When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
They are necessary, the threads don't seal tightly. You are supposed to change the washers any time the plugs are removed, but I've never known anyone who does that.
Ed, I think you are asking a good question. I just checked through the Ford Service Manual (Book 3644-50-E May 1,1950) and looked for every reference to spark plugs. I saw no mention of plug washers or gaskets. Just a torque specification of 24-30 ft-lbs. I even checked the interwebs to see if I could see a picture of an original Ford factory replacement spark plug and look for a washer. I did not see any pictures so it is still a mystery to me.
Tom
What Ross said above in reply frame #5. I've never purchased a plug with the flat sealing surface that did not have a sealing crush washer. I've changed at least my fair share of plugs as it was common practice to change plugs at 10-12K miles back when. Ford went to the tapered plug sealing surface that did not require a crush washer when they went to the Y block. I believe the 223 had the tapered sealing surface.
BTW, I f the plugs are torqued to specs, the washer does not distort, at least the old Champions did not.
Last edited by raytasch; Jan 16, 2022 at 07:15 PM.
Reason: Error in typing