Why machine 0.060 off 8mm rockers?
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Davros99
- Posts: 1
- Joined: Thu Feb 09, 2017 10:49 pm
Why machine 0.060 off 8mm rockers?
I’m building a Jake 2270. I’m ready to do my valve geometry. I’m using the 911 swivel adjusters. I have to measure and cut my pushrods for the setup … so why does taking less than 1/16” off the rocker arms to use the swivel type even matter. The swivels have clearance when turned down just one turn ??? I mean 0.060? Push rods are fitted. What’s it doing for me?
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vanapplebomb
- Posts: 25
- Joined: Wed Sep 04, 2013 1:17 pm
Re: Why machine 0.060 off 8mm rockers?
Look at where the pivot is on a 911 adjuster vs a standard solid rocker tip. Hint hint, treat the distance between the ball and the face of the foot as an extension of the valve tip. You have moved your pivoting point of contact farther out from center on the engine.
On top of that, you still need extra room for the foot to swivel.
If you are not countersinking, then .060 sounds reasonable.
You can usually get by pretty easy with half that with a good countersink. I did this with a 90deg countersink and stopped countersinking just shy of the oil drilling. You want the drilling to remain in the threads for back pressure to properly lubricate the rocker shaft. The adjuster then sits partially up inside the rocker, still able to pivot.
On top of that, you still need extra room for the foot to swivel.
If you are not countersinking, then .060 sounds reasonable.
You can usually get by pretty easy with half that with a good countersink. I did this with a 90deg countersink and stopped countersinking just shy of the oil drilling. You want the drilling to remain in the threads for back pressure to properly lubricate the rocker shaft. The adjuster then sits partially up inside the rocker, still able to pivot.