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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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Well I won’t lie, I could spend that much on trailer tires about any time. So it’s not like I just need to blow the money. Lol

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I have some questions

What 18" steering wheel did you use and do you have a picture

What insulation do you go with and how much of the cab did you do.

Do you have any pictures of your hood mounts and rollers?

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The steering wheel is an sci brand called classic polyurethane steering wheel. I got it from Raneys and I think it was the cheapest one. 

The insulation, I bought off Amazon. After some research. The first layer is a sound deadener. Something like hushmat and dynamat. I put it on every surface I could in the cab. (It’s an adhesive back) Inside the door skins. On the floor and up the firewall as far as possible. Even the bottom side of the floor pan. Up the back cab wall to the bottom of the window. The entire cab roof. Second layer was a adhesive backed 8mm thick foam. Stuck it right over the sound deadening material. Third layer was thermal insulation foam with a foil back. Then on the floor and up the firewall I layed in the factory floor mat and a layer of mass loaded vinyl for a little extra sound resistance. Put the foil back under side of the hood and outside on the firewall as much as possible.

The hood rest set was off a doner  truck. The rollers were gone but I was able to make some peterbilt replacement rollers work on my mounts/rests. The Pete rollers were like 6 bucks each. It took a little trimming and trial and error fitting but it all worked out. 

A8E61787-BE60-4CD5-81CB-E8539B0A6AC9.jpeg

5D6B21B6-ED77-42B0-8197-8B7A93BCD7C9.jpeg

427CEA2A-7644-4161-8F21-AAF0BCDA58ED.jpeg

D48C4A3F-9E84-4C1C-B20D-FE701FF5FB8D.jpeg

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That’s clever and funny. Lol

i did order an adapter for the 1” shaft when I ordered the wheel. I probably should have said that 

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There is a cup or whatever on the top of the column under the wheel that’s held by a single Phillips screw. I should mention that on my particular truck I had to trim or grind or machine about 1/8” off the top of that cup before the new steering wheel hub adapter would clear without rubbing a little 

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Posted (edited)

Just an FYI, I put jakes on my 237.  Waste of money?  Likely for all I do with it.  BUT...I'm pleasantly surprised on how well it actually works.  For even my little 30K lb truck, it does hold it well on hills.  I was over in PA the other weekend and they have this brutal hill over by Milroy.  It held my speed without having to touch the brakes.


I'm sure if you have 80K lbs it isn't so great.  Better then nothing I suppose.   Major parts are hard to come by and pretty costly too.  I needed one lash cap(for the early large stem valve).  NLA from Mack, I posted on FB and a guy send me one for free.  Ever so grateful for FB at times like that.  Basic rebuild kits aren't bad, but if you need big pieces,  Ouch.  It was a simple bolt on.


The whole problem with Mack is the small cubic inch and lower compression then a Cat/Cummins.  That takes away from the effectiveness of a Jake.  Mine shows 5# of boost on the gauge while working.  The lil 237 only makes 15+ lbs under load.

Edited by Freightrain

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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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