Quote:
Originally Posted by Keith Seymore
Do any of you all run an adjustable restriction valve in the system?
(No further questions, your honor).
K
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LoL, ask all the questions you want Keith. It's a learning experience for all of us. There is always something that gets over looked. And then we get that Ahh moment.
Anyhow, I've run the vacuum units all with a vacuum relief as you posted in the pic. (VCV101A)You can see mine in the picture that I posted.
This is what I have been told. If you run too high a vacuum on the engine it tends to pull oil away from the piston pins. Now other builders have told me it's an old wives tale. Actually I think the guy at GZ motorsports told me not to worry about it. I have settled on around -11 psi. All I'm try to do is get rid of any blow by at WOT. I'm not running a vacuum pump to increase H.P. I have 2 engines with GZ vacuum pumps, one on the street and one on the 505 cu in and no oil leaks at all. Added bonus.
Engine has to be totally sealed up for running a vacuum pump. No PCV installed either. I've installed a fitting on the appostive valve cover and connect a vacuum gauge and monitor it through the rpm's. The relief valve is installed on my vacuum pump and is fully adjustable for whatever you set it at. I put a cable tie through it as it came loose on on run.
One other thing I forgot mention is pulley sizes do affect operation of the vacuum pump. From my understanding it only needs to spin half the rpm of the engine.
Hope this helps.