300 I6 to 6.9 IDI Swap
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300 I6 to 6.9 IDI Swap
Guys, I'm in the process of helping a friend swap a 6.9 IDI in place of his 300 I6. The truck is an 86, has a t18, and is 4x4. The engine came with a 2x4 t19 bolted up, so we just swapped the bell-housing over to the t18 since the input shafts are the same. We bolted in the diesel engine mounts and started lowering the new motor in. When the motor is resting on the mounts where it should be, there is still an inch and a half to two inches of space between the engine and transmission. 
The t18 and t19 are the same length. It was my understanding that the I6 extended farther forward than the V8 engines instead of farther rearward, and that the rear of all the engines end up in the same location once bolted in. Is this not true? Last year I installed a 7.3 liter Powerstroke in place of the 302 in my Bronco. In that swap, all the driveline was in the correct position and everything lined up. Both engines use the same mounts, and I installed the mounts in the same manner, so the transmission being located farther rearward seems to be the only possibility.
The t18 and t19 are the same length. It was my understanding that the I6 extended farther forward than the V8 engines instead of farther rearward, and that the rear of all the engines end up in the same location once bolted in. Is this not true? Last year I installed a 7.3 liter Powerstroke in place of the 302 in my Bronco. In that swap, all the driveline was in the correct position and everything lined up. Both engines use the same mounts, and I installed the mounts in the same manner, so the transmission being located farther rearward seems to be the only possibility.
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Joined: Jun 2004
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From: Casa Grande
I would think the 300 extended farther forward AND rearward because of the 2 extra cylinders in line.
Please keep us informed on how the swap goes and how the IDI performances compared to the 300.
Please keep us informed on how the swap goes and how the IDI performances compared to the 300.
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From: Virginia
I believe you are correct, the bellhousing parting line is always in the same place. To verify this, you could look up the front driveshaft part numbers for a 300 I6/t18 f250 and a 6.9/t19 f250. If they are the same part number, the transfer case/tranny would have to be in the same location. I believe Autozone carries the front driveshafts now if you wanted to look.
The diesel has it's own set of motor mounts as does the I6. You are using all the correct pieces for the diesel correct? The frame perches for the I6 have to be taken off for any v8 swap, and the correct frame perches have to be installed.
The diesel has it's own set of motor mounts as does the I6. You are using all the correct pieces for the diesel correct? The frame perches for the I6 have to be taken off for any v8 swap, and the correct frame perches have to be installed.
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
Also, be sure the motor came from a truck, not a van. There are some differences. The motor plates for the diesel bolt on top of the crossmember. Trying to remember, but I think the I6 mounts did as well, do not confuse the mount plates though.
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Thanks everyone! I'll go ahead and look up the driveshaft part numbers, good idea. The engine is an 85 from an f350. We're using the mount plates from the donor truck. We're using the core support, radiator, springs etc from an F350 as well. Pretty similar swap to mine except we don't have to re-wire the truck to make it work, lol. I'll continue updating this thread as we progress. We can't work on it again till this weekend, but I believe we'll have it ready to run or pretty close to it by next week. Does anyone know the best place to buy SCA's?
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Just checked Autozone and Rockauto's websites, and both the engine options use the same front driveshaft, so it would stand to reason the transmissions are in the same location as you proposed. Good to hear. Now I just need to crawl back under there and see whats up. It was almost 4 in the morning when we ran into this issue, so taking another look with a fresh pair of eyes may quickly reveal the issue, lol.
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Post Fiend
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From: Ottawa, Ontario
Also, the drivers side van manifold, is very different from that of the trucks.
And it's from an '85 F350. So word of advice.....DO NOT USE THE BLOCK HEATER on it!
Proper thing to do is cut the cord, or remove the block heater all together.
The early 6.9's (83-85.5) have a high risk for cracking the block at the block heater freeze plug if it was used.
If you need, or like to have a block heater, best thing is to installed an inline circulation/heater in the heater core lines.
And it's from an '85 F350. So word of advice.....DO NOT USE THE BLOCK HEATER on it!
Proper thing to do is cut the cord, or remove the block heater all together.
The early 6.9's (83-85.5) have a high risk for cracking the block at the block heater freeze plug if it was used.
If you need, or like to have a block heater, best thing is to installed an inline circulation/heater in the heater core lines.
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Thank you for the advise. I thought I read that somewhere a while ago, and was just planning to zip tie the cord out of the way somewhere so it wouldn't be used. From what I gather, as long as it has a good set of glowplugs in it, there really aren't any issues with starting. The Powerstroke was a manual from the factory.
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
was wondering if it was a case of the input shaft not lining up, therefore holding it back. reason I had asked was to try to compare that is all. I have had some that just didn't want to cooperate at all, but did finally go.
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Here you can see the diesel mounts bolted in.
This is the cutting we had to do to make the passenger side mount fit and allow access to the nuts on the underside of the mount. We also had to drill the lower two holes.
This is after we installed the diesel bellhousing.
This is a shot of the two motors sitting next to eachother.
This is the cutting we had to do to make the passenger side mount fit and allow access to the nuts on the underside of the mount. We also had to drill the lower two holes.
This is after we installed the diesel bellhousing.
This is a shot of the two motors sitting next to eachother.