I am looking at buying a used dump truck. Found one that appears great. It has a 18k front, 44k rear, double frame, new bed, new tires, m11 cummins, 8LL, and around 500k miles. Everything seems perfect about the truck except it is moderate to heavy blowby. It has goes oil pressure (26 at idle and 41 when running both at 180 degrees) but I wonder how concerned about the blowby I should be. The price is good but not if i have to drop 10-15k on rebuilding a motor. Any advice?
18K front axle seems light to me?
I have looked (online) at over a hundred in 300 miles of me and 90% have 12k fronts. I know I want more than that but this 18 is the heaviest I have seen.
It sounds like it was atleast spec'ed to be a dump truck and not a converted highway tractor. Depends on how bad the blowby really is hard to say from just words on the internet.
May be a good candidate for a drop axle. You never know, could be one bad cylnder, could be all of them just normal wear, could be just some stuck rings that need to be driven hard and put away wet a couple times to get them working right. You could pay to have the engine borescoped, see if there's any obvious issues in the liners?
Most of the Cummins line runs a lot of blowby. I've seen plenty of the L10 and M11 engines puffing pretty hard for quite a long time. Cummins has a test that measures crankcase pressure that will give you a good idea of how much time you have left before tear down. If the vapor is fouling the area around where the opening is the engine is likely on borrowed time. It is not a big deal to in frame depending the pollution stuff that might be hanging on the sides and top. Judging from the engine model and transmission the 18K front ends seems a bit heavy from what I'm used to seeing. I seem to recall those being under some bigger horsepower engines.
I have saw m11s have a lot of blowby to the point were the hose were lengthend to keep oil that ranout from geting on every thing. Other than it looked bad it ran good was used every day then retired to be used on a farm hauling grain.
This sounds to me like a factory made vocational truck. 18k front axle will get you bigger brakes and dual power steering for alot less road walk. 44k rears are a little old school, most everything I have seen lately is 46k. I hope it has a Hendrickson suspension. John C. and Old Doug are right on about those series motors, if it carries good oil pressure and starts easy when cold without alot of white smoke, forget the blowby. I worked on lots of L-10's and M-11's and for whatever reason blowby was just a quirk they seemed to have. I have made the extended length hoses like Doug mentioned to clean up a drooler
Around here dump trucks are just always nose heavy, but then this state in it's infinite wisdom only allows you 34,000 on a set of tandems? We end up with 22K front axles and 12.00 steer tires for a solo, lol.
Thanks for the replies guys. I pulled the trigger and the truck is being shipped to me this weekend. I talked to my mechanic and he echoed your comments that it is fairly common on the M11 and not to be too worried if the oil pressure is good. Worst case if I needed to do an inframe he said he could do it for 7-8k which really isn't a deal breaker considering the price of the truck and the fact that if I did it I would have a new motor. I was wrong on the axles. They are actually heavier than I thought. 20k front and 46k rears. In Texas I am limited to 54k gross with 20k on the front and 34k on the back so my axles are plenty good with the weights I can legally carry. The suspension is chalmers and the tranny is a 8LL. I am pretty excited about it.
That'll do. It isn't so much the front axle you worry about it's the springs and hangers, the lighter setups when you're bouncing across job sites with a load on they'll pop main leaf eyes and break the spring hangers. You should be fine with that setup, and hell it's so pretty I'd drive it, LOL :notworthy
Nice truck! It looks like you have room for a air lift axle. Where I used to work we ran air axles even though our trucks were too short to legally benefit from it. Owners wanted those extra brakes to drag the truck down in those seemingly daily competitions with dumb car drivers, just a thought.