Kav

Hi Paul - Have you checked the boost pressure of the turbo. If your pressure is low, the Puff limiter will cut back your fuel and it wont pull properly. It might pay to check the turbo numbers as I have heard of second-hand motors that were "runners" that had the 350 Turbo taken off and an old 237 turbo put in its place. The 350 motors are usually good performers as they were originally 350 at 1800 rpm, and when you run them at about 2100 rpm they go very well. They will stay with a 400 Cummins all day if they are set right.Regards - Michael.

Hi Sean, If you want to do a quick and much cheaper job, you can just take the governor housing off and replace the bearings and check the kidney weight pins- I have got this done this several times. Most pump shops will only do just that if you take the complete pump to them and will charge a lot extra. As Rob said,if you want to get the whole pump checked out and maybe re-calibrated, then the only way is to take it off and put it on a test bench.Best Regards - Michael.

Hi grant - The old FR radiator that I have here would be too high by about 3 or 4 inches to fit under the bonnet.- Michael.

Hi Grant - The radiator on the Australian FR was narrower and taller than the early R Model with about the same surface area. The FR that I had used a soldered top and bottom tanks instead of the bolted tank of the R Model. The bottom mounts appeared to be the same. I don't know what the earlier F models, with the crossover steering had in them. The later Econodyne had a different radiator, more like the FR.-Best regards - Michael.

Hi everybody - If the radiator tubes are badly blocked , detergent cant always get down them so you have to unbolt the top tank and carefully push a dip stick down to the bottom tank. Another cause for overheating can be the impeller in the water pump breaking away from the hub, especially the early pressed stainless steel Mack impellers. Best regards - Michael.

Hi Tony, as Rob and all have said, The first thing is to give it more fuel but if you want to go a different way you can get more boost by upgrading the existing turbo to the 350 turbo, or by machining out the original compressor housing in the turbo and fitting the larger compressor wheel.I have done this in the past and at the same time I made up a short funnel shaped adapter to take the 4 inch outlet on the turbo out to 5 inches so that there is a 5 inch pipe right to within an inch of the turbo. This makes a big difference to the acceleration as the turbo spins up quicker. I also put lagging on the exhaust from the turbo back and fitted the 5 inch muffler to keep the noise down. With this system it goes better then the original straight through system without the muffler. Either way you must keep a close eye on the Pyrometer on the long hard pulls. The other thing is - do you have the big air cleaners fitted? The original cleaners restricted the air to the turbo and shortened the turbo service life. An air ram on the top of the air cleaners also helps with the boost, especially at higher speeds. Best regards - Michael

Hi everybody, I have been using it for about 15 years. The main thing I use it on is Planetaries and Hub reductions. They run about 10 to 20 degrees cooler compared to oil. The seals don't leak anywhere as much as it seems to stick to them and keeps them flexible. In the Hubs on the loaders and tractors I use 100% Lucas with no other oil. In the Mack diffs when I am changing the oil I put a 4 litre container in each diff first then top it up with oil. I have had very good results with it. Best regards - Michael.

Hi everybody, Years ago I had the same trouble - I could not get two of the bolts out of the starter. A couple of months before,I was turning and the truck was hit from behind so hard that it broke the fifth wheel king pin and tipped the trailer right over and back onto its wheels . Some time after this happened, two of the bolts that hold the clutch housing to the block broke off and were loose in the clutch housing and they completely wrecked the end of the thread on the starter bolts that protruded into the housing and mushroomed them over. I could only undo them about half a turn and they would go dead tight. I cut the heads off the starter bolts with the oxy to remove the starter, and then ground the bolts off up against the housing and screwed them inwards into the the clutch housing to remove them. The starter was damaged but repairable. Your story reminded me of this. Regards- Michael.

Are your cab mounts good. I once had trouble with the cab sometimes putting pressure on the gear lever in 4th and 5th Gears. -regards - Michael.

I agree but what he was originally referring to is the early maxidyne pistons that we had here used to burn up and fail if you gave it too much fuel. When the Econodyne series with the front intercooler was released they fitted better pistons to them with a better insert around the top to stop them burning. At the same time they fitted heavier Con Rods as some of the earlier maxidyne rods failed. We used to set the 237 pumps up to the specs of the 285 and fitted 285 turbos, but you have to watch the Pyrometer on a long hard pull to keep the heat under control. As Rob said you need a 10 or 12 speed transmission to get the best out of them.If you increase the torque screw, the extra fuel at low revs puts a lot more strain on the bottom end of the motor and the early blocks were not as heavy as the later E6 blocks. Best regards - Michael.

Hi everybody. I have a Modine Radiator with an attached Intercooler which has the numbers N-109162 and 1A16898 and the date 18/5/94. It is unused and it is exactly the same height as an R Model Radiator, but a bit narrower. Can anybody identify what it was built for or how big a motor it was designed for. I am looking to use it on a rigid truck so it should be adequate. Thanks best regards - Michael

Hi David - Where do you attach the PTO to the rear of the 6/10/12 speed boxes? I have never seen one here in Australia only the side mounted ones. Joe is right about spreading. This is the way I have done it for the last 30 years but it is not as convenient as the 5 speed where you can throw it in and out of gear easier when spreading.Best regards - Michael

Hi Jason - Don't forget that you have to put the 6 or 10 or 12 speed into a gear and the hi-lo-rev lever into neutral to use your PTO to lift your dump. It's no bother if you are always dumping in a single tip but if you are trying to spread the load, it can be a nuisance as you have to keep dropping into neutral to lift the hoist. For spreading, the system on the 5 speed or the old 6 speed O.D box is simpler where you don't have to put the main box into a gear, only when you want to move forward. Best Regards - Michael.

Hi Al and everybody, Does your Air Compressor intake come from the manifold? I had an E6 that had a split in that little intake hose and it used to open up under pressure when it got hot, and send the pyro up. Regards - Michael.

Hi everybody, over the years I have always carried and used an air hose to pump up the start tank. I have found that you always have to use two tyres with about 100psi in them to get enough pressure in the tank to start the truck. The problem is not always getting enough air to work the starter but enough pressure to open the dump valve on the start tank. There are at least 4 different types of dump valves, and some dump valves will open at 70 psi whereas most of them need closer to 90 psi to activate them. Years ago I tried unsuccessfully to pump up the tanks with the 12 volt compressors that were around then. After about 15 minutes they used to melt - never to go again. The modern 4wd compressors should be much better- the only way is to try them. Supercheap and Repco both have 12 volt compressors which they claim will do the job, but the duty-cycle beats a lot of them once they get to about 50psi, and this is not enough to start them. Certainly the small petrol powered compressor mounted in a tool-box is the ideal thing if you remember to carry petrol all the time. It is essential to have a guage on the start tank as you can top up the tank if the pressure is a bit low, rather than waste that pressure that is already there. We were fortunate over the years as we mostly left the trucks at the Quarry and used the End loader to pump them up if they ran out of air, but if they were left at the other end, we used the tyres. Best regards - Michael.

Hi all - The first Superliners in Australia had the 3408 Cat. They were a bit heavier on fuel but they were great pullers on road train and heavy float work. Best regards - Michael.

Mike, I agree with you on this point. When the "C" Motor and Maxidyne motors were fitted to the early R Models here in Australia, the air tanks seem to have been cut down in size to about half of what the 711 motors had. There is not a great deal of difference in the weights of the tanks as the heaviest part was the ends, however if you are short of space the shorter tank can sometimes help. On one truck I put a small Mack air start tank on it and converted the old big air tank to hold the hoist oil for the tipping trailer, without even moving it from where it was mounted. Best regards Michael.

Hi Rob and all. Before bulk distribution of fuel was introduced here in the 1960's, the oil companies here were very fussy about not putting diesel fuel in galvanized drums. There were still a lot of old heavy Galvanized Drums in circulation from WW2, but they were very particular to put only Petrol or Kerosene in them. Their story was that the Sulfur in the Diesel reacted with the Galvanizing and with a little moisture from condensation, formed Sulfuric Acid which, among other things, corroded the Barrels and delivery Valves in the Injector Pumps over a period of use. Apparently the Oil Companies had to compensate some users who had bought diesel fuel which had been stored in the Galvanized drums and caused damage to injection systems. Best regards Michael.

Hi Monty and all. This is the way that I have always flushed the Block/Radiator on all the trucks and machines. First of all take the radiator cap off, then take out the drain tap on the side of the block or the tap on the Brass pipe on the lower Mack hose and replace it with a quick release hose fitting. Then you can put your garden hose onto that fitting and flush it out the top. After you have flushed it for a while, pull the water hose off and plug an air pressure hose in place of it for a quick blast. It will lift a lot of rubbish out. Keep alternating the hoses until it is clear. This method is good if you have oil in the radiator as it pushes it out the top. The old treatment we used to use was a handful of washing soda in the radiator and run it hot for an hour, flush it out till it is clear, then change the filter. Best regards - Michael.

Hi M5040, The numbers on the blocks which were produced in the early 1980's don't necessarily mean much as Mack in Brisbane were retro-fitting intercooler kits to the ESI 237 motors to take them up to the 285 motor. They fitted the tip turbine/intercooler unit, the larger Turbocharger and changed the delivery valves and barrels in the injector pumps to take them up to around 300hp. These were done as a paid job for the customers after the intercooler units were released. It made a big difference for road-Train work. These trucks would still have all their original numbers and markings of 675 instead of 676 which the were then. There is no reason why this conversion could have been done anywhere else also. If you bought a new block from Mack they did not always have any engine numbers at all so you could stamp the original 237 number to simplify registration. Best Regards - Michael

I have a cab that used to have a walk-in sleeper fitted - now I want to revert back to a normal cab. How hard is it to change the rear cab panels and where do I cut them - or do I just fill in the missing piece from the rear window down. I have a donor cab shell. Regards - Michael.

Hi Grant I would be fairly certain that what you have is the C Motor which was 250 HP. It was the most common in the Flintstones and F models before the Maxidynes were released, in conjunction with the Maxitorque gearboxes. If the block had been replaced with a new one from Mack , it would not necessarily have an engine number , nor would it have been painted any colour at all. I have a Maxidyne motor which was never painted until I got it and it has no engine number. best Regards - Michael.

Hi Rob and Jeffro , I find that if you are using the truck every day they shift easier. Before I changed the regulators on the ten speed I had trouble getting it into reverse and also if it hasn't been used for a while you sometimes have to flick the little lever a few times. Sometimes it helps if you put a kit in the switch. You used to be able to get a Spicer kit with just the rubbers that you need. Buntines in the Northern Territory who had hundreds of Macks, apparently used to run higher pressure in them (maybe full supply pressure) but I once saw one of their twelve speeds with a broken reverse selector when it was traded in to Mack. Another thing - do you have anything that builds nests in the exhaust hose in the changer. We have wasps who seal the pipes with mud nests and that doesn't help the change. Best regards - Michael.

Hi Jeffro - I also had a 1969/70 R model with a Maxidyne and the 6 speed Overdrive. They took the place of the double Overdrive Quad Boxes when the Maxidynes were fitted as we were told that the Quads would not stand up to the higher torque. They still used the Quads with the 250 HP C Motor. By using that box with the .6 overdrive, you could use the old slow diff ratios. The one I have , has 7.49 diffs in it and that used to do about 58 MPH. The original diffs were about 8.25 and Western Transport changed them when the truck started doing the Toowoomba to Perth run in about 1971. Best regards - Michael.