Balancer bolt size

[Von Writter]

I'm looking for a high performance balancer bolt for the 300. Does anyone know the size, i.e. dia. Thread per inch and length of one? I can't seem to find one anywhere listed as a 300 fit! Also is there a source for the water pump pulley new that anyone knows of? Thanks.

[The Plankster Prankster]

and what would cause you to want a "high performance" bolt? its a grade-8 bolt of suitable size for the job, i've never heard of one failing, so whats the motivation to replace it?

[StrangeRanger]

Grade 8 isn't even close to what he needs it for. He's building an aircraft engine he needs or at least wants it to be flight rated AN hardware. But he obviously does not have the original bolt to get the sizing information so he's just asking for dimensions so he can order what he needs.

[Von Writter]

Strange Ranger beat me to it. But I think I should have a good bolt (Like an AN) and a heavy washer but what size are they??? I don't have one to measure so I thought someone might know.

[*Fordman*]

i know the 300 and 302 use the same bolt.

[Von Writter]

Oh Thanks a bunch Fordman, I'm all set now!

[The Plankster Prankster]

ok, that makes sense now - i forgot you were building for an airplane. i'll try to find time to look for a spare one and measure it

[Von Writter]

I'd appreciate it Prankster, then I could double check it against the 302. I'll be ordering 4 of them so I would like to be doubly sure .

[The Plankster Prankster]

the bolt is 5/8-18 x 1 3/4" long, and the washer has an OD of 1 3/4" and a thickness between 1/4 and 5/16"

[Von Writter]

Hey Thanks a bunch Plankster, I really appreciate it a lot! A 302 bolt is 2 inches under head but the threads are the same so If I have to shorten it I can.