Project Muscrate… Reaching for the sky!
i everyone and welcome back! Well, for the very astute readers that noticed I missed a month I have an excuse, err, explanation. My stinking computer died! Apparently the brand of computer I own has a tendency to go tits up for no apparent reason and you guessed it, lucky me got the shaft. But, very lucky for me, I found a local computer repair shop that was able to retrieve all of my pictures and other important files and I’m back in action! So, let’s get to it!
This month I won’t leave you in suspense any longer and at the end of the article I will give some actual on-track test results. First, though, I need to finish up a couple of engine related items. In the last article I was preparing to install the Moroso “Enhanced” 4 vane Vacuum Pump (#22642). Most of you by now are probably familiar with the concept of using a vacuum pump on an engine but let’s just touch upon a few of the benefits.
Any engine will have a certain amount of what is commonly referred to as “blow bye.” Blow bye is a bad thing for us. It reduces power and contaminates the oil among other things. Another bad thing for an engine is moisture in the oil, which is hard to prevent when you’re racing in what is sometimes 80% humidity and/or especially if you burn racing methanol. What’s a racer to do, you ask? Get a vacuum pump.
A vacuum pump is a simple tool. Its basic function is to suck, in a good way of course! All right, get your mind out of the gutter, you. By pulling a vacuum in the crankcase, the piston rings will be able to seal much better, which translates into more power depending on the type of rings you are using. It also helps prevent any excess oil from getting into the combustion chamber and making detonation a reality. It will also remove any moisture in the system and send it to the catch can, keeping your oil nice and clean. That’s the basics.
The traditional way of connecting the pump is to install a fitting onto one of the valve covers towards the front and up high near the intake. This is a good location that will generally be up and out of the oil enough as to only have some oil mist finding its way into the hose, along with whatever amount of moisture is in the air.
Moroso makes a neat fitting for this purpose, (#22635), that is a -12 AN size baffled fitting that threads together and is sealed with an o-ring for a leak free seal. This is much easier and cheaper than having to weld a fitting onto the valve cover. Also, traditionally in the opposite valve cover a vacuum relief valve is installed to regulate the amount of vacuum the engine crankcase will see. Moroso also sells a nice billet aluminum unit, (#22638), that is easily adjustable by simply unscrewing the outer housing from the inner, and either adding or subtracting shims to adjust the relief valve spring pressure. It’s much the same principal as using valve spring shims.
Typically, you don’t want to exceed more than 12-14 inches of vacuum unless your engine has been specifically built to make full use of the vacuum. Too much vacuum in the crankcase can actually starve the wrist pins of adequate oiling, and cause big problems if not corrected. All the above is the “normal” way of connecting a vacuum system, so, of course, I did things a little different.