Oil pump piston, some questions.

[elgyqc]

Originally Posted by JFP in PA

1. No, the new spring has a higher rate, which raises the oil pressure slightly at low RPM.
2. Yes, the chamfer is the trick, it stops the mushrooming and prevents the piston sticking in the bore.
3. See #3.
4. It is the pressure bypass system for the pump.

For around $20, you get everything new and do not need to machine anything...........

Thanks for the info. You make such a great contribution to this forum!

Because I am an ornery old fart I may just try experimenting with a machined piston and a washer added under the spring to see if I get the same result for free. It is easy to change the piston and spring and I have 3 engines I can experiment with.