Bill, These GZ pumps (review linked) are for street applications. Does your oil pan have a windage tray to keep the mist down?
http://www.lsxmag.com/tech-stories/engine/tech-review-gzs-vacuum-pumps/
Tom - Thanks for link. I looked at those pumps, Moroso and Star Machine. No windage tray in the oil pan but this would be connect to the valve cover when the road draft tube is now connected so I am thinking (hoping) I won't run into a problem.
Bill, you've made so many modifications on your engine, amazing really... I responded just so others would think about crankcase pressures..
Small changes like restricting the breather hose on an engine with a PCV can reduce oil leaks, and improve vacuum wiper operation...
I wonder if an electric powered pump would be do-able on automotive engines.
I am always interested in learning more about engines and how they operate... Your series of posts on making a 226 into a beautiful powerhouse is fantastic...
Larry - I used to believe that anything was doable but this is project is at the point where I question that idea. The easist, and most common, means to drive a vacuum pump is from the crankshaft pulley.
My engine only has one crankshaft pulley available and it is 7.25 inches diameter. In order to turn the pump at a reasonable speed, the driven pulley needs to be about 10" diameter.
The model renderings at the right show a Star Machine Mini vacuum pump mounting to the existing AC compressor bracket. The two unused holes in the bracket are the attachment point to the log-style intake manifold (not shown).
That arrange would work but the large pulley looks ridiculous. One comment I got was "nice Mercedes steering wheel you have there."
I did look at using a 12V DC electric motor to drive the pump. I like that idea because I could use PWM to control the pump speed based on feed back from a pressure (vacuum) sensor. This model rendering shows the concept.
The problem with an electric motor is the power limitation. I was told (but didn't listen) that the Star pump needs about 3KW (4HP) to achieve about 27" HG. I don't need anywhere near that vacuum so I decided to experiment with a 1/2HP motor. The one shown here is a Leeson Ironhorse motor.
So far, this is going nowhere but I do have a couple of more ideas to explore.
Backing off from the electric motor idea, I returned to the mechanical drive design and decided to try a speed reducer. Finding a small reduce that can handle the high input speed (close to 10,000 rpm) from the large diameter (7.25") driver pulley was a challenge.
The model rendering here shows an Apex 3:1 planetary installed in front of the Star Mini pump.
I thought I had hit a home run with this design until I realized that I had installed the reducer backwards. Instead of slowing the pump down, I had increase its speed by a factor of three.
Turning the reduced around is possible but not an easy task because out end is not designed to support the load a driver pulley. To use it backwards, I needed to design a front bearing support for the pulley shaft.
The model rendering here shows the idea. The section view show a bearing in the front plate. If I were to use this, a second bearing would need to be installed to properly support the pulley shaft in a manner that doesn't transmit a load to planetary gears.
Unfortunately, I don't have the machining capability to make the adapters required to connect the pump to the motor or reducer. The geometry is too complex and would need to be sent to a machining center for fabrication. One-offs are expen$ive.
I am now back to the electric motor idea and doing some testing to determine the vacuum pump power requirements at the operating points I need for my engine (vacuum level and blow by volume).
Maybe I'll just reinstall the original draft tube...