Hardness of headbolts, Lock washers?

[harrison20002]

A friend came by yesterday with a question I couldn't answer. All his cylinder head bolts on his 9.9 appear to be corroded. He wants to replace them but doesn't seem to be able to find replacements locally. Here in the San Joaquin Valley of Ca. we have trouble finding parts as we have very few shops that that carry much of an inventory of anything Marine.<br /><br />He wanted to know if he could use a #5 x 5/16" bolt in place of a factory bolt. And since I advised him to use "Never Seize" on them should he use lock washers?<br /><br />He knows I get most of my advise from this BB so I promised I'd check for him. Thanks a lot for an answer. Happy Boating, Hal

 

[petryshyn]

Re: Hardness of headbolts, Lock washers?

Hello harrison20002!!!<br /><br />I wouldn't recommend using anything other than original, but........if none available, I'd use grade 12. If I was stranded on a desert Island, dying of starvation, maybe and only maybe I'd use grade 8. Never would I use grade 5, even starving..... A soft bolt will stretch over time and result in head gasket leaks. If you have a blind hole (no compression exposed to head) then its not so critical.<br /><br />

 

[clanton]

Re: Hardness of headbolts, Lock washers?

If the hex head is still there, just clean and repaint. I would use OMC gasket sealer or aviation form-a-gasker pn 765-1210 from NAPA, without lock washer.

 

[harrison20002]

Re: Hardness of headbolts, Lock washers?

Thanks Schematic & Clanton; I'll pass the info on and we really appreciate the help.This is another of the times this BB has saved me from making an A** of myself. I told my Buddy I thought the grade 5 bolts would work. I have also written down Gasket Sealer in my notes. Thanks again. Hal

 

[clanton]

Re: Hardness of headbolts, Lock washers?

I may have comfused you about the gasket sealer. The sealer is to be used in place of the Never-Seize, paint the threads and shank of the bolt, messy, but you will be able to remove them later.

 

[petryshyn]

Re: Hardness of headbolts, Lock washers?

Ditto Ditto on the Clanton!!!<br /><br />If those bolts are only cosmetically corroded, Re-use them. Aviation gasket glue is great for sealing and thread lube.

 

[harrison20002]

Re: Hardness of headbolts, Lock washers?

No Clanton, you didn't steer me wrong. I keep a list of different products so I can substitute them for somethng else I've done this every since this BB showed me how to use PB Blaster or Kroil instead of WD 40.<br /><br />Thanks again guys, you sure save me a lot of time. Happy Boating, Hal