Can someone tell me the purpose of the spring and filter? I'm just curious about the function.
I'm adding a mechanical oil pressure gauge and it says to remove, alter the screen and reinstall. I'll do this, but wondering what this spring/filter does

 

That is the oil screen for the tappets. Do not leave it, or the spring out. The adapter for a gauge will directly replace the cap plug. And don't put too much faith in whatever gauge you install....

 

Thanks for the reply. I reinstalled the spring and filter, just didn’t know what they did

thanks again

 

The oil that passes through that screen has already been through the oil filter, not likely anything would ever show up on the screen, unless you had rust in the oil tank....

I quit checking the screen on my `89 Evo decades ago.

 

You might want to take a look. I found some stuff in my screen once. I check it about every 2nd or 3rd oil change.

Not that it really applies, but the first time I looked at that screen on my shovel, it was so full of stuff it scared the crap out of me.

carl