Some of you guys may remember the spin test machine I built about a decade (!) ago. We learned a lot about valvetrain dynamics, specifically on the 427 SOHC. The machine is powered by a 5 HP electric motor on a variable frequency drive. It is capable of spinning the camshaft up to 5,500 rpm, corresponding to 11,000 crankshaft rpm. Here are a couple of pictures from back then:
Here's a YouTube clip of the machine starting up at low speed:
https://youtu.be/-Slp184d0sYThis is a typical clip of a high speed valve event test I did with the stroboscope:
https://youtu.be/XCRrONYwBk0We learned a lot, and broke lots of valvetrain parts. Since then the machine has sat in a corner of my garage, unloved
Well, it's now back for a second life! I've built a fixture that bolts onto the spin machine which lets me run automotive oil pumps. I use a SOHC stub cam on cam bearings in a frame. The pump mounts to a removable block and engages the cam drive gear, just as on an engine. Oil is recirculated into a reservoir pan. Here are some shots of the latest configuration:
The two pictures above are from early in the build. I've added temperature, flow, and pressure measuring instruments, an adjustable valve to set flow restriction, and a dyno torque measuring system. The machine has evolved a bit as I figured out what didn't work
Now it seems to behave pretty well!
Here's what it looks like now. You can see the pressure gauges, and the big "FML 250" box is for the turbine flow meter. I went through three other types of flow meters before I finally got this to work!
Here's the dyno torque arm on the motor, and the display:
I also added magnetically mounted splash shields to help keep the oil where it belongs:
Here's a Melling M-57 HV oil pump for the FE, mounted on the drive block and ready to test:
Obviously there are a TON of details that I won't bore you with, but I'm happy to answer questions. This has been a big undertaking...
So what does this thing do? I can test an oil pump at any flow restriction and temperature I want, with any type of oil. For the first test, I got a blueprinted Melling M57-HV high volume pump from Precision Oil Pumps. I used conventional 10W-30 oil and set the hot idle pressure at 30 psi, corresponding to a quality new engine build. (Thanks, Brent Lykins for that recommendation!) Oh - Temperature is 200 degrees F. Believe it or not, just running the machine up for several minutes will put that much heat into the oil.
Here's what the flow and pressure look like. There is a bit of internal pump leakage at low speed, which is why the curves jump up off - idle. I re-ran several times to verify this. Also, notice how the flow breaks down at high rpm! This is due to the pump cavitating and aerating the oil:
(Note that I've also attached the chart so you can read it better...)
I was surprised by the cavitation at the top end. Here's something even more surprising. This is the clear outlet line from the pump under normal operation:
Here is the same outlet line after the pump has been bypassing / cavitating for several seconds. Those are air bubbles in the oil:
I don't know about you, but I don't like the idea of something like that going into my bearings. To be fair, this is after several seconds at 7,500 rpm. It does take some time for this much air to get into the oil. Still, the flow curve drops off right away which shows that cavitation has started.
Anyway, this is what I'm up to! More to come
I just got a POP standard volume M-57 pump to run. I'll be doing a comparison of the standard and high volume pumps under the same conditions. Fire away with questions!