Engine Swap: 6.9L IDI into a 1976 Highboy
#1
Engine Swap: 6.9L IDI into a 1976 Highboy
I have a 1976 <NOBR id=itxt_nobr_0_0 style="FONT-WEIGHT: normal; FONT-SIZE: 100%; COLOR: darkgreen">F-250</NOBR> Highboy (4x4) divorced transfer case, with a tired 390 and four on the floor. I read somewhere that a 6.9 liter IDI (non-turbo) Diesel from a 83-87 truck should work with my current transmission. If it would work, how many other changes would need to be made?
I have my eye on a donor truck, an 83 F-250 <NOBR id=itxt_nobr_1_0 style="FONT-WEIGHT: normal; FONT-SIZE: 100%; COLOR: darkgreen">4x4</NOBR> that was rolled. The body is trashed but the engine runs and has fairly low miles as far as diesels go. The bed of my truck is shot but I am planning to put on a flat bed with recessed gooseneck to pull my 28 foot gooseneck cattle trailer.
How do the <NOBR id=itxt_nobr_2_0 style="FONT-WEIGHT: normal; FONT-SIZE: 100%; COLOR: darkgreen">horsepower</NOBR> and torque ratings compare between the two engines? I'm not sure how many miles are left on the 390 and the donor truck is $500.
I have my eye on a donor truck, an 83 F-250 <NOBR id=itxt_nobr_1_0 style="FONT-WEIGHT: normal; FONT-SIZE: 100%; COLOR: darkgreen">4x4</NOBR> that was rolled. The body is trashed but the engine runs and has fairly low miles as far as diesels go. The bed of my truck is shot but I am planning to put on a flat bed with recessed gooseneck to pull my 28 foot gooseneck cattle trailer.
How do the <NOBR id=itxt_nobr_2_0 style="FONT-WEIGHT: normal; FONT-SIZE: 100%; COLOR: darkgreen">horsepower</NOBR> and torque ratings compare between the two engines? I'm not sure how many miles are left on the 390 and the donor truck is $500.
#3
83 and 4 are the least desirable of the 6.9s the block was upgraded sometime in 85 and I belive the commpression was raised too. 87 is the most desirable of the idis as they had the upgraded rockers and at least some of them had the better glow plug system, both of them is a direct swap on the older ones.
You will be happy with the 6.9 in your 76 with your tranny, you will have to do some fabbing on your frame mounts, and it is probably best to do some clearancing on the crossmember. on mine I did nothing to the crossmember but had only 1/8 inch clearance between the oil pan and the crosmember, so I used (built solid motor mounts) I eventually broke the bellhousing twice (finally beefed it up) and I belive the solid mounts caused this. I had to notch the frame to use the diesel radiator but had no problems here. You will also have to modify (build) clutch linkage to use a hydraulic and if you dont reinforce the cab where the master cylinder bolts up you will have to later after it cracks. I used a 66 brake master cylinder on mine but I'm now going to change the cab and will change to the regular master cylinder. I put nearly 400,000 miles on this setup, with a lot of them under severe use with very little trouble. I liked it well enough I'm going to restore it, and now have most of the parts to do so.
Things I am going to change this go around are.
Motor mounts I am going to dump the solid mounts, but instead of fab work on the crossmember I will try adding a body lift, Just enough to clear the mounts.
I will be using a ZF trany for the overdrive, to make it more highway friendly for todays speeds. When I originally put this together we had nationwide 55 speed limit and it was fine for that.
I will reinforce the cab when I install the cab and cluth linkage, so it won't crack and have to be repaired later.
And the above mentioned clutch master cylinder.
You will love it when done, and none of this is even remotely hard to do. Good luck.
You will be happy with the 6.9 in your 76 with your tranny, you will have to do some fabbing on your frame mounts, and it is probably best to do some clearancing on the crossmember. on mine I did nothing to the crossmember but had only 1/8 inch clearance between the oil pan and the crosmember, so I used (built solid motor mounts) I eventually broke the bellhousing twice (finally beefed it up) and I belive the solid mounts caused this. I had to notch the frame to use the diesel radiator but had no problems here. You will also have to modify (build) clutch linkage to use a hydraulic and if you dont reinforce the cab where the master cylinder bolts up you will have to later after it cracks. I used a 66 brake master cylinder on mine but I'm now going to change the cab and will change to the regular master cylinder. I put nearly 400,000 miles on this setup, with a lot of them under severe use with very little trouble. I liked it well enough I'm going to restore it, and now have most of the parts to do so.
Things I am going to change this go around are.
Motor mounts I am going to dump the solid mounts, but instead of fab work on the crossmember I will try adding a body lift, Just enough to clear the mounts.
I will be using a ZF trany for the overdrive, to make it more highway friendly for todays speeds. When I originally put this together we had nationwide 55 speed limit and it was fine for that.
I will reinforce the cab when I install the cab and cluth linkage, so it won't crack and have to be repaired later.
And the above mentioned clutch master cylinder.
You will love it when done, and none of this is even remotely hard to do. Good luck.
#4
#5
the tranny is diffrent as far as i know use the tranny out of doner truck what state are you from the horse power is not important the 6.9 will give you reliable power and would pull a house down there is a guy with one in a bronco and in an old 70s truck im not sure on mounting but the pros will help with that i would put an idi in any truck they are strong powerful motors sorry missed the part about the manual tranny i think the expert has already helped you good luck
star do you have any pics of that truck
star do you have any pics of that truck
#7
I live in southern Minnesota. My donor truck is acutally an 85. So if I am understanding all of this, the 6.9 should be a direct bolt on to my current tranny? I have also considered using the tranny from the other truck, if necessary. Not sure how it would work with my transfer case though. Would the 7.3 non turbo also fit my tranny?
Im 16 and have had a fair amount of engine experience. I'm looking to do this as easily as possible and I don't have a lot of cash to spend. I'm not set on doing this swap but just trying to get some more info before deciding what to do with it. This will be a summer project so I'm not sure if I want to jump into buying anything just yet.
Starmilt- Do you have a Highboy? What year? also what did you pull your diesel out of?
Im 16 and have had a fair amount of engine experience. I'm looking to do this as easily as possible and I don't have a lot of cash to spend. I'm not set on doing this swap but just trying to get some more info before deciding what to do with it. This will be a summer project so I'm not sure if I want to jump into buying anything just yet.
Starmilt- Do you have a Highboy? What year? also what did you pull your diesel out of?
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#8
#9
awsome im planning to build a truck with an idi from the frame up i would love a 79 4x4 crew that will be an awsome truck
#10
76 highboy the 6.9 is out of an 85 but any 83 to 94 idi will be the install.
For a donor you would need 87 down so you have the bellhousing to fit your 4 speed.
BUT if it was me I would use a ZF5 tranny tranny out of two wheel drive 88 up so you will have overdrive and you will have a very capable rig that will be way more effeciant than your FE engine.
For a donor you would need 87 down so you have the bellhousing to fit your 4 speed.
BUT if it was me I would use a ZF5 tranny tranny out of two wheel drive 88 up so you will have overdrive and you will have a very capable rig that will be way more effeciant than your FE engine.
#11
If the body is as nice as the pictures I will take my time and It will be my last pickup.
#13
Hopefully I will have pictures tommorrow. It will be a couple year project it is 2 wheel drive (first change) and I will at the very least use a ZF5, but I think I will hold out and use a ZF6 in it with a gv for double over.
If the body is as nice as the pictures I will take my time and It will be my last pickup.
If the body is as nice as the pictures I will take my time and It will be my last pickup.
#14