Re: [MBZ] Theory vs Practice
Diesels use very little fuel except when accelerating since heating air at high compression ratios yeilds plenty of pressure to spin the engine (and hence the need for a governor -- engine runs away at constant fuel addition above what is required for idle, What happens, I think, at low load is that combustion temps are low due to the very small amount of fuel injected, and the flame goes out before all the fuel burns properly. The resultant :sticky' soot clogs up the rings so you loose compression, and can cause the valves to stick open from buildup on the stem. You get low compression from leaks, and loose power. A good highway run burns all the carbon off, and the high temps get rid of the crud, so the rings seat properly again and the valves seal, etc. Diesel engines are built sturdy to cope with the high compression -- this requires larger carnkpins and bearings, etc, and are usually also built for endurance -- full skirt pistons, generous block castings, etc. Not light, but since the peak pressures from fuel/air ignition are actually considerably lower in a disesel than in a gas engine, if the oil is changed and nothing breaks, they don't wear much. From what little I've seen, what kills them is worn out cylinders, probably from failure to change the oil enough, followed by running out of oil and engine seziure. Occasionally an oil filter housing lets go or an oil pump (or pump chain) breaks, other than that, it takes abuse to kill them. My friend Hans had a W126 chassis come in for an oil change with more than 500,000 miles on it, nothing but routine mainenance. He even had a 350SDL in the shop with 350,000 on it in there! Peter
Re: [MBZ] Theory vs Practice
Yup, that's theory alight...
Re: [MBZ] Theory vs Practice
rumor has it that Peter wrote: Diesels use very little fuel except when accelerating since heating air at high compression ratios yeilds plenty of pressure to spin the engine (and hence the need for a governor -- engine runs away at constant fuel addition above what is required for idle, ???!!?!! Are you saying that the high compression creates enough pressure that there is enough energy to spin the engine with no fuel? That, my friends, would be perpetual motion!! My diesels are good - but not _that_ good... Philip, not really an engineer - but I look like one. Sometimes.
Re: [MBZ] Theory vs Practice
--- kevin kraly [EMAIL PROTECTED] wrote: My experience is that my cars tend to run better when they're driven hard. What does running hard like this mean to the transmission? Would that wear down the transmission faster? If that's the case, I'd rather run the engine at lower efficiency than having to shell out 2K for a new trannny. David 83 300DT __ Discover Yahoo! Stay in touch with email, IM, photo sharing and more. Check it out! http://discover.yahoo.com/stayintouch.html
Re: [MBZ] Theory vs Practice
What does running hard like this mean to the transmission? Would that wear down the transmission faster? That's hard to say. Generally, everything wears faster when the car is pushed harder, but driving at low RPM builds up carbon which can kill an engine over time. The tranny usually shifts more crisply when accelerating hard, so it's probably a matter of which thing you want to replace, a carboned-up engine or a transmission. Anyone care to jump in on this one? Kevin in Hillsboro Oregon 1978 300D 132K miles, Ingrid 1978 300CD 200K+ miles, Vinnie 1982 Mazda B2200 diesel pickup, 142K miles, Gopher
Re: [MBZ] Theory vs Practice
--- kevin kraly [EMAIL PROTECTED] wrote: pushed harder, but driving at low RPM builds up carbon which can kill an engine over time. I thought Diesel Purge could clear up the carbon buildup? David Yahoo! Sports Rekindle the Rivalries. Sign up for Fantasy Football http://football.fantasysports.yahoo.com
Re: [MBZ] Theory vs Practice
David Johnson wrote: What does running hard like this mean to the transmission? Would that wear down the transmission faster? If that's the case, I'd rather run the engine at lower efficiency than having to shell out 2K for a new trannny. I'm convinced accellerating hard is actually easier on the tranny in my 300D Turbo. When I accellerate moderately, it tends to flare or hang during shifts. When I accellerate hard, it shifts firmly and crisply. A firm shift *has* to be easier on the internal clutches and bands. Besides, it's a Mercedes automatic. It'll blow up no matter what you do. ;) The one in my car has already had one rebuild, according to the previous owner.
Re: [MBZ] Theory vs Practice
Anyone care to jump in on this one? Kevin in Hillsboro Oregon Kevin and all. About my experience of running hard and transmission wear: For 5-6 years, I autocrossed w/my '80 300SD in the GWS series in the DC area. The series runs for 8 months, once a month. That's over 40 times out, each w/about 6-8 runs thru the course. So the total is between 200-300 runs. My tactic at the start line was - In S gear, run revs up to about 2200 rpms while holding the brake on. Then dump the brake. Floor the accelerator pedal. The turbo is spooled up so there is little lag. Truly, it is driving like you stole it around a 60 sec. course. All the while being careful to not hit any course cones. I also disconnected the vacuum line to the shift modulator, giving me VERY crisp gear changes. Did use up a lot of BFG R-1 race tires. Even given that kind of exercise, the trans is still in the car and never has had a problem of any kind. I do change trans fluid/filter about every 10kmiles. She still gets off the line w/lots of vigor. In September, we will be at the GWS Tri-O-Rama doing time trials, autocross and acceleration runs. Take care, Chuck Phoenix, AZ On Tuesday, June 28, 2005, at 11:31 PM, kevin kraly wrote: What does running hard like this mean to the transmission? Would that wear down the transmission faster? That's hard to say. Generally, everything wears faster when the car is pushed harder, but driving at low RPM builds up carbon which can kill an engine over time. The tranny usually shifts more crisply when accelerating hard, so it's probably a matter of which thing you want to replace, a carboned-up engine or a transmission. 1978 300D 132K miles, Ingrid 1978 300CD 200K+ miles, Vinnie 1982 Mazda B2200 diesel pickup, 142K miles, Gopher ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net
Re: [MBZ] Theory vs Practice
a crisp shifting tranny will last much longer than a soft shifting one. kevin kraly wrote: What does running hard like this mean to the transmission? Would that wear down the transmission faster? That's hard to say. Generally, everything wears faster when the car is pushed harder, but driving at low RPM builds up carbon which can kill an engine over time. The tranny usually shifts more crisply when accelerating hard, so it's probably a matter of which thing you want to replace, a carboned-up engine or a transmission. Anyone care to jump in on this one? Kevin in Hillsboro Oregon 1978 300D 132K miles, Ingrid 1978 300CD 200K+ miles, Vinnie 1982 Mazda B2200 diesel pickup, 142K miles, Gopher ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net -- Kaleb C. Striplin/Claremore, OK 89 560SEL, 87 300SDL, 87 300SDL, 85 380SE, 85 300D, 81 300TD, 81 240D, 81 240D, 76 240D, 76 300D, 74 240D, 69 250 Okie Benz Auto parts-email for used parts
Re: [MBZ] Theory vs Practice
you need to get yours adjusted properly. David Brodbeck wrote: David Johnson wrote: What does running hard like this mean to the transmission? Would that wear down the transmission faster? If that's the case, I'd rather run the engine at lower efficiency than having to shell out 2K for a new trannny. I'm convinced accellerating hard is actually easier on the tranny in my 300D Turbo. When I accellerate moderately, it tends to flare or hang during shifts. When I accellerate hard, it shifts firmly and crisply. A firm shift *has* to be easier on the internal clutches and bands. Besides, it's a Mercedes automatic. It'll blow up no matter what you do. ;) The one in my car has already had one rebuild, according to the previous owner. ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net -- Kaleb C. Striplin/Claremore, OK 89 560SEL, 87 300SDL, 87 300SDL, 85 380SE, 85 300D, 81 300TD, 81 240D, 81 240D, 76 240D, 76 300D, 74 240D, 69 250 Okie Benz Auto parts-email for used parts
Re: [MBZ] Theory vs Practice
Kaleb C. Striplin wrote: you need to get yours adjusted properly. Quite possibly. It shifts fine at light throttle and full throttle. Not so hot in between. I don't have the special gold-plated gauge to measure the internal trans pressure, though, so I'm afraid to monkey with it.
Re: [MBZ] Theory vs Practice
you can make your own pretty easy, lots of folks have. David Brodbeck wrote: Kaleb C. Striplin wrote: you need to get yours adjusted properly. Quite possibly. It shifts fine at light throttle and full throttle. Not so hot in between. I don't have the special gold-plated gauge to measure the internal trans pressure, though, so I'm afraid to monkey with it. ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net -- Kaleb C. Striplin/Claremore, OK 89 560SEL, 87 300SDL, 87 300SDL, 85 380SE, 85 300D, 81 300TD, 81 240D, 81 240D, 76 240D, 76 300D, 74 240D, 69 250 Okie Benz Auto parts-email for used parts
Re: [MBZ] Theory vs Practice
hey hank...interesting math, but i didn't go anywhere near mexico city or high elevations...the cruise along the west coast of mexico (not baja) is essentially along the coastal lowlands...so it was mostly attitude (not altitude) and which music in the player that influenced speed and therefore mileage. Drag (air resistance) is approx. proportional to the speed squared and inversely proportional to air density. Driving from Arizona to Mexico City is uphill just about all the way with southern AZ at 1000' elev. and Mexico City at 7300'. You had several variables to influence your mpg, speed, altitude, and grade. Last spring I got 31mpg going from Albuquerque 5300' elev. to Farmington NM 5600' elev. at 75+ mph with a few 7000' passes. I've never gotten that good an mpg at lower elevations and I'm starting to think I had less drag because of the thinner air due to evel. and cooler temp. Prior to this I thought Chevron diesel had more BTUs and I think it may. In Tulsa I also experience better mpg using Phillips vs Texaco diesel. 73 Hank WD5JFR - Original Message - From: JJJ [EMAIL PROTECTED] To: Mercedes mailing list [EMAIL PROTECTED] Sent: Tuesday, June 28, 2005 7:15 PM Subject: Re: [MBZ] Theory vs Practice when i drove my '86 300sdl to mexico last year (7000 miles), i mostly watched the mileage...if i went 75 or below, i might get 27-8mpg...around 85mph, i might get 25mpg...when we cruised at 105 for two hours at a time on the new toll roads (and in utah), i got 19mpg... the car gets about 25mpg around town with my foot in it... but when i came back, diesel in washington state was more than high-test and sorta scotched any idea of diesel economy! but, if mexico don is ready for us again, i'm ready to entertain any mileage experiments offered for another run next winter ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net
Re: [MBZ] Theory vs Practice
Here I going again, jumping to conclusions. Got quit that. Hank - Original Message - From: [EMAIL PROTECTED] To: Mercedes mailing list [EMAIL PROTECTED] Sent: Wednesday, June 29, 2005 11:57 AM Subject: Re: [MBZ] Theory vs Practice hey hank...interesting math, but i didn't go anywhere near mexico city or high elevations...the cruise along the west coast of mexico (not baja) is essentially along the coastal lowlands...so it was mostly attitude (not altitude) and which music in the player that influenced speed and therefore mileage. Drag (air resistance) is approx. proportional to the speed squared and inversely proportional to air density. Driving from Arizona to Mexico City is uphill just about all the way with southern AZ at 1000' elev. and Mexico City at 7300'. You had several variables to influence your mpg, speed, altitude, and grade. Last spring I got 31mpg going from Albuquerque 5300' elev. to Farmington NM 5600' elev. at 75+ mph with a few 7000' passes. I've never gotten that good an mpg at lower elevations and I'm starting to think I had less drag because of the thinner air due to evel. and cooler temp. Prior to this I thought Chevron diesel had more BTUs and I think it may. In Tulsa I also experience better mpg using Phillips vs Texaco diesel. 73 Hank WD5JFR - Original Message - From: JJJ [EMAIL PROTECTED] To: Mercedes mailing list [EMAIL PROTECTED] Sent: Tuesday, June 28, 2005 7:15 PM Subject: Re: [MBZ] Theory vs Practice when i drove my '86 300sdl to mexico last year (7000 miles), i mostly watched the mileage...if i went 75 or below, i might get 27-8mpg...around 85mph, i might get 25mpg...when we cruised at 105 for two hours at a time on the new toll roads (and in utah), i got 19mpg... the car gets about 25mpg around town with my foot in it... but when i came back, diesel in washington state was more than high-test and sorta scotched any idea of diesel economy! but, if mexico don is ready for us again, i'm ready to entertain any mileage experiments offered for another run next winter ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net
Re: [MBZ] Theory vs Practice
Mitch, The gas engine may well be more efficient at full throttle, but that efficiency is offset to some degree by compression stroke power loss which increases as intake vacuum decreases. I am theorizing that the diesel efficiency curve is steeper than the gasser curve. Bruce --- Mitch Haley [EMAIL PROTECTED] wrote: B Dike wrote: On the other hand, a gasser has much less compression, and compression power loss is proportional with throttle setting due to their intake air butterfly. Backwards. Sucking a vacuum in the intake causes loss in efficiency. Your gasser will see maximum horsepower-hour/btu of fuel when running full throttle at peak torque rpm. Gearing up and using more throttle opening when requiring low power increases mpg in a gas engine more than it does in a diesel. The best reason to drive a diesel like you stole it is to keep it clean of unburned fuel residues. ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net Bruce 82 300CD 333kmi 'His' 85 300CD 234kmi 'Hers' 75 240D 185kmi 'Theirs' (Back in Commission) 77 240D 199kmi 'The Brown Car' __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Re: [MBZ] Theory vs Practice
Not nessasarly true about blowing up. MY 1982 380SEL 487,000 miles on the orginal tranny. Filter always changed at roughly 50-60,000 miles. Don On 6/29/05, David Brodbeck [EMAIL PROTECTED] wrote: David Johnson wrote: What does running hard like this mean to the transmission? Would that wear down the transmission faster? If that's the case, I'd rather run the engine at lower efficiency than having to shell out 2K for a new trannny. I'm convinced accellerating hard is actually easier on the tranny in my 300D Turbo. When I accellerate moderately, it tends to flare or hang during shifts. When I accellerate hard, it shifts firmly and crisply. A firm shift *has* to be easier on the internal clutches and bands. Besides, it's a Mercedes automatic. It'll blow up no matter what you do. ;) The one in my car has already had one rebuild, according to the previous owner. ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com http://www.buymbparts.com For repairs see www.oldworldauto.com http://www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net -- Don Teresa Merriman Market Place Mexico Vacation Rentals Property Administration
Re: [MBZ] Theory vs Practice
I'm convinced accellerating hard is actually easier on the tranny in my 300D Turbo. When I accellerate moderately, it tends to flare or hang during shifts. When I accellerate hard, it shifts firmly and crisply. David, This is my theory as well. Less slippage should mean longer life as does less carbon in the engine, so keep on driving hard! Kevin in Hillsboro Oregon 1978 300D 132K miles, Ingrid 1978 300CD 200K+ miles, Vinnie 1982 Mazda B2200 diesel pickup, 142K miles, Gopher
Re: [MBZ] Theory vs Practice
I thought Diesel Purge could clear up the carbon buildup? It can clean up injector nozzles pretty well, but I'm not sure about carbon that's built up over time. Marshall once said that it could take thousands of miles of hard driving and long highway runs to clean up an engine in a car driven with a light foot mostly in the city. Kevin in Hillsboro Oregon 1978 300D 132K miles, Ingrid 1978 300CD 200K+ miles, Vinnie 1982 Mazda B2200 diesel pickup, 142K miles, Gopher
Re: [MBZ] Theory vs Practice
B Dike wrote: Mitch, The gas engine may well be more efficient at full throttle, but that efficiency is offset to some degree by compression stroke power loss which increases as intake vacuum decreases. N! Vacuum is the enemy of efficiency. On a gas engine with constant compression ratio, the energy consumed in compressing the intake charge is a relatively constant fraction of the energy harnessed in the combustion phase. If what you are saying were true, you could increase efficiency by adding an extra head gasket and decreasing the compression ratio. The opposite is true, high compression ratio leads to higher efficiency, until you reach the point where detonation becomes a factor.
Re: [MBZ] Theory vs Practice
that tranny still workin'?...maybe it likes the warm weather
Re: [MBZ] Theory vs Practice
My experience...mostly following Marshall's advice: I bought a 300SD last September that had been driven with a light foot for 19 years. Had 188K when I bought it. Now has 206K. Mostly highway miles. Diesel Purged a couple times, drove/drive it hard/italian tune ups on the open road. First valve adjust (when I just got it) showed how HORRIBLE the carbonization was. Had the valves adjusted recently and injectors replaced and the engine was pronounced very clean. Used Diesel Hi-Test for a while too (expensive). RUNS SO MUCH BETTER NOW! Also added the BERU new glow plugs the do pre-glow, starting-glow and post-glow and those also are wonderful and I think the post glow keeps soot down and is a tiny help in the battle against carbonization. Simply, I made excuses for alot of long road trips. Kept car in 3rd when around town 45 mph and lower...saves the tranny a bit too. Low RPM city miles are BAD for coking. Christopher --- kevin kraly [EMAIL PROTECTED] wrote: I thought Diesel Purge could clear up the carbon buildup? It can clean up injector nozzles pretty well, but I'm not sure about carbon that's built up over time. Marshall once said that it could take thousands of miles of hard driving and long highway runs to clean up an engine in a car driven with a light foot mostly in the city. Kevin in Hillsboro Oregon 1978 300D 132K miles, Ingrid 1978 300CD 200K+ miles, Vinnie 1982 Mazda B2200 diesel pickup, 142K miles, Gopher ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net Christopher McCann, Raytown, Missouri -1985 300SD, 206K miles, Wulf http://don.homelinux.net/mbz/Chris -1976 240D, ManyK miles, AKP-Wagen (Alternativen Kraftstoffs Prüfenlastwagen = Alternative Fuel Test Vehicle) -1998 Toyota Sienna CE, 99K miles, The Van __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Re: [MBZ] Theory vs Practice
B Dike wrote: On the other hand, a gasser has much less compression, and compression power loss is proportional with throttle setting due to their intake air butterfly. Backwards. Sucking a vacuum in the intake causes loss in efficiency. Your gasser will see maximum horsepower-hour/btu of fuel when running full throttle at peak torque rpm. Gearing up and using more throttle opening when requiring low power increases mpg in a gas engine more than it does in a diesel. The best reason to drive a diesel like you stole it is to keep it clean of unburned fuel residues.
Re: [MBZ] Theory vs Practice
My experience is that my cars tend to run better when they're driven hard. When I first picked my 300CD up down in Southern California, it was sluggish, but once it was floored up the grapevine, it ran better, and during the rest of the trip running 75-80MPH, it got nearly 30MPG. When it's driven lightly around town, mileage isn't nearly that good at only 22-24MPG. Gunning it away from every stop light is great too. Kevin in Hillsboro Oregon 1978 300D 132K miles, Ingrid 1978 300CD 200K+ miles, Vinnie 1982 Mazda B2200 diesel pickup, 142K miles, Gopher
