What's a double key pulley vs single key pulley?
- Thread starter blumnday99
- Start date
The double key has a slot for a second woodruff key. Instead of the turning load being put on one key, it's shared between two. The shaft has to be machined for the second key.
So I'm assuming a stock procharger D1SC shaft is made for a single key pulley. When does it become advantageous to switch to a double key pulley?
You would be correct. I really don't know. I think a lot of people are in the 20+psi range with a single key and no problems.
what he said
When you go to a large blower like a 6-71 or larger it is a MUST to have the crankshaft cut with a double keyway and run a steel SFI double keyed harmonic balancer (not a fluid filled balancer).The stock cast balancer with the combination of the small single key in the crank will not hold up to the torsional load applied to the nose of the crankshaft from the superchager. The engine should be built for a blower this large any way and should already have a steel crankshaft. For a cobra i rec. double keying a 3.4
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