1986 Mack DM 685S Restoration HELP!

[Freightrain]

Lots of freight lines used 237 to run the road so it will get the job done.  Not quick, but reliable.  Friend ran asphalt for years with a tandem R with a 237.  Made him lots of money.  No comparison to 600 hp of todays trucks, but no payment each month!

 

As for shredding the 13 spd?  Keep the rpms up.  My old triplex doesn't like the 237 either but I shift at 1500 rpm and it doesn't bang on the gearsets.

Edited June 23, 2022 by Freightrain

[67RModel]

2 minutes ago, Burmy said:

How quick will the motor shred the trans? 200K miles 50K miles?

Who really knows. Here we are talking about how the truck might or certainly will wipe out the transmission but it might not either. Something might give up before that. Like you said. Just run it as is until it needs fixed than have a plan already in place for when it does go.....

[Burmy]

On 6/22/2022 at 2:48 AM, blackdog2 said:

That engine is a 1974 it is not recommend to increase HP if it was mid 80's then yes with push in freeze plug's not screwed in ... 

How does my 86 DM have a 1974 motor in it ha? I was thinking the 1974 was the emission compliance like it says in the picture below. But then it does say date of mfg. does MFG mean manufactured ?

[MACKS]

55 minutes ago, Burmy said:

Yes agree, it is weird a lot of the trucks i'v driven don't come with EGT gauge from factory. 

 by big balls do you mean torque? it seemed to get up to speed quick but going up a hill empty it seemed to want to lug down. So i'm just wondering how it will do loaded doing 55mph up a hill. I'm not worried about its capabilities off-road at the jobsite. 

That engine has all the power in the lower rpm range all the way down to 1200,that’s when they really pull,1200 to 1400..

[67RModel]

4 minutes ago, Freightrain said:

Friend ran asphalt for years with a tandem R with a 237.  Made him lots of money.  No comparison to 600 hp of todays trucks, but no payment each month!

My '94 RD triaxle dump is a 250hp mechanical E7 with a T2070 trans and she is slow but insanely reliable and economical to run. I get my doors blow off by just about everything but I couldn't care less since I get paid hourly and don't have to work to make a payment. 

[Burmy]

On 6/22/2022 at 3:24 AM, Dirtymilkman said:

Another "Manders Special"   Everything they sell is pieced together. Getting parts for a truck you buy from them is a nightmare. You usually use your Vin number for parts, on a Manders Special, everything is mismatched and the Vin is worthless in identifying anything. You want a twin stick 6 speed in that truck or a 5 speed. 

I am starting to see just how pieced together this truck is! It is leaving a very sour taste in my mouth! I do not like the thought of a twin stick they get annoying to run after awhile haha. probably because they are before my time, and I am not good at shifting them !!

[67RModel]

4 minutes ago, Burmy said:

How does my 86 DM have a 1974 motor in it ha? I was thinking the 1974 was the emission compliance like it says in the picture below. But then it does say date of mfg. does MFG mean manufactured ?

Yes on MFG = Manufactured. Original engine gave up the ghost at some point and someone had that one laying around. Their problem was solved. 

[Burmy]

50 minutes ago, blackdog2 said:

Mack trans will take 1800 lbs torque ......12-14 is the torque of fuller ?......being in a dump truck it will be work hard ?

yes it will be worked hard. off-road and over loaded often! See the picture of our RD, that is what this DM will be doing!

[Burmy]

23 minutes ago, mowerman said:

Yes my opinion are used to run up 237 you are not going to be happy with her if you’re doing any kind of highway work i’m trying to figure out how an 86 still has a 237 it should be 02 85 or 300+ good luck take it back and tell him you want your money… Bob

I told that to Joe, that I probably wouldn't of purchased the truck if I knew it was a 235hp and he never responded back. 

[Burmy]

23 minutes ago, 67RModel said:

Yes they are torque monsters given their displacement but as you know low on horsepower so you wont be breaking any speed records and hills at highway speeds will slow you down noticeably. That is just the physics of moving 70-80,000 pounds with 235 horsepower. However, you can lug this engine down to around 1100 - 1200 rpm and let it pull there without any adverse affects.

Ok, I did notice right off the crack the engine idles much lower then our E7 RD 

[MACKS]

On 6/22/2022 at 4:32 AM, blackdog2 said:

Check trans to see if it is 12513 or 14513 if 12 the little Mack will tear it up ?

 

He needs a triple counter shaft transmission like a 5 or 6 or 12 speed,not sure what other trans has triple countershaft..

[Burmy]

22 minutes ago, Freightrain said:

Lots of freight lines used 237 to run the road so it will get the job done.  Not quick, but reliable.  Friend ran asphalt for years with a tandem R with a 237.  Made him lots of money.  No comparison to 600 hp of todays trucks, but no payment each month!

 

As for shredding the 13 spd?  Keep the rpms up.  My old triplex doesn't like the 237 either but I shift at 1500 rpm and it doesn't bang on the gearsets.

are the 285's just as reliable the ENDT 676? I'm ok with not quick, I just don't want to be going 10 mph up a hill haha. I totally agree with the no payments!! No payments is way cooler to me then a $100K financed truck!

[Burmy]

41 minutes ago, 67RModel said:

Who really knows. Here we are talking about how the truck might or certainly will wipe out the transmission but it might not either. Something might give up before that. Like you said. Just run it as is until it needs fixed than have a plan already in place for when it does go.....

Is there an 18 speed that can handle this kind of motor? the motor I would love to have in it is a 2 valve 285hp with a large fuel pump to get it up to 300hp - 350 hp. I think I want to stay with the E6 motor just for the old school feel/ sound.... DO YOU THINK ITS WORTH KEEPING IT THEN AND RUNNING IT FOR NOW AND SLOWY FIX IT UP AND REPLACE THINGS AS NEEDED OR DO YOU THINK I SHOULD SEND IT DOWN THE ROAD AND WAIT FOR A DM 886 WITH A 285 MOTOR? WHICH WILL BE MORE IN THE $20k - $25k.

34 minutes ago, 67RModel said:

My '94 RD triaxle dump is a 250hp mechanical E7 with a T2070 trans and she is slow but insanely reliable and economical to run. I get my doors blow off by just about everything but I couldn't care less since I get paid hourly and don't have to work to make a payment. 

yes they are insanely reliable and can take a lot of abuse! which is why I'm a little nervous to send the RD down the road and have this DM take its place, I don't want the DM to be a problem child. Keeping both isn't an option because one will be sitting way to much and become a mouse heaven!

32 minutes ago, 67RModel said:

Yes on MFG = Manufactured. Original engine gave up the ghost at some point and someone had that one laying around. Their problem was solved. 

and my problem begins!

Edited June 23, 2022 by Burmy

[Burmy]

14 minutes ago, MACKS said:

He needs a triple counter shaft transmission like a 5 or 6 or 12 speed,not sure what other trans has triple countershaft..

I could settle for a 12 speed would love to put a 18 speed in it someday (if it can handle the motor or the 285hp motor down the road)

[terry]

1 hour ago, Burmy said:

I could settle for a 12 speed would love to put a 18 speed in it someday (if it can handle the motor or the 285hp motor down the road)

I have seen plenty of 18 speed fullers behind 460 mack engines, should be a piece of cake behind a 285.    terry

[mrsmackpaul]

Well my 20 cents worth of useless advice

 

Dont be to hard on old ,ate flogged the truck to you, any truck over about 10 years of age wont be original and will be changed quite a lot to suit what you want 

 

So keeping this in mind I would start collecting bits and pieces to make it into what I want it to be 

Keep using it until it goes KAPUT then start chucking your stuff into make it what you want 

 

Also some advice from a fellow truck driver at Springsure in QLD Australia one day, was about to head off in my 320 hp Mack pulling a road train, up around a 100 ton (220,000 pound) heading south to Roma and have to climb Carnarvon Gorge, now this is really really steep and has bought plenty of trucks undone, it has "caution trucks must use low gear" signs for climbing the hill, only place I have ever seen this for climbing a hill

Anyway this truck driver says to "dont worry lad, plenty of blokes have climbed that with a lot less power pulling more weight than you have" 

Moral to the story is you have plenty of power for anything you will ever want and unless your running coast to coast that extra power isnt gunna make much difference to your day, slow and steady and enjoy the view 

 

Paul

 

 Top photo was a late model KW that electronics had gone KAPUT on Carnarvon Gorge and couldn't lift off (wheel spininning on dry hard bitumen) 

Bottom photo is after I over took him stopped there, had to split up his road train and pull a trailer up at a time 

Guessing he was a 600 hp monster, horse power only gets you so far 

[Dirtymilkman]

Here you go. 

https://minneapolis.craigslist.org/dak/ctd/d/eyota-1984-mack-dm686s-tri-axle-dump/7495814182.html

[mowerman]

On 6/23/2022 at 1:44 PM, Burmy said:

are the 285's just as reliable the ENDT 676? I'm ok with not quick, I just don't want to be going 10 mph up a hill haha. I totally agree with the no payments!! No payments is way cooler to me then a $100K financed truck!

And that’s no  bullshit I  are used to do 12 miles an hour up the grapevine with loaded doubles I hated that engine like freight train says it’s OK if you’re running around locally they seem to do a real well till  you hit fifth Gear then they fall in their face It’s really weird it’s doing a fine job till it gets to high gear the engine  seems to lose half its power bob

Edited June 25, 2022 by mowerman
Misspelled

[mowerman]

9 hours ago, Dirtymilkman said:

Here you go. 

https://minneapolis.craigslist.org/dak/ctd/d/eyota-1984-mack-dm686s-tri-axle-dump/7495814182.html

Man that’s a pretty good price … Bob

[Freightrain]

On 6/25/2022 at 12:35 PM, Dirtymilkman said:

Here you go. 

https://minneapolis.craigslist.org/dak/ctd/d/eyota-1984-mack-dm686s-tri-axle-dump/7495814182.html

Single stick 6 spd?   Looks like a 12 spd handle.   

[mack86]

I have a 1981 r685 thats 237 with 6speed single stick its air shift for lo hole and reverse ownd sinse 1992

[Freightrain]

Didn't realize they used that same handle for multiple transmissions.

[Burmy]

On 6/25/2022 at 2:50 PM, mowerman said:

And that’s no  bullshit I  are used to do 12 miles an hour up the grapevine with loaded doubles I hated that engine like freight train says it’s OK if you’re running around locally they seem to do a real well till  you hit fifth Gear then they fall in their face It’s really weird it’s doing a fine job till it gets to high gear the engine  seems to lose half its power bob

Ya that's what I don't want. I was thinking with the 285hp motor, turn it up to 300/ 350, with a 18 speed tranny, 24.5" tires with 4.17 rears I could hit the bottom of the hill with enough speed and momentum and split gears on the way up keeping the rpms higher and not loose to much speed before getting to the top. 

[Burmy]

On 6/25/2022 at 11:35 AM, Dirtymilkman said:

Here you go. 

https://minneapolis.craigslist.org/dak/ctd/d/eyota-1984-mack-dm686s-tri-axle-dump/7495814182.html

I wish I woulda found that truck first ha! If that has a 300 motor, is it a ENDT or a E6. Don't ENDT's only go up to 285hp from factory? I would want to change the tranny on that truck and get rid of the front pizza cutter steers, those tires will sink on most of my jobsites! 

[mowerman]

Yes 50 hp is a big difference… Bob