7.3 or 6.9

[funny farmer]

I bought a 1988 F-350 a couple of months ago from a friend. Engine was rebuilt and the truck was customized with flatbed, step ups, and a heavy duty kick *** bumper. I know that the standard for that year was a 7.3, and the starting instructions on the visor says 7.3, but he seemed to thought that it was replaced. My neighbor, who supposivley is a diesel guru, said yep 6.9. But when I bought a new air filter, fuel filter, and starter they were all for a 7.3 Are the parts interchangeable? If I have to I"ll take a picture of it, there is no noticeable markings on the motor at all. It would be nice to know for sure, because I have some more questions about it and want to get my facts straight. I was thinking of putting a turbo in it if possible and I need new glow plugs. I'm new to diesel and it seems like everything is entirely different, I don't even have the gas engine figured out yet.

 

[Diamondpilot]

Here is some info I found. If it is indeed a 1988 and has the origional engine its a non turbo 7.3 which was just a bored out version of the 6.9 so it makes since that parts like starters and such would interchange.


The first 7.3L was produced from 1988-1993. The original 7.3L diesel was a non-turbo charged indirect injection (IDI) engine, followed shortly after by a turbocharged version. It was very similar to the previous 6.9l IDI diesel engine, which was simply bored out for more torque. This engine is not considered in the powerstroke family. In 1994, the 7.3L underwent some changes. The 7.3L was changed to a direct injection (DI) engine from the original IDI engine.[1] Ford also added electronic fuel injectors and gave it the name Power Stroke.[1] This model produced up to 250 hp (190 kW) and 525 lbｷft (712 Nｷm) of torque. The new 7.3L DI Power stroke had "single shot" HEUI (hydraulic electronic unit injectors) fuel injectors and ran a 15ｺ high pressure oil pump (HPOP) to create fuel injection pressures. The turbine housing was a 1.15 A/R. In 1999, an air to air intercooler was added. The intercooler cooled the charged air from the turbo making it denser. The cooler, denser air would increase the horsepower potential of the engine, while also reducing exhaust gas temperatures (EGTs). The turbine housing was changed to a .84 A/R housing and a wastegate was added. The "single shot" HEUI injectors were upgraded to "split shot" injectors. With larger injectors, the HPOP was advanced to 17ｺ to increase fuel pressures. The 7.3L DI Power Stroke was in production up until 2003 when it was replaced by the 6.0L. In 2003 Ford Motor Company split the year, early 2003 the 7.3 DI was available, and the later part of the year got the new 6.0L. The 7.3 IDI and 7.3 Powerstroke are not the same engine at all except manufactured by International for Ford. This is known to be the longest lasting and most reliable powerstroke engine.

Chris

 

[powerstroke444e]

Diamondpilot I think your either a ford guy or know how to cut and paste. Either way great explaination.
funny farmer I would say you need to look @ the serial plate on the engine if its still there but I have not seen a 6.9L in 1988 unless it was put there by someone, I did see some 6.9L in 1987 trucks that where work trucks XL or cab and chassi trucks back hay day of adding turbo's to the old IH's.
Either way make sure who ever does the work that they know what they are doing and don't run the engine up past 2700-3000 rpm as that is why most of them failed weather or not the operator would admit it or not.

 

[funny farmer]

Wow that was alot of info, I'll have to go back and read it again, firing order is 12734568

 

[Builder]

Great history of Ford diesel engines, but what the Op wanted to know is the difference between them externally, so he knows what engine he has.

Firing order is the same. Externally, they look almost identical except the 7.3L has a new fuel filter,fuel heater & water separator unit. Most external parts will bolt up between a 6.9 and an early 7.3L. I remember my 6.9L-a whopping 170Hp & 338 ft lbs! Model year 1988 is when the changeover took place.

The 6.9L has shorter cylinder head towers than the 7.3L and the 7.3L has bigger head bolts with larger/taller cylinder head bolt bosses with ribs on the sides. The 6.9L also has centered glow plugs while the early 7.3L has offset glow plugs. That might be the best external indicators.

It was a good diesel at the time. IMO, it was a better diesel than the early 7.3L because the cylinder walls were thicker & less prone to cavitation. The 7.3L has thinner cylinder walls, so if it's an '88 7.3L it's probably well cavitated unless the owner religiously added anti-cavitation additives.

I also thought of another idea and that would be to grab the engine serial number if it's visible and call IH or maybe a helpful Ford service dept if you know one.

 

[Diamondpilot]

Diamondpilot I think your either a ford guy or know how to cut and paste. Either way great explaination.
funny farmer I would say you need to look @ the serial plate on the engine if its still there but I have not seen a 6.9L in 1988 unless it was put there by someone, I did see some 6.9L in 1987 trucks that where work trucks XL or cab and chassi trucks back hay day of adding turbo's to the old IH's.
Either way make sure who ever does the work that they know what they are doing and don't run the engine up past 2700-3000 rpm as that is why most of them failed weather or not the operator would admit it or not.

I am a Ford Diesel truck guy but I cut and pasted that. I have personally never seen a non turbo 7.3 or a 6.9 so I am no expert there. Did have a turbo 7.3 that was great but a deer did the truck in.

Chris

 

[Dmace]

The first 7.3L was produced from 1988-1993... ...In 1994, the 7.3L underwent some changes. The 7.3L was changed to a direct injection (DI) engine from the original IDI engine.

Technically the first 7.3l IDI Diesel was 1988-1994.5. They switched to the Powerstroke DI turbo 7.3l half way through the model year as a 1994.5. I know this because my 1994 model year Ford F-350 Dump Truck that I just sold was a 7.3l IDI non-turbo motor. Good engine - Bad Tranny...

If I remember correctly, the info sticker on the driver side door jamb said the engine size and I remember it saying 7.3l on mine. Check there...

 

[Willl]

and I need new glow plugs.

Why do you need new glow plugs ?

 

[funny farmer]

Technically the first 7.3l IDI Diesel was 1988-1994.5. They switched to the Powerstroke DI turbo 7.3l half way through the model year as a 1994.5. I know this because my 1994 model year Ford F-350 Dump Truck that I just sold was a 7.3l IDI non-turbo motor. Good engine - Bad Tranny...

If I remember correctly, the info sticker on the driver side door jamb said the engine size and I remember it saying 7.3l on mine. Check there...

the dummies painted it over.

 

[funny farmer]

Why do you need new glow plugs ?

**** thing wont start after it sits for a few hours, I need to spray just a minimal amount of starter fluid in it, and it fires right of, runs rough and loud for 15 seconds and warms up and runs fine. I took one of those cheap testers and touched one end to the glow plug and the other to the positive battery cable, and no light on all but 2 of them, and I think I lost them 2 by now. Does that sound right?