Hot bulb diesels

[rpeebles]

How efficient are they? And can they run on just about any oil?

[deniseO30]

some are kinda large here's one.. nice 45 HP.. weighs oh, about a ton?



http://auto.howstuffworks.com/hot-bulb-engine1.htm

dunno about heating fuel on boat, but they did do it back in the day!

[deniseO30]

Think I could fall asleep listening to this one! (just an old Diesel)
[IMG][/IMG]

[Leftbrainstuff]

Many years ago it was possible to run many diesel engines, with the old style pintle injectors, on anything from sump oil ro used cooking oil. With any of the modern 'clean diesels' your options are limited. Increased wear is usually the result.

[Capt Len]

Wow that was great . I grew up with open valved Easthopes spraying oil on my bunk and the old make and breaks but the best was the hot bulb semidiesel on the sv Havorn. I sailed as crew on her in the Med and across to Trinidad back in "67 She on her 2nd childhood now.Second voyage to Tahiti but the engine ... Wow.

[SloopJonB]

Originally Posted by deniseO30

some are kinda large here's one.. nice 45 HP.. weighs oh, about a ton?



HowStuffWorks "Making it Go"

dunno about heating fuel on boat, but they did do it back in the day!

A TON??? That FLYWHEEL must be close to that. And I thought my old one lung Yanmar shook! That looks like one of those slow turners where the skipper rings the engine room for 2 more rpm.

[Capt Len]

It's not the fuel that was heated, just the hot bulb.We used a pump up kerosene blowtorch for the initial start.Hung from the deckhead a on designated coat hanger and blew directly into a depression on the outer surface of the hot bulb. This took a while so you needed to know where the rocks are. Then ,with the piston at just past TDC a shot of compressed air. Then a shot of air and fuel and then again. and again. If you were dancing to the same music the 6 ft dia two bladed prop is now waiting for pitch command. Good thing the old Colin Archers were built hefty because the entire stern nodded to the beat.

[klem]

To the OP's questions, yes they can burn a wide range of fuels. They won't burn anything but anything relatively similar to diesel in combustion properties usually works.

As for efficiency, they are not super efficient for their horsepower and they are really inefficient in terms of power to weight. The fuel burn rate of newer engines is better for a handful of reasons including modern injectors (precise fuel timing), modern combustion chamber design, rpm (faster=less ring leakage), modern valves (better airflow).

They are really neat engines though. My personal favorites are the old direct reversing engines in a lot of tugs but these are certainly cool.