O-Rings - Knock Pins @ Head Gasket

Mrburnn · Post by **Mrburnn** » Wed Nov 15, 2017 11:20 am

Good morning,
Can anyone tell me why the 11x2.0 O-ring used to seal the two knock pins at the head gasket of a 305 motor is green? Is the O-ring made of a special material? will any 11x2.0 rubber O-ring work as well?

Thanks!
Mrburnn

Mrburnn · Post by **Mrburnn** » Wed Nov 15, 2017 12:27 pm

FYI, the part number for the O-rings I am questioning is 91303-259-000. Thanks again!

G-Man · Post by **G-Man** » Fri Nov 17, 2017 3:53 am

As far as I know they have always been green. They are obviously different from black ones but I don't know in what way.

Presumably temperature is an issue in that area so probably extended temperature range. Not sure if silicone rubber was available back in the day but that might be the difference....

G

Mrburnn wrote:FYI, the part number for the O-rings I am questioning is 91303-259-000. Thanks again!

LOUD MOUSE · Post by **LOUD MOUSE** » Fri Nov 17, 2017 7:41 am

I agree.
So far I haven't seen any info stating why to that question. ....................lm

G-Man wrote:As far as I know they have always been green. They are obviously different from black ones but I don't know in what way.

Presumably temperature is an issue in that area so probably extended temperature range. Not sure if silicone rubber was available back in the day but that might be the difference....

G

Mrburnn wrote:FYI, the part number for the O-rings I am questioning is 91303-259-000. Thanks again!

Mrburnn · Post by **Mrburnn** » Fri Nov 17, 2017 12:46 pm

Thank you for the input guys. I will play it safe and order new green O-rings. I have started the re-assembly of my '67 CL77 so I will post some pictures in (hopefully) the near future.

MrBurnn