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Macktruckman

Eaton behind maxidyne

Question

I have a 1978 R685ST with a 285 maxidyne and the 2 stick 6 speed with 4.17 rears and tall 24.5’s. Truck is getting a new cab this week and paint job. Old cab is rusted out badly. I have an Eaton RTO14909MLL from a wrecked mixer truck with E7, I think has mounts that will work. Now would be the time to swap transmissions if I want. I was thinking it would help lower my rpm at highway speed and give me a little more top end and maybe help me out on hills. I live in an area with lots of hills. Pull a lowboy to move my equipment and pull an end dump. I like the 2 stick but the gap from 4 to 5 is pretty big with all the hills and I can only get about 60 mph or so on flat ground to the floor tached out. Transmissions look to be within 1”-2” of each other in length. U joints different. Would it be worthwhile to swap? Since the cab is off anyway 

thank you 

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I usually see 23 lbs or there abouts in a hard pull with the 285.  Maybe 24 but I don’t think I’ve seen it make 25. One guy said he has a 350 with tip turbine making 30. 

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Boost increases with HP rating.

I had the turbo rebuilt on mine a few years ago.  I thought I had issues, but it was not actually the turbo.  For the money I just had them go through it since the motor had sat for a long time and I had little knowledge of the history.  I had thoughts of making it bigger, but left well enough alone.  Wishing I had changed it now.  I'd like to see 20# and what difference it would make.  I bumped the fuel up a few notches as it wouldn't even get to 900*.  Now it gets to about 1000*.  Needs more cool air!  (ugh, that's the hot rodder in me.  I need to leave it alone)

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800-900 is the hottest I’ve ever seen mine. I’ve been considering giving it a little bit more fuel and see if it made a power difference. I’d have to call my pump shop to see what they say and how to go about it. I have a Robert Bosch pump not the American Bosch. 

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I haven't messed mine up too bad.  Still gets 9 mpg in the hills of PA with the cruise set at 65 mph. 

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Hmm. Might be worth a little tinker. I just don’t wanna hurt anything. 

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Ya, me neither.  It's got to get my race car to everywhere I need to go.  Thus, never enough power!!!!!  LOL!!

Don't know what it takes to bump a RB pump?  The AB is just 6 screws in the lid and one nut.

I played with the original NA 673 that was in my truck.  It ran like a scalded dog after I spun the nut a few turns.  Mileage suffered horribly!!  I then ran it back down.  It was not quite so snappy, but it's only 180 hp to begin with.  Can't say I saw any major improvement when I bumped the 237.  Just a tad bit more heat, thus I figure it must be helping some.  I think I turned it 2 flats on the nut.

 

Not sure what needs to be done to make your 285 a 300?  or 300+.  Just money?  LOL!

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My picture below.....1959 B61.  I've done a ton of work over 17 yrs.

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It won’t show me a picture. I might not have the clout yet. Haven’t been a member here long. What transmission does your B have now?

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Posted (edited)

Hmmm, the signature pictures should always be available? 

The truck still runs the original Triplex.  I have a 4spd Spicer Aux behind that.  I stretched the truck about 5 yrs ago and put a 42" bunk on it.  Instead of a carrier bearing, I got a 6041 box off a friend.  Gives me a 5x3x4 with 4.10 gears.  She'll run 85 flat out.

 

Try this:

IMG-20180116-202556-655.jpg

 

Back in 2001 when I bought it:

Mvc-001s.jpg

 

My rig:

SDC10864.jpg

Edited by Freightrain

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That’s awesome. That really looks great. I’ll bet the 237 is a pretty good improvement too over the stocker. I’d love to have a b someday. When I was a kid there was one b here with a mixer drum on it and it had a quadraplex or triplex. It was amongst several R’s and one old offset cab U with a naturally aspirated engine. Nobody wanted to drive it or the b. No power. Lol. They finally made the b into a water truck and before I was big enough to ever drive it, a guy that’s a friend of mine and a few years older was driving it along the top of a tall dike of a retention pond they were building on a job and it slipped off the side and rolled over 3 or 4 times. The driver was not injured other than banged up. He wound up threaded between the shifters. He said when it all stopped, his hard hat was laying upside down with about a half a quart of oil in it. Still now he laughs and says he has no idea where that oil got into that hard hat. Lol. 

So anyway, I never got to drive a b model. That was 30 years ago. It was scrapped. The water tank was cobbled up it’s now on the old offset cab truck and it’s still here but hasn’t ran in a couple years.

I sure like your b. Nice looking little rig. 

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Thanks.  It is a long term project.  Every few years I throw money at it.  Motor, air ride, bunk, cruise control, A/C, air starter, new alum tanks.  I just put new(NOS) doors on it last winter.  It needs a transmission.  The ol Triplex is pretty beat.  It buzzes, rattles and clunks......but still gets me there.

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That’s what my r is I guess..

long term project. Is the air starter a good thing?

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Some(well most) laughed at me for doing it.  Just another "Cool thing from back in the day" I wanted to do.  I gathered up a starter, freshened it up with bearings and new nose cone bushing.  Local buddy gave me a couple steel tanks.  BMT member offered me a nice R model Alum tank(you can see it in the top picture under the bunk).  I rebuilt the valve and installed it.  Holds air all winter.  Works fine for a "toy" truck.  Gets looks when  you hit the dash button!!

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I did notice the tank and I thought it was extra fuel tank. I have never actually seen a truck with air start. Do you only need one battery now?

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I still have two in the box, but not really needed.  I already had them relatively new when I swapped it over. I stared with 4-6v with series/parallel switch when I bought the truck.  I swapped it to 12v and neg ground the next spring. I bought 4-12v batteries.  It would zing that lil 673 over.  It would start, unaided, in 19* weather!  Those batteries lasted 10 yrs.  I then put just 2 in the truck, and that is what is still there.

I joke about betting someone I can leave my lights on all night and starting it with ease(not telling them it's air start).  Haven't snookered anyone into a bet, yet.

 

Here is one of the first starts after installation:

 

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