Vavle Train Torquing

A

aNotchAbove

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Jun 7, 2006

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Apr 15, 2007

#1

• Apr 15, 2007

• #1

I'm a little confused about how to torque down rocker arms. I've read about tightening the fulcrum bolt to 'zero-lash' where there is that first bit of resistance in the pushrod. Then tightening the bolt another half to full turn. I've also read that they have to be torqued down to around 20ft/lbs. Using the first method, the bolts aren't as tight as 20ft/lbs, but if I torque them down to 20ft/lbs I'm afraid thats too tight. Can anyone shed some light on this? Thanks!

 

RYC CUKR

Founding Member

May 19, 2002

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Orlando

Apr 15, 2007

#2

• Apr 15, 2007

• #2

Chilton's calls for 18-25 ft/lbs.. The way that I have always done it is tighten them down until you have some resistance while turning the pushrod and then tighten another 1/2 to 3/4 turn and then lock them down. That is for stud mounts.

For pedestals I have always done the same type of method. The only big difference is that if you can go more than 3/4 turn to reach the 18-25 ft/lbs then you need shims for your rockers and if you can't go more than about a 1/4" turn to reach the 18-25 ft/lbs you need slightly longer pushrods so that you can get the correct preload on the lifter.

 

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aNotchAbove

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Jun 7, 2006

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Apr 15, 2007

#3

• Apr 15, 2007

• #3

On two seperate H/C/I install guides and the Haynes manual it says ft/lbs. Just wondering, as its very unlikely that 3 different sources are wrong. Oh, and they're stock fox rockers on stock heads.

 

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aNotchAbove

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Jun 7, 2006

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Apr 15, 2007

#4

• Apr 15, 2007

• #4

So it looks like I need to shim my rockers. Anyone know what size shim I should start with? I'm running ported and milled E7's (0.030"-0.040"), stock rockers, stock pushrods, and comp cams conical springs.

 

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aNotchAbove

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Jun 7, 2006

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Apr 15, 2007

#5

• Apr 15, 2007

• #5

I just read somewhere that zero-lash and the 1/2 turn isn't required for stock (non-roller) rockers, only if you have roller rockers. Is that true?

 

RYC CUKR

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May 19, 2002

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Orlando

Apr 15, 2007

#6

• Apr 15, 2007

• #6

Yeah,

I don't know where I got the in/lb thing so it been fixed.

If you do need to shim them you can get the FRPP kit from summit

Here is the link for them

http://store.summitracing.com/egnsearch.asp?N=700+4294772728+115+400070

I would probably start with a .030" shim to try to make up the difference from the milling.


The chilton's manual shows using a lifter bleed down tool and then checking clearance between the valve stem and rocker with a feeler gauge. I have never used a lifter bleed down tool but rather have done as I described earlier for pedestal mount rockers.