Adventures with dipstick warmer - Page 4 - PeachParts Mercedes-Benz Forum

vstech · #46 02-20-2015, 04:16 PM

Quote:

Originally Posted by strelnik

I would like to congratulate the mnany fine technicians who have added to this thread.

When I do my experiment, I will post temp data using the dipstick warmer I have.

I also have in mind a second experiment to determine the actual temp of the dipstick heating surface. If it is above 350, then it's going to be doing some damage to the oil

I would not recommend powering the warmer without it being submerged... It won't last long (think seconds)

If you want an idea of how hot the element can get, try this experiment... Get a coffee mug, fill it with clean motor oil, put a candy thermometer in it( a meat thermometer won't go high enough) and plug it in, be ready to unplug it. It won't take long to raise the temp in the mug. Then get out your calculator and find the heat raising factor of motor oil, and compute the volume of oil in the mug ( likely 1/16 gallon or 8 oz.) time how fast the temp goes up 100 degrees, and then figure out the heat.
(It's 3.06 btuh's per watt of electricity I think, so 90 watts is 2700ish btuh's)

funola · #47 02-20-2015, 04:41 PM

It will last more than a few seconds. I'd say 5 to 10 minutes. If it burns out, good riddance! The way to get a somewhat accurate measurement of the surface temp of the heater is with a small thermocouple and NOT with an IR thermometer. HF sells a DVM with thermocouple probe for around $30.

funola · #48 02-20-2015, 05:03 PM

[QUOTE=vstech;3444468]......the oil in funola's drum only gets to 100F because of the wattage of the filiment and the volume of oil surrounding the bulb... put the same bulb in a saucepan of oil and it would eventually burst into flames...
........./QUOTE]

The same bulb (40 W) in a saucepan of oil will not burst into flames. It is hot but not that hot because of the increase in surface area of the bulb glass compared to the surface area of the filament (lower heat density on the glass compared to the filament).

The reason 2 x 40 W bulbs can heat 55 gal barrel of oil to 100F is because the barrel's side and top is insulated, and the bulbs are submerged at the bottom, with 100% transfer of heat to the oil. The barrel is in a unheated garage and maintains 100F no problem when it's 0 F ambient. I have the barrel's thermostat set at 100 F, I think I can set it higher and it will heat it to a higher temp. How much higher? IDK without trying. It is not just how powerful a heater you have, but how fast (what you are heating) is losing heat (how well it is insulated).

moon161 · #49 02-20-2015, 06:49 PM

BTW, I love the out and out heat transfer speculation on my part and everyone else's. This thread is becoming quite enjoyable.

Will it all come to an end when someone gets a dipstick heater and it's actually boring?

vstech · #50 02-20-2015, 08:55 PM

[QUOTE=funola;3444558]

Quote:

Originally Posted by vstech

......the oil in funola's drum only gets to 100F because of the wattage of the filiment and the volume of oil surrounding the bulb... put the same bulb in a saucepan of oil and it would eventually burst into flames...
........./QUOTE]

The same bulb (40 W) in a saucepan of oil will not burst into flames. It is hot but not that hot because of the increase in surface area of the bulb glass compared to the surface area of the filament (lower heat density on the glass compared to the filament).

The reason 2 x 40 W bulbs can heat 55 gal barrel of oil to 100F is because the barrel's side and top is insulated, and the bulbs are submerged at the bottom, with 100% transfer of heat to the oil. The barrel is in a unheated garage and maintains 100F no problem when it's 0 F ambient. I have the barrel's thermostat set at 100 F, I think I can set it higher and it will heat it to a higher temp. How much higher? IDK without trying. It is not just how powerful a heater you have, but how fast (what you are heating) is losing heat (how well it is insulated).

Actually, it's not just about how fast (what you are heating) is losing heat either... (I know, you didn't say it was, I'm just completing the picture!) in addition to that, there is the factor of the temperature differential, the heat absorptive quality of the media, the boiling temp of the media, and the latent heat of vaporization of the media...

For instance, take water (simply because I know more about its properties)
1 lb of water takes 1btu to raise the temp 1 degree F. If you have a 1000 btu heater, you can raise the lb of water assuming it starts out at 32F as a liquid. It will rise to 212 F and stop. Because water not only needs 1 btu per pound per degree F raise, it also requires 900 btu per lb to change state and become a gas. So the 1000 btus will enter the water, 160 go into the water and the rest build up the heat of vaporization in the attempt to change state...

Oil, not only has a higher heat of vaporization, the vapor is combustible, so once the heat builds up in the small space of the coffee cup, it likely will burst into flames.

funola · #51 02-21-2015, 10:42 AM

[QUOTE=vstech;3444662]

Quote:

Originally Posted by funola

................
Oil, not only has a higher heat of vaporization, the vapor is combustible, so once the heat builds up in the small space of the coffee cup, it likely will burst into flames.

Deep fryers heat the oil to 370 F. I don't think a 40 W light bulb can get the oil that hot. There's plenty of oil vapor coming from a deep fryer. If what you say is true, there'll be a lot more kitchen fires.

Lucas · #52 02-21-2015, 03:42 PM

Quote:

Originally Posted by moon161

BTW, I love the out and out heat transfer speculation on my part and everyone else's. This thread is becoming quite enjoyable.

Will it all come to an end when someone gets a dipstick heater and it's actually boring?

Qualitative scientific research. Will the light bulb burn your finger.

Sent from my iPhone using Tapatalk

INSIDIOUS · #53 02-21-2015, 04:54 PM

Quote:

Auto ignition takes place at approximately 273º to 420ºC (523º to 788ºF),depending on the type of oil, the amount of impurities in it and usage

Deep fryer cooking oil ^

strelnik · #54 03-04-2019, 12:19 PM

Quote:

Originally Posted by funola

What, no welding? That's too simple and cheap to make! If you build a small plywood box for the light bulb that fits around the oil pan tightly, it would make it more efficient. Add more light bulbs as needed to increase wattage.

I could do this but that's a lot more cumbersome than plugging in a heater cord.

I have a friend in Sweden in a place called Öland who has a 1952 170DS. No block heaters on the older OM 636 so he made a tin box and fills it with charcoal to heat the block area and oil. Starts right up.

I have to see whether my latest heater cord went bad or if the block heater unit itself is bad. Didn't think that the cords went bad so quick.

It was 9 degrees this morning but the 240D started right up with no heat. It is well-tuned.

Sugar Bear · #55 03-04-2019, 01:28 PM

Consider using a synthetic oil during the cold season. It alone makes a major difference.

Good luck!!!