Nice find. I'm partial to the 2-stroke Detroit. Some may not like the 92-series, but they're decent engines in their own right. Their issues are typically with cylinder liners. Welcome to the family!
Thanks Cheese Wagon
I love the sound of the 2-strokes, and this one ROARS.
It does have some bugs to work out, like oil consumption. I'll be working on that and chassis maintenance this summer. Tentative roof raise next summer.
Thanks Cheese Wagon
I love the sound of the 2-strokes, and this one ROARS.
It does have some bugs to work out, like oil consumption. I'll be working on that and chassis maintenance this summer. Tentative roof raise next summer.
Unless it's excessive (a loose term with 2-strokes) I wouldn't bother. Screamin' Jimmys are known for a few things besides their awesome sound -- oil consumption, oil leakage, coolant leakage. They don't call 'em "green leakers" for nothing. Can't kill them unless you do something truly stupid though.
If no one here is familiar with servicing these, you may want to get in touch with BusGreaseMonkey on YouTube... They are and have done many videos on buses with such engines.
A lot of it is in ensuring the rack is set properly. If yours runs away, don't be afraid to throw a phone book or rags in the turbo / air intake or shoot a fire extinguisher in there -- it's a lot easier to replace a damaged turbo or clear paper debris from the cylinders than to replace an entire engine. The only way to shut down a runaway mechanical diesel is to kill the combustion process by reducing the air available.
Choking them is easier on them than a rod through the block. Detroit 2-strokes are made to run higher RPM, so they're more forgiving of a runaway condition than others. But you don't want to let it runaway for ten minutes before you do something.
Don't take my word for it - there are a few runaway 2-stroke videos on YouTube in which the owner does exactly what I've mentioned.
Runaways are in reality very rare, and are generally from being so worn out that they start useing the lube oil for fuel. Or the oil seals in the blower have gone bad and that puts oil right into the intake air.
What is your oil consumption? A quart every 1000miles would not be enough to be concerned with.
Runaways are in reality very rare, and are generally from being so worn out that they start useing the lube oil for fuel. Or the oil seals in the blower have gone bad and that puts oil right into the intake air.
True, but don't forget that the rack is sometimes known to stick and cause a runaway as well.
True, but don't forget that the rack is sometimes known to stick and cause a runaway as well.
I doubt Ronnie's forgotten much about DD's. The guy lives and breathes em!
Like seriously, the guy's a mechanical genius. So is his better half Dee.
If I ever destroy my bus' engine I won't replace it with another one. I'll do whatever I gotta do to get ronnie to slap a 2 stroke into mine, if I can!
On the 6v92 you need to pay attention to your coolant, making sure its treatment levels are in range. And if you overheat it you could loose liner seals. We all know what that entails. But that's an issue on all wet liner engines.
Runaways are in reality very rare, and are generally from being so worn out that they start useing the lube oil for fuel. Or the oil seals in the blower have gone bad and that puts oil right into the intake air.
What is your oil consumption? A quart every 1000miles would not be enough to be concerned with.
Thanks for all of your interest, I appreciate any help i can get.
I drove the bus about 3,000 miles after purchase, using 5 gallons of oil in the process. The blower is high on my suspect list, as it slobbers a lot. That job will tax my abilities, but its gotta be done.
I think my compressor is passing a lot of oil too. It appears to be a rare unit. I thought I found a compressor on eBay but the seller couldn't locate it for shipping. <sigh> I am reluctant to send it out for rebuilding as I fear never getting it back.
Does my DDEC II engine have a rack? I think not, but this is my first DD 2 Stroke.
Again, thank you for your feed back
Rich
A 2-cycle DD with a DDEC won't have issues with runaway that a mechanically injected engine will but you still have the issue of sucking up lube oil to fuel the engine.
One thing that is extremely important in regards to oil in a 2-cycle DD is you HAVE to use the correct oil or you will increase your oil consumption.
The only oil you should use is Delo 100 40 wt. You can use other brands that are equivalent but you need to have a low ash oil that has the ZDDP still in the oil. Without the zinc and phosphorous you will have more wear in your engine especially on start up. If you use a multi-weight oil, particularly a newer formulation that is formulated to not foul a exhaust particulate system, you run the real risk of breaking oil rings.
Proper pH in the coolant is neutral. You don't want either acid or base. You should have a coolant filter on the coolant system. It should have a additive package built into the filter. If the filter has been on for more than a year it is past time to change it.
A 2-cycle DD with a DDEC won't have issues with runaway that a mechanically injected engine will but you still have the issue of sucking up lube oil to fuel the engine.
One thing that is extremely important in regards to oil in a 2-cycle DD is you HAVE to use the correct oil or you will increase your oil consumption.
The only oil you should use is Delo 100 40 wt. You can use other brands that are equivalent but you need to have a low ash oil that has the ZDDP still in the oil. Without the zinc and phosphorous you will have more wear in your engine especially on start up. If you use a multi-weight oil, particularly a newer formulation that is formulated to not foul a exhaust particulate system, you run the real risk of breaking oil rings.
Proper pH in the coolant is neutral. You don't want either acid or base. You should have a coolant filter on the coolant system. It should have a additive package built into the filter. If the filter has been on for more than a year it is past time to change it.
Thanks, this is really useful, I am starting to get more and more involved and just love it!
The Delo 100 40wt oil (or equivalent CF2) is absolutely and positively the ONLY oil that should be run in that 6V-92. I have a few threads on here regarding the oil issue and would be helpful for you. 5 Gallons to go 3k miles is not too bad at all really.
In fact I'd be willing to guess that the oil you bought and filled it up with on the trip home was probably a multi-grade oil since that's all you can find today on the road without special searches and getting it before you leave and carrying your supply with you. But you didn't know so you used what you found. This most likely made the leaking and consumption get worse.
I still drive a Crown with a 6-71 in commercial service and it uses a gallon every 500-800 miles. This is the gross normal for a DD 2-stroke. The oil doesn't have to leak out where you can see it either, it tends to get out as vapor from the air box drains and the exhaust. That's one reason they are so difficult to keep clean as the vapors condense on the engine and all across the back of the bus.....have you noticed this yet. Wash it and within a few miles it has a film on the back from various sources attracting dirt and carbon from the exhaust. The reason is that the engine block is positively pressurized by the engine blower causing any vapors to seek and find a way out through any gasket, bolt, seal, or the designed in air box drains.
This is all part of the charm of owning one of these magnificent beasts. It could be that someone may have added a multi-grade oil to make up the lost oil (hint-you maybe?) and this alone would explain your excessive loss/usage and if it exhausts blue smoke when accelerating from a stop that's another clue to it having a multi-grade oil in it.
I have personal experience with Crowns with DD's being brought in for engine repairs due to excessive (blue) smoking and oil leaks from everywhere on the engine. We call this slobbering with oil coming out everywhere. All that was needed was a complete oil, (and filter), change to the Delo 100 CF2 40wt and upon test driving it, ALL of the symptoms disappeared within about 20 miles of driving it around. I suggest you try this first before doing anything else, this will at least ensure you have the correct oil and give a baseline to look then for other causes. You should also plan on finding a source for Delo 100 or equivalent CF2 lowest ash content MINERAL oil from one of the few left who still make it and get a case or two and always carry it with you because you will NOT find it on the road much anymore.
Don't argue or try to find contradicting facts online saying multi-grade oil is OK. One guy did this pointing out Detroit Diesel manuals said it was OK....BUT these were older manuals and after a very short time of field experience feedback from large fleet users they reversed themselves and once again recommended that ONLY Delo 100 CF2 MINERAL oil and not synthetic (delo 400) was the only oil to be used in straight 40wt. Just do it. And carry a supply with you. A full set of all filters is also a good idea too but filters are easy and can be found. Maybe not when you need one in the wilds of the great wide open West at O'Dark thirty on the side of a deserted road somewhere.
That would be two sets of BOTH fuel filters(Primary and Secondary) for when you get that load of contaminated fuel, two extra oil filters and the water conditioner element whatever is on the bus. Carry an air filter too just in case. Any belts too since they are REALLY hard to find when you need one in a hurry. Air bags too, full air-ride I think since they are essentially Phantoms modified for School bus standards, a spare one of each size assuming front and back are different bags, as well as a spare leveling valve, these are ridiculously cheap too. They aren't hard to find with the luxury of pre-planning and they don't even cost that much, but needing one on the road after it's blown is a whole new level of pain. With a supply of these easily fixed but hard to find in a hurry parts on board you should not have many serious problems keeping it up and running enough to find a safe harbor and mechanic on the road. Just saying. Be prepared.
As an aside I know this bus and the Alliance bus lines where it came from here in Ontario CA. Quite a few of theirs, they had Crowns mostly, have been purchased by folks looking to convert them and keep on trucking with the excellent vehicles they are. Crowns and Gilligs are very much in the class of their own and represent the pinnacle of design and execution for the longest lasting school, and sometimes even a few coaches, ever built. You should do well with this Gillig.
Coachwork: Crown, integral. (With 2kW of tiltable solar)
Chassis: Crown Supercoach II (rear engine)
Engine: Detroit 6V92TAC, DDEC 2, Jake brake, Allison HT740
Rated Cap: 37,400 lbs GVWR
Yeah, another 2-stroke Detroit on this forum! Treat that engine the way it should be treated, and it will be your friend for life. I'm slightly curious though - what is its HP rating? I'm wondering why Gillig used a MT64x transmission with it.
I also remember seeing these Gilligs at Alliance when Rick Gregory was there, plus their four Super IIs. I miss those days.
Thanks for all of your interest, I appreciate any help i can get.
I drove the bus about 3,000 miles after purchase, using 5 gallons of oil in the process. The blower is high on my suspect list, as it slobbers a lot. That job will tax my abilities, but its gotta be done.
I think my compressor is passing a lot of oil too. It appears to be a rare unit. I thought I found a compressor on eBay but the seller couldn't locate it for shipping. <sigh> I am reluctant to send it out for rebuilding as I fear never getting it back.
Does my DDEC II engine have a rack? I think not, but this is my first DD 2 Stroke.
Again, thank you for your feed back
Rich
I missed the first time your mention of the weird/rare (air?) compressor.
Most Detroit 2-strokes have used common as grass Bendix air compressors that are bolted directly to one of the engine accessory pads on the back of the engine. This is to the front of the bus on rear mounted installations. It's extremely simple and reliable and used on all of the DD's I've ever seen for years now. The other pads are usually used for the power steering pump, and on highway coaches even the huge 50DN 24V 225 Amp alternator. All very clean mounts internal geared driven, with no belts to fail and using engine oil for lubrication and cooling.
It may be possible that Gillig didn't have the physical room in the engine bay to mount the air compressor directly to the engine so were forced to add brackets and belts to the rear of the bus, (engine front). I've seen this with other engines like the CAT3208 and Cummins 8.3/L11 but they have different setups for accessory drive pads, if any, and one reason why the DD's were so popular and used so much, among other benefits, by so many bus and coach builders.
Air compressors aren't expensive or hard to find. And if there is a reason to have to keep the one already there I'm sure you can find a good quality place that will rebuild it and/or offer an exchange rebuilt one for your core. This is very common for this class of heavy duty truck and bus components and they are still manufactured today so should be readily available.
The air compressor is most likely a species of Bendix and even if not you should be able to find a common replacement Bendix that will do the job. Don't fall into the mental trap of thinking you MUST use only what was originally installed on the bus since even Gillig managed to offer some measure of customer requirements and custom equipment.
Nowhere near as much as Crowns which were essentially all custom built to individual specs literally by hand in a low volume manner. Gillig made the successful transition to a much more standard and high volume production designed and manufactured product line, that's why they are still in business and Crown isn't.
Thanks Cowlitz Coach, I will learn how to test the coolant to keep that healthy.
And thank you Crown-Guy for your detailed responses. I did get the sermon on Delo 100 ONLY from the seller of my bus. It was indeed an Alliance Bus. "Al" in Ontario CA had arranged for a case at his local O'Reilys, and I ordered another case during a stop in AZ. You are right, it slobbers badly everywhere it stops and I did wash an awful lot of oil off the rear of the bus. It isn't coming out of a wet exhaust, but it does smoke a little on the road somewhat more when cold.
I agree 100% on carrying spares for the road. I have replaced the rear air springs and bought spares. Just ordered a leveling valve. Cheap, I oughta buy another. Filters and belts too, as spares are cheaper and easier when you have time to shop.
My air compressor has an odd 52 degree tilt in its crankcase. It just barely fits between the gearcase and the bus chassis. I actually found an eBay listing for one, but after buying it, the seller 'couldn't find it'! Darn, it was reasonably priced too. I want to go through these oil potential oil drains of compressor and blower seals, and to clean out the slobber check valves and catch can but I'm only an average mechanic. It'll like take me all summer.
Thanks to Iceni John as well. I am happy to have a DD 2-Stroke and look forward to being a part of this community.
Highest regards to you all!
Rich
Coachwork: Crown, integral. (With 2kW of tiltable solar)
Chassis: Crown Supercoach II (rear engine)
Engine: Detroit 6V92TAC, DDEC 2, Jake brake, Allison HT740
Rated Cap: 37,400 lbs GVWR
Quote:
Originally Posted by Phantom5824
Oops, sorry Iceni-John, I forget to add that the 6V92TA I have was said to be 277 HP, and yes it is a MT647 Allison.
Regards
Rich
That's an unusual combination. As long as the engine's not turned up too much an MT64x will handle the torque, but a 277HP engine is close to the transmission's limit. Maybe your engine has different torque than mine, or maybe there wasn't space to fit anything else, or who knows? I suspect you have a very short driveshaft, shorter even than mine, because your rear axle is closer to the back of your bus than mine is, and that will dictate what length of transmission can fit. I've never examined a Phantom school bus closely, and it would be interesting to see what's the same and what's different to my bus. (I did see however that the hydraulic control unit for the Super II's radiator fan is a Gillig part, complete with Gillig part number! I wonder how much other cross-pollination took place between those two companies?)
John
PS - You may have a Bendix Tu-Flo 700 or 750 air compressor, and they're still rebuildable and worth keeping. Keep the access hatch for the rear of the engine completely accessible if your building a conversion, then it's easy(ish) to get to the compressor and pump if needed. Too many folk block that hatch, then guess what?!
Phantom5824
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