confused!

[TexasT]

I don't think a lockwasher is a good idea. It doesn't spread the force equally around the head and I think that is why the heads are coming off. I think some locktite(maybe blue, but that green and red stuff works too I guess) is a better solution to keeping the fastener in the hole.

[blown1]

 I thought the lock washer (when compressed)  would spread the clamping  load,
but,  stock bolt do not use any washer at all, but do have a shouldered bolt,

I think I'm going to test  some of the "grade 8" bolts I have,  torque wrench and a vice, see what
values  they  require to snap off.

[motorhead]

Can Buick V6s fit larger diameter pushrods than 5/16"?  There is little added value in going to thicker wall thickness vs. larger diameter. There is also a lot of strength and stability to be gained (aka. resist pole vaulting valves) by going to a bigger pushrod, and there is not an attributable effect on valvetrain mass (weight over the nose of the rocker tip or mass of the valve).

I had a custom set of pushrods made by Trend to combat this issue in the wagon.

[good2win22]

Can Buick V6s fit larger diameter pushrods than 5/16"?  There is little added value in going to thicker wall thickness vs. larger diameter. There is also a lot of strength and stability to be gained (aka. resist pole vaulting valves) by going to a bigger pushrod, and there is not an attributable effect on valvetrain mass (weight over the nose of the rocker tip or mass of the valve).

I had a custom set of pushrods made by Trend to combat this issue in the wagon.

Had an 80 year old machinist still working in the shop tell me to skimp on anything else you want but never on pushrods.

[blown1]

took it apart, slowly looking for anything out of place or odd.
 nothing, except broke another rocker are bolt,
so,  took  some new ones I had  and set the torque wrench at 30 lbs and snapped  it off first pull,
 this is 5/15 ,  broke at where threads end and solid bolt starts,

so tried another, this time at 25lbs,  hit 25 , was ok,  tried again, the head snapped off.
checked  US recommended torque  specs,  5/16, grade 8 is only 18 ft lbs

so....obviousl y chinese crap!  I'm guessing they are equivalent to  grade 3 , maybe?

but nothing out of the ordinary  on the valve train,  no wear marks anywhere,  checked cam timing, spot on.,
no valve to piston marks,but valves sure are close together,  again ,no  marks.

lifters look new (they are) pushrods  are spotless, no marks anywhere,
 rockers  show nothing,     
regardless, going back to  hyd flat tappet,  and 80 lbs springs,  (which I'll set up at 90 if possible)
and back to setting pushrod length, again!

[Steve Wood]

Factory spec was 25 lb ft according to the manual.  I would be scared to death to go past 20, myself.  Also, I would much rather use studs in this application-particularly if I were using the support saddles.

[Just a Six?]

I had oversize push rods made for my roller setup from Manton http://mantonpushrods.com/
I think they are 11/16 on my stock heads without any mods to fit. Very easy to deal with & shipped in 48 hours.

[Just a Six?]

Might have been 11/32 now that I think about it?

[Steve Wood]

11/32's would be correct

[motorhead]

11/16" would be impressive.

[Just a Six?]

11/16 would be rather large now wouldn't they!   

[reality]

http://ls1tech.com/forums/dynamometer-results-comparisons/1256314-dyno-results-11-32-pushrods-vs-5-16-pushrods-also-5psi-tire-pressure-diff.html

[TexasT]

I can't see why you couldn't run larger pushrods, though one might have to do some grinding on the head for proper clearance. I would think there is enough "meat" on the head for that. Just one more thing to do with fancy cool guy parts.

[earlbrown]

I had to put my heads in a mill for stock sized pushrods to clear.  Turns out the holes aren't anywhere near concentric with the actual pushrod location.


I put layout dye on the VC rail and used a small square to located both sides of the pushrods.  Then put a 3/8th hole where they actually belong.   I have a sinking feeling a lot of the ''my lifters are noisy'' posts are actual pushrods kissing the heads.

[reality]

If you are running roller rockers you could change the spacers around to suit.  Careful not to lose the needle bearings