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Discussion Starter #1
I have (4) of these pumps on engines, one just completely locked up, other 3 are all older and probably right behind it. I always drain the tank after the race and put some oil in the pump when the lines off to lubricate it.
I called aerospace and they want to sell me a rebuild kit for $115, I only wanted the vanes, they said they will sell me 3 vanes for $99!, Wow.
Anyone know of a cheaper replacement vane for the pumps, all are 3 vane pumps. I am told they are Kevlar, wondering if something made out of nylon, Teflon would last longer?
 

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A friend of mine just had his lock up. The vanes were fine but when he got it apart it was the bearings causing the problem.
 

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I forgot to add it may be Vesconite material for the vanes.
 

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EFI/N2O JUNKIE
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They are pretty to look at though aren't they.......... I went with Star, yeah, very blah looking, not cheap, but has been bulletproof! OK, gotta spray a can of brakeclean though it every 50-75 passes when I change my oil, no big deal, a few thousand passes and it is still perfect, but not pretty...........
 

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Seems like they all like synthetic oil. I always prime mine when it’s been sitting for a while. Lots of street miles @50% on my GZ. I’m following this thread for an answer.
 

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I've been running the large GZ Motorsports vacuum pump for a couple of years now on the streets, it only gets a small amount of oil mist for lubrication and is still working fine.
 

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Discussion Starter #9
All the pumps are about the same cost wise aren't they?. I've only seen one other pump lock up on a car my son was driving, and it was a moroso. I've had good luck with the 4 that I own up to now.
Upon disassembly, I did notice that the bearings were shot on front and back due to the housing bore being undersize causing a lot of "crush" to the bearing, they were not easy to get out, must have been a hard fit when they assembled it at 4:30 on a Friday!
I think the bearing problem is what locked it up and not the vanes as I originally thought.
 

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All the pumps are about the same cost wise aren't they?. I've only seen one other pump lock up on a car my son was driving, and it was a moroso. I've had good luck with the 4 that I own up to now.
Upon disassembly, I did notice that the bearings were shot on front and back due to the housing bore being undersize causing a lot of "crush" to the bearing, they were not easy to get out, must have been a hard fit when they assembled it at 4:30 on a Friday!
I think the bearing problem is what locked it up and not the vanes as I originally thought.
How much press fit did it have?
 

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Discussion Starter #11
I could not measure it when it was factory assembled. Considering the amount of effort it took to remove the bearings, I am guessing a lot, I had to take out .0015 to remove the score marks and get the hole round again, the aluminum bore is much softer than a bearing. Now it has about .0002 press fit. When I put new bearings in with the vane holder and assembled without vanes it spins much nicer, should last much longer now.
I also don't run much belt tension at all, there is no actual load on the pulley so no need to run it tight like an alternator. I was told by aerospace that less tension will increase bearing wear..... So will less bearing interference.
 

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Gotcha, it does sound pretty darn tight. Arbor press put it right in the hole. LOL I like running the cog belts so there is no tension at all. Can you even get that type of sheave for Moroso or Aerospace?
 

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The Liquor Makes Me Think
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I wonder if teflon or delrin would work. Both are tough, self lubing and oil resistant.
 

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You based your purchasing decision strictly on price.
And you know this how? Maybe he thought it was a much better looking vac pump than yours and thats why he went with it. I know that's what I did.
 

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Yea, you're right. Inexpensive AND shiny. The two best reasons to choose a performance component.
You got 2 out of the 3. It also does what it's suppose to do just fine. 🤔
 

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EFI/N2O JUNKIE
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Yea, you're right. Inexpensive AND shiny. The two best reasons to choose a performance component.
This Steve? Whomever it is, you're cracking me up!
I have put thousands of passes on my Star setup. Have it all. Mandrel, separator tank, sportsman pump, relief valve, valve cover fitting. If I ever get the coin together I will put the same exact setup on my wives mid 10 second ride, the stuff works! I did it for two reasons, the main being to help stop oil leaks! The second was for my heavy nitrous days.
 

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If I ever get the coin together I will put the same exact setup on my wives mid 10 second ride, the stuff works!
Dang Mike, how many do you have? I can see why you would have to save up. LOL
 
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