The official 6bt conversion thread

[mljjones67]

confused I must not of seen that movie!!

[customcrewcab]

dang i thought all car guys have seen that movie. mel gibson in a 1970 falcon with a clutched blower!

[mljjones67]

Whats the name of it? I have seen parts of it I think. Is it madmax? I dont like those kinda movies.

[customcrewcab]

madmax was the fist one. the second one is the road warrior. that one has the gyrocopter in it.

[mljjones67]

Might have to rent that one then. The gyros back then were pretty crazy.

[Zeke71250]

Without even figuring in the cost of "refreshing" my current engine... I kinda guesstimated some figures.

I had no plans of ever driving a bump on a daily basis - but if I did and managed to get 10mpg:
300 miles a week at 10 mpg = 30 gals
30 gals @ $3.00 = $90 a week. $4680 a year.

Now, with a 4BT and figuring about 22mpg:
300 miles a week at 22 mpg = 13.6 gals
13.6 gals @ $3.00 = $40.80 a week. $2121.60 a year.

If your bored enough to check my math, feel free - I ain't always the brightest star in the sky. But, with a savings of $2500+ per year, it would seem fairly easy to recoup the investment... and have a daily driver that I'd actually ENJOY.

Somewhere in this thread I saw some things that I'd like to get confirmation on... and didn't see some things I'm curious about.

1. It was said a four speed is a waste of time. Is this true regardless of your axle ratio?

2. Is this harder to do in a 2WD? Should I bother?

3. Does this swap require a change in fuel lines or any special treatment of the fuel tanks? I've heard a swap over from fossil-diesel to biodiesel requires some upgraded components because biodiesel is corrosive.... just wondering if some similar theory applies to switching from gas to diesel?

4. I know this is very subjective - but is it reasonable to think that this can be accomplished without having prior knowledge of diesel engines and no previous experience fabricating anything?

[averagef250]

The cummins powerband is very narrow and low. a truck 4 speed isn't very comfortable.

The 4BT likes to cruise at 1700-1800. Gear your truck for that on the freeway with a 4 speed and you'll have an adventure getting it up to speed.

The 5 speed makes the narrow powerband bearable and really gets the most from the little bugger.

I don't know what's involved with an older 2wd swap as far as motor mounts go. It shouldn't be too difficult, but welding and fab skills or the ability to pay someone else to do the work is needed.

The only change to the fuel system is adding a return line to the tank. If you have two tanks this gets really complicated. If you just have one it's easy. Just solder a tube in the sender flange and run a line to it.

#4 is very relative. If you're mechanically inclined and able to learn as you go and not give up I don't see why you couldn't get it done.

A stock height 2wd bumpside with proper gears would get better than 22 MPG with the 4BT.

Guys have broke into the low 30's with lighter trucks and the 4BT.

[mljjones67]

Anyone else out there wanting to do this swap? I might have an extra 4bt???

[Redcap]

I would love to do this swap...just gotta get caught up on bills.

[Zeke71250]

Thanks Dustin.

I tried to figure the FE a little on the high average and the 4BT a little on the low side.

Engine work on mine is a year or more away - so I'll have plenty of time to weigh the pros and cons. I just don't want to do a butchered up job on it... especially if I have to modify parts of the frame... motor mounts I could probably handle - but fabricating a new crossmember would be a little scary.

[hardtailjohn]

Just a thought....if you have 2 tanks, there is a "dual" fuel valve made for big trucks that would work perfect. I had one on my '75KW. It's just like 2 fuel valves "stacked", so that you control both the feed and return when you flip the handle...that way you're always returning the fuel to the tank your using from.
JH

[71PA_Highboy]

Nevermind... looks like he doesn't stock them any more....

www.BCBroncos.com

He sells a valve made for just that purpose - it has 6 ports.

hth,

eric

[averagef250]

A 6 port valve would make it a pretty easy deal. I've seen them electric, but didn't know they were made in a manual version. I prefer to have just one tank myself. Every rig I've owned with more than one tank always gave me fits with the one(s) I didn't use all that often. A 20 gallon tank means a 400+ mile range with the 4BT. That's good enough for me.

Pretty sure you wouldn't need to modify a 2wd frame whatsoever. Just the engine frame stands would need modified.

The strange thing is everyone I meet that loves the whole 4BT swap concept ends up doing it to a 4x4. A friend of mine has an EFI six in his bump 2wd F-100 and getting low 20's freeway with it. He's all over the 4BT idea, but figures he'll find a 4x4 to do the swap into as it'll still get rediculous mileage.

[mljjones67]

?

[customcrewcab]

do they use those in ups trucks?
i would like to find a 70 shortbed 2wd and swap one it. use it as a daily driver.