Cummins don't do it and even the factory doesn't know why, at least hey're not claimimg some genius engineering ability they don't actually posses! I AM going to run the correct coolant and the addative, cheap insurance!

 

I was thinking only light trucks. Slipped my mind about all of the full size barges running around with them.
You're a brave man to swap in one of those 4.3's. . As far as I've ever seen, they were no better with reliability than the 5.7's were.

Jason

 

I've done a little research on them, and their reliability really isn't all that bad - in the hands of someone who knows how to properly drive and maintain a diesel.

Problem is, back when they came out, Joe average bought one without knowing anything about diesels, treated them like a gasser, and then complained long and loud when they didn't hold up. Remember, this big, wide, wonderful knowledge base you and I are using - the internet - didn't even exist in those days....

To put it in perspective, if a Cummins is a million mile motor, and a Navstar is a half million mile motor, these old GM diesels are like a 250k - 300k motor. The one I have has just a tad over 100k on it.