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Old 06-13-2019, 06:39 AM
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Oil Separator/Vacuum Pump Issue

Ran into an issue at the track last time out. Out of the blue, I had a zero vacuum reading on the gauge and best I can figure after cleaning up everything is that oil sprayed out from the keyway in the dampener.

My vacuum setup is a Star Sportsman pump, Stef's Oil Separator and a Moroso catch can. I pull from the end of the valve cover over to the oil separator which feeds the pump and then any residual goes over to the catch can. Pretty tight setup as I only use a piece of flex hose between the pump and catch can, everything else is braided stainless and AN fittings. Most of the time flex line and push locks are used for all the lines, but I don't like that setup.

I warmed up the engine yesterday and tried all the tricks I had to find where it was losing vacuum at. The engine idled just fine so my thinking was I had either a valve cover or oil pan seal sucking air. I couldn't find a thing, but I took the connection off of the valve cover and verified that I had vacuum being pulled by the pump however I thought that it was weaker than what I expected. I verified that the gauge line connection was good too. I shut it down and was totally mystified. Finally, I figured I would drain the catch can and oil separator tanks. Just about zero oil/water out of either of them - a few drops which was really strange. Normally I can get a good sized dixie cup filled from either one after just a few passes. Finally I removed the top on the oil separator and there it was - the can is loaded with multiple layers of dense foam rubber - similar to the closed cell stuff used to stuff windows for cold drafts. The top piece had been pulled upward in the can and sucked over into the main center tube of the can - this feeds the vacuum pump. I got all of this straighten out, fired the engine and within a minute had my normal 6" of vacuum at idle.

Hopefully this was just a one time thing. But it also proves that no matter what problem we run into working on our rides - there is always an answer. Finding it can be a long road, sometimes expensive but you have to keep questioning what is happening and pay attention to the clues that you are given.

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Old 06-13-2019, 07:47 AM
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A whiffle ball will hold the foam down if it happens again.
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Old 06-13-2019, 11:26 AM
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Originally Posted by johnsongrass1 View Post
A whiffle ball will hold the foam down if it happens again.

Excellent idea!! Thank you!
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Old 06-15-2019, 06:59 AM
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I run a Moroso separator and a Star pump. It's got the same foam baffling you mention but the shape of the can at the top prevents it from being pulled out of position. I also take some brake clean on the inlet to the vacuum pump every so often to clean it. It does help.
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