Geoff Weeks

Its been a coupla months now. I can't get the correct liners to fit this block, too big around, too tall but listed for this engine. I found a N.O.S. block with liners already installed, 1st arrive cracked, dropped at the factory! Inside a factory sealed box, no damage to the double wall box, but the casting was deformed and cracked. 2nd one arrived in good shape. This is one of those things where you can see the obvious failure, but not the "hidden" failures that lead up to it. The engine failed due to improper assembly, the gasket protruded into the bore, and the piston hit the gasket and shattered. What wasn't obvious until complete tear-down, was he didn't replace the front crank bushing when he installed a -.2mm reground crank, and he didn't remove the timing gear off the crank and forced it though the bushing damaging it. He also "lost" a couple of springs in the gov assemble and tried to shorten the remaining one! So even if could have got the liner in, I would still have had an engine with major problems, low oil pressure and a governor that wouldn't hold the engine speed correctly or might even overspeed. All the "hidden" problems showed when I stripped the original block and started building the replacement. I'll end up with a unit that cost me about what I could have paid for a running unit from a rental house, but I'll have essentially a "new" engine that should outlast me. A cautionary tale about buying un proved things at auction.

The tip turbine and Low Flow cooling were both attempts to better charge cooling without have to re design the front of the truck for enough room for an CAC cooling radiator (Air to air). once trucks were being redesigned anyway, the reasons for the tip turbine and low flow systems went away. Having the charge cooler in front of the radiator give the best cooling, and what has become the std today. At the time, Mack tip turbine was revolutionary, both Cat and Cummins were still using water cooled aftercoolers, and low thermostat temps, to walk the fine line between good block temp and enough cooling for the charge air. After Macks success, Cummins used the low flow system to run the "super cooled" multi-pass radiator coolant through the aftercooler, before sending it the engine. Cat never did and opted for the cooler in front of the radiator, which meant that their engines above 400 hp could not be fitted to many trucks. Cat engines below 400 hp still had the old water cooled aftercooler.

Spicer's sales pitch was "0 to top speed with only 5 stick movements". 14,16, or 20 possible selections.

Where you have to be careful is in the lower gears, that applies to any transmission, it the higher ranges it isn't going to damage something as easily. I would shy away from double overdrives, with the one exception of the RTLO's. 1st there is too much wasted in gearing up and back down, all that goes into heat. 2nd there is the driveshaft issue, have to do the math and make sure you are staying away from critical speed at all and 1/2 true critical at cruise. The RTLO's are really a single overdrive front box with an underdrive splitter, where one stick position down is direct, and top gear is something like .76??? in the front, and when the splitter is in 12th is something like .86. Not a true "double over" where there are two gearsets over driveing the input to a faster output. It is all in how it is plumbed in the trans that makes it seamless, kind of like when the went to the Xbar top cover on the RTO's you can't tell by the shift pattern if it is an RTO or an RT

In my book a 15 is a 12 anyway, and it is a transmission looking for a reason to be. I can see why fleets would spec them as it are a little more "idiot proof" than a 13 or 18. For me if I need the deep bottom end, I would choose 2 spd axles over an 18. 18 has the 15 beat any way you look at it, but in the wrong hands can get expensive quick I have a RTO 14615 in the Marmon, and the only reason it is still there is I retired before I could swap it out. Run what you came with until you have the money and time to change, but when you make the change, make it for the best possible spec's for how you are going to use it, or save your money. Just because it may be slightly better is not reason to jump from one compromise to another. The difference in cost when buying a 10 vs. a 13 or 18 on the used market is going to be a few hundred, but you still have all the costs of the bell, mounts and clutch over what you have now. I would sit tight with what I had and wait until the ideal set-up can be had. Do the Math! crunch all the numbers, startability, top speed, cruising speed RPM, jumps between gears etc.

I think grain trailers can be either full trailer like you posted or pup with convertor dolly. One things for sure, you'll not be backing that out 1/4 mile at speed unless you are a whole lot better than I. I did know someone who could and did back 80' stretch trailer with pipe at 25-30 mph for a long while. Too much to go wrong quickly for me to try it. Same guy also backed a boiler and jeep into a garage in one go, I can do it, but not in one shot.

I wouldn't have a 15 in anything if I had a say. I have one in my Marmon and hate it. If gearing for slow RPM at high road speed, steps between gears are critical to having something that works well. If using an Eaton, then look are rear gearing and transmission as a package. What you choose in the axle will effect if you want a RTO or an RTLO 13 or 18 My use was different than your, a lot more weight and wind resistance, but also a lot more displacement at power (ATA 3406). Being able to drop a gear and gain ~250 rpm vs ~400 rpm is the difference between a 13 and 15. I know right now you are thinking "I'm going up in HP I will not need to drop a gear" but there will be times you will and going to 1650-1700 is a lot better than 1900! I still say what you have will handle what you are putting through it, I wouldn't put a driver in it, but driving it yourself it would take it just fine.

That is only true for engine that use a rocker to work the injector. Engines with an injection pump (mech Cat and Mack) there isn't the rocker to trip the the exh valve at injection. So on those they have to use a valve on an adjacent cyl to trip and the timing isn't exactly right. It is why a mechanical Cat's Jake isn't as good as one on a Cummins. Once mfg went to electronic common rail with the cam pushing the injector and the electronics adjusting timing an duration, Jakes matched those of Cummins. 2 stroke Detroits had there own problems, keeping a Jake on those limited.

Yeah, my "education" was decades ago, but I still remember that today.

Caught me out the 1st time I ran the overhead on a Mack. Couldn't figure out what I did wrong! Once learned never forgot.

Start by breaking the system in 1/2. Test at the 7 pin plug to determine if it is a truck or trailer problem.

3/4" breaker bar and cheater pipe are my go-to for stuff like that. Cheap to replace if something lets go. I have a torque multiplier for going back together.

Drop in a N-14 or a Big Cam 4 444 and that would make a sweet heavy haul rig, even on walking beam.

I wonder what its original vocation was? 1st thought was "turnpike doubles" but not with that wheel-base. Daycab cabover with V8 must have done something that required that? Day cab cabovers don't shorten things very much from a single bunk sleeper, and having the sleeper is nice. So back to the 1st question.

4 people in a U model cab must have been crowded! Hope there wasn't too many shifts required.