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Another F800 Build

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8.2K views 36 replies 12 participants last post by  MJDoppler  
#1 ·
I've had my 1992 F800 now for just over a year now. It's a crew cab cab and chassis, 7.8L diesel, 9 spd Eaton-Fuller, rated at 33k GVWR. I plan to build a flatbed for it to haul my stretched CJ7 and tow my travel trailer. I am considering eventually installing air ride on the rear, probably a Kelderman system, to help soften the ride a little to take some of the stress off of the trailer tongue. There is no GCWR anywhere on the truck and VIN searches have come up negative as well. GVWR of travel trailer is 9500lbs, estimated weight of F800 is 15,000, and estimated weight of Jeep is 6,000. I am fairly confident that I am well within the safety margins of each GAWR, GVWR, and GCWR but how would I properly calculate a GCWR when the manufacturer didn't set one since it was sold as an in-complete vehicle? I'll post some pics when I can get around to it since I don't have a photobucket account yet. One of the first things I need to do is the 1g to 3g charging system conversion, tires, and flatbed design. Any shared knowledge is greatly appreciated.
 
#2 ·
Not sure i would waste my money on a kelderman air ride when u can go to a yard, buy a frame cut, drill a bunch of holes and have a suspension that was designed for your truck.

If u cant convert the title to an rv u may have to get a cdl reguardless if its private or not. The need for one is state law dependent.
 
#3 ·
Already looked into the licensing and working those details out already. If I knew someone that had a mag drill I would go the route of the cut out suspension but I can't justify buying the drill for a, possibly, one time use plus possible need to swap axles so hubs all match. Air ride is probably a year or more down the road at least. Operational and usable are priorities, on a low budget. Thanks for the input.
 
#4 ·
Air brake or hydraulic? 33k GVW I'm guissing is air. My L8000 is with the same GVW.

You're well under the GCWR, don't worry about it. 15K is probably inluding a well built bed. My L8000 is ~18k with a 22 ft high cube box and lift gate. Once agin, no where near max load.

What HP rating do you have? Do you have an intercooler? I expect you'll have a 210 hp, hopefully an intercooler too. Maybe P-pump, if not it's an MW. Mine is 92 and has the intercooler and p-pump. The 7.8 is a good solid motor and capable of good power. They went up to 270 stock, though that was with a larger turbo than the 210/240 and I think only on the intercooled units. Bumping the timing and fuel up some makes a big difference and is easy to do. Better turbo and you can probably easily hit 300+ hp.

How much is the Kelderman vs a cuttoff? Would think you could rent a mag drill for fairly cheap since you only need it for a bit.
 
#9 · (Edited)
Air brake or hydraulic?
What HP rating do you have? Do you have an intercooler? I expect you'll have a 210 hp, hopefully an intercooler too. Maybe P-pump, if not it's an MW. Mine is 92 and has the intercooler and p-pump. The 7.8 is a good solid motor and capable of good power. They went up to 270 stock, though that was with a larger turbo than the 210/240 and I think only on the intercooled units. Bumping the timing and fuel up some makes a big difference and is easy to do. Better turbo and you can probably easily hit 300+ hp.

How much is the Kelderman vs a cuttoff? Would think you could rent a mag drill for fairly cheap since you only need it for a bit.
Air, 210HP, intercooler, P-pump 120, has a new Garrett turbo on it just haven't figured out which one it is yet. Kelderman is big money compared to cutoff, just haven't found much of a salvage yard in my area yet.
 
#5 · (Edited)
No need for a mag drill. Can't count how many holes I've drilled in my F700 frame with a 120v drill and bits sharpened with an angle grinder. The frame is thick but fairly easy to drill.

An Hx40 or an S300 series Borg Warner is a good turbo for these motors. IMO a 60mm Hx40w is great if you keep pump tuning mild. If you an on cranking the pump go with an S366.
 
#12 ·
I agree on the mag drill comment - I probably have drilled 20 holes in my IH frame, and never had a problem. These were mostly 1/2" though. Trick is to step up your drill bits. I also had the luxury of doing a few every day - it would have been a job trying to do all 20 in one afternoon. You have to lean into the drill pretty hard.
 
#8 ·
just buy a star, nothing worse that blocked pics in a thread. i got a complete 3.92 FL70 rear cutoff for $500.00 out of craigs list. took me a day and a half to install and cost about #20.00 for new bolts. page 14 in my toterho thread. mine is 33k gross with air brakes and registered as an RV. according to my friend the CHP DOT guy i'm good to go without a class A
 
#13 ·
totally agree, buy a star, post all kinds of pics that don't go away.....

And I can't help but wonder if you could pull leafs out of a 21K spring pack to soften the ride, since you would probably never need that capacity anyway?? Worst case is you might get a little axle wrap in low gears and need a torque arm. Would be cheap and easy to try....
 
#10 · (Edited)
Same as mine. Bump the timing up to 15* or so and push the plate fully forward. Turbo is a t4 IIRC.

Timing adjustment:

Ford 6.6 & 7.8 P-pump timing (92-93) - TheDieselGarage.com

HX40 isn't a direct bolt of but looks like it wouldn't take much to adapt. IIRC the flanges (in & out) are different on the hot side and I think the outlet on the cold side is also different. I have a 8.3 HX40 (least that's what it was sold to me as) I was going to put on but never did.

I just drove mine up from CA at ~25k gross and was easily able to hold 60-65 most of the way dropping to 35-40 on 5-6* grades - that's with the plate forward and timing only, no other mods. Max EGT was about 1150, so I wouldn't want to go much higher on fuel without more boost. I saw about 15 psi max.

I have a L series manual that I think covers the F series if you need anything looked up. May be able to scan specific items if you need them but something of a pain with what I have at the moment so can't do much.
 
#11 ·
To give you an idea. First video is a 58mm Hx40 with a non-gated 19cm housing. Fuel is turned up to hit about 1150* EGT and 19 degrees timing. Was a good setup, super loud turbo whistle from the tail pipe.

https://youtu.be/zY8oWIwhOps

Second is an S366/.91ar with a 6/6 billet compressor. Injection pump just about maxed (240hp stock) peak EGTs 1150*

https://youtu.be/5ho1L_uGTsY
 
#14 · (Edited)
i pulled 3 leafs from the front. shortest first then every other leaf. flipped the 1" spacer block for near a 4" drop. now it sags to one side an 1". on the plus side it rides nice. i pulled a 6 or seven leafs from the rear, yes to the wrap. in order to take that many springs out of the back you have to have new spring bolts. i jerry rigged it with spacers but then i never left the yard with it. i was told to redrill the bolt holes in the spring clamps to prevent spring wrap on the front during braking. once pointed out i could see where it would make a difference. the RTO9513 is on the hit list for the scrape yard if somebody dosen't save it, $50.00. 2 years on craigs list is long enough

for some reason i thought i was in jones518's thread. anybody need a good 13spd??
 
#17 ·
i'm going to put air bags on the front to square it up. i should have taken the bottom 3 springs instead. we are working on the trans deal, i just told him i'd deliver it for fuel, lunch and a beer. since i'm retired and need an excuse to fawk off and all :D
 
#19 ·
Easy one for a parts guy to find is a 95 E350 with a 460. They are like the traditional 1G mounting, and with a threaded top hole. The Taurus ones dont have the threaded top hole, but super easy to find at a bone yard. These days I usually bring in my part numbers for fear of what they may look up.
 
#26 · (Edited)
If you plan on turning up the fuel any I would ditch the stock turbo asap. An Hx40 or S366 is a good match for the 7.8. The Hx40 will spool faster but run out on the top end before the S366 does. The 60mm inducer Hx40 has 6mm on the stock turbo and the S366 is 12mm bigger. There are two inducer sizes of Hx40, 58mm and 60mm. I personally ran a 58mm with a 19cm turbine housing and was pleased with it. My 7.8 is automatic so the driving habits with the S366 are great, but it may be a bit laggy with a manual transmission.

Maybe not the best brand (china) but this turbo is spec'd out really nice to match up with a manual.

http://www.ebay.com/itm/HX40W-35382...ange-T4-Twinscroll-/141611196444?hash=item20f8af601c:g:n7UAAMXQUmFSp4t0&vxp=mtr
 
#27 ·
If you plan on turning up the fuel any I would ditch the stock turbo asap. An Hx40 or S366 is a good match for the 7.8. The Hx40 will spool faster but run out on the top end before the S366 does. The 60mm inducer Hx40 has 6mm on the stock turbo and the S366 is 12mm bigger. There are two inducer sizes of Hx40, 58mm and 60mm. I personally ran a 58mm with a 19cm turbine housing and was pleased with it. My 7.8 is automatic so the driving habits with the S366 are great, but it may be a bit laggy with a manual transmission.

Maybe not the best brand (china) but this turbo is spec'd out really nice to match up with a manual.

HX40W 3538215 Turbo for Dodge RAM 4" Exhaust Downpipe Flange T4 Twinscroll
Thanks for the info, I'll try to to get better access to the turbo data plate this evening and see if I can get more info on it regarding compressor and inducer sizes. I've got little experience with turbos but have learned a lot over the years of maintenance and repairs of my 6.0. I figure if I can make my 6.0 run again a mechanical diesel will be no problem!
 
#29 ·
Anyone have a good source for exhaust parts? I originally planned to re-stack it with dual's but have decided to go weed burner instead. I believe it had an air horn on the top of the cab at some point since I have a 1-1/8" (approx) hole in the cab on the driver side. So I'll be looking for one to plug that hole with as well.
 
#34 ·
Well the newest update is there is no update, been paying off some debt. I did get the tires I was looking at brand new never been on the road mounted on brand new wheels. Problem is the wheels are hub piloted and mine are stud piloted so Ill be doing a tire swap soon. Anyone need a set of four new hub piloted 22.5" wheels?
 
#35 · (Edited)
Well after much delay in this build, translated into I haven't gotten anywhere with it, i have decided to sell the F800 and look at other options. Here are the details on the truck.

1992 Ford F800 Crew Cab, Cab and Chassis
119K miles
7.8L Diesel
Bosch P-pump (PES6 P 120)
Eaton Fuller 9 Speed
33K GVWR
Air Brakes
Rockwell Rear with 4.30 gears and electric locker
New turbo (maybe 10 hours run time)
17-1/2 ft frame behind cab
PTO ready with in cab controls
Clear title (titled as private truck)
$2500

PM me if interested.

https://oklahomacity.craigslist.org/hvo/6555399640.html