88 Chevy 2500 6.9 IDI swap

FoxNotch · Dec 18, 2022

I'm helping my father out swapping a 6.9 IDI into his 2500 Chevy. You may be wondering why, I sure am also.
He's had the Chevy for 20+ years but the 350/th400 is shot. The truck itself is straight and rust free. He's had a number of IDI's and always had good luck and got this 6.9/C6 setup from an '84 econoline based short bus (low mile after reman.) for free. So here we are. He helped me with my coyote swapped fox so now I'm helping him.

We've got the engine/trans fitted in really well. Only fitment issue left is a starter. With the old style starter the solenoid hits the frame. With a hi-torque starter the motor hits the frame. It's near where the IFS bolts in so I'm trying to avoid notching the frame.
There is room, just neither starter positions correctly to clear. Does anyone make clockable starter for these engines?

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Jesus Freak · Dec 18, 2022

I don't know about the starter question, but this sure is fascinating! If it wasn't so right, I'd say it was wrong. You're even going to use the C6? Is the driveline company that will have to make your drive shaft going to charge you triple, because a C6 will be mated to a Chevy differential? Please keep us posted on this!

FoxNotch · Dec 18, 2022

Jesus Freak said:
I don't know about the starter question, but this sure is fascinating! If it wasn't so right, I'd say it was wrong. You're even going to use the C6? Is the driveline company that will have to make your drive shaft going to charge you triple, because a C6 will be mated to a Chevy differential? Please keep us posted on this!

Yes going to stick with the c6. He doesn't want to do anything fancy, this is really just a run around truck. I'm going to try to talk him into a gear vendors OD unit instead of re-gearing the 4.10 12 bolt in it now. We'll see.
Usually we make the driveshaft and take it somewhere to get balanced so it shouldn't be a problem.

Will keep up to date on it, but this is a back-burner project so progress will be sporadic.

Jesus Freak · Dec 19, 2022

FoxNotch said:
Yes going to stick with the c6.

Will keep up to date on it, but this is a back-burner project so progress will be sporadic.

Another option for OD is the E4OD, it'll be just as hard to find a gear vendor as it will be to find a diesel E4OD but they do make a stand alone controller for it. As long as he only wants 50-55mph the C6 will be fine.

u2slow · Dec 19, 2022

I'm quite sure you could find a drop-in 3.42 axle or a used r&p at a much lower cost.

FoxNotch · Dec 19, 2022

u2slow said:
I'm quite sure you could find a drop-in 3.42 axle or a used r&p at a much lower cost.

I'm not worried about changing gearsets. Just would like to pick up the OD and keep a tall gear.
Ultimately, it doesn't need to do much heavy hauling or high speed so probably will keep the basic c6 and regear. I'm just always looking to do a little extra.

u2slow · Dec 19, 2022

When I had a 6.2L suburban, I was in a similar spot with a th400 and 4.10 axle.

I ended up doing a SM465 4spd manual swap and a 3.21 axle. I might have had $500 into the pieces. Highway mpg went from 12 to 17! Didn't sacrifice anything on the low/slow end with the 6.5:1 1st gear.

I wish I had a solution for your starter conundrum. If it's not too far from fitting, can you shim the engine up or sideways? These box frames can be cut open and have a recessed area welded back in too.

FoxNotch · Dec 20, 2022

u2slow said:
When I had a 6.2L suburban, I was in a similar spot with a th400 and 4.10 axle.

I ended up doing a SM465 4spd manual swap and a 3.21 axle. I might have had $500 into the pieces. Highway mpg went from 12 to 17! Didn't sacrifice anything on the low/slow end with the 6.5:1 1st gear.

I wish I had a solution for your starter conundrum. If it's not too far from fitting, can you shim the engine up or sideways? These box frames can be cut open and have a recessed area welded back in too.

I wish we could do a manual, but his arthritis is too bad to be shifting gears.

With the original style starter it would be a relatively small notch (and box out like you said). What I don't like is that it would be end of the solenoid where the cable connections are that would be in the notch.
That's why I gave the hi-torque type starter a shot since it relocated the cable connections.
Truck's out of the shop for a week or so, so if I strike out on a simple solution I'll look more closely at what kind of notch needs to be made.
Can't move the engine around much. It fits like a glove where it is, but it's tight in every direction.

Thanks for the input.

Black dawg · Dec 23, 2022

do you have pictures of the starters you are trying to make work?

u2slow · Dec 23, 2022

Black dawg said:
do you have pictures of the starters you are trying to make work?

I looked them up on rockauto to see if there was a 3rd type. It seems there basically 2. Both look like gear-reduction; the motor and solenoid swap positions depending which one.

Black dawg · Dec 23, 2022

As far as readily available starters for these, there would be the delco (non gr) the mitsubishi (long somewhat offset gear reduction) the nippondenso (2.5kw and 4.kw) the 4kw takes up much more room. There have been a few different ones over the years, the one that I am thinking would work is a planetary gear reduction starter. It isnt much bigger than a sbc delco non gear reduction starter. I probably have a couple cores.....

Black dawg · Dec 23, 2022

Went out and found one. Leece neville part number 35259620. Very small and short starter. About 7.5 long from the base of the flange, and 4 inch motor diameter...

FoxNotch · Dec 23, 2022

Black dawg said:
Went out and found one. Leece neville part number 35259620. Very small and short starter. About 7.5 long from the base of the flange, and 4 inch motor diameter...

Interesting, thank you. I'll look into that.

We pulled the truck back into the shop today so I'll get a few pictures of what I have and how they fit tomorrow.

Thanks

FoxNotch · Dec 26, 2022

We ended up just notching/boxing the chassis. It wasn't as bad as I thought.

Thank for all the input though.

FoxNotch · Jan 6, 2023

Starter's fit. Fuel system done.
Next hurdle is figuring out a radiator. The ford van/truck radiators that came with this engine are 10" too tall. Seems chevy went for the short/wide style on these trucks.

So I need to find something 20" tall (and up to 40" wide) but with an inlet (1 3/4") on the passenger's side top and outlet (2") on the driver's side bottom.

Chevy uses the opposite orientation in anything 88-98. And I skimmed through Ford and Dodge pickup options for 80s/90s trucks and they're all too tall.

Looks like a radiator for a 2000 f150 fits the bill, I'd just need to find a heavy duty version. Maybe from a lightning.

Any other thoughts on where I might look?

88 Chevy 2500 6.9 IDI swap

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