| Author |
Message |
Steve Krane (Steve_krane)
Registered Member
Username: Steve_krane
Post Number: 11
Registered: 1-2007
Posted From: 76.176.33.74
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 10, 2007 - 11:05 am: | |
I'm about to spend my first summer with a 1961 GM 4106, 6V92TA/V730. Does anybody want to offer advice regarding maximum engine temperatures when pulling a long grade. I'm happy to go as slow as need be if that's what it takes. I don't have a transmission temperature gauge in the cockpit. Is that bad? |
Pete/RTS Daytona (Pete_rtsdaytona)
Registered Member
Username: Pete_rtsdaytona
Post Number: 314
Registered: 1-2005
Posted From: 72.40.13.201
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 10, 2007 - 11:46 am: | |
Direct from "DA BOOK" (RTS 6V92TA/V730- Detroit Diesel Cooling section Chapter 5 - Dated 1988
Using a 170 degree thermostat:
<>Engine Thermostat operating Temperatures 170-187
<>Max Temp 210
<>Alarm Temp 215
Using a 180 degree thermostat:
<>Engine Thermostat operating Temperatures 180-197
<>Max Temp 210
<>Alarm Temp 215
Pete RTS/daytona |
Mark Renner (Boomer)
Registered Member
Username: Boomer
Post Number: 47
Registered: 11-2006
Posted From: 12.180.53.193
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 10, 2007 - 12:57 pm: | |
My advise is to never ever let it go over 200 deg. I base that on years of experience. If you do exceed 200, you MIGHT be able to get away with it, but are you willing to bet a cracked cylinder head on it? The numbers in the factory manuals are perfect world; that is, when the engine is new, the heads have never been overheated or surfaced (milled), etc. Kind of like the performance numbers for aircraft; they are in the performance charts based on a brand new aircraft, with a test pilot at the controls; perfect world conditions. If the conditions that you are operating your coach in result in an inability to keep the engine at 200 or below, than you have other issues with the coach that you need to correct, perhaps radiator inefficiency, slipping belts, lugging it, or other things. So the question is: are you a gambler? You might be able to exceed 200 without damage, maybe even multiple times without damage. Maybe not. If not, a cracked cylinder head is awaiting. I base my opinion on years of experience. I'm also sure that this will open a lively discussion because there will likely be lots of my fellow bus nuts who swear they have run their engines hot without damage. Just gear it down, keep the RPM up so the blower is putting a lot of air through the engine and enjoy the ride. This advise of course does not pertain to 4 cycle engines, such as Series 40/60, Cummins, Cat, etc. You can operate them at a considerably higher coolant temp without damage than the DD 2 cycle engines. One other thing. To operate your engine correctly, you must have an accurate temp guage. Most coaches have electric guages, and the resistance of 40-50 feet of wire does not necessarily result in an accurate reading at the dash board. So if you don't have a "manual" guage with the capillary tube in the engine compartment, you will never know what the real coolant temp is. Cross reference your electric dash guage with the rear guage so you know what the engine coolant temp is at all times. You'll find there is quite a difference between the two in most cases. |
larry currier (Larryc)
Registered Member
Username: Larryc
Post Number: 43
Registered: 2-2007
Posted From: 207.200.116.13
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 12:52 am: | |
Steve,The hi heat is not good but what is really bad is letting the engine cool off fast. I always cool my engines off before I go over the top of the mountain. Just gear down and back out of it that last half mile before the summit, then alternate between brake and fuel a couple times after you clear the summit. Put small amounts of heat back into it that way so the heads don't go from hi heat to cold real fast. I've had some strong engines that built alot of heat over the years, and never hurt one using these driving techniques. As long as they are full of coolant, they will take a beating, its cooling them off or letting them cool off to fast that cracks heads and shrinks (breaks) head bolts. If you used the trans cooler that ran with the setup you bought, you should be ok. Check the trans temp with the hand held unit at the top of the hill if you can safely. If you have belts turning its not real safe to do that. |
Cameron Jones (Crazy71)
Registered Member
Username: Crazy71
Post Number: 36
Registered: 12-2006
Posted From: 75.179.153.89
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 12:58 am: | |
I have always heard that the old flathead fords would crack heads after clearing a big hill due to cooling off too fast. |
Richard Bowyer (Drivingmisslazy)
Registered Member
Username: Drivingmisslazy
Post Number: 1862
Registered: 1-2001
Posted From: 75.108.72.204
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 8:25 am: | |
I thought that was one of the purposes of the thermostats. I doubt that cooling off from 200 to 180 would cause any problem.
Regarding to old Fords, we generally took the thermostats out in summer. I do not however recall ever cracking a head.
Richard |
Gary Pasternak (Cessna5354)
Registered Member
Username: Cessna5354
Post Number: 2
Registered: 2-2007
Posted From: 64.12.116.130
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 8:56 am: | |
Great Info Everyone tells me that the DD will do everthing well, except overheat...
My queestion is when driving 70 for hours then I pull over to shut down I try to slow to 60 several miles before, and once stopped I idle (fast) for 5 minutes. This is a carryover from turbo aircraft procedures.
Is this overkill ???
Take care,
Gary Pasternak |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 104
Registered: 8-2006
Posted From: 207.231.81.22
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 11:59 am: | |
Gary,
Can I pose a question in support of your comment?
What is the difference between an aircraft turbo and a diesel turbo? The answer is other than size and weight, essentially nothing. So, can you coke the oil in either if you don't cool down before shutting off? You bet! General Motors (EMD) locomotives all have a lube pump and 20 minute timers which operate after a shutdown to keep cool oil in hot places.
I idle my 12V71 for five minutes also.
Amtrak bought 25 passenger engines in 1974 equipped with two 12V71T engines to power the new electric passenger cars. The factory temperature shutdown switch was set for 100 degrees over expected high ambient, 215.
George |
Gary Pasternak (Cessna5354)
Registered Member
Username: Cessna5354
Post Number: 4
Registered: 2-2007
Posted From: 205.188.116.13
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 12:44 pm: | |
George, WOW I would love to check out that special one in one hundred bus you have. 12V71T is as close to a locomotive as one can get.
I loved the old Sac Train Museum. Have not been back to that area in 10 years but loved it when I worked in that area.
Take Care,
GP |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 105
Registered: 8-2006
Posted From: 207.231.81.22
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 7:30 pm: | |
Gary,
My bus is a 12V71N, and yes all 100 of these came with V12s, and the way I understand it, 82 were converted to 8V71 with a 740 automatic about 1974. 18 were supposedly left with the V12 for service in the Canadian rockies. Only problem is the four speed stick... Too high in low and reverse, and too much spread between 1st & 2nd, and kind of too much between 2nd & 3rd. The 82 with the V8 were all turboed shortly after their conversion, due to being gutless. These are really different in the back, the crank pulley is actually IN the rear bumper, as is a large micro v belt, and the driven pulley on the auxiliary drive. The driven pulley shaft extends thru the drive and runs a 9 ton air conditioning compressor with the usual hydraulic unloaders. Stacked above the input shaft are the alternator on one side, and the power steering pump on the other side, turned at twice engine rpm. Beside the input gear, are the air compressor on one side, and the fan hydraulic pump on the other, both turned at engine speed. Lubrication is provided by a sprayer mounted in the top of the housing, connected to main eng oil pressure. The bottom of the unit is drained back into the crankcase.
If I remember correctly, the 12V71n is rated 475 hp, and the 12V71t is 550?
This summer, the "buzzin dozen" comes out, to be replaced with an 8V92TA, so I have room to put in an Allison, plus the 92 came with Jakes!
Best wishes,
George |
Gary Pasternak (Cessna5354)
Registered Member
Username: Cessna5354
Post Number: 5
Registered: 2-2007
Posted From: 152.163.100.13
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 11, 2007 - 8:20 pm: | |
George,
Did the orig. drivetrain drive both dual axles, or did it just drive one axle, with dual "tags"??
I have read the history as to the use of this vehicle to deliver packages, pre-FedEx. I came from a small town in W.Va. and used the bus lines for deliveries until mid 80s. I recently needed a replacement diesel fuel tank located in Va. Bch. area and Greyhound was still the cheapest way to Atlantic City ($38.00)
Best to you in the repowering.
What is the fuel burn on the 12 cyl?
Gary |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 106
Registered: 8-2006
Posted From: 207.231.81.22
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 12, 2007 - 2:43 am: | |
Gary,
An MC6 is a 'conventional' 8 wheel bus, 102" wide, known as a "Supercruiser." The "Scenicruisers" had the dual tags. MC6s have standard single tags. 13.5 X 24.5 tires on the steer and drive, 12 X 22.5 on the tags. No spare carried for the tags, but they were equipped with a seperate air cutout valve for each tag. There is also a chain hook on the frame, and I think the idea was to unload the flat tag and jack it up off the road with a small bottle jack, and continue to the next depot?
It didn't come to me with an odometer, but looking at map mileage on a couple of 1000 mile trips, and fills of the 200 gal tank, it appears to get about 8 mpg. The steering pump is noisy, so you can hear engine speed in the steering wheel. At 85 mph, the engine is not real close to the governor, and still accelerating, I just didn't want to throw off old tires, or get a ticket.
George |
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