Oil pressure relief piston - plastic

While removing the piston from the bottom of the pressure relief valve on my oil console, we cracked and lost the plastic that is held in by a screw. Not wanting to purchase another one for $120 or so, I was wondering if it might be possible to replace the broken plastic. It should be simple enough to cut a circle out of a plastic sheet or even 3D print one.

(Why is this plastic?)

My question is, why is this plastic and what kind should it's replacement be? ABS? Replace with aluminum?

Do I even need to replace it? Spacewise, the missing piece doesn't cover much space.

Thanks!

Attachment 616566

What model year or part number for the console ?

It is from a 1972 oil console. The current part number is 93010707600. I'm just being cheap and trying to avoid paying $124 since we broke the plastic taking it out.

Thanks

Attachment 616628

At the time, bakelite was used before later plastic replacement.

I would use bakelite, nylon or teflon

My understanding is overpressure in the oil filter console for operated at 9.1 Atü for model 72. The material choices dimensions etc are of course a factor as if the chosen stuff disintegrates could be an issue. I’d suggest it also important to be confident that any local “have a go” work at repairing the parts as mentioned in OP still results in it operating to the original design spec in any over-pressure situation. Things on the circuit may now be 5 decades old. I understand the earlier 69-71 over-pressure protection was designed to operate at lower figure (8 atü) so was not a consistent figure over the years. Source is a Porsche technical bulletin. This information being from an old factory source of mid 73 using old school atü is shared for historic hobby interest only. Not sure still applicable. Do not rely on it for precious engine. I recommend a competent expert does the work on any part that was designed to protect in certain scenarios and at the appropriate accurately defined pressure figure .

Steve

Thank you so much for your replies. I have decided to try PEEK and have purchased a 2mm sheet to cut/form.

The material properties are of good heat and chemical resistance as well as strength. I'm thinking it can't be much worse then what was in there originally.

https://sybridge.com/top-5-heat-resistant-plastics/