Vacuum pump question

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BBC71Nova
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Vacuum pump question

#1 Post by BBC71Nova » Wed Dec 21, 2005 10:11 pm

I notice that most everyone running a vacuum pump has the pump intake coming off of one of the valve covers. I seem to remember seeing someone who had the intake floor plumbed in the area in front of the distributor. Is there a reason for not doing this? Putting a hole in the intake sort of sux I guess but it seems like it would be more convienient than having it attached to a valve cover. Would it not pickup less oil being there versus a valve cover?

Also, the Moroso pump seems to get a lot of press but is it that much better than a GZ?

Thanks,
John

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#2 Post by John_Heard » Wed Dec 21, 2005 10:48 pm

I can't personally say how well putting the suction on the intake would work, but I would like to try it some time. The main reason I would want it there is to "maybe" help oil return a little bit in the head. It makes sense to me to put it in the intake valley. Worth trying I think. I did hook my vacuum gauge up to the intake valley floor and that seems to work ok, I haven't noticed any oil in the line.

I do know on a BBC that it doesn't work putting it on the fuel pump block off cover. Tried that one and got WAY too much oil there at low RPM. Maybe that would work if you built some some kind of baffle setup, but I know it doesn't work without a baffle. I have seen that location work with crank case evac on a small block though without problem, so that might work on a SBC.

Regarding the Moroso vs. the GZ, actually I think it's the other way around. Does the Moroso really deserve the press it gets vs. the GZ pumps? I think not if you look at the better reliability and air flow the GZ offers.

BBC71Nova
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Joined: Wed Nov 30, 2005 9:59 am
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#3 Post by BBC71Nova » Wed Dec 21, 2005 11:26 pm

I hear you on the GZ pumps. They get good press too. I guess I was just giving Moroso pump the benefit of the doubt given the price. It does sound like the new style pump the offer is better than their first gen though. For some street time I think GZ may be the best route. Product Engineering has a sweet looking pump but with all the goodies it is rather pricey.

I may try the intake plumbing. Guess I'll have to find someone to weld a bung into the intake or something.

I was thinking too about getting an aluminum fuel pump blockoff which should be thick enough to support tapping. If I could tap it then I could install the vacuum relief down there out of the way. That is if I just put on that little brass relief. Not sure if have the relief horizontal would cause problems but worst case I could get a brass 45degree street elbow fitting which would make the relief more vertical.

Thanks,
John

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#4 Post by John_Heard » Thu Dec 22, 2005 8:23 am

To be fair I should mention that I do have a business relationship with GZ Motorsports, my company handles their website. I will note that I was a customer before they became a client of ours though and I do use their products on my own car.

In regards to the Moroso, their 3 vane pump has a reliability problem from what I've seen with either the vanes needing repaired often or the set screws loosening up on the shaft. I have not heard of that happening with their new design/big pump.

I would think the intake would be thick enough to tap? Unless it's a sheet metal one that is.

On the little "grainger" brass vacuum relief valve. That's the one I use on my car. You might like to know that there are some issues with that valve. First of all it cannot support the air flow needed to control the largest GZ pump and it does have a tendancy to leak. I have not had a problem with mine leaking yet that I'm aware of, but it's something to watch for if you use that valve.

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