Broke the rocker shaft stands

Posted By: AutoEngineer

Broke the rocker shaft stands - 08/02/11 12:03 AM

I just had a pair of 906 cast iron heads fully reconditioned. I was going to use a set of new steel stamped HD rocker arms, shafts and pushrods. To get the recommended hydraulic lifter preload I used .030 +.020 steel shims under the rocker shafts. The new fast ramp cam had a larger base circle and the heads were milled.

At the final valve train assembly torqued the shaft brackets to 25 ft.lbs. and now I noticed that ALL rocker arm stands were cracked. Some had one crack, but the worst had three in the radius of the stand. Deepest crack was almost 3/4".

I guess I am not the first one who has got a problem like this, but how have you solved it?

Posted By: POS Dakota

Re: Broke the rocker shaft stands - 08/02/11 12:14 AM

can't the stands be machined down and blocks made up to take their place?

Posted By: HEMIFRED

Re: Broke the rocker shaft stands - 08/02/11 12:18 AM

Quote:

I just had a pair of 906 cast iron heads fully reconditioned.

not a quality job if no one bothered to check the heads for cracks first

Posted By: lewtot184

Re: Broke the rocker shaft stands - 08/02/11 12:30 AM

i've seen that happen when people use concentric steel shims. i've used eccentric soft aluminum shims without problems. there is a way to tig weld the cracks. i had a pair repaired once without any problems. using the correct filler rod and the welder knowing what he's doing is a must.

Posted By: MR_P_BODY

Re: Broke the rocker shaft stands - 08/02/11 12:36 AM

I gather you werent using the tapped shims... if not
the shims you used will push the sides out when you
tighten the shaft down... mill them off and have blocks
made up or get the W-2 race head stands and mill the
stands off the proper amount... not sure if any of the
BB heads use the separate stands

Posted By: Chris2581

Re: Broke the rocker shaft stands - 08/02/11 12:56 AM

Quote:

not sure if any of the BB heads use the separate stands

The BB heads until I think 1962 used stands.

Posted By: 451Mopar

Re: Broke the rocker shaft stands - 08/02/11 01:44 AM

Milled mt stands off and used these:

http://www.billetracingparts.com/Max%20Wedge%20Stands.html

Posted By: Cab_Burge

Re: Broke the rocker shaft stands - 08/02/11 01:49 AM

Quote:

Quote:

not sure if any of the BB heads use the separate stands

The BB heads until I think 1962 used stands.

1963 was the last year for the seperate BB rocker shaft stands, 1964 and later have the cast in pedestals. 1964 was the first year of the six bolt valve covers also

Posted By: bumps440

Re: Broke the rocker shaft stands - 08/02/11 02:13 AM

Quote:

Quote:

Quote:

not sure if any of the BB heads use the separate stands

The BB heads until I think 1962 used stands.

1963 was the last year for the seperate BB rocker shaft stands, 1964 and later have the cast in pedestals. 1964 was the first year of the six bolt valve covers also

The old max wedge cars used rocker stands.
get the billet aluminum ones as someone pointed out
put the stands on the shafts next to the old stands and try to determine how much to cut down the cast old ones.

Posted By: MR_P_BODY

Re: Broke the rocker shaft stands - 08/02/11 04:00 AM

Quote:

Quote:

Quote:

Quote:

not sure if any of the BB heads use the separate stands

The BB heads until I think 1962 used stands.

1963 was the last year for the seperate BB rocker shaft stands, 1964 and later have the cast in pedestals. 1964 was the first year of the six bolt valve covers also

The old max wedge cars used rocker stands.
get the billet aluminum ones as someone pointed out
put the stands on the shafts next to the old stands and try to determine how much to cut down the cast old ones.

Looks like the set posted above are the max wedge stands
with a MP P/N

Posted By: sshemi

Re: Broke the rocker shaft stands - 08/02/11 09:31 AM

i have used those shims under the rockershafts on multiple engines and never had any problems.
Aldough i have one 906 head that has the stand cracked but never used any shims on it.

Posted By: JohnRR

Re: Broke the rocker shaft stands - 08/02/11 02:02 PM

Quote:

I just had a pair of 906 cast iron heads fully reconditioned. I was going to use a set of new steel stamped HD rocker arms, shafts and pushrods. To get the recommended hydraulic lifter preload I used .030 +.020 steel shims under the rocker shafts. The new fast ramp cam had a larger base circle and the heads were milled.

I guess I am not the first one who has got a problem like this, but how have you solved it?

By using the correct parts.

[quicktree]I don't care who has done what for how long or who says it in their sales pitch ... rocker shims are for correct rocker to valve tip geometry. if you cut your heads and your pushrods are too long you need adjustable pushrods or the correct length pushrods.[/quicktree]

But as said have the stands machined off and replace them , set their height so your rocker geometry is correct THEN get the correct length pushrods .

Posted By: AutoEngineer

Re: Broke the rocker shaft stands - 08/04/11 07:17 PM

Thanks for the all good advice

I am using Karakashian's cam and followed his advice on setting the lifter preload except one issue. I was not careful enough when I had to stack two concentric steel shims to obtain correct preload.

Quote:

"Karakashian sets the lifter preload at 0.010 inch. Because of the nonadjustable rocker arms, this is accomplished using special shims that fit under the rocker shafts. This preload setting is especially critical after having the heads milled or changing the cam."

I should had trimmed the lengths of the steel shims to get them to �nest� together better and prevent distortion of the stand, OR I could had used eccentric soft aluminum shims, OR shorter pushrods...

Here's Hughes Engines instructions for trimming the steel shims

http://www.hughesengines.com/Upload/productInstructions/ROCKER_SADDLE_SHIM_INSTRUCTIONS.pdf

I guess am going to have the stands milled off and using the separate stands, but a few cracks were really deep and therefore should have tall stands.

Is the height of the Max Wedge and W-2 race head stands the same?

Posted By: mac56

Re: Broke the rocker shaft stands - 08/04/11 07:45 PM

Quote:

Milled mt stands off and used these:

http://www.billetracingparts.com/Max%20Wedge%20Stands.html

That is some good info there. Not even expensive.