Piston Squirters- 930 vs. 964

[piggdekk]

ah ok, thanks. They looked like squirters but I'll look closer next time.

[Harpo]

Good afternoon Kevin,

I was planning on using a blue printed 964 pump in my 3.2. Sounds like a need to upgrade my squirters to 2.0mm from what ever the factory installed in my 3.0L case.

Thanks

[KTL]

Hi David,

I think 930 squirters (1.5mm size) would be sufficient as well. Reason I say that is because the 930 engine of course uses the 930 pump and other than that, the rest of the 930 oiling system is basically the same as the 3.2 and 3.0 engines

I believe the 964 is able to use an even larger squirter (2.0mm) because of the revised chain housing and oil piping in it. The 964 oil delivery volume there is much less because it was intentionally sized to reduce the oil volume to the cam/rocker housings. Said to be 50% per the tech document page I pulled from a 964 vs. 993 engine comparison document for factory after sales training. Since the oil delivery is reduced to the cam housing, it would appear that the squirter size is able to be increased without compromising the "bottom end" oiling.

One other thing to keep in mind when you use the 964 pump, you'll want to think of using the spacer in the vertical pressure relief valve location on the case- 13A in the parts diagram. I recall William Knight saying that if you don't use the spacer, you'll get less oil pressure. I think I can attest to that because I changed my oil pump in the former 3.0L engine case to a 964 pump when I rebuilt that engine and I noticed only 60 psi of high rpm pressure on my mechanical oil pressure gauge in the dash. Whereas when I had the typical 3.0L pump, it ran 80 psi. That was in a racecar with a AN-4 hose from the top of the engine all the way to the dash for a VDO mechanical 100 psi gauge. It was an interesting and helpful gauge to have, being able to see actual psi number and how pressure changed depending on temperature and rpm while driving. Worked really good.

So I think William's mention is correct. I wasn't aware of the pressure relief spacer until after that engine went south shortly after I built it. Not saying the lack of the pressure relief spring spacer was the cause of the problem. Just saying I observed the lower oil pressure that he mentioned elsewhere on the forum. I've never been able to find what's different in the engines that prompted the use of the spring spacer. But it's also used in the 993 engine as well- last picture below taken from the 993 factory manual. It's in the 993 parts diagrams too (not pictured here anywhere)

Hope that helps