
Geoff Weeks
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Everything posted by Geoff Weeks
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It is not a steady voltage but pulses on and off. Of course, since it is in series, there has to be a path to ground. A test light works better than a meter in this case.
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I think the OEM gauge would be the same one used on the lighter R/S series and will be the late King Seeley type thermal gauge. These are like Ford and Chry used in the 60's and 70's, with a "regulator" ahead of the gauges and a resistance type sender. The regulators go bad and the gauges also. This is if you want to use the OEM gauge in the dash, if you are hanging another gauge, then never mind.
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My year Goldwing was the last with the kick-start as well as electric.
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Confirmed 1113218 as the complete model number of the MT-30 I have, which is correct for an RD inline. Shaft turns by hand, but I didn't lug a battery to it or it to a battery to see if it will motor. Given how long it has been sitting I would go through it anyway, but I can confirm with a battery if someone is serious about it.
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Mack A20 water pump
Geoff Weeks replied to Carson's topic in Antique and Classic Mack Trucks General Discussion
My thoughts are: If it isn't leaking why worry? If it is, I would note how far the pulley flange and impeller are pressed on the shaft, then disassemble. with the shaft and bearings out of the housing you can assess the housing, and what went wrong. New bearings and seal and any repairs needed. Really only way forward on something like that. Waterpumps are fairly simple devices. The only caveat is to be careful not to damage the impeller, housing or shaft when taking apart. Make a puller to pull the pulley flange off, look at the impeller for puller holes, if there are none, the likely the shaft and impeller can be pressed out the back together and separated on the bench if you even need too. Going together make sure to press the flange back to the same depth while supporting the impeller end, the depth is what puts the preload on the shaft seal. NO HAMMERING. Did my share on the British Buses when parts were not available, or at least not readily available on this side of the pond. Industrial pump seals are made in most types and sizes and it is a good bet the Mack pump uses one of them. -
No the BLD takes an SAE-1 mount. Early RED (Big IHC six) used the SAE-1 also, then at some point (may be when the big six became the "RD" series), they went with the SAE-2 and a bigger starter. The MT-30 looks a lot like a scaled down MT-40. Bolt on and rotatable nose cone and 3 equally spaced bolts but unlike the big truck starter that have 5/8" bolt hole, the MT30's are smaller (7/16"?) from left to right: SAE1, SAE2, SAE3
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There are at least 1/2 dozen sending unit profiles that were or are in use. No "one size fits all" Old AC, new AC, King Seeley, VDO, SW, and more that I can't remember right now. Some are easier to come by then others.
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That is fine, the offer is open to anyone who can use it. I have no use for it (anymore) and hate to see it go to scrap or just sit in my storage trailer. It does seam (Delco MT-30) to be a orphan, and the SAE-2 mount is not being made or at least not found on newer starters, so if you have something with one, used may be your only choice. SAE-3 and SAE-1 starters are commonplace and you can buy new.
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So it does look like it has the Holley dist. Let me know if you want the starter (free), I could try and box it up but last time I looked for a guy it was real expensive to ship, but if someone was passing through...
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He'll always be racing the fuel gauge to the fuel stop!
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I looked in my books, and there are a few Dist it could have. Also depends if it is driven from the front of the engine or back. (Fire trucks had two, both front and back and dual plug heads) I would guess single could have either depending on what the engine was in. There was also a early "transistorized" ign at one point (looks to be early GM), and to my surprise it did have vacuum advance. Also makes a difference if it had a cable tach or Gov and cable tach, or just gov. So tag number is going to be needed Early IHC used Delco dist but Prestolite and Holley were also used so to be sure get the tag number.
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Tried to do some more digging on the starter numbers. Same basic model so it might be as little as how the nose cone is indexed, or could be a different drive. Either way I am finding rebuilds in the upper $300 to mid $400 range plus core charge. If you just want it for a spare/core it would be worth having around, SAE #2 housings are not common any more. I think this one spins, I haven't tried it, but if you are interested, I'll dig it out and put a battery one it.
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Carb numbers for model 852 FFG for V-401 Manual 391-937-C91 List number (4438) Manual 391-938-C91 List number (4679) Auto trans 391-939-C91 List number (4378)
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Just checked, it is the one I am thinking about an MT-30 with SAE #2 mount. The one I have came off an RD inline and is one digit different (according the the catalog, I haven't looked at/for the tag on it) but is also the MT-30 with SAE #2. I don't have spec's on the drives, but wouldn't be surprised they were the same. If you have a cost effective way to get it from western Iowa, it is yours for the asking. According to my Delco book it should have a 1113217 starter, and the one I have "should be" an 1113218 for an RD inline.
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I may have a starter for that. They use a type that is kind of rare, an SAE 2 if it is the starter I am thinking of. You can have it for free, but getting it to you would cost more than it is worth last time I looked into it. I might also be able to ID what carb it has or should have on it
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Welcome Pogey, 25+years ago I was moving the same type loads, 12,000 front axle with 16,000 lbs springs, 40K rears, and a 23K pusher. I took that up to 170,000 lbs a few times. I guess not much changes. I did have a lighter frame, however. 400 Cummins and Eaton 13 through a 14" organic clutch. My guess is your power is more than we had back then, but the job doesn't change. Edit: didn't notice this was an old post, and he hasn't been back since, Oh well.
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Knowing the why is paramount, how can be picked-up. I was re-rationing a diff, I had the pinion at a local gear shop, and needed the spigot bearing peened on the shaft, so while it was there I had them replace the other two and set the pre-load (easy to do in a press). They gave it back with 0 preload on new bearings! When I pointed it out they claimed I didn't know what I was talking about, rather argue I brought it home and re-set. I guess theirs last long enough to get out of warranty, so good enough for them. 0 pre-load will outlast too much pre-load, but not nearly as much as correct pre-load. Knowing why is the key.
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While I would agree with the above in general, I have learned from experience on "heavy duty" spark ign engines without vacuum advance, that getting it right on spec does bring advantages. So worth the effort if you can. If you can't then at least you can get somewhat close.
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Hamilton Fuel injection is another one. The TBI are more or less GM TBI clones. I don't like TBI as it has most of the vaporization and throttle icing problems of a carb without the advantages of port injection. I don't know that one is made to feed that big LV engine either.
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Air conditioning problems
Geoff Weeks replied to Concrete cowboy's topic in Modern Mack Truck General Discussion
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I had similar problems with the vents freezing shut in the real cold weather. At first I thought it was the cross over line with a slug of water in it (low point in the system) but later I realized that if I took the cap off it would flow to the draw tank. Seamed to happen when I was running in real cold weather (-20 to -30f) fuel and air in the tank were warm enough but the moisture in the warm tank would freeze the vent.
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Air conditioning problems
Geoff Weeks replied to Concrete cowboy's topic in Modern Mack Truck General Discussion
Ahh, I see I suspect that front cover that is screwed on is a dust cover keeping water and dirt out, and is a conventional clutch below that. Kind of like the old chafe shield on the Harrison A-6. I think I can see a clutch coil behind the pulley. If he has one of those, I would pull the cover so I could see what the clutch is doing. I haven't run up against one of those yet. The clutchless are a worse almost throw-a-way compressor. I was pondering how it could push instead of pull, now I don't think it has too. Thank you for the picture. I never thought much of the APADS, make it more complicated than it needed to be. I had mine set up with Hi and Lo cutoffs, and the low would lock-off until re-set. It would shut the system if 25% of the refrigerant (or there abouts) had leaked, and there was a secondary low pressure that would prevent clutch pull in below about 45 psi on the high side. One pound loss on a 4 lb system and you might not even notice it in the cooling unless very hot. It would throw some for a loop, but was like the old thermal limiter fuse GM used to use, it could shut down before all pressure is lost, keeping some oil in the compressor. -
Air conditioning problems
Geoff Weeks replied to Concrete cowboy's topic in Modern Mack Truck General Discussion
I've never seen what you are saying it has, do you have a picture? How is the pulley retained if the clutch is behind? How is the air gap adjusted? Where is the electo-magnet and how does it pull? It can't push the internal plate out so must pull something. In automotive there are some totally clutchless compressors the have a movable swash plate and a shear point on the shaft in case it locks up. Supposed to 0 out if it is low on refrigerant, and supposed to shear if the compressor locks. Lots has changed since I got out of commercial work, so am open to learning new stuff I haven't (yet) seen. -
Air conditioning problems
Geoff Weeks replied to Concrete cowboy's topic in Modern Mack Truck General Discussion
I wasn't aware of any trucks that were "clutchless" compressors (variable displacement) that turn the shaft all the time like some cars, but stand to be corrected on that. Those types have a control valve in the compressor that move the swash-plate to 0 instead of a clutch. Big pain in the rear. All others have a clutch on the front that can be observed. Sanden's I'm aware of all have clutches, with it turned off the center bolt will not spin with the pulley. If it is clutchless than there have been a lot of problems with the control valves in the compressor not moving it to high displacement. You'll see low high pressure and high low pressure. The the charge is known to be correct by weight, then we can move on to pressures and temp readings. It is possible the Tx (if used) is stuck in its lowest flow position, but my experience is that is unlikely, not impossible, but not the 1st place I jump to. Does this truck have a bunk unit also? -
Air conditioning problems
Geoff Weeks replied to Concrete cowboy's topic in Modern Mack Truck General Discussion
1st 62 deg is not good at idle unless it is 125 deg or hotter outside. Unless you removed the refrigerant, weighed it and put it back in, you can't have checked the amount in the system. Pressures in the system tell you the temp of the refrigerant, and therefore how well it is moving heat, but not how much is in the system. Until the amount in the system is known to be correct by weight, it can be impossible to diagnose further problems. Poor condenser performance is often a problem on older systems, the condenser is low an out front, and subject to all the debris and chemicals the road can throw at it. 1st order is to leak check the system, as it still has enough in it to operate. Go over the whole system with a good sniffer. pay special attention to the compressor shaft seal. Have someone raise the engine speed to around 1500 or so while you watch the compressor clutch, may be put a white mark on the face of the clutch and pulley and watch to see they are turning at the same speed (clutch not slipping). If you can't find a leak, the clutch is not slipping, then recharge with the measured amount the system calls for, and start looking at the heat loss across the condenser. gas should enter hot (almost burn you but exit warm, just above ambient. You should be able to run you hand along the tubes from top to bottom and feel a steady drop in tube temp, no cold spot and no sudden change in temp. Most system see a condensing temp (pressure) of about 30-40 deg over ambient temp, on the hottest days, the closer the temp of the refrigerant leaving the condenser the better it will cool. My truck would see temps between 15-20 deg above ambient temp on the exit of the condenser, but I over sized the condenser from stock and was running R 134a in an R 12 system, still it would get the evaporator cold enough to trigger the frost switch (32 deg) with outside temp of 95 deg while running down the road. I suspect your system is low, but without pressure and temp readings I can't tell you if that is even a possibility. Low refrigerant has a tell tail pressure readings, so it can say it is low, but not that it is filled to the correct amount, that can only be done by weight to any accuracy.
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