Old school IDI diesels?

[29chico]

I have an '85 F250 4x4 with the 6.9 International diesel.  Just like the 6.2 GM diesel it has a full mechanical Stanadyne fuel injection system 'cept for the one 12v+ wire to tell the pump to flow fuel.  It is bolted to the Ford c6 trans.  I feel very lucky to have this old beast of a pickup passed down to me from my father.  It just loves a 20% mix of biodiesel .  I have done the majority of the servicing and repairs on it since he got it back in '85.

highdesertranger:

I have been curious for a while why you appear to prefer the GM 6.2 diesel to the GM 6.5 diesel?  I have an associate who has two GM pickups that both have the GM 6.5 turbo IDI engines.  He claims that the 6.5 is superior.  What is your take on that?  Anyone that wishes to also opine on this subject is welcome of course.

These questions are for everyone:


I am also interested in any IDI diesel that was used to power light to medium trucks back in their era.  I am a fan of Cummins 4&6bt IDI diesels also and would like to know more about them.  Like what years with what features were the most reliable?

I had a '66 F250 gasser way back in the day and the owners manual had info on a 4 cylinder non-turbo diesel option for that year.  Does anyone know anything about that engine? One guy thought that it was a Perkins diesel.

 

[highdesertranger]

well I really don't prefer the 6.2 over the 6.5. they are basically the same motor the 6.5 has a slightly bigger bore the later 6.5 had a one piece rear main seal. I just bored my 6.2 .020 over so technically it's not a 6.2 anymore. it's kinda like the 6.9 and 7.3 Ford, basically the same motor. highdesertranger

 

[Willy]

All, I can say is that a 7.3 IDI in a van is a nightmare to do major work on. ..Willy.

 

[29chico]

All, I can say is that a 7.3 IDI in a van is a nightmare to do major work on. ..Willy.

Since there is some rust developing on the cab of my F250 I was toying with swapping my driveline to a van chassis.  Your experience had made me flush that idea.  I'll just replace the cab at some point.

 

[cognitive dissonance]

Not certain about the f250, but Ford did use a Perkins 4cyl. in the Ranger Diesel of the same era.

I'm no expert on Cummins diesels, but I have played with them enough to know that the early rotary injection pumps will support as much power as any sane person would want to make, but give measurably better fuel economy than the later inline "P" pump.  Yet, everyone wants the P pump because "it makes more power". 

It isn't often I can get what I prefer at a lower price, so that misperception is fine with me!

 

[cognitive dissonance]

BTW, "IDI" is an International Harvester/Navistar term.  It derives from "indirect injection" but not all diesel engines from that era are indirect injection.  The Cummins engines are direct injection.

The Harvester part of International was merged with Case.  (Case then went on to use Cummins engines!) The remainder of International became Navistar.  The IDI's and the Ford Power Stroke are all (technically) Navistar engines.  If you're looking at a van or a bus with a Navistar T444E engine, that's the 7.3 Power Stroke! 

All of the older engines we're talking about in this thread have mechanical injection pumps. Mechanical vs. electronic injection is probably a better dividing line.

 

[speedhighway46]

If we are talking mechanical vs electronically controlled injection, there are some advantages to electronic (computer) controlled engines to tell the total story of one type vs the other.

Admittedly on a larger scale than the terrific 7.3 (which I have in my Excursion) is the Cat C-15 I have in my Peterbilt Motorhome conversion. One of the advantages of the electronic engines is cold weather starting. My vehicle normally sits unused during Jan, Feb and early March. I normally do a "winter start" every couple of weeks. Even in temperatures down below zero my old Cat (930,000 miles) starts every time. My model engine is the first "ground up" 15 liter engine designed by Cat (6nz) and was made prior to the 2007 round of emission control requirements and headaches.

Lots of room to work on this engine, reliability, and almost guaranteed starting. Pretty hard to beat! My 7.3 2003 Excursion has lots more pollution control stuff hanging on it, but it too has been bulletproof for 160,000 miles and starts in sub zero weather also if you plug it in when it's really cold out.

Thanks.

 

[BlackNBlue]

IDI = indirect injection. The Navistar 6.9 and 7.3 fitted in pre-94 Fords is an IDI engine, as is the GM 6.2/6.5, but not the Cummins B-series; those are DI. After 94, Ford started using the electronically-controlled PowerStroke (confusingly, also 7.3l displacement).

I'm a mechanic that's seen a lot of diesels, mostly small imports and some tractors, not a diesel specialist. My impression is that modern engines start easier not because they're electronic, but because they're direct-injected. I was working on a farm in Iceland with two tractors, both direct-injected. One was a 6-cylinder common-rail turbo with fancy electronics, the other a one-wire 4-cylinder non-turbo. The latter had a much easier time starting below zero, but didn't have half the power or smoothness of the common-rail six. It also smoked and smelled more. The easiest one to start was an even older Deutz zero-wire (you had to pull a cable to cut airflow to "strangle" the engine to shut it down!)

Ford used a Perkins 4.135, license-built by Mazda and with a Mazda transmission, in 83-84 Rangers. Lovely engine, weak gearbox.

Earlier Ford step vans used a Hercules diesel that's nearly impossible to find parts and information for. Other than the ones mentioned, I'm not aware of any diesels Ford used in light-duty ("350" and under) vehicles, but I'm no Ford specialist by any means.

 

[steamjam1]

As I recall from several careers ago, the older Ford 6.9 and 7.3 had headbolt, and headgasket issues. And the fix was to buy a kit that strengthens the assembly with thicker head bolts and better head gaskets.

 

[WrenchLife]

Love the old International IDIs, all in all they are a good motor, they have enough power to do the job but not enough power to break things. Don't have to worry about speeding tickets either. They also run great on waste motor oil.
Had a 94 turbo idi 7.3 F superduty with 520,000 miles when I sold it. Drove it daily for 2 years, I think I filled it with diesel maybe 6 times. 12 mpg on oil.