View Full Version : How smooth should the blower bores be?

06-14-2005, 02:07 AM
I took the blower down, and was surprised how rough the bores were???

There are concentric marks on the entire case, as though the rotors were rubbing...

Is this blower usable, or is this normal?

See pics for detail...


06-14-2005, 03:06 AM
That's what mine looked like when I did the rebuild, except mine also had some porosity from the casting process.

06-14-2005, 09:14 AM
I Dont think that will cause any kind of noticable difference
if you had some slight grooves

I have rebuilt several Blowers that also had grooves from rub marks and they all made excellent power with the grooves

What I would Do If i were you
Is pick up a Low mileage Rotorpack from a GTP and install it into that blower a long with a set uf new rotorpack rear bearings

06-14-2005, 09:22 AM
That's normal and is from debris getting into the SC. No big deal.


06-14-2005, 11:23 AM
Did some A-hole run this without a fiter, or does it just happen???

The other pics I've seen don't seem to have these groves....


06-14-2005, 11:32 AM
I think a lot of people don't latch the filter housing correctly (like the local grease monkey) and this allows dirt to enter the system. Almost every blower I have seen have some scoring on the walls and tips of the rotors. Some are worse some are better.


06-14-2005, 11:34 AM
its normal to see some its debris from god knows what mine was real bad I painted the outer walls with high temp paint it filled in the scratches.

and sealed up the blower to rotor gap some picked up almost 1 lb boost from this,
mine was bad, if anything fill in the scratches with high temp paint and wipe away the exess . dont paint the rotors it comes off spins very fast but on case it stays on check your air filter

06-14-2005, 02:23 PM
Thats what happened when you OD 10% +

06-14-2005, 04:14 PM
You can lessen the damage if you were to clean your blower of all of the oil accumulated on the rotors.The oil coats the rotors and the dirt stays in the blower and contributes to increased rotor damage.

06-14-2005, 04:41 PM
Thats what happened when you OD 10% +

To my knowledge, this blower was never overdriven....