Geoff Weeks

I had a pump motor on an RGN. Came out of a power generating station. Had to take the center boards out of the RGN for the shaft to sit down between the rails. I remember it being heavy as well as tall. That was a big sucker!

They were popular "chip" trucks for tree surgeons. So Ok when empty but loaded they struggled a bit.

505 CID, so no surprise it isn't a speed demon.

Most of those had a 8.3? C Cummins. Most weren't much of problem, I remember run solenoids and wiring being being chief problems. Could be worse could be an 8.2 fuel squeezer Pontiac (whops, Detroit).

older direct drive starter will spin the same direct on either polarity (as you found out). PMGR (permanent magnet gear reduction) starter will spin backwards on reverse polarity. To reverse direction on a wound field motor, you need to reverse the current in the field relative to the current in the armature. If you reverse both, they still spin the same way. With permanent magnets for the field, they will stay the way they were magnetized when the motor was made, and by reversing the flow through the armature, you have reversed the armature relative to the field, and vola, it spins the opposite direction.

Sorry to hear that. I tried running 300 hp with today's loads and speed and found it lacking, esp in the wind. With me it was an 855 Cummins, so could be built up higher. E6, I don't know, may be other can advise on what your choices are. 300 would get down the road fine on a nice calm day, get 35 mph side wind and you were down below 50, sometimes way below 50.

There are many ways to go from mechanical drive to electronic output. However if the tach in question is designed to be driven from the ECM can-bus then it becomes much harder. 1990 sounds to early for that, but I'll let other comment on what they know. If the tach in question is a stand alone electronic then 1st I'd look for 3/4"x 16 TPI port on the bell housing for a pick-up to 'read" the ring gear. Failing that, there are devices that can screw into the mechanical drive on the engine and give a pulsed output that can be read by the tach. I take it you now own this truck, and it isn't something you're looking to buy? If I didn't own it, I wouldn't buy it without knowing fully what I am buying.

North Korea has the "bomb" and isn't any better, but we haven't yet invaded them! Any rogue state can make a "dirty bomb" and stick it on a missile and lob it anywhere spreading contamination and death. It doesn't have to be a thermonuclear device to do major damage, doesn't have to be highly enriched. No, I don't want more countries in the nuclear club, we had an agreement, that was less than ideal, but allowed monitoring and restrictions. Trump (1) pulled out and said he was going to get a much better agreement (never did, like most of his claims) and now we are where we are. It was Trump who pulled from the agreement not Iran. As far as Afghanistan, It was Trump who negotiated the time of withdrawal. No plan, no drawdown. Biden had 5 months to come with a workable plan while still fighting. He failed, I agree but his hands were also tied by Trumps agreement with the Taliban. The pull out date was set by Trump. Unlike Trump, other presidents honor the agreements signed by their predecessors. You make an agreement you stick with what was agreed. If you want to change, you sit down and make a new agreement while honoring what you agreed to before. You don't rip up and walk away. It just shows that you can't be trusted in anything you have agreed to. Why negotiated with someone who will not do what they said the would? We have become a pariah on the world stage, someone who doesn't honor what they agree to. Being the biggest bully on the block may make short term gains briefly, but will stain you for a long long time and make it harder in the long term. In terms of the equipment left on the ground, it is a small price to pay for getting the airman back safe. May be it should have been anticipated that those planes were too heavy for the landing strip, and use smaller aircraft from the get-go. It isn't like we haven't been down this road before. 2 more lost isn't going to make much difference and I doubt those will be the last two.

Can't say I've seen "MP" on the regulator, but that doesn't matter. Regulator (even those that are marked for polarity) will function fine on either. It was just the point material was place on the points that were optimized for one polarity. It made them last longer in the days where generator and point (mechanical) regulators were common. Now it doesn't pay to make and stock two regulators for every application. They make one, and figure it will last long enough. So little call for mechanical regulators these days. It has been like that for 30 years or more. I have two trucks from the 40's and both regulators are still going strong. One I'm sure is the original, the other may be or may have been replaced at some point. If you have the truck wiring stripped out and are starting from scratch, then I would wire neg ground until I found something that didn't work right (gauge). then decide if it is better to replace that with a neg ground unit or switch to positive ground.

1st look at the generator regulator, sometimes they are marked as to polarity. 2nd does the truck have a working ammeter? If so hook up the batteries and turn on all the lights, wiper, heater etc and see which way the ammeter needle moves. If it moves toward the + side of the ammeter you have the wrong side of the batteries going to ground, if it moves toward the - side, you have the correct side grounded. There is very little to do to switch from one polarity to the other on the old generator system trucks. Everything will function just fine on the reverse polarity with the exception of some electric gauges, most will read correctly but some types will read backwards. Of course any modern radios will be damaged with the wrong polarity. Alternators will be damaged, but not generators. Once you have determined which polarity, all you need to do is "polarize" the generator. This is most easily done at the regulator. With the engine off, jump momentarily from the "bat" terminal to the "A" or gen (not the F or field) terminal to establish the magnetism in the field poles shoes of the generator. That is it! If you still can figure out what it was from the get go, choose one polarity (I would suggest neg ground as it will make any accessories easier) and set it up for that polarity.

Thanks for the update.

NTC NT88

I got 1.3m out of original build on an 855 Cummins. The rest is hard to say as they were all overhauled at some point before I got them. At 1.3m it had no problem running, just a problem keeping oil off the outside, it leaked from just about every gasket. I ended up doing an out of chassie overhaul on it. ($1500 in parts). AFAIK it is still running today.

So you are saying it has been apart before? Still that isn't all a bad thing. things replaced before they cause more damage.

Like Joey, I would oil the bushing and push the pin through without the piston then see how much if any "wiggle" the pin has. I had a job that required me to "break all the rules" of engine building. I found that you can get years of good results with used parts, even those swapped from another used engine. Ideal, no, but it taught me that perfection can be a bad thing just as wear can. I have pulled dry liners out of one block to be inserted into another. I have replaced broken valve springs caused by excessively worn valve guide, on a hot engine on the side of the road, to have it go a few more year before the head of the valve dropped. The repair was only supposed to last the "season" and the head was supposed to come off. Promises made but not kept by the owner.

I recently repaired a D950 Kubota, the useable wear limit was .2mm on the crank bearings, the 1st undersize on the bearings was also .2mm! While I doubt that engine would have good oil pressure if all the crank bearing clearances were .2mm (~.008"), when assembling a used crank with new bearings it would be highly unlikely that you would be far off the new part range for bearing clearances. In my case the clearances were within the spec's for new crank (re-ground) and new bearings.

What many people fail to understand, there are spec's for new parts fitting together and "usable wear limits" which are far greater. If within the "usable wear limit" the mfg is saying it is good enough to be re-used. Not as good as new parts but not determental to placed back in service. You use the 1st when assembling new parts together and the other when reusing parts that are already in service.

Be careful of perfection being the enemy of good enough. What are your plans for this build? Another 2M miles build? or a engine that can go another 1m miles? Yes, there are specs for new parts, often there are spec's for usable wear limit. having built many engine with success, I would use my "mechanic's feel" for things like pin bushings. I know that isn't what the "book" lists as the spec for new parts going together, however as long as it is within usable wear limits it will give satisfactory results. Even slightly outside usable wear limits it would give a fair lifespan. So this comes back to what your plans are for the engine. If you are doing it for hire, and offering a guaranty, then spend the money for reconditioned parts or to have your parts reconditioned. If, however you are building for yourself, can accept a little risk, and have the basic understanding of what it required and can make your own judgement, then "feel" is good enough. I see Joey was writing about the same time as I was.

I've read numerous reports that the 2nd airman has been safely rescued from Iran. I think I can speak for most of us, that is a huge sigh of relief.

I believe all the switches on the system are grounding switches (ground for low oil/air high water temp). so will show "power" when the switches are not grounded. At least that is how the vast majority I have seen work. Ground any one of the switches and the buzzer come on.

Another way to look at it that may help: If you had a "normal" truck and wanted to see why the Cummins fuel solenoid wasn't working and what to check to see if there was power there with the key on, you would clip one end of the test light to either the frame or engine block and use the pointy end to the stud with the wire from the ignition switch, and if the light lit, you would know you had power to the solenoid. Nothing is different when the truck is positive ground, you hook the test light up exactly the same and the results you see are exactly those of a "normal" truck.

yes, just different terms. It refers to the the wire that is carrying the current when one side of the circuit is grounded to the frame or surrounding metal. Look at it this way: You could run two wires from the battery (positive and negative) to every device and the surrounding metal could be "neutral" neither + or -. Instead of doing that you tie one side (either positive or negative) to the metal and eliminate one of the two wires. Ships houses, many things use the two wire method so any metal you touch is not a part of the circuit. Low voltage vehicles they cut the wiring in 1/2 by using the body for one of the wires. It makes no difference from an operational stand point which polarity is tied to the chassie. Positive or negative, it makes no difference, Light bulbs, most motor, many gauges, will function without any changes. Volt meters and some designs of temp and fuel gauges, you have to have the + lead connect to "ground" and - lead goes to feed (hot, live, whatever term you use).

Ok, then anything that is ground, the frame, the steering column, etc will light the light. Anything that has "hot" power will not. Move the clip to the positive (ground side) and the light will light when the probe touches something that is "live". I think what is confusing you is you are so used to positive being "hot" and negative being "ground", but your system is the reverse.

At that vintage polarity only matters with some gauges, alternator (but not generator) and any radio with transistors. What type of test light are you using? If you are using a non powered one like pictured, normally the end with the alligator clip gets hooked to ground (positive in your case) and the item being tested wire will supply the negative. Cummins solenoid doesn't care about polarity, it will work just fine on positive ground.

As a contractor for the state, it is definitely a commercial enterprise, which just goes to show the hypocrisy of some of the laws.