[stevej66]

I have a new Weiand 671 and am having a problem with pressure in the front gear housing at 3500 rpms and above. Weiand says it is ok but if I don't vent it, it leaks by the front nosecone seal. If I vent it, it comes out the vent under pressure at 3500 and above. What is the causing this and what is the fix.
Thanks,
Stevej66

[41willys]

I would call Weiand and ask to speak with a supervisor of tech support. You will get pressure in the front cover, but the pressure is not supposed to be relieved unless repairs are being made and the front cover is being removed.

You will obviously get pressure in the front cover, but the fact that it is puking fluid states that it is excessive. This could be caused by an issue from the blower case to the backside of the front cover. At 3500+ RPM's you are making boost, and the pressures are making it into the front gear housing. Could be a seal, a bad gear housing, or a bad case.

That is just my guess.

Jason

[techinspector1]

Never having rebuilt a Weiand, I'll give this a shot anyway. It seems obvious that the gear housing is getting pressurized from boost. Pressure could get into the housing, the way I see it, by one of the following ways:
1. Porous front cover casting.
2. Casting not flat and parallel with the blower case, allowing boost to push past the rotor shaft seals.
3. Faulty rotor shaft seals or perhaps seals that were installed backwards (if that's possible??).

Like I said, no hands-on experience at it, just trying to help you think it out.

41 Willys, sorry, I was typing my reply and you had already posted.

[41willys]

Techinspector, de nada.

I am still trying to figure out why he was told it is normal, or that Weiand tells him it is o.k. I was thinking the same thing you stated, just not as detailed as yours.

Jason

[techinspector1]

1. They don't want to be bothered with after-sale support.
2. They don't have to clean up the mess.
Those would be my best guesses.

Like you said, I'd be gettin' hold of somebody who could make it right, all the way to the chairman of the board if necessary.

[BOBCRMAN@aol.com]

I am far from an expert on the subject. But, my B&M/Weiand blower also has had some vent issues since new. A simple/terrible venting system. Now has over six thousand miles in a street rod. I just clean up the drips when I wash the car/motor.

I asked one of my customers, an engineer on the supercharged GM 3800 engines project, about the venting problem.

His reply was that GM also had venting problems. Theirs is a much more sophisticated setup. But, they settled on venting thru the drive shaft of the blower. Somewhat solved their problems.

You are going to get some pressure in the front cover.

[techinspector1]

Thanks Bob. It's beginning to sound like everybody has the problem to one extent or another. The Rube Goldberg side of me can envision a catch can mounted higher than the housing, stuffed with steel wool and vented to atmosphere on the top of the can. Whatever oil blows up into it will, by gravity, flow back into the housing when the motor is shut off.

[stevej66]

Thanks,
I've already done that and it has so much pressure it will empty the oil reservoir.

[stevej66]

Originally Posted by 41willys

I would call Weiand and ask to speak with a supervisor of tech support. You will get pressure in the front cover, but the pressure is not supposed to be relieved unless repairs are being made and the front cover is being removed.

You will obviously get pressure in the front cover, but the fact that it is puking fluid states that it is excessive. This could be caused by an issue from the blower case to the backside of the front cover. At 3500+ RPM's you are making boost, and the pressures are making it into the front gear housing. Could be a seal, a bad gear housing, or a bad case.

That is just my guess.

Jason

Jason,
Thanks for the input. I was just informed by BDS that there has to be pressure in the gear case for the seals to work properly. Also I should not vent the case but use a manual pressure relief valve to periodically relieve pressure to prolong seal life.
Thanks again,
Steve

[stevej66]

Originally Posted by techinspector1

Never having rebuilt a Weiand, I'll give this a shot anyway. It seems obvious that the gear housing is getting pressurized from boost. Pressure could get into the housing, the way I see it, by one of the following ways:
1. Porous front cover casting.
2. Casting not flat and parallel with the blower case, allowing boost to push past the rotor shaft seals.
3. Faulty rotor shaft seals or perhaps seals that were installed backwards (if that's possible??).

Like I said, no hands-on experience at it, just trying to help you think it out.

41 Willys, sorry, I was typing my reply and you had already posted.

Thanks for the input. I was just informed by BDS that there has to be pressure in the gear case for the seals to work properly. Also I should not vent the case but use a manual pressure relief valve to periodically relieve pressure to prolong seal life.
Thanks again,
Steve

[stevej66]

Originally Posted by BOBCRMAN@aol.com

I am far from an expert on the subject. But, my B&M/Weiand blower also has had some vent issues since new. A simple/terrible venting system. Now has over six thousand miles in a street rod. I just clean up the drips when I wash the car/motor.

I asked one of my customers, an engineer on the supercharged GM 3800 engines project, about the venting problem.

His reply was that GM also had venting problems. Theirs is a much more sophisticated setup. But, they settled on venting thru the drive shaft of the blower. Somewhat solved their problems.

You are going to get some pressure in the front cover.

Thanks for the input. I was just informed by BDS that there has to be pressure in the gear case for the seals to work properly. Also I should not vent the case but use a manual pressure relief valve to periodically relieve pressure to prolong seal life.
Thanks again,
Steve

[41willys]

That is correct, you will have pressure in the front cover, but not to the point it is blowing out the oil.

Keep in mind that the manual release should not be used often.

Jason