The official 6bt conversion thread

[FORD428CJ]

Here is a web site to check out for ya!

www.4btswaps.com

http://www.fordcummins.com/

[Mooosman]

Thanks for the pics! One last Q though: do you happen to have a pic of the engine bay from the passenger side?

All of the other pics look great. Where did you get the air cleaner housing and tubing? Is it just a universal sort of deal, or is that what the bread trucks actually use?

Nick

[LincTex]

Where did you get the air cleaner housing and tubing? Is it just a universal sort of deal, or is that what the bread trucks actually use?

Both.
My engine came with a CA6815, it is about $45 at Napa (Napa number FIL6268)


http://www.napaonline.com/MasterPages/N ... ter+(Gold)

[Mooosman]

Thanks, Linctex, that looks like it will work nicely.

So, I'm assuming that since the 4bt was a conversion in these vans, that they didn't bother to make a specific air cleaner assembly for them? They just used a universal sort of thing?

Nick

[LincTex]

They just used a universal sort of thing?

Yeah, pretty much. Those are kind of spendy, IMHO.
I used a 92 Dodge Cummins airbox with my engine (I also went with a bigger turbo).

[460 crew]

I have a stock airbox and elbows off an 05 dodge cummins if someone is interested for a conversion?

[averagef250]

The real early 83-88 or so 4BT uses a real small compressor H1C turbo with a 2" inlet. Most 4BT's use the same H1C as the 89-93 dodges with the 3" inlet. The 94 and newer dodges use a 4" inlet.

The 95-98 or so dodges used the HX35W which is a pretty good upgrade from the H1C. It's essentially the same turbo with a smaller, wastegated turbine. You can bolt an HX35 turbine housing on an H1C.

If by chance a guy decides to run an HX35, the easiest way to deal with the 4" inlet is to flip the exhaust manifold mounting the turbo up top and stick a 4" K&N filter on it.

[LincTex]

The H1C from my 93 6BT has a 4" inlet. It also had the crappy 18cm turbine housing, which I swapped out for a 12cm (man what a difference in spool-up!)


I don't like cotton-gauze K&N style air filters, they let way too much dirt through. OK for race cars but bad for a diesel that you want to last for 100's of thousands of miles.

[averagef250]

You're right! I thought they were all 3" inlet on the early versions, but I've got both 3 and 4" H1C compressor housings from 6BT's.

Didn't realize the K&N's were that bad of a deal. The donaldson filters are nice.

[LincTex]

My H1C is a very, very late 93 unit.
It looks identical to the WH1C but is missing the W.

I think they made a change in the design first, then decided that they needed to make a differentiation in the model number. Whatever......it works great on my 4BT with the smaller housing. It actually worked really well with the 18cm housing, but was slower to spool up. Now it is perfect.

[mljjones67]

Here is a 6bt what do you all think?
http://www.ksl.com/index.php?nid=218&ad ... cat=&lpid=

[LincTex]

Here is a 6bt what do you all think?

It is a 94 or newer engine. It is also missing all the acce$$$ories

I sold a '93 engine, all there and complete, for $1250

[Art]

New to this forum, not new to the "bumpside" trucks by any means - I currently own four of 'em:
69 F250 4WD with a 440 Chrysler and 727 transplanted in by me
69 F100 2WD 302, T-18, 2.75 gears in the 9" and 360,000+ miles on it - my daily driver
68 F100 2WD 360 T-18 2.75 gears 31,000 original miles
72 F100 2WD shortbed missing drivetrain (was 360/T-18)

The first two trucks I have owned since 1989 and have been completely restored... The third only needed paint. The fourth was one too nice for me to leave in a Colorado junkyard. None have any rust and I am in SE Wisconsin where everything rots.

I also have four or so of the "dentside" trucks as well. One of them is used for winter use as it is a rusty 79F250 4x4 with a rebuilt 400, C6, married 205, and 3.54 trac-loc'd D60's in the front and rear. The others are basically rusty parts trucks.

Anyways, I am seriously considering a 6BT swap into the '79 F250 4WD and am looking for advice. 9MPG with a trailer really sucks. Best unloaded ever was 11MPG. I prefer an automatic for easier snowplowing, as well as the smoother torque application to the drivelines, U-joints, axles, etc... I do prefer a 727 over a C6 though. I have rebuilt several 727's for local drag racers and a couple C-6's for other's trucks. Remember, I converted the 69 F250 4WD of mine to a Chrysler 440 and the conversion looks like it was made to fit. Zero issues whatsoever. However, the price of fuel has tripled since making another 440 Chrysler transplant ( this time into my 79F250 4WD) not so interesting...

I have learned that some Dodge 727's in 4WD applications uses 23 splines ( I have one) and later years a higher count. I also know my married 205 has 31 spline input... That brings me to some questions:

1.) Any ideas on an easy method of combining an automatic trans (that fits onto the back of a Cummins without one-off adapters) onto my 31-spline married 205?
2.) Are the "flywheel housings" (the trans adapters, not the clutch housings) interchangeable between the 4BT and 6BT?
3.) Are the flywheels interchangeable between the 4BT and 6BT?
4.) Are the starters interchangeable between the 4BT and 6BT?
5.) Anyone have or know of an available 727 with the diesel bellhousing?
6.) Anyone have or know of an available 6BT to dodge automatc flywheel housing and flywheel and converter, and...?
7.) Is it possible, and if so, what is required to fit a C-6 behind a 6BT?


I also am considering transplanting a 4BT into my daily driver 69F100. It typically runs around empty (4040#) at 15-18MPG , but I do occasionally I pull a 7000#GVW car trailer with it (12MPG@75MPH). I think the stock 1984 2V 302 in there now is only around 140HP.

This thread really has the gears in my head turning. A friend has three 105HP 4BT's that are cores. At least two were in stick-shift Ford bread trucks as the ford small-block flywheel housing indicates. I probably could make one good engine out of the three. That brings up another set of questions:
1.) What is a fair core price for a non-running 4BT that is complete?
2.) What about just the long block assembly (no turbo, inj. pump, or other accessories)?
3.) Would the T-18 live behind a 4BT at ~150HP? What about ~200HP?
4.) If not, would a NP435?
5.) Would the 2.75 ratio 28 spline 9" rear axle survive? It does give me about 2000RPM at 60MPH.

[mljjones67]

Look what popped up today Here.
http://www.ksl.com/index.php?nid=218&ad ... cat=&lpid=

[averagef250]

Art, I think every one of your questions has been answered if you read through this thread.

Price questions are all very relative. These engines are in such high demand right now that finding one in useable shape for under a couple grand is a good deal any way you slice it.

You don't really rebuild these engines. I mean, you fix what's broken and put it back in service. If it needs a head, you replace the head, if it needs bearings, you do bearings. Rings, injectors, injection pump, etc. If you do everything yourself you could do everything for $1K-$2K depending on what it needs.

If you bring it to Cummins and have them go through it you might as well go buy a new powerstroke and be ahead in the end.