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Discussion Starter · #1 ·
I would first like to thank everyone who gives out advice on this forum. This project would have never happened for me without you guys. I don't have many post but I think I have read every post in both the main and buildup forums. Almost every question I had was answered by someone elses thread.

My 4bt came out of a 1985 f350 breadvan that I bought locally. It is now in a 1989 2wd f150 with 3.08 rear 29" tires and a borg warner 4 speed transmission. My goal is too get the best Mileage possible. I will probabally trade the tranny for a mazda 5speed OD from a similar year f150.

This was a pretty simple swap (with your help). I would say that they probabally dontget much easier than this. I did have to make new motor mounts though. They were easy too but it took some time.

I drove 2 miles and got up too 55 mph which is about 2000 rpm. The 4bt had pleanty of power through each gear. I still need to hook up the alternator, cooling fan, and gauges. So far the swap has taken about 25 hoursof labor over a weeks time. It would take far less time if I did it again.

I would like to especially thank 4bt4me, averagef250, dieselcruiserhead, mcinfantry, driverswanted, and paul. Your posts were very helpful.

Thanks

Cornfeed
 

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Congrats! How does it feel with how your setup, better than stock I bet... Any pics?
 

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Cornfeed

Please post specs. I am about to do this swap hopefully and I have the same year Bronco. I need to see how that thing is looking.

By the way Congrats.

Patrick
 

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Congrats

Congrats on getting the swap done!! Let us know how you like it and how it does.

I was wondering what you did for motor mounts. Did you fab a set or did you find them from somewhere?
 

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Great to hear it's going! What engine did the truck have previously? I ask because I think the 4BT with mounts from a Ford van chassis bolts right into any 1980 or newer 300/4.9 six frame stands. The Mazda tranny or the ZF will work great for you. I'd say whichever one you find for cheap. Keep us posted!
 

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Best rpms for best MPG?

"My goal is too get the best Mileage possible. I will probabally trade the tranny for a mazda 5speed OD from a similar year f150."

I was wondering what is generally considered to be the best cruise rpm range for these 4bt engines? If the goal is highest MPG in a 4000-4500 lb pickup?

Will a 4bt in good condition cruise at 1200 rpm? 1500? more ? less?

What can this guy expect for fuel mileage at the ideal gearing/rpms?

Thanks
 

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I bet he could do high 20's freeway. I don't think lugging the engine will get the best MPG. Keep it in it's sweet spot where it's happy. Skinny tires at the right pressure, good alignment, etc. help a good bit too.
 

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I bet he could do high 20's freeway. I don't think lugging the engine will get the best MPG. Keep it in it's sweet spot where it's happy. Skinny tires at the right pressure, good alignment, etc. help a good bit too.
With O/d I bet, 30's saying I consistantly pull 30's and thats spinning 33's or 35" tires...
 

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"My goal is too get the best Mileage possible. I will probabally trade the tranny for a mazda 5speed OD from a similar year f150."

I was wondering what is generally considered to be the best cruise rpm range for these 4bt engines? If the goal is highest MPG in a 4000-4500 lb pickup?

Will a 4bt in good condition cruise at 1200 rpm? 1500? more ? less?

What can this guy expect for fuel mileage at the ideal gearing/rpms?

Thanks
Somewhere in the 1800-2200 rpm range.
 

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Discussion Starter · #11 ·
I havent gotten any fuel mileage numbers yet. I am having trouble getting fuel into my tank. I swapped the fuel tank over from the breadvan because it is twice the size but the filler spout dosen't line up very well so I have to pour fuel in very slow. I will probabally just switch back to the original tank.

I have only driven 2 miles so far but I do feel that I have more power than I did with the original 300 six cylinder gas engine.

I used the motor mounts that came with the breadvan. I did have to change the frame stands to accept the mounts. I have pictures of these that I will post as soon as I can figure out how to get the pictures from my phone to the computer. I thought that the 4bt might bolt right in since the breadvan originally had the same engine as my 89 f150. I was looking at an 86 f150 with a 300 six, and I think that my 4bt would bolt right in to that vehicle. That would make for a very easy swap.

Averagef250, Will the mazda 5speed OD tranny interchange with my borg warner 4 speed without changing driveshaft length? Do you know if the speedometer cables are the same? I was hoping to trade my 300 engine for the mazda tranny. What should I look for when buying this transmission?
Thanks for your help.
 

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I would empty your old tank and use it. If you have to plumb it for a bigger line it is not a big deal. In fact I would regardless and make sure you get a return line in it also. If you search member bgilbert on the Diesel Truck Resource he has a big line fuel system write up and pictures in his gallery. Simple and effective and plenty of fuel delivery for even a high HP rig. Fuel lubricates these VE rotary injection pumps, I don't think a fuel system upgrade like big line plumbing is a waste of time even for a 105 hp engine.

I have a spare plastic tank assy. off a 92 D250 Diesel truck if you want it. I am only a couple hrs from you I think. You would have to figure something out for a gauge though, it's a pcm control fuel gauge sytem, it would likely work with a more electrically inclined individual than myself...
 

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I'd like to see how you had to modify the mounts. Ford frame stands are the same in all 1980 and up E and F series trucks with the 300 six 2wd and 4x4. I've never had to modify them for the cummins, just loosen the engine side mounts on the block to get the lower stud in then retighten after it slips in.

The T-19 is a lot different from the M5R2. The Mazda is a lot longer and uses a slip yoke. The shifter is 3" or so further back and the tranny mount is in a different spot, but the same rubber mount works.

The Mazda trannies have a very bad leaking habit from 3 rubber plugs at the rear of the top shift plate. If they get even a pint low the pocket bearing and thrust die quickly. The fix is 3 dorman 5/8" steel plugs #555-108. Check a used one to make sure it was run on ATF. Gear oil is instant death for one of these. There's a magnet in the drain plug. Check it for pieces of bearing cage, under a teaspoon of shavings is fine. You'll want to find the 88-91 M5R2 as it has a mechanical speedo. Your T-19 speedo cable will slip right in. If you find a '92 and newer M5R2 you can't put a speedo cable in it, but they do have a far better 5th and reverse synchro assembly than the earlier tranny that might be worth swapping in if you have the opportunity. Wiggle the input shaft. a little side to side is fine, these trannies like about .005" end clearance, but if you can "clunk" the input around it has bearing or other issues. If you're so inclined, pull the top shift cover off and check the synchro clearances. Push the synchros one at a time squarely against thier respective hub. Bad Mazda synchros will have less than .030" showing between the synchro teeth and the gear face. Good ones are .040"-.060". You can usually eyeball them.

The Mazda units are pretty solid, actually impressive as to what they can handle if you keep them full or a little overfull of dexron 3. The M5R2 in my '71 has 390K miles on it from an '89 F-150 4x4. I drove the truck to the shop 20 miles with no 3rd or 4th synchros. The pocket bearing and thrust were trashed and it was filled with gear oil. $10 in the two bearings, $20 in synchros and regrinding the mainshaft thrust surface in the lathe and it's good to go for a good while longer.

Another place to find an M5R2 is from a T-bird super coupe. The supercharged V6 cars run a special M5R2 believe it or not as an upgrade from the T-5. The T-bird trannies need the truck top plate and shifter to work in a truck though.
 

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Congratulations Cornfeed! Glad you got that same feeling we all get when we get'em running. Glad I could pay back. The internet really is a wonderful invention that gives us such power to learn.
 

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Discussion Starter · #16 ·
I have driven my f150 about 30 miles so far. I am very pleased with the power and surprised by the noise. It is not loud at all in my opinion and I don't even have a muffler on yet. I was also happy with the lack of vibrations. The shifter knob shakes just a little bit at low RPM.

Today I swapped over the alternator from the gasser to the 4bt. I did this so I wouldn't have to change the ends on my wiring harness. I had th hack the alternator mounts a little too make it fit but it works good now. I also hooked up the stock oil pressure and coolant temp gauges. Now all my gauges work except for my tach. I am unsure if my fuel gauge is reading right but I am confident that it will work when I switch back to the original tank.

Average250
Thanks for the advice on the Mazda tranny. Does it use the same clutch slave as my T19?
The motor mounts on my 4.9 gasser came almost straight out from each side of the block and the studs pointed almost straight down. The mounts on my 4bt had studs that pointed down at almost 45 degrees. The holes in the frame stands were in the right place but I didn't think there was enough flat surface to surface mating area to work well. I didn't think of loosening the frame stand to get the stud started as you suggested. I will post a picture of my frame stand modification soon.

Thank you all for your kind words. This is a great web site

regards

Cornfeed
 

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Sounds great!

To run the stock Ford gas tanks I cut the pressure and return lines off the engine and connect them to an automatic transmission bypass filter adapter kit. Most sellers of bypass filters make and sell these. What it'll do is bypass most of the fuel back to the tank and give the engine just a bit of pressure to take what it wants. The AT fitting return fitting works great for the diesel fuel return too.

The clutch is the same T19/M5R2. All Ford truck is the same except the newer ZF 460 and diesel manual transmissions.
 
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