hey, I know there's a few diesel freaks here. I'm hunting for a '80's/early 90's Ford diesel truck to replace my '97 5.4L gasser. I won't go into all the reasons why right here yet. Just kinda want to go back to old school technology. Not really looking at the Powerstrokes at the moment. Anywho, anyone have any experience with the 6.9 liter IDI? I have my eye on a couple for sale locally. The one that looks to be the best condition has an auto tranny (which I'm not real nutz about). I don't tow anything real heavy, pretty much just 2 or 3 snowmobiles would be the worst case(so far). But I need to go up our twisty canyons roads, up to about 7,000 altitude to the parking areas.
Would ya try this with an auto tranny, and be happy about it? Would ya even be happy doing it with the 6.9 L vs the later 7.3L non-turbo? Just looking for thoughts here. My current 5.4L Ford isn't a tow demon, as the '97's were the first year of this engine, and were only rated at 225HP. So I'm used to not screaming up the canyons anyway.

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past MB rides:
'68 220D
'68 220D(another one)
'67 230
'84 SD
Current rides:
'06 Lexus RX330
'93 Ford F-250
'96 Corvette
'99 Polaris 700 RMK sled
2011 Polaris Assault
'86 Yamaha TT350(good 'ol thumper)

I haven't driven a pickup with the 6.9 but I did drive a 26' U haul with that engine and I was surprised how well the 6.9 moved that huge truck.

Not sure what auto trans is behind the 6.9 but I know the one on the Powerstroke is somewhat life limited.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Best web site is oilburners.net. Check out the technical stickys. More good, reliable information there than anywhere--including your Ford dealer! ( All the old guys who actually knew these engines have retired!)
6.9 have thicker cylinder walls than the later 7.3 IDI, so are less prone to cavitation.
A turbo REALLY wakes up these diesels.
The BEST Injection pump is a Moose Pump, or Baby Moose--when you need to replace your IP. The Moose products are pricey, but perfectly calibrated. If you remove the IP--NEVER remove the 2 bolts and the round housing---I know that looks like the simple way--but it will lead to disaster--read all the IP info on the website.
Any posts by Mel Agne, on that website are worth paying attention to.
The 6.9 IDI w/o turbo won't exactly scream up the canyons to 7000 feet, but it will pull anything you want up there, albeit a bit leisurely.
Go to you local Ford Dealer, or International dealer and get a small pack of coolant test strips. Check to be sure they are not out dated. Use the strips to check the level of the anti-cavitation chemistry in the cooling system.
Most common rear axle ration is 3.55 VIN code 19 for Ford, or 29 for Dana, H9, or B9, orC9 for limited slip.
Better ratio for towing is 4.10, but top speed is limited.
Check ATF. Change, if burnt. Add cooler if burnt. I used to pull off the transmission cooler lines, and slip a vinyl tubing over them and empty into a 5 gallon bucket, while I added fresh ATF with the engine running. Complete change at about 4 gallons.
You need a special wrench to remove the fan clutch from the water pump. If you ever remove the fan clutch, be SURE to firmly re-tighten with the special wrench before starting the engine--otherwise, when you shut off the engine, you may hear a slight spinning sound followed by a thud as the fan unscrews itself, and impinges on the radiator....

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

Awesome info! Thanks
I have read about the cavitation issue on the 7.3L's. Didn't have a clue what it was at first. Did some digging and got edumacated. Weird phenomenon
I may go test drive that one with the auto and see how it feels. They want waaaay too much for it, but it's been listed for sale for over a month now(for the price I assume), so should be negotiable.

__________________
past MB rides:
'68 220D
'68 220D(another one)
'67 230
'84 SD
Current rides:
'06 Lexus RX330
'93 Ford F-250
'96 Corvette
'99 Polaris 700 RMK sled
2011 Polaris Assault
'86 Yamaha TT350(good 'ol thumper)

The cavitation issues on the 7.3 are overblown, mine has over 200k and is fine. I have heard of four cases directly that a person said "this happened to my truck". The rest are all "my buddy" type stories.
Any trans behind a 6.9 is not an overdrive, and that is a real negative point IMO. The 7.3 had a ZF 5speed or E4OD behind it, so mileage will be better. The pre-Powerstroke forum at ford-trucks.com is pretty active, there are a couple guys doing some nice builds there. Lots of good info, and a couple sources for performance and replacement parts.

The Ford 6.9 is common until recently when Ford went out of the ambulance business.

Can't say enough good about that engine. They take a huge beating often with shoddy maintenance. For a big city truck, 50k miles/year is common and with decent maintenance wwill go an easy 300k miles before replacement.

They are all auto boxes and I cannot remember having a tranny problem.

If you're really stuck on a 6.9, find a later "B" engine, used in '86 and '87 IIRC. It has the gear reduction starter and the later GP system. The 6.9 is a better cold starter than the 7.3, but not as clean running. Check the engine when cold for external coolant leaks at the head gaskets. If slight, it shouldn't be an issue. Regarding glow plugs on either engine, get the OEM parts from the local Ford dealer and do the job once.

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'83 300D, 126K miles.

I agree with your general comment, but you are 200K miles away from knowing whether it is fine, unless there is some test to determine how the coolant side of your liners are doing.

My wife and I got lucky when we bought her 2000 F350 with the 7.3. Every few years she gets the urge for a new truck, which is understandable given that she hauls trailers full of horses up and down the interstates and cannot afford to break down. Every time the subject comes up, we ask some diesel expert what he thinks and he says, "Don't sell that truck." It has about 145,000 on it now. It has been maintained to the book since new with Motorcraft antifreeze, DCA, coolant flushes, frequent fuel filter changes, and oil changes with Rotella and a quality filter every 3,000 miles. It runs better than new.

Sorry for the hijack.

I guess in another 10-20years I'll know for sure. Until then, I'll keep running silicate free long life coolant, which according to all reports completely eliminates cavitation from liner vibration. Running a water wetter can also help if you're stuck on using the green stuff, as it reduces the high surface tension at the root of the problem.
The early 6.9s had a habit of cracking externally by the center core plug, where the block heater is installed. They also had a subpar glow plug system. 86-87 both of those issues were fixed. If you want more power, though, the 7.3IDI is still the way to go. Head studs are much cheaper, and the compression is slightly lower to reduce cylinder pressures, hence the easier starting of the 6.9. You can always cut the piston crowns as well, it doesn't take much to make a big difference in numbers with compression that high. They can be reliably built to 250hp, about stock for a 7.3PSD. There are guys who claim 400+hp as a daily driver, but I am sure they are not stressing that engine daily.

I knew I came to the right place for advice
The 6.9 I'm planning on looking at is an '86. I did hear they were improved. There's an '89 7.3 that a friend of mine test drove and said it runs and drives great. Has 130K miles, which isn't bad. But I'm kinda nervous about the cavitation issue. I'm going to try and buy some test strips, and then go take a look at it I guess. I've wondered how much to REALLY worry about this issue though. I read on a diesel forum somewhere where the concensus seemed to be that it'll happen at around 150k miles if it's been really neglected, and this one is approaching that. I stopped by and looked it over and kicked the tires one day, but no one was around. Maybe I'll go back to take a second look.

__________________
past MB rides:
'68 220D
'68 220D(another one)
'67 230
'84 SD
Current rides:
'06 Lexus RX330
'93 Ford F-250
'96 Corvette
'99 Polaris 700 RMK sled
2011 Polaris Assault
'86 Yamaha TT350(good 'ol thumper)