The official 6bt conversion thread

Engine, ignition, fuel, cooling, exhaust

Moderators: Ranchero50, DuckRyder

Post Reply
mljjones67
Blue Oval Guru
Blue Oval Guru
Posts: 1341
Joined: Sun Aug 06, 2006 5:41 pm
Location: Utah, Springville
Contact:

The official 6bt conversion thread

Post by mljjones67 »

Thought I would put up an official thread for the 4bt. Didn't want to continue to hi jack the other thread!! I think this is an awesome idea. :thup: :clap:
Here is a couple web pages I have found so far!!
http://www.4btswaps.com/forum/showthread.php?t=242
http://www.4btswaps.com/forum/index.php
Last edited by mljjones67 on Mon May 12, 2008 2:40 am, edited 1 time in total.
nevrenufhp
New Member
New Member
Posts: 134
Joined: Mon Feb 21, 2005 8:51 pm
Location: California, Modesto
Contact:

re: The official 4bt conversion thread

Post by nevrenufhp »

Very nice way to be able to drive a full size truck on a daily basis.
67 F100, 300(Offy intake, Edelbrock 500, 274*/.518" lift cam, heddder, duraspark & Summit CD ign), 4spd, power steering swap, front disc and hydroboost.
08 VW R32
increase diesel fuel rate site:
http://www.freewebs.com/nevrenufhp/index.htm
mljjones67
Blue Oval Guru
Blue Oval Guru
Posts: 1341
Joined: Sun Aug 06, 2006 5:41 pm
Location: Utah, Springville
Contact:

re: The official 4bt conversion thread

Post by mljjones67 »

Here is the start of this discussion on another thread.
http://www.fordification.com/forum/view ... 020#196020
User avatar
averagef250
100% FORDified!
100% FORDified!
Posts: 4387
Joined: Fri Mar 17, 2006 12:58 am
Location: Oregon, Beavercreek

Post by averagef250 »

I'll get some pics of the 4BT in my '71 hopefully tomorrow. I will also be putting a 4BT into a '94 F-250 4x4 next week. It has a great running injected 300 in it that will be up for grabs too if anyone's interested. I'll be taking lots of pictures of the whole process on this one. I'll also be learning quite a bit about what engine electrical stuff a '94 F-250 does and does not need for the gauges to work right with a diesel that only needs one wire to run. I'll need to drop the tanks and switch them out for the 87 to 89 style with the low pressure fuel pumps. We'll likely be aftercooling this one as well. Might go as far as porting the head and camming it too.

Have you found any 4BT's or a 5 speed for sale locally Mike?

The pic is the only halfway decent one I have of my '71 right now. Just put here so you guys could see what kind of truck can pull down 25 MPG with a 4BT.
You do not have the required permissions to view the files attached to this post.
1970 F-250 4x4 original Willock swivel frame chassis '93 5.9 Cummins/Getrag/NP205/HP60/D70
User avatar
FORDification
Site & Forum Admin
Site & Forum Admin
Posts: 8047
Joined: Sun Jul 11, 2004 12:52 am
Location: Kansas, Wellsville
Contact:

re: The official 4bt conversion thread

Post by FORDification »

Thanks for the link, Mike. I've just added those forums to the Automotive Messageboards Master List on the Links page. :thup:
____| \__
-O-----O- Keith
'67 F-100 2WD SWB ~ '69 F-100 4WD SWB w/7" chop ~ 1975 F-250 Ranger XLT Supercab Camper Special
ImageImageImage
My '67 restoration video
-> Posting and you! <-a MUST watch for all!!
mljjones67
Blue Oval Guru
Blue Oval Guru
Posts: 1341
Joined: Sun Aug 06, 2006 5:41 pm
Location: Utah, Springville
Contact:

re: The official 4bt conversion thread

Post by mljjones67 »

No problem Keith
I have not found one yet. I haven't really looked other than in the local classifieds. I like the flat bed on your truck. I think I might go that route too. I would like an aluminum one though. Do you like it better than the regular bed?
User avatar
averagef250
100% FORDified!
100% FORDified!
Posts: 4387
Joined: Fri Mar 17, 2006 12:58 am
Location: Oregon, Beavercreek

Post by averagef250 »

I prefer a normal bed myself, but really depends on what I'm doing with the truck. I don't feel guilty when I throw chains or parts on the flatbed like I would if it were a real nice bed. The diamond plate flatbed I built is real stout, but actually weighs less than a pickup bed. The headache rack looks real sharp and gives the truck a tough look, the burly 4BT rattle doesn't take any away from that either.

My '70 has a nice bed that I rarely put anything in with a toolbox up front. Everything I need usually fits in the toolbox and half the time I'm towing a trailer so I don't need the bed.
1970 F-250 4x4 original Willock swivel frame chassis '93 5.9 Cummins/Getrag/NP205/HP60/D70
User avatar
theskytoucher
Preferred User
Preferred User
Posts: 471
Joined: Wed Jun 07, 2006 2:53 pm
Location: Arizona, Cottonwood
Contact:

re: The official 4bt conversion thread

Post by theskytoucher »

Could we get a thorough definition of wat a 4bt is just so everyone knows exactly wat we are talking about here???
Thanks
-Troy-

1996 Dodge ram 1500 4x4
1976 Ford F-150 4x4

Quando Omni Flunkus Mortadi
When all else Fails Play Dead
User avatar
theskytoucher
Preferred User
Preferred User
Posts: 471
Joined: Wed Jun 07, 2006 2:53 pm
Location: Arizona, Cottonwood
Contact:

re: The official 4bt conversion thread

Post by theskytoucher »

Thanks!!!! :fr:
-Troy-

1996 Dodge ram 1500 4x4
1976 Ford F-150 4x4

Quando Omni Flunkus Mortadi
When all else Fails Play Dead
User avatar
19674x4
Blue Oval Fanatic
Blue Oval Fanatic
Posts: 903
Joined: Mon Jun 27, 2005 12:31 am
Location: Oakland Oregon/Sheridan Wyoming

Post by 19674x4 »

averagef250 wrote:I'll get some pics of the 4BT in my '71 hopefully tomorrow. I will also be putting a 4BT into a '94 F-250 4x4 next week. It has a great running injected 300 in it that will be up for grabs too if anyone's interested. I'll be taking lots of pictures of the whole process on this one. I'll also be learning quite a bit about what engine electrical stuff a '94 F-250 does and does not need for the gauges to work right with a diesel that only needs one wire to run. I'll need to drop the tanks and switch them out for the 87 to 89 style with the low pressure fuel pumps. We'll likely be aftercooling this one as well. Might go as far as porting the head and camming it too.

Have you found any 4BT's or a 5 speed for sale locally Mike?

The pic is the only halfway decent one I have of my '71 right now. Just put here so you guys could see what kind of truck can pull down 25 MPG with a 4BT.
you get 25 mpg in that thing, wow :cry:
My Photo Album
2012 Cummins-the luxury Tow Pig
1967 F-250 highboy 352, np435(((((((sold))))))))) My first true love
1968 F100 SWB. 360, np-435, flatbed, currently acting as a hornest nest and bee hive.
1971 F-100 4x4 Step-side. 360, np-435, 70k origional miles- needs allot of love.
User avatar
averagef250
100% FORDified!
100% FORDified!
Posts: 4387
Joined: Fri Mar 17, 2006 12:58 am
Location: Oregon, Beavercreek

Post by averagef250 »

It's hard to get worse than 20 with a 4BT. The bread trucks that most of these engines came in weighed several tons, were as aerodynamic as a barn and ran 3 speed autos or 4 speeds with 4.56 rear gears. The bread truck engines spend most of thier lives on the governor and they still got 15 MPG or better.

nevrenufhp is right about other adapters out there. There's ways to bolt a cummins to just about any transmission. The Cummins makes quick work of most autos though, I'd strongly recommend a manual. If you're going to bump one up, you'll also want to go with the dodge NV4500 bellhousing and tranny. With that you can run a 13" clutch. The SBF style adapter limits us to a 12" clutch that, even with the best organic clutch, will slip over the 300 horse range unloaded, less than that towing.

300 horse and 700+ lb/ft is very easy for under, possibly far under $500 in ebay/craigslist parts. What the guys bumping up thier 5.9's don't want is what the 3.9 loves.

As far as starter and gauges, if you get one from a a ford chassis bread truck the sensors are correct for our trucks gauges. The starter has it's own high capacity relay built in, the fenderwell mounted one won't handle the juice. I just run a 10 awg wire from the existing starter relay to the "S" terminal on the starter. I make all my battery cables from 4/0 and 6/0 welding cable and solder and shrink tube the ends. The 4BT takes a lot of juice to start, but they start instantly. One big battery will start it fine. Just a key tap and VROOM, RATTLE, RATTLE.

Another thing worth mentioning, These engines are very heavy and very efficient. They hardly need a radiator. The stocker 3 core 300 six radiator with a small electric fan is all that's needed to cool one of these.

Probably the most expensive part for the conversion is a power steering pump. Most of the breadtrucks only came with a vacuum pump for power brakes. Most of use like our power steering though. I try to run the first generation dodge 5.9 saginaw pump, I've been lucky and found them with the extra return for hydroboost. These pumps can be upwards of $150 on ebay and sometimes very hard to find. You can usually find several combination PS and vacuum pumps for sale on ebay, but these are almost always $200++ and they are very expensive to rebuild when they go out. I figure the point of the diesel is simplicity so I stick with the standard, proven saginaw pump and convert to hydroboost power brakes.
1970 F-250 4x4 original Willock swivel frame chassis '93 5.9 Cummins/Getrag/NP205/HP60/D70
ChrisB
New Member
New Member
Posts: 73
Joined: Thu Jul 28, 2005 6:57 pm
Location: Southern California

re: The official 4bt conversion thread

Post by ChrisB »

I can testify to the lack of cooling capacity needed for this and similar engines. By VIN lookup my 72 came with a 300 I6. It now has a 6BD1T(5.8L inline 6 made by Isuzu). I'm not sure if the radiatior is a 300 replacement or something for a 360/390, though I suspect the latter based on some pics I've seen at Summit. Anyway the inlet and outlets were moved on a top-bottom flow factory copper/brass radiator very similar to what I have in my 69 with a 360 originally (now 500 Cad).

It has an unshrouded mechanical fan, which almost seems unnecessary. Coolant temp typically takes its sweet time getting up to 170 indicated and then stays there as long as I have some load. At idle it gradually falls a bit.

The biggest test for cooling was pulling 6-7K up the Las Vegas towards Baker, CA grade in mid 90* temps. 30-40 mph at 2200-2400 rpm with 5-7 psi boost for however many miles that is climbing from roughly 2000 ft to about 5000. The temp rose to 180 but took a long time to get there and came down to 170 immediately at the top of the hill.

The fact that it no longer held the normal temp, means cooling system was beginning to be overtaxed as the temp climbed with the Tstat theoretically wide open. It was so mild and the final temp of 180 (assuming correct) is so mild it is a non-issue.

I would assume a 4bt or 6bt at a similar power level would need about the same, with an edge to the larger engine needing more, but not by much.

The 500 powered 69 would pull that same task easily but probably at 220-230*. It has the same sized radiator and mechanial fan with a shroud.
User avatar
averagef250
100% FORDified!
100% FORDified!
Posts: 4387
Joined: Fri Mar 17, 2006 12:58 am
Location: Oregon, Beavercreek

Post by averagef250 »

I plan to run the factory supercool radiator and shroud with the 6BT in my '70. The 6BT will be up around the 800 lb/ft mark and will pull in excess of 25K regularly (17K pound D47U cat and 8K pound trailer). I may upgrade to a Dana 80 for the rear. I saw a dodge D70 the other day with it's ring gear side carrier bearing squished an 1/8" into the axle tube from cummins torque.

I pulled that weight over the steepest passes we have here with the old 390 in 4th gear, 2500 RPM and 1/2 throttle and the water temp was around 210 with the supercool on an 80 degree day, the oil was probably around 300 though. 15 miles of straight up with that load the 390 only had 25 lbs oil pressure at the top, usually ran 55.
1970 F-250 4x4 original Willock swivel frame chassis '93 5.9 Cummins/Getrag/NP205/HP60/D70
User avatar
hardtailjohn
Preferred User
Preferred User
Posts: 422
Joined: Tue Dec 07, 2004 10:24 pm
Location: Montana, Marion

re: The official 4bt conversion thread

Post by hardtailjohn »

Dustin, what rear ratio are you running? I guess I'm asking what RPM the little Cummins is happy at??
JH
Never trust a grinning idiot holding a big hammer!
User avatar
averagef250
100% FORDified!
100% FORDified!
Posts: 4387
Joined: Fri Mar 17, 2006 12:58 am
Location: Oregon, Beavercreek

Post by averagef250 »

4.10's and 35" tires. The gear spread is perfect with the close ratio M5R1.
1970 F-250 4x4 original Willock swivel frame chassis '93 5.9 Cummins/Getrag/NP205/HP60/D70
Post Reply