[Pneumatic]

Hi all,

I have a 455 bored and stroked to 474. Multiple attempts to get a rear main seal to work have been unsuccessful, a lined bored block doesn't help.

I'd like to add a vacuum pump before I pull the engine again for another seal attempt, in a hope it sorts the issue. The car is only driven occasionally on weekends, it has a 3500 stall converter, manualised TH350, probably ~550hp engine. There doesn't seem to be any downside to fitting the vacuum pump to this spec engine.

My question is, what vacuum pumps do people recommend on a street car? I was interested in the GZ as some people have said it's quieter and better suited to a street car than the Moroso pumps. I don't know too much about the star machine or aerospace pumps. I've read the star machine didn't like oil. I've read the "vacuum pump choices" thread in the race section, but most discussion is race car focused (obviously).

Butler make a kit with what I think is the GZ VP102, but the bracket mounts the pump really low. I need to mount the pump higher, the bottom of the pump can't be lower than the bottom of the head, or it'll hit my tubular front suspension arms.

I asked Butler if the bracket can be setup to mount the pump higher, they said I'd have to modify the bracket to mount it higher. I'm not keen on buying a bracket I know I'll have to modify. The bracket in the photo on the item page looks different to the one on the instructions so it's hard to judge how easy it would be to modify. I did find a photo on these forums of what looks like the GZ mounted higher.

I'm in Australia, postage from the US is pretty crazy so returning an order that doesn't fit is very expensive.

Any photos and advice of street car set-ups would be great. I was hoping to find a kit with pump, bracket, pulleys and mandrel. Mandrel needs to work with my Romac balancer and alloy v-belt pulley (hopefully without hitting my fan blades). The car is a 67 Firebird.

Thanks!



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[Don 79 TA]

I've been using the GZ pump for over a decade now in my car
i like it
i wish i went with the #12 line, as that stuff is adding up in price now, so i recommend to anyone to use the largest lines you can
i think he only sells the 104 pumps now, which is good, i would suggest perhaps slowing it down for street use as its supposed to generate more vacuum quicker
i used the Butler mounting kit and balancer pulley kit,
the one GZ sent me had to be for a SBC.BBC as the crank madrel was so long and didn't match the keyway, let alone the bracket setup takes some finagling, not saying it wont work, but the butler setup..... 1-2-3 easy as pie....
my setup is posted on GZ's website, but since then i've gone with different hoses. I have the #12 to put on now. Holy crap is this stuff getting expensive (hoses, fittings, etc)
i have the 102 pump and want to move up to the 104 when funds permit.
also, as we all know, make sure the engine is sealed up good, any leak will make it hard for the pump to do the job correctly (well not the pump, but the whole point of using this type of setup).

[i82much]

This is a lot cheaper, a lot less work, and helped considerably on my car:

https://mewagner.com/

[78w72]

Have you verified its the real seal & not the rear rubber U seal at main cap to pan? Very common to leak in that location and can look like a rear main, went through that on my recent stroker with a pan that used the early U seal design.

[Elarson]

I bought the Tin Indian Performance bracket and mandrel kits for my streetable road race car. I already had a Moroso pump and wanted to mount the pump high, like you.

http://tinindianperformance.com/Tin%...%20systems.htm

I haven't installed or run it yet, so I can't offer a review. Just putting it out there as a choice.

As an aside, Tin Indian makes an interesting selection of clever little problem-solver parts; and they don't get much press.

Eric

[ta man]

I have a Star Machine sportsman on mine..bracket, mandrel , hoses. vent tank came in a kit from SD Performance..pump sits up high.

[65madgoat]

I don't see the need for a vacuum pump in your situation. No need. Fix the rear main and run a proper PCV system. I use the ME Wagner myself but last motor did not (just regular PCV valve) and made the power you are at and was driven a lot with no issues.

[Pneumatic]

No matter how good a PCV is, it won't help at wide open throttle because there is no manifold vacuum at wide open throttle.

Thanks Don 79 TA. I can confirm GZ only make VP104 pumps now, so that is what they and Butler supply. GZ said "We've discontinued the VP102. The VP104 with the vacuum Control valve mounted in the pump will work well, and we can run it slower so it will last longer than the 102"

SD Performance is not an option as they burnt down and are closed.

Butlers website has died overnight so I need to wait for it to come back. I am trying to clarify what their current bracket looks like. I think the one in their instructions is the old style (which a member on this forum had with it swapped around to mount the pump higher), and the kit page is the new bracket but the photos are terrible so I can't tell what it looks like.

[grandam1979]

How come no one uses a evac in to the exhaust from valve cover? All my race cars have all had them except for one with a pump.

[Pneumatic]

Originally Posted by grandam1979

How come no one uses a evac in to the exhaust from valve cover? All my race cars have all had them except for one with a pump.

The exhaust evac is good for race cars with open headers. I am asking what people do on higher performance street cars that still run mufflers and drive reasonable distances in traffic.

[73LeMans]

If you check out post 27 in this thread, I go into a bit of detail on why I went the way I did with my pump. https://forums.maxperformanceinc.com...=840467&page=2

Its by no means a comprehensive anything on vacuum pumps, but just why I ended up where I did. Been running the pump for 3 years now and it works great.

[OCMDGTO]

Originally Posted by grandam1979

How come no one uses a evac in to the exhaust from valve cover? All my race cars have all had them except for one with a pump.

I've been running one on my car for the last couple months with full exhaust. Not enough time for a solid conclusion. Mook on here has run one for several years and puts a lot of miles on his car.

[grandam1979]

Originally Posted by OCMDGTO

I've been running one on my car for the last couple months with full exhaust. Not enough time for a solid conclusion. Mook on here has run one for several years and puts a lot of miles on his car.

I do also with full exhaust just don’t see it much.

[Pneumatic]

Originally Posted by 73LeMans

If you check out post 27 in this thread,...

Thanks Mark, that is really helpful. I need to go and measure my Romac balancer.

From what you've described the Butler mandrel should fit.

I'm still trying to clarify what the latest Butler bracket is. Their website has 2 photos, which are completely different brackets for the kit. I think the bracket you have might be the older one that isn't sold, and the new one might be similar to what GZ sell for the pump.

GZ make a fixed mandrel setup (can't change the pulley) that slides inside of the balancer and uses a long balancer bolt. I'm not keen on that set-up and I'd have to check the Romac ID is the same as stock (from photos it looks thicker walled, smaller ID than stock). They make adjustable designs with 1" shaft, but not for the Pontiac.

[Gach]

Haven’t had rear main seal issue..I run EVAC with full exhaust just for precaution. I run the baffled breathers. I do race not that often, just don’t want take chances.
Do put quit few street miles though.

[TinInjun]

Butler’s GZ kit will not fit a first gen Firebird. The only kit they sell that will work is the Moroso one. Trust me I know. Been there tried it. Butler was informed of this and handled the situation very professionally. I’m surprised that they didn’t tell you that up front.

[Pneumatic]

Originally Posted by TinInjun

Butler’s GZ kit will not fit a first gen Firebird. The only kit they sell that will work is the Moroso one. Trust me I know. Been there tried it. Butler was informed of this and handled the situation very professionally. I’m surprised that they didn’t tell you that up front.

Their exact response when I said the location in their photos is too low and I need to mount it higher was;

"The kit comes with the brackets to mount in shown area, but that doesn’t mean that you can’t modify/change the brackets to mount in a different location as needed."

Hence my questions on this forum. Shipping things to Australia and shipping them back when they don't fit is very expensive.

I'm going to have to ask them for photos of what the current bracket actually looks like. How long ago did you try their kit, perhaps it was the older bracket?

[TinInjun]

I tried the GZ kit in February of this year. The lower bracket is designed for the lower mounting of the pump. I could not figure out any other way to mount it to make it work with the pump mounted higher up on the head. Threw in the towel and returned everything. Exchanged it for the Moroso kit that fit perfectly.

[GOAT8U2]

I'm doing this next...

Dual valvecover breathers
Intake Pcv (10an fitting) to catch can
Closed catch can to intake through outlet #1
Catch can out #2 to electric pump (check valve)

I'm modifying a GM smog pump (2-3" max) with a stronger motor, 5mm shaft electric pump soon to solve the same problem. You'll want at least 5" at WOT to help the Crankcase pressure, I'm going to have before and after vacuum tests on the pump soon. If this works I'll post back as going belt driven seems a bit much.

[Pneumatic]

I have made a bit of progress.

Butler website needs updating. This image of the full kit has the OLD bracket design that they don't sell anymore;


The second image is the new bracket;


I asked if they had a drawing or image of the new bracket, and they said no. I said they should update their kit photo. They did manage to find a few more photos from when they did the mock up, so I could at least see how they have the plate and spacers;


The plate and spacers is very similar to what GZ sell directly. I have also been talking to GZ Motorsports, and they sent me the CAD file for the bracket they would recommend for the Pontiac. I printed out a template for some test fitting. The normal low spot that lines up with 3 head bolts is too low and hits my suspension;


I'm looking at mounting it upside down and drilling an extra hole for the 3rd head bolt. There is a position which doesn't need an extra hole but it might be too high and the belt might hit the front of the waterpump pulley. Anyway, I think this bracket will be able to be made to work;


Unfortunately GZ don't have an adjustable mandrel. They have a fixed mandrel but it slides inside the harmonic balancer and uses a really long single bolt. I am not sure my Romac balancer is the same ID at that point as the stock one so I am not confident that will work (also not keep on the mounted method vs the 4 bolt mounts of the adjustable mandrels). I am thinking I will get an adjustable mandrel from either Butler (steel, cheaper) or Tin Indian (aluminium, more expensive).