86 2WD F150 6.9IDI Conversations

[Chris Wowowski]

another thing to realize, the OBS f150s and f250/350s share the same body, so in reality the only difference is the frame and suspension. It's still a truck, so as long as you aren't going to be pushing it to the max you should be fine.

No pushing it here. Just want a noisy, cool truck with a straight shift. If it turns out to be a good truck I'll swap a D60 into just because and maybe tow a bumper pull around Knoxville.

 

[franklin2]

I had a 1975 that had a 1971 429 in it when I bought it. Now that thing would RUN! It's the one and only reason that I HAD to buy it. The way it fit in there, I believe it must have originally had a 460 in it. I knew another guy who had a F150 extended cab with a 460 in it. It's been almost 30 years, but it seems like it was a 1976.

Popular swap I believe. To get rid of the crappy 351m. The 400 is not much better but can be made better with some money. 429/460 bell and motor mounts match right up to those engines.

 

[IDIBRONCO]

Popular swap I believe. To get rid of the crappy 351m. The 400 is not much better but can be made better with some money. 429/460 bell and motor mounts match right up to those engines.

I wasn't sure that they had the "M" engines in 1975. They may have. I'm not a fan of them. I know that you can build them up to get some pretty good power out of them, but I'd rather start with a 460 to build up.

 

[Thewespaul]

400m was available up to 1982 at least, I had one in my first bullnose.

 

[Chris Wowowski]

I honestly would not worry about the extra weight. Same as having a heavy passenger in the front seat. Figure a 302 weighed 550lbs and the 6.9 is 750 or 800. Take it for a drive and make sure the wiring isn't a hack job with wire nuts or anything like that hooking it all together. If it looks factory and he swapped the whole harness from a 6.9 and swapped it in I would have no problem with it.I think that would be a great combo for decent mileage, probably over 20 mpg in an f150 with 3.08 gears and less weight than an f250.

On the electrical side what should I confirm? I know it has a FSS cut off switch in cab, glow plugs control switch in cab..........power to the alternator (obviously) What about the cold idle circuit on the IP? Where does that get it's control from? The truck was a Houston Texas so cold was not an issue. It will be living now in East Tennessee.

Anything else anyone can think of? I mean it's a tractor engine in a truck body. I've worked on JD powered generators and know all the needed was the above, but we did not use glow plugs, or have a cold circuit on the IP's.

Thanks. My buddy is going to look/ pick this up Sunday and he is skeptical of the conversion.

 

[IDIBRONCO]

What about the cold idle circuit on the IP? Where does that get it's control from?

It gets it's power through the factory wiring harness. Since your truck doesn't have the factory diesel harness, if you want to add it to your truck, you could run a power wire from a switched source (on and off with key) to one side of the fast idle "sender. This is below your thermostat housing with two spades sticking up from the top. From the other side, you then run a power wire to both the fast idle solenoid and the timing advance (that's the one on the driver's side that isn't the FSS). This will make it work like factory. Just make sure that your original power wire has a fuse in it just in case something ever happens.

 

[Chris Wowowski]

It gets it's power through the factory wiring harness. Since your truck doesn't have the factory diesel harness, if you want to add it to your truck, you could run a power wire from a switched source (on and off with key) to one side of the fast idle "sender. This is below your thermostat housing with two spades sticking up from the top. From the other side, you then run a power wire to both the fast idle solenoid and the timing advance (that's the one on the driver's side that isn't the FSS). This will make it work like factory. Just make sure that your original power wire has a fuse in it just in case something ever happens.

Thank you. I figured it was a simple to do, and will be needed in December.

 

[IDIBRONCO]

and will be needed in December.

It may be needed sooner depending on your altitude. It doesn't mater which side of the sender is which. It's just a temperature controlled switch. When the coolant reaches a certain temperature (about 120 I think) it opens and power no longer goes to it. You don't want a constant power supply going to the sender because when the engine cools off enough, the switch closes again and would always keep power to your solenoid and advance. It may burn one or both of them out plus it could drain your batteries.