Semi-diesel?

Aug 18, 2004 10 Replies

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I don't want to get into the whole when is a diesel not a diesel debate again, but is this really as described - a semi-diesel made in 1954?


My point, as I'm sure you know Martin ;-) being that I thought the semi-diesel as a species had died out well before the 1950's.

Ah, a sensible answer - thanks Dan. I guess that is going to be a few bobs worth then? Must be pretty desirable for narrow boats etc.

See you at Barleylands? Starting handles at dawn then ;-)

Turning in now. Night Night.

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A diesel is a diesel whether it is a semi or diesel surely :-))

Interesting lump all the same.

Martin P

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Semi-diesels carried on for much longer than was to be expected considering the age of the technology. They were attractive to marine use particularly as they are much lower stressed than a full diesel, usually a simpler fuel system, and many were able to be reversed without an expensive gearbox. Lamp start Lanz Bulldog tractors were also made well into the 50s.

Regards

Dan

Like all these things - it will need 2 bidders to get a reasonable price. It is also uncommon, so that may put off boat owners due to lack of spares availability, plus it's in Ipswich which isn't the handiest of places to get to. Would be nice driving a large genny though....

Dan

I used to have a little Seffle semi-diesel which was from, ISTR, circa

1964. I have been led to believe that bigger semi diesels for fishing boats were available in Scandinavia well after that date. Not seen firm evidence of that, though.

Cheers Tim

Tim Leech Dutton Dry-Dock

Traditional & Modern canal craft repairs

Are you per chance implying that my answer was far from sensible Sir, choose your weapon and meet me at a quiet spot for a duel :-))

Martin P

There was also one on Harry Matthews Engineads website this week, described as a Saab....

Located in California :-))

Peter

-- Peter & Rita Forbes snipped-for-privacy@easynet.co.uk Engine pages for preservation info:

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Bolinders were still making their W series until quite late, and as Dan has mentioned already the Lanz engine was also still made into the 1960's.

Main differences as I understand them:

Semi-diesels have sprayers rather than injectors. Compression ratio is lower and insufficient to create ignition by itself when the engine is cold. Injection pressure is much lower than a full diesel and the pump is a simple piston type with volume control. External heat is usually required to get the beast going. Reversing of the engine is possible by varying the fuel timing, implying that most if not all are also two-stroke engines with symmetrical port timing.

Some of that applies to Hot-Bulb engines as well.......

Peter

-- Peter & Rita Forbes snipped-for-privacy@easynet.co.uk Engine pages for preservation info:

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