Rocker shaft bolts

[harvenator]

Any other people here have a problem shearing rocker shaft bolts when torquing to 30 #'s? I've busted a few of them and I know the torque wrench is accurate.
Also need a source for some new ones at a reasonable price.

 

[swinger340]

Ive had seasoned bolts strech. Usually can tell they are streching before they break. Ive replaced mine w/ grade 5 bolts from harware store and then they tourgued down fine.

 

[crackedback]

SB or BB?

SB should be about 17-18 ft/lbs IIRC as they are 5/16 bolts. Isnt' the spec on SB's 200inch/pounds

BB is a 3/8 bolt which should be about 25-30#

 

[green1]

Some books say up to 30- snap. Buy grade 8 from Ace Hardware, install with 3/8" ratchet hand tight, then 1/2 turn.

 

[Demonracer]

Everytime I build/rebuild an engine I replace the rockers arm shaft bolts with new grade 8bolts. It's cheap insurance on big blocks and small blocks. JMO

Bill S.

 

[416stroker]

I was told that depending on the brand of shafts you have (stock), that if you over tighten them, it will distort the shafts. I go 18 ft/lbs on mine and they are thicker than factory shafts. Never had anything come loose. But I'm using studs and nuts too so maybe that's why??

 

[RedFish]

There is a misprint in a bunch of the books out there. 18 ft lbs. is correct.
At least the broken bolt is fairly easy to back out in most cases.

 

[harvenator]

I found a set of bolts and dividers from Mancini Racing for $30.00 delivered.

Thanks guys. I'll be sure to limit the torque to 18 on the new ones.

 

[71beater]

Just saw on Fleabay... Ehrenberg sells grade 8, 1/8" longer than stock and recommends 22lb/ft.....
$20.00?
Just puttin' that out there...
(and I'm sure you could get them at yer hardware store for much less)