Howdy, I've been lurking for a few days because I found a 1986 F350 Crew Cab 4X4 4-speed SRW that's in good shape online. The 6.9L has ~200k on it.

I'm looking for a full size truck as a work truck, but do not want a new truck because I prefer the mechanical diesels. Yeah, I've been looking at Cummins 12V(s) as well, but prefer the Ford because they actually have crew cabs and a SFA in the 1-ton series.

The rig will have ~1500lbs and up to 2000lbs in it quite often when working.

Would the aforementioned '86 hold up to that weight in the bed? Does the 4-speed have a granny gear similar to the SM465? If so, I assume it's not highway friendly, so would a Ford 5-speed tranny bolt up to the 6.9? How about the existing xfer case?

Maybe this is a pipe dream, but I'd like to get a manual tranny (5-speed preferably) Ford one-ton crew cab 4x4 IDI and use it as my business rig. How's the reliability of the 6.9?

Love the old body style too.

 

welcome to FTE, the 6.9L is an extremely reliable motor, and it will handle 1-2 tons in the bed all day long. ive hauled 6 ton of hay on a trailer and 2 ton in the bed of mine before and its an automatic, the c6 diddnt like it very much but it held up just fine. the 4 speed has the same final drive ratio as the c6 but has a low hole 1st, we have a 460 with a 4 speed and with the dump bed loaded to the hilt with stumps or gravel or fire wood i can consistently start off just a little above idle in low. the zf-5 could be put behind the 6.9 but it would require a bellhousing swap with a driveline swap. its just a little too much work for the average person.

any one who tells you that the IDI 7.3 was an upgrade over the 6.9, just walk away they dont know what they are talking about. the 7.3 was created by boring a 6.9 .111 out. if you turn them up too much you get cylinder pitting.

actually the first crew cab ever made(if i remember right) was the 53 powerwagon

if you were to get a 12V get the 94-96 model, it has the p7100 IP, its extremely superior to the Bosch VE pump for ease of adding power and
reliability

 

I'd get an '87 CrewCab 6.9L 5-spd. that is the newer body style though.

The Cummins-Dodges from '94-early '98 are all Bosch P7100 equiped (12V).
The early '98 truck was a QuadCab instead of a ClubCab so it has the "sucide" doors but not a true CrewCab. Dodge was too dumb to build a CrewCab in those years, would have been the best truck ever.

I'd rather have an IDI with a turbo than a NON-CrewCab Cummins, INEED my CrewCabs plus I have always had a "thing" for CrewCabs anyway.

To answer your question though you absolutely CAN put the ZF-5 behind a 6.9L. I would use the Single Mass Flywheel/clutch system off of the 6.9L though instead of the Dual Mass out of the 7.3Ls.
Plenty of guys on here have done the swap so there's lots'a info.

 

I WANT THAT TRUCK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

i want it aswell

 

mechelement,
Welcome to FTE and the IDI diesel forum.

The 4 speed probably has a 4.02 low gear ratio, very common behind the diesel.
There were some granny first gear transmissions used with a 5.11 low gear ratio.

For starting out in hard pull situations, I frequently use low range 4x4 with the front hubs turned out to get moving.
I have mine licensed for 20K gross weight, and usually exceed that several times a week.
And that is with the 4.02 low gear ratio, 3.55 gears in the axles and 33" tires.
Better than toasting a clutch.

Stock springs should handle close to 2 tons if you drive sensible.

 

Thanks for the info. I'll keep my eye open for a decent '87 - more like keep my ear to the ground because they seem rare. I don't have a problem retrofitting things or tinkering on things. I did a frame off restoration and build on my '89YJ - RamJet 350, SM465, D300, SOA, 37s, regeared, air lockers, etc.

I'm not overly familiar with the 3/4 ton front ends on the older generation Fords. What did they call that setup? It's not a SFA, it seems to be split with control arms.

I've read a lot about the 7.3L and have seen a pattern of thin cylinder walls and something about the pH of the coolant used or else it'll eat through the walls. I've read about the earlier 6.9 blocks, and the 1/16" diameter smaller head bolts.

I've seen the "first half of '98" 2500s with their "quad cab". For some reason that is a REALLY desired year (last of the 12V probably). Dodge had crew cabs in the 80s. IIRC, a highly desired swap is a Cummins into an '86 Dodge Crew Cab.


I need a crew cab and prefer them as well.

That old Power Wagon is sweet. There's one on YouTube where a guy put a 12V into it.

What sort of turbo setup can you put on the 6.9L? That would be a great option for me because of the mountains around us.

 

its called twin traction beam TTB, me and my friends call it weeble wobble because it wont stay in allignment worth a chitt try find an 85 and up 1 ton and it will have a SFA

 

In regard to the 7/16" head bolts stretching... Can you just increase the grade of the bolt to avoid the stretch?

Would a non-turbo become a sluggish turd when changing elevation, say from 750 feet to 1 mile above sea level?

Dodge/Cummins, do you have a turbo on your 6.9L?

 

All of the IDI turbo's will bolt on either the 6.9 or 7.3 engine.
Late 85, 86 and 87 were the best 6.9 engine blocks.

As for the head bolts, ARP sells head studs that eliminate the head bolt stretching problem.

All NA diesels suffer from lack of air at high altitude.
A turbo will eliminate that problem.
Diesels need air, the more they can get the better.
So the most important upgrades are exhaust and intake mods.

Where are you located in Idaho?

 

I've been reading about the header, y-pipe, larger exhaust diameter and ram air mods too. I'll see what happens. I have to find one first anyway.

Are the ARP head bolts just a higher grade?

I live in Boise, ID just several blocks away from Boise State University.

 

Nice place, I spent a weekend there way back in the 70's when I was driving over the road.

Great people and great scenery, I had a very good time there.

The ARP studs are a much higher grade metal, and are studs instead of bolts.
Studs and milling the pistons down are two of the mods I did to run high boost.

After seeing what my head gaskets looked like when I took them out, anything over 12 PSI is high boost on a 6.9 engine.
I am running twice that much now.

 

No I don't have a turbo on my 6.9L.
I'm probably gonna swap the 7.3L turbo out of my '94 into the '86 someday, build the 6.9L up and turbo it and stuff it into my '94.

Your exactly right about the early '98 QuadCab, the only trucks that are 12V AND QuadCab. '98 was also the first year you could get a Cummins in a shortbed (QuadCab only). As others have stated: it's the "HOLY GRAIL" Dodge-Cummins truck.

I am in the SSSLLLOOOWWW process of building an '86 CrewCab, 1-Ton, long-bed (which is really rare, most were shortbeds and 3/4 ton) into a Cummins powered 4wd.

What I'd REALLY like to build is a late '60s-'71 PowerWagon CrewCab. "Modernize" it with insulation, A/C, cruise controll etc. '94-'98 12V, one of my Allison 545 trannys, some kind of O.D., divorced Ford NP205, Dana 80 and late '80s-'91 Ford Dana 60.

 

why a 60's-71? i think that the 49 powerwagon looks the best. but thats just me i guess

 

My grandpa had a '68 Fleetside CrewCab when I was growing up with a built 413 in it, I was really little but even then I thought it was THE coolest truck ever.
Every time I see one I can see my grumpy old Grandpa with a permanent scowl on his face chewing on the unlit remnant of a Swisher Sweet cigar.
I was riding in the rear seat with my Dad hunting one time with my Uncle in the front seat and Grandpa driving. We were on a nasty snow-covered, rutted logging road road and we came around the corner face to face with the same truck only a std. cab.
There was nowhere to turn around so the other driver got out to come talk to us.
The guy was a CARBON COPY of my Grandpa right down to the cigar stub!
My Dad and Uncle looked at each other like we were in the Twilight Zone.
He walked up to my Grandpa as he rolled down the old crank window and said "Power Wagons HEAD-ON!"
All the rest of sat stunned as the two old codgers talked it up like they'd been friends their whole lives.
Anyway, I'd find the money for that truck if I knew where it was even though I want a long bed and it was only a short.

The real reason is they are "modern" enough you could "improve" it and live with it every day and take it on long trips. That's dificult/impossible to do with the old military-based PowerWagons.