Well, I always thought they did.
Just done a 'refurbish' on an old Benford dumper - single cylinder Petter diesel with an AVA engine. (Direct injection).
I couldn't find a new piston and barrel - this thing was so down on compression that the motor would turn over on the crank handle whether the decompression lever was on or off - seriously it made no difference, the wheeze between piston and barrel could be heard 100 yards away.
I duly informed the owner that it was knackered, and we would need a new piston and barrel to go any further and it would never run again like it was. (I had fitted a new injector by then, as the old one was seriously damaged).
The owner appeared, and being built like a bear cranked the engine over....it started up immediately!
Believe me, I reckoned the compression ratio was about 6:1 - how it started I'll never know
John
Just done a 'refurbish' on an old Benford dumper - single cylinder Petter diesel with an AVA engine. (Direct injection).
I couldn't find a new piston and barrel - this thing was so down on compression that the motor would turn over on the crank handle whether the decompression lever was on or off - seriously it made no difference, the wheeze between piston and barrel could be heard 100 yards away.
I duly informed the owner that it was knackered, and we would need a new piston and barrel to go any further and it would never run again like it was. (I had fitted a new injector by then, as the old one was seriously damaged).
The owner appeared, and being built like a bear cranked the engine over....it started up immediately!
Believe me, I reckoned the compression ratio was about 6:1 - how it started I'll never know
John