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Cal-look/High Performance => Pure racing => Topic started by: Diederick/DVK on June 19, 2009, 16:40:45 pm



Title: Having heads machined for dual springs
Post by: Diederick/DVK on June 19, 2009, 16:40:45 pm
I'd like to get a pair of heads machined for dual springs, and as the VW shops are quite busy this time of year i was thinking of having it done at a machine shop nearby who just did my rotors today. I enquired about perhaps having cylinders turned down a .05mm or something and I was thinking with all the computer machinery they have they may be able to cut heads for dual springs.

But as they have no experience I need to know what to ask them. The ID of a pair of scat duals is 17.4mm, but that doesn't say much for the OD of the guide boss. Also, does the guide need to be cut as well? Any thoughts are welcomed.

Please let me know. I might be in the Bill Fisher book, but I don't have that one handy at the moment.


Title: Re: Having heads machined for dual springs
Post by: Shubee2 (DSK) on June 20, 2009, 03:31:11 am
They Cut down the boss and top of the Guide when they compute your Valve lift Clearence depending on the cam and Rocker set up you use    Why are you wanting to cut the Barrels down? .005 ?


Title: Re: Having heads machined for dual springs
Post by: FDK/mrpedrini on June 23, 2009, 17:45:59 pm
I'd like to get a pair of heads machined for dual springs, and as the VW shops are quite busy this time of year i was thinking of having it done at a machine shop nearby who just did my rotors today. I enquired about perhaps having cylinders turned down a .05mm or something and I was thinking with all the computer machinery they have they may be able to cut heads for dual springs.

But as they have no experience I need to know what to ask them. The ID of a pair of scat duals is 17.4mm, but that doesn't say much for the OD of the guide boss. Also, does the guide need to be cut as well? Any thoughts are welcomed.

Please let me know. I might be in the Bill Fisher book, but I don't have that one handy at the moment.
Hey Died, I had this dilemma a while ago.... I have my guide bosses cut to 15,7mm.....occording to the inner diameter of the spring shims i gonna use...(they're 15.8 inner diameter...Take a look @ the CSP catalog...good luck!!! D


Title: Re: Having heads machined for dual springs
Post by: GreenTom on May 25, 2010, 11:03:05 am
sorry for digging out the old topic, but I have to do the same.
I've got Bug Pack dual springs (not chevy ones just typicale dual springs).
the cam W130 and 1,1:1 rockers, should I ask the machine shop to cut around the valve guide (ally bit around the guide) to the dimeter of 15,7mm to the same level as the outer spring seats? Should I ask them to cut down the valve guide also (make it shorter up to the ally)?
thanx for advices.

cheers Tom.