m5040

With fuel prices and road speed considerations, how hard is it to find the single axle 117 differential with the high speed 3.71:1 ratio and what are they worth?

I have a EM6 300 with over 500k on it that I know of. When I lug it down to 1100 rpms, the oil pressue is maybe 30psi. Has anyone used straight weight oil (like 30w) in their engines? I live in CT but don't use it after November. The straight weight oils really keep the 2cycle Detroits together.

I had my 84 EM6275 changed to a 300 by a old time Mack mechanic, he said he put "bridges" on the main bearing caps.

Ok, I will keep it in mind, I am leaning toward 11 leaves and looking around locally. Thanks for looking.

Connecticut, kinda heavy to ship I would guess

My 84 R model single axle just broke a rear leave and it only had 7 in main and 10 in helper (was a jiff lock truck). Seems like most dumps have at lease 9 or 11 leaves in the main. The spring shops rate the 9 and 11 springs as 23,000 lb. Can anyone shed light on what the difference is since they are rated with the same weight capacity? They also make a 11 leaf HD with 27K capacity. But I am kinda looking for a used set (and wont be able to tell 11 standard or 11 HD).

Maybe everone knows about this, but if you take a nylon wire tie and strap it onto the airchamber push rod and tighten it so the long end is in line with the airchamber face, it will indicate the brake stroke when brakes are set/applied. This allows for a quick visual on how good your brake adj is. A normal 30 can has a 2" usable stroke. When the parking brake is set, you should see far less then 2" between the wire tie and the airchamber face. A fresh adjustment is about 1/2 to 3/4"..... Keep um safe

Same here, don't have permission

It is my belief that the R models that have the air to air aftercooler in front of the radiator are the better ones. You can usually tell this in the pictures that show the grill. Once you see the two together you will be able to pick it out easily.

My last truck had a Jake brake. I liked the way you could shift faster when double clutching with the jake, how it would kinda burp and help quickly match the speed for a gear change. Now my truck has a dynatard and it has no clutch switch. It seems that I could try and feather the accelerator pedal to do somewhat the same thing. Any advise on the best way to use the dynatard when shifting, or should I just install a clutch switch like the jake?

What is the min oil pressure before you have to start to worry? I was at a tractor show and a guy was telling me how the 6cyl Mack engines would starve #5 main bearing when the oil pressure starts to get low from a worn engine...... then as I am driving around in my EM6-275 in aw on how much torque it has at 1,100,,,1,000.....900 rpms that I mentally made a connection on what he was telling me about. High torque potential at those low revs when the pressure drops off. Now I am wondering how much truth there is in that statment? My gauge reads about 33psi at 800rpms and doesn't increase until you bring it up to about 1,100 rpm (hot). {and where did the little checkbox go that you could click to e-mail you when somebody responded to your post?}

I have a EM6-275 and had the oil pan off. It did not come with the main bearing steel "bridges" like the 300 has. I installed a set since I had the pan off. This makes me think there is more to the 300 then just the pump/injectors.

The paper elements are basicly for the efficiency, they are like 99% compared to 80% for oilbath. So with the oil bath, 20% of the grit is getting into your engine's cylinder and wearing the rings. Not good for power. Otherwise, genericly speaking, the higher the horsepower engine, the more CFM it needs and the larger the aircleaner. If you notice some of the over the road tractors have dual outside aircleaners, like for the old KTA600 Cummins. So if you find a filter with a larger diameter outlet, or rated for a higher HP engine, you might get a little extra HP from better air flow. Oh and the 80% efficiency, is only at high RPM. At idle and low r's, it lets more dirt through. This is because the low airflow is not splashing the oil up onto the wire mesh inside the filter.