| Author |
Message |
Johnny (67.241.166.69)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 23, 2003 - 7:17 pm: | |
The latest thing at work is older than many of the drivers: 1961 TDH-5300, aka a GMC New Look transit. It has a 6V71 (no turbo and REALLY gutless, so probably a 2-valve), 3-speed auto (replaced the original 2-speed), and I think it's a 35'er. Mileage is about 1,700,000, with the engine overhauled (in-frame, says Da Boss) at ~950K. Even at WOT & max RPMs, it only blows a tiny bit of (black) smoke.
Well, I was supposed to drive it for ~6 hours on a commuter route today (I ran ~40 miles in 6 hours, so that should tell you a lot about the nature of the route). Unfortunately, it only had about 1/4 tank of fuel, so Da Boss said to fuel it first. Problem: I don't know where we fuel the diesels. He said he'd take me there, and hitch a ride back to the yard with another driver while I started my route--that'll work.
I fired up the Detroit, charged the air tanks, & filled out my paperwork. Da Boss got in, shut the doors, & we headed for the Citgo station. Well, we were about halfway there, running ~40MPH, when I mentioned the engine was kinda loud. He said he couldn't hear it (he's pretty deaf, and it's ~30' away from the driver), but noticed it seemed to lay down at ~40MPH, as though it wasn't getting fuel. Other than that, it was OK, so he finished the drive. When we got to the Citgo, he went to put it in neutral...and his face went totally white.
Unknowingly, he'd put the shifter in "2" rather than "D"--so that 6V71 ran ~12 miles right on its governor! The bus tops out at ~65 (with the engine SCREAMING), so can anybody venture an educated guess as to:
1) What RPM's this thing was turning? Speedo is accurate (+/- 1MPH at 50, paced by a police car), and drive tires are 11R22.5's.
2) Did we hurt anything? I know Detroits like to rev, but spinning against the governor for 15+ minutes can't be good for any engine.
BTW: It has no power steering (no big deal for me), and bias-ply tires (12x22.5's on the front) SUCK on those awful roads! |
Henry R. Bergman, Jr. (Henryofcj) (65.194.145.59)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 23, 2003 - 8:09 pm: | |
Bet you it did not hurt it one bit and actually helped clear out the injectors because....
....hear is another old firemans story; Years ago the master mechanic would pick on young hoseman....
....and tell them to take a fire engine or ladder truck from the shops and run it down the freeway...
.....at max rpm (2450) for about 20 minutes at 60-65 to blow out all the carbon, soot and stuff.
They always ran better after being "blown out" Bet your newlook ran better after being stuck in second. |
RJ Long (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 23, 2003 - 9:14 pm: | |
Johnny -
Relax, DaBoss didn't hurt anything, 'cept your eardrums and his pride.
If the bus has a V-730 three-speed auto in it, 40 mph in 2nd gear is about 2100 rpm, which is the normal governor setting for the two-stroke Detroits. If the bus had highway gearing, 2100 in 2nd would be between 45-50 or so, and it would top out a little over 70 mph.
You can run a Detroit two-stroke on the governor all day long, and the only thing you'll damage is the fuel expense account.
Post the VIN on this bus, and I'll translate it for you. . .
BTW, how do you like driving the Fish? (Other than it's poor acceleration. . .)
RJ
PD4106-2784
Fresno CA |
Johnny (63.20.60.193)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 24, 2003 - 7:18 am: | |
Actually, it's not bad. Other than being outrun by a diesel Rabbit on 3 cylinders, that is. The ride is surprisingly good, with little wallowing (though those front bias-plys suck). The steering is pretty easy, even without power assist, though it's something like 12 turns lock to lock, which makes for some arm-flailing in parking lots. The brakes held up well (though they squealed like crazy after ~20 minutes of stop and go), and much to my surprise, the 3/4-million-mile DD fired right up in 0-degree weather without the heater and with no ether. It certainly didn't pretend to LIKE it, but it started.
Also, when did the TDH's get dual air systems? This one has dual air-I figure a retrofit when it was overhauled, ditto for the yellow-knob parking brake, low-air buzzer, & 3-speed shifter gate.
Also, this might be a record: in 6 hours, it only used 2 quarts of oil. The guy we bought it from knows his DDs--the valve-cover spew is almost nil!
Also, any tips to get it to run >160 degrees in 15-degree weather? Running all day at 140-150 coolant temps can't be good for any engine.
RJ: Wouldn't most New Looks call for 12R22.5 (or even 12-22.5 bias-plies) as OE? If so, how big a difference would the 11R22.5's on the drives make to top speed?
Also, the air compressor didn't cut-out until 130psi. Every other truck I've dealt with cut out at 120-125psi. Is this a problem? |
Guy Bouchard (209.162.160.90)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 24, 2003 - 3:00 pm: | |
High RPM on a Detroit isn't really a big problem. In 30 odd years of working on Detroits I've seen some scary governor settings come in.I've had a customer come in with a 4-71 that had been set to run a sawmill with the engine governor adjusted to run at 3800 RPM. He claimed he had bought it like that and he ran it for two years with no problems. It came in to repair oil leaks. Right now we are running a V12-71 with 255 injectors up to 6200 RPM with the pistons, rods ,heads and crankshaft stock; been running for five years in a Kenworth Puller truck. THIS IS NOT TO RECOMMEND THIS PRACTICE, only to show that running on the governor of a Detroit as RJ said will only affect your fuel expense.
Guy 4905 |
Don KS/TX (205.187.92.150)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 24, 2003 - 8:11 pm: | |
Wow Guy, screeming 6200 rpm! Does it smoke? |
Guy Bouchard (161.184.194.252)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 25, 2003 - 1:00 pm: | |
Don;
Smoke,scream and Flame. Gets some scary once in a while. It doesn't run at 6200 steady. It settles down and pulls around 3800- 4200. Not recommended for warranty or long life, but goes to show Detroits aren't your average diesel mill.
Guy 4905 |
Henry R. Bergman, Jr. (Henryofcj) (65.194.145.34)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 30, 2003 - 1:21 am: | |
And I thought N160's were HUGE for a little dinky 8V53! N255's? Very cool indeed.
6000 rpm with a 12V71TTII(?) Detroit? Wow!! And here I thought 2450 was really high.
Would love to hear the whine of that screaming machine. Detroits forever!!! Thank you Guy |
Johnny (67.241.232.27)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 30, 2003 - 9:57 pm: | |
I bet that might even drown out the straightpiped Cummins Ram 2500 4x4 (with 4" stacks & flappers) I see (and hear) around Quincy. Well, maybe..........
I need one of those. |
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