ok to do this?

is it ok to run an upper pulley like this?



low overdrive situation... like 15%

prefer fact vs opinion

 

I've seen guys run like this at over 30% OD with no problems.

 

They run that way on the crank don't they? No difference. The pulley will take the load either way, regardless of overdrive, and the snout won't care.

-Brian

 

I agree, but when I asked on this forum before, someone came on here and said there pulley cracked when they did it. We ended up with a 12" snout so I never tried it.

 

this is what i was thinking... in my mind i can't see why the pulley would know the difference whether it was running top or bottom. now the snout... i could see it getting stressed if you hung it way out there and pushed the od way up

then there's this... wonder if the crack was 'placement' related or a pulley issue? would love to know the details surrounding it. pitch, od, pulley age/cond, etc

 

I see no reason not to do this
just watch the rear studs for stretching or breaking as the leverage is higher with the longer front drive

 

great point man... that did cross my mind too. if i end up running it this way i'm gonna build a support to go under the front of the snout

appreciate all the input guys

 

How long is your snout?
I have run for several years with 5.25" (might be 5.75") long SSI snouts without any extra supports.

 

For the pulley there will be no difference. But you are creating much more load on the shaft in the blower snout so I would not do it. Don't forget that the diameter on the snout of the crankshaft is much bigger then the diameter of the blower snout shaft.

Frank

 

this is no different to using a 2.5" spacer behind the pully.
iv always been told its a bad thing and increases bearing load on the snout ect which i can see,
but on the other hand its done by teams in pm where the blowers are set back,
i was surprised at just who does this and if its not a problem for a pro blower guy its no problem for me,

 

You might want to think about a billet front cover. That's a lot of leverage on a cast cover.

On the bottom, the hub is on the crank with a tight fit, close to a main web.Maybe 3 inches from the main.

On the top, the cover is bolted to the blower, the snout is bolted to the cover.Then the pulley is bolted to the snout.From the face of the blower, to where the pulley end, it's maybe 7 to 9 inches. Inside, the coupler is bolted to the gear, the snout shaft is slip-fit to the coupler, and the bearings are about in the middle. Nothing fitted on top like the bottom.

I'm sure it's been done, but it might be ugly if something pulls down, and breaks.

 

I did it for a couple years on a Littlefield 14 helix, cast cover with a 6.5 in snout turning 40 over.
Never had an issue with pully, bearing, cover or studs