I have a 92 F250 that the 7.3IDI suffered severe block damage from "cavitation". I'm having a hard time finding a replacement 7.3IDI motor that i can actually afford. I have found several 6.9 diesel motors in my area though. Can you guys tell me if it would be an issue swapping from a 7.3 to a 6.9? Any pro's and cons to this? I have a standard transmision in it. Are the blocks pretty much the same??/Needs some help on this issue..Anyone know where i might find some info on this swap? Or is it a better idea to just go back with the 7.3? Sorry for all the questions..

Thanks......

 

I did the swap except with a C6 trans.
Differances are:
1. Fuel filter mount; use your current 1, bolts right on. You will need to use current feed from filter to IP also. Or use filter from 6.9 and eliminate possible leak at fuel heater connection and use cheaper filter.
2. Injector line to #1 probably different, for timing adapter. you can use either 1, if you use 7.3 line use adapter also.
3. Head bolt are smaller on 6.9; If you are turbo'ing with more than 10PSI, might want to use studs ~$300, I did, others have not, your call.

4. Balanced different. But supposedly crank is the same (supposedly same PN#) it is just the flywheel and balancers are matched. I have read "Ford" recommends changing balancer and flywheel to 7.3 items and you are OK (1 of the other user read the paper). Just make sure both are from same eingine 7.3 or 6.9.

 

Also, if rebuilding, or just as a precaution. Might want to consider repair sleeves for balancer and crankshaft rear seal. Sleeves are cheap, just tool is expensive, but it can be done carefully with block of wood and hammer. I did crank just so there would be no need to pul engine if it leaked, glad I did. I did not do balancer and it leaks, a little. I have new repair sleeve now but have to pull radiator to get balancer off.

 

Oh yeah, use your rockers from the 7.3 unless your 6.9 is later model. Don't use a 83 6.9, supposedly weaker heads, combustion ratio is definetly lower. Also early 6.9 (not sure if it was 83 or 83-84) was prone to cracking around block heater if heater was used frequently. I would still go with the late 6.9 just to be safe with the cavitation issue unless you know the entire history of the 7.3 and if it had the DCAs kept up.

 

forgot to mention glow plugs and glow plug relay. Use the ones from the 7.3 the GPs will screw in place on the 6.9 then use the original 7.3 relay and wireing

 

x2 with what rolape is saying, i just did the swap and its pretty simple....

 

Yeah, the 6.9 is almost the same as the 7.3. It should be a straight forward swap. You could look into sleeving your 7.3 down to 6.9 as well. That would greatly reduce the possibility of cavitation. I would keep up with SCAs anyway, though.

 

x2 with what Eatont is saying, its cheap insurance.

 

X3 on the SCAs. I use them in mine just to be safe, after spending $2500 to rebuild an engine that was gauranteed to run when I bought it. I am not taking chances.

 

forgot to mention. Swap or atleast save the sending units from original engine. Hook up a gauge to a sender for an idiot light makes gauge act wierd. I didn't save sender and had to go buy new.

 

where do you live?

nvrmind i see your profile say TX