5/16"washers on engine

when i dis-assembled the engine parts, i found 5/16' lock washers under the 5/16"cyl head nuts and also the barrel . i have the part numbers, but want to know what the washer ID, OD and thickness are?

I don't believe any lock washers are called for under any nut on the head or block to case nuts. Plain washers are used on head fasteners, and plain washers are also used under all of the barrel nuts with the exception of the front, central 3/8th'', no washers at all. I'd go ahead and order the correct part numbers for these as hardware store items will squash under torque and not hold up. Also OD on many of them are specific to application.

Also, I have to add that the plain washers under four long barrel through bolts on the 850 are often jammed/rusted into the recess. Take care that you don't add an extra one.

Hi 850Dunstall.
Hardened washers can be bought from fastener suppliers.
http://www.astm.org/Standards/F436.htm
Ta.


No commercial interest in fastener suppliers! I am just a customer.

Biscuit said:

I don't believe any lock washers are called for under any nut on the head or block to case nuts... .

Click to expand...

exactly! so finding lock washers means so cheap B@$+@rd PO used what was handy. between Andover & Old Britt i have been able to determine that i have the correct washers for the long 3/8" socket head bolts, but the rest i will have to replace.

Needing thanks for the link for the F436 washers, sure i can get those local

I like these for my nortons and BSA's. They fit within the head machined areas. extra thick and hardened. No more crushing the head. I drill them out for the 3/8 bolts. Use as is for 5/16. $8 life time supply.
http://www.mcmaster.com/?orderview=new# ... 30/=x1pcqo