Swiftun crankshaft with five main bearings, instead of three
Posted: Sat Jan 15, 2011 6:41 pm
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Swiftun crankshaft with five main bearings, instead of three
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Re: Swiftun crankshaft with five main bearings, instead of t
Posted: Sat Jan 15, 2011 6:48 pm
Re: Swiftun crankshaft with five main bearings, instead of t
Posted: Sat Jan 15, 2011 7:04 pm
Doh!
Re: Swiftun crankshaft with five main bearings, instead of t
Posted: Sat Jan 15, 2011 8:20 pm
The description is a bit missleading... It's a crank designed like a modern 5 bearings crank, with two "dummy journals". It uses only 3 main bearings, but has - according to Swiftune - a much improofed counter balance due to it's design."
"Starting with a clean sheet of paper we have designed the new DC5 crankshaft with five main bearings, instead of three, so creating two “false” journals which enables the counterbalance to be doubled. Just as important the new design allows straight, no-off set con rods to be adopted – a first for an A series engine. They save weight and reduce the longitudinal side thrust on the piston. The DC5 con-rods are ¼ in longer than standard with the benefit that the reduced angularity at the small end reduces lateral friction losses on the piston under power."
Look at the pic from theother thread Vegard/Mark posted - it's quite obvious and very simple:
"Starting with a clean sheet of paper we have designed the new DC5 crankshaft with five main bearings, instead of three, so creating two “false” journals which enables the counterbalance to be doubled. Just as important the new design allows straight, no-off set con rods to be adopted – a first for an A series engine. They save weight and reduce the longitudinal side thrust on the piston. The DC5 con-rods are ¼ in longer than standard with the benefit that the reduced angularity at the small end reduces lateral friction losses on the piston under power."
Look at the pic from theother thread Vegard/Mark posted - it's quite obvious and very simple: