My engine is being done right now.When I told my machine shop I was supercharging he told my something about needed to have a extra bolthole drilled on my crank or the pulley of the SC would tearup the crank.He was saying something about a keyhole orthree way key, something like that.Has anybody heard of this?Thanks

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89 formula 350, 73000k, 9-bolt 3.27, gutted MAF,dynomax muffler,gutted air box,kn,accel 8.8 coil wires,dunlop 60/235
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Yes, the pully that runs the belt has a key way to keep the pully from sliping on the crank. if you are putting a blower on it, there is the chance that you are going to shear the key off. this happens more on Roots style blowers that put a larger load on the crank than the centrifugals do. for large boost apps, this is a good idea, but i bet that there are a bunch of guys here on list that are running good amounts of boost that do not have second or third keys.

 

iv been running my blower for three years
and run the max boost i can and never had
a key strip on me.

check out my simple page at:
Http://darcom.home.texas.net/

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388 SuperRam, DFI, Vortech R trim ,N.O.S.,alki injection,
Dart sportmansII heads,50 pound injectors, Headman full headers
duel 3' exhaust,and Flowmasters, Ford nine inch with 370's
Ronal rims with Nitto drad raidals.

 

Is the key part of the crank or the pulley?What happens if the key strips? Will it cause less damage if the blower is self-contained like the Procharger? Thanks again!

 

The one that I saw first hand sheered the key right off flush with the crank. if you can imagine 1/2 the key was in the groove in the crank & 1/2 the key was in the groove in the Ballancer. knowing how hard it is to get a ballance off when the key is good imagine trying to get one off w/the key sheared off & little pieces of key stuck inbtween the shaft & the ballancer. it is a royal pain in the rear.

But as DARCOM said, there are a LOT of guys out there that dont see this, 'specially with the centrifugals. it is when you run large boost 6-61's & 8-71's (& i suppose large centrifugals as well) that they put a large load on the pulley to turn. if you have ever tried to turn a blower by hand you know what this is like. now try to spin it under pressure & @ 6000 rpm. this is LOAD.

BW

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Bobalos
aka Bob W.
www.r71camaro.homestead.com
r71chevy@earthlink.net
<><

 

i supose if the key did strip it would mean
that your motor would run but your accesserys
would not turn or turn slowy and would
eventuly were out the snout on the end of the
crank.
the key is a peace of hightencle steel thats
shaped like a half circle and fits in a slot
between the crankshat and harmonic balancer.


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388 SuperRam, DFI, Vortech R trim ,N.O.S.,alki injection,
Dart sportmansII heads,50 pound injectors, Headman full headers
duel 3' exhaust,and Flowmasters, Ford nine inch with 370's
Ronal rims with Nitto drad raidals.