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Old 06-09-2018, 06:04 PM   #81
Join Date: Mar 2018
Location: MO
Posts: 115
Year: 1978
Engine: Detroit 6-71
Originally Posted by Crown_Guy View Post
I've given the info here before, so, for the umpeenth time and in miniature condensed form, here it is again.

Forget about that spring on the throttle. It's fine and until it finally breaks, just leave it alone. You can find them at any hardware store. I replaced one recently, I got an assortment package from Home Depot. It's just a simple return spring. Nothing magical or part numbered about it. You'll know when it fails because the throttle pedal won't come back up all the way, but you can push on the back of the pedal to return it to idle while driving, until you can get down there and replace the spring. I'd get a package in advance and carry it as part of your on-board replacement parts kit. Like you already do, right, with oil, water, belts, fuel filters, oil filter, water conditioner, etc. and tools.

First, to answer your question of tripping the emergency engine stop damper while engine is stopped,,,, absolutely. Go ahead and check it out for proper function and that you can reset it again. That's how it's done by a mechanic anyway. It's simply a trigger-sear type release mechanism and the stop button energizes the pull-in solenoid coil to release the latch so it allows the spring driven damper plate to close off the air intake to the blower. This should be checked occasionally anyway for proper function. As you found out, it's all right there under the floor hatch in full view.

Everyone, don't over think, or complicate the normal engine shutdown operation of the governor stop lever. It simply needs to be moved about 30 degrees and held there until the engine stops. Simple and easy to understand and visualize. The air actuated piston merely pushes it in that direction with air pressure and holds it until the air bleeds out of the bus air system.....or until the key is turned on again and the driver wants to run the engine. It's not so hard to turn by hand and hold in the off position that anyone should be able to reach in and turn it and, hold it till the engine stops. Just turn it in the same direction as the air actuator is trying to move it.

The stop lever is the short one of the two. All it does is stop the engine. Or lets it run. By the way, with no air pressure or anything affecting it, the Stop/Run lever is held in the RUN position at all times. This means that if the engine is cranked inadvertently, for any reason, it WILL start and run normally. Nice if you want to bump start it, but not so nice if you are fooling around and accidentally crank it while being entangled with stuff that goes around with the engine. Could ruin your whole day.

AGAIN, the engine STOP lever is the one that the air actuator is pushing on. All you need do is move it by hand in the direction the air actuator is pushing it. It's a mechanical lever that moves the fuel rack in the head to zero fuel, overriding the governor, thus shutting the engine down. Got It? Nothing more complicated than that. It's simple to reach, it's right in front of you as you look in from the left side, and easy to move. Nothing to worry about, no fans or belts, just reach in and turn it clockwise in the same direction the air actuator is set to move it. Hold it till the engine stops. Things might be hot, so be careful and, maybe use gloves, the exhaust manifold will be hot for sure.

This functions exactly the same way on ALL Detroit 2-stroke highway vehicles I've ever seen or driven. I've even had to physically remove the shutdown actuator from the governor top plate once, due to an electrical system fault in order to allow the engine to run so I could finish the trip. Once you understand what's going on here, and it's dead simple, you can add modifications to air lines and such in order to override the normal system operations in order to regain control and finish your journey with little fuss or muss.

I concur completely that the guy at the tire shop, with no idea of what a Crown is, or how it works, tried to shut it off with out waiting for the air pressure to build up. I would have thought the brakes wouldn't release, but the primary and secondary air systems were working against him on this. Enough to release the brakes, but not enough for all the accessory systems to be up and running yet. I STRONGLY suggest that you leave instructions with future shops to NOT try starting, or move the bus, without contacting you first. Remember they have never seen a Crown before, and the DD installation has it's own special quirks we take for granted, but not everyone is clued into the secrets.

By the way, this is how we all learn and grow in our experiences with these. I know I did, and most everyone else I know has been through similar things. Welcome to the club and I bet you won't soon forget this either. You could consider putting an easily pushed aside safety cover over the emergency shutdown button to discourage inadvertent operation of the button, even by you sometimes, by an Ooopsy. All it takes is a single push to actuate the damper. Then it's time to get out and reset it by hand. Make sure the reset handle is reachable and usable from the left side engine door so you don't have to lift the floor hatch. If it needs attention to function, or possibly requires modification to a larger handle or whatever, then the time to do it is at your leisure in your yard with tools at hand, and not on the side of a road somewhere in the snow and ice, raining cats and dogs etc. Well, you get the picture. Proper, Prior, Planning, and all that can really pay off.

Anticipate in advance the critical items that can put you down, hard, full stop, and try to install plumbing and/or electrical work arounds to get around those failures, to keep on driving. For instance, Fuel filters. A spare set, mounted in place, and plumbed, so all you need do is turn valve(s) and keep on going.

An easy to use engine priming system to re-prime the engine. It can be as simple or as elaborate as you want, but it should be all plumbed and ready to go for when you eventually find yourself running out of fuel, usually in the darkest most empty stretch of highway you can imagine. At that point you'll finally find out just how hard it is to find any mechanic who really knows how to re-prime a 2-stroke, and it ain't pretty, I know this from first hand experience. But it wasn't my screw up, so I got to stand back and watch them go through three (3) count'em 3 mechanics before they found an old gray haired guy who had the knowledge and the tools at hand to get their MCI 8-71 primed and running again. You should do whatever you can to install a proper re-priming system you can handle by yourself if needed. Soon. It will save you a whole bunch of trouble later.

Running a bus out of fuel, back in the day, was a fire-able offense and we all acted accordingly. You should always be aware of your fuel state, and where to get fuel, at all times. But be prepared to recover gracefully, just in case.

You should consider one or two easily reached air fittings, front and back, maybe one with a truck style glad-hand like what truckers use on trailers. These air taps can be used to air up the bus to release brakes etc., if it needs towing, as well as for use by tools or outside accessories in a pinch.

A high current proper battery plug, to charge, or use to jump start the engine. Installed and ready to go, eliminates all the hassles with clamping on to battery posts and jumper cables. Many ideas about how to do this with house batteries and generators etc. Think it through and plan and install it ready for the day you'll need it, and you won't regret it.

Think first about how to keep the vehicle running and usable and easily limped to a service facility. This should be paramount before worrying about what kind of wood flooring or trim to use on the interior. Without a safe and reliable vehicle under you, all you have is a fancy trailer that won't be moving anytime soon, not even Spam in a can, just carpets in a can. How much fun can that be.

Stuff like this should be thought about in advance and provisions made to work around quickly when things fail on the road. This will make life much simpler and you'll have confidence you can get yourself out of nasty situations while still retaining control of your expenses.
Thanks for all th information man! I am going to try the emergency stop again to make sure itís working. Also I do want to have back up options in case of breakdowns like an extra alternator, extra belts, filters, etc. Do you know what kind of belt I would need as far as part number or size for my Detroit 6-71 pancake?
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Old 06-12-2018, 10:54 PM   #82
Join Date: Mar 2018
Location: MO
Posts: 115
Year: 1978
Engine: Detroit 6-71
Okay so I wired our AC panel and RV 30 amp inlet today to test out, here is the YouTube video I posted on our conversion YouTube. For anyone who wants to see and give any feedback of what we can do better or anything they see that might be off.
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