6.9 conversion in the Bronco

[BigNorm]

I'm keeping my future options open. I like the look of the Cummins 4BT but availability seems to be a problem. I like the 6.9/7.3 ideas because Agnem said it's basically bolt in. Well. the engine is anyway. I have some questions to Agnem or anyone that might know. I've read up on all the moostang posts up to now. It's a really cool modification.

My first question is how much room is there between the engine and the crossmember? This is important because I chopped my crossmember (not recomended) and now it's supported with a piece of 1/2" plate which resides no less than about 1/4" below my hamonic ballancer. I'm guessing I'd have to build a custom crossmember or burn the one out of the donor if/when I get one.

My second question is is the 2" body lift necessary or will it fit without the lift. For what I do I'd like to keep the body as close to tera firma as possible but if it's necessary I suppose 2" is not a bad compromise for a cool oil burner under the hood.

My third question is how many pounds of fuel pressure is necessary to feed the 6.9? I had thought of purchasing a tank out of a fuel injected Bronco and using that as it comes with a fuel return line as well which I believe is needed to for the swap.

Last question for now. After all is said and done what kind of mileage is Moosestang giving you? I'm hoping it's a big differrence from the "gasser" I'm running now which is only yielding me around 8 mpg. Thanx. NORM

 

[typ4]

The best place to find a 4bt is frito-lay trucks and the like. We bought some used ones at work for 3500 each and they are intercooled and run real well. :Sly

 

[Mr_Roboto]

My third question is how many pounds of fuel pressure is necessary to feed the 6.9? I had thought of purchasing a tank out of a fuel injected Bronco and using that as it comes with a fuel return line as well which I believe is needed to for the swap.

NORM

A fuel injection pump would give WAY too much pressure and would make the low pressure side of the IP leak. All you need is a regular carbureted tank setup and run the line to the lift pump on the engine.

To run a return line, take the sending unit off the tank (to get it away from fuel vapors) and drill a hole and epoxy or braze in a tube for fuel return.

 

[BigNorm]

Makes sense. My sending unit will be easy to get to if I ever do this. I'll be dropping it through the bed soon and making a3/16ths skid for it to sit on. It'll have a flat belly then.

 

[geonc]

Norm, If the Bronco in question is the one in you avatar, you may just want to consider the 4bt ....unlesss you like the idea of having 1 k lbs pull you over or plan on adding some tractor weights to the rear

Not to mention the torque will prolly grenade your "lincoln" locker ;p

 

[BigNorm]

Norm, If the Bronco in question is the one in you avatar, you may just want to consider the 4bt ....unlesss you like the idea of having 1 k lbs pull you over or plan on adding some tractor weights to the rear

Not to mention the torque will prolly grenade your "lincoln" locker ;p

What this lil thing?

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I don't think so. The outers or tcase would go first methinks.
But I believe you are right. The 4bt seems what everyone is recomending between here and pirates. Now if the motors were easy to find.... Can parts be found at the local Nappa?

 

[Agnem]

Norm, thanks for making it over from FSB to continue the discussion we started with PM's. To answer your questions, I initially used the frame mounted fuel pump from the stock EFI engine on the Moose Stang project, and it DID work sort of. It worked well enough to make the engine run, but the high presure was too high, and the injection pump timing becomes unstable. There were no leaks however. You would have to substitute the factory pump with a Holley Red or equiv, that yields 6 to 8 PSI. The Holley Red is very popular in these circles, and most of the guys eventually convert from mechanical to electric because it is so convienent for fuel filter changes, and troubleshooting. As for the front crossmember clearance, I'd have to see a picture of what you have to get an idea of what trouble if any you might have. The clearance of an IDI in a Bronco is the same as it is in any F series, so if you spot one nearby, you can just take a look and get an idea. I did not have to do the body lift to make the engine fit. I just wanted to do that to make working on things easier, and to give me some added clearence for my side pipes which I knew I was going to run.

 

[geonc]

What this lil thing?

You must be registered for see images

I don't think so. The outers or tcase would go first methinks.

WOWZERS! You weld that with a fusion reactor
Looks like spray transfer mig ;p

Guess the tires bark a bit when turning on hardpack

 

[RLDSL]

Here's a 4bt on ebay http://cgi.ebay.com/ebaymotors/CUMM...058959312QQcategoryZ33615QQrdZ1QQcmdZViewItem

I think I saw another one, rebuilt, but the guy wanted an insane core charge

--------Robert

 

[BigNorm]

Thanx for the comments guys. You are right. The hubs do not get engaged on the street accept for deep snow. I tried driving with just one locked once and don't really like the way it pulls to the one side. Thanx for the ebay link. I won't be buying a diesel for the bronc any time soon. I still have alot of projects to get done with it. I love the whole idea though. When/If I do it I'll probably set up the whole drivetrain in advance in the garage. Right now I'm thinking that the 4BT hooked to the np435 backed to a NP203/205 doubler would be the ticket. As described elsewhere it wouldn't be light. One thing I like about running leafs is if I need more support I can just add another leaf or 2. I've got a complete rear F350 pack in my yard of which I'm only running the Main leaf on my truck right now. Of course there's more variables but everything in the wheelin game is a compromise. When it comes down to it the thought of wheelin' an oil burner just seems cool. Thanx again for all your help. NORM

 

[flatlander]

It's too bad you're in Nevada. I have a 75 F250 hi boy with an nP 203 Tcase that I'd sell for parts.

 

[Black dawg]

have you considered the little detroit, they are much lighter and are real inexpensive.

 

[BigNorm]

have you considered the little detroit, they are much lighter and are real inexpensive.

I'm totally new to diesels as far as how they work and what's out there so bring it on. I'm up for anything right now. This would be ideal for what I want: An economical diesel which is light yet still produces good torque. What is the "little detroit"? Thanx for posting.

 

[Agnem]

We went to the Kaufmanns dyno event this past Saturday. The Bronco seemed to be a welcome distraction from the repetative cookie cutter Dodges that dominate the event. I got several accolades about it, and quite a few thumbs up. The only other conversion that was there was a 92 with a 12 valve 5.9 in it, owned by a guy who trashed the IDI rep and had nothing good to say about them, hypermax turbos, or most things in general. In short, he had a big L stamped on his head, and admitted to abusing anything he owns with unbridled zest.

 

[BigNorm]

There's alot of those in the wheelin' community as well. I don't really have a set group I go with. I'd like to have a group of mature adults who enjoy wheeling and fabrication that don't need to become drunks to have a good time. I don't want to lable the whole. It's the few that give it a bad rep. :draw