Vacuum. One c, two u's. Got it.
On the last go 'round, under spirited driving, the valve cover breathers would always emit an oil mist that would just make a mess of everything I spent hours trying to keep clean. (no pcv system) Coupled with the factory oil dipstick making a bottle rocket out of itself at the track, I knew I needed to somehow relieve the growing crankcase pressure.
Rumor has it, the cure for my woes, plus any weeping seal one might have, would be a vacuum pump. I could probably have gotten away with an exhaust scavenging system, or even tying rags to the breathers, but I never really liked the way any of that looked. Plus the vacuum pump was super shiny.
Butler makes it real easy when choosing a thought out system. I had to educate myself in vacuum pump-ology, pulley ratios and pump speeds, so the last thing I wanted was to spend additional time sourcing all the right parts. Plus, I sold my previous set of Butler sheet metal covers to The Raven's brother and knew I was going to purchase the same again, sans breather holes, so why not make it all happen in one place? I made a few calls to ensure fitment with my very old balancer and bought the kit.
Tip#10 If you're going to put engine parts on the dining room table, make sure the wife isn't home to see it.
Installation was straightforward as it uses the same lower case H pattern standoff many of us are used to. In addition, because its from a Pontiac source, it has a very well thought out adjustment arm that may or may not be on upside down in this pic, that connects to a water pump bolt -
To connect it to the crank, the supplied mandrel is drilled for a stock Pontiac 4 bolt and 3 bolt Chevy pattern. I simply enlarged the 4 holes in the mandrel to accept the bolts I was using with my Fluidamper and Ram Air Restoration pulley and got to mounting it up. That did NOT go as planned. (does anything?) I'm starting to think its me.
The holes in the mandrel didn't line up with the pattern on the Fluidamper. It wasn't even like a flexplate thing where they would line up a certain way (at least this you cant attempt to put on backward!), these were way off. Well %$&.
Tip#11 Always check to see if parts fit before modifying them
Unfortunately, this style mandrel doesn't register on the damper pilot - it relies on the bolts to get it concentric. I can't just elongate the holes and now expect it to work. So to catch you up, yeah, I just ruined an integral part of my vacuum pump kit.(in record time!) And this is where it gets good.
I called Butler to ask if they had any other mandrels for the kit. Nada. They had a blank one they offered to send me, but this was the only type available.
You know, I love all things Butler - except this piece. Don't get me wrong, I've dealt with the Butler family on many occasions and always received top notch service and quality parts. These guys are class acts and I'm proud they are a part of our Pontiac community. But after looking at the mandrel, knowing it was rather heavy, didn't register on the balancer , and didn't quite spin true in my drill press, I decided I had to go another route. Here the thing, and I know we didn't discuss anything technical yet, so bear with me >>> Because I had already spec'ed out the pulley sizes of this system based on the 3.5" crank pulley in this kit and am now returning it along with the mandrel, that now meant the 4.5"pulley on the GZ pump had to be swapped out, because the new supplier I found, didn't have any 3.5" pulleys. (pump speeds are important dontchya know) Here is why its good - Butler allowed me to return it all - the crank pulley, the GZ pulley, the v-belt, AND the modified mandrel I drilled. On top of that, they even changed the wording on their web site to make sure this doesn't happen again. Sure, I called them prior to all of this and they said it would fit my Fluidamper and yes, the wording was somewhat misleading, but those are mistakes and they happen. Its what they did with that mistake that makes all the difference. Class acts indeed.
While dealing with all of that, I was also researching who could make me a mandrel I could deem acceptable. In order to do that, I had to figure out what I had to work with. Break out the measuring slide thingy!
I got a bunch more pictures of me taking every measurement of that damper, but I wont post them. (you're welcome) It does remind me of a tip that might actually be useful however-
Tip#12 - A lot of companies are more than happy to share their technical drawings with you, should you ask. Much easier having all of the measurements in a digital format like pdf, than to transcribe all my crummy scribbling that may or may not be 100% accurate. (Some companies even supply 3D models if you're capable to handle them)
Armed with the tech diagrams, I could now start to have an intelligent (at least I thought it was intelligent) conversation with the pump vendors. I talked to a handful them - Star Machine, Aerospace Components, and GZ Motorsports.
I had some requirements for this mandrel -
- it needed a 4 bolt, 3.3" bolt circle configuration
- it needed to register on the damper pilot
- The mandrel shaft size to be the racing standard, (1.000" bore / 0.125"
keyway) so pulley selection would never be an issue
- it needed to be long enough to allow a belt center line 3.8" off the face of the balancer (or somewhere close) to be in line with the pump.
As luck would have it (Ive been sort on that lately!) the Fluidamper has a bolt pattern just like the internally balanced big block Ford. (4 bolt, 3.3" circle). Well, that will certainly broaden my search, wont it?
I finally settled on
Jones Racing Products.
As with most of these mandrels, you can put that pulley anywhere you want and as long as you have the right spacers to take up the slack, its a simple and quick method to move things around, or even add on to later. (pump bracket definitely on backwards here!) I had to open up the recess on the back just a tad so it would register on the Fluidamper, but my machinist made quick work of that on his lathe.
As alluded to earlier, each spinning component has a speed at which you DONT want to spin it, so making sure each component's speed at max engine RPM (7200 for me) stays within its comfort range, can only be dictated by the pulleys in play. They are critical to get right. GZ says no more than 6K rpm with this pump, but also prefers it spin at 64% -75% of engine speed.
It makes your head explode until you realize there is a useful calculator for all of this on the
GZ Motorsports Tech Page. I also found this page super helpful when trying to make this information sink into my thick skull -
Helpful pulley calculations
All this pulley talk actually got me thinking about the alternator. What would that be spinning at peak engine RPM? I know I wont spend a lot of time at 7200, but if I want my alternator to survive, I should probably get an idea of what its going to be turning.
Here is the difference between the new pulley from Jones, and the stock v-groove I was running prior. 2.6" vs the new 3.0".
This brings the alternator down from almost 17K+ rpm (@7200) to 15K, which is more acceptable. It does drive the alternator a tad slower, so hopefully it still generates some voltage at idle.