[DeTomaso] Rocker installation

[Henrik Svensson]

Hi

Then I'm on the right track when looking at adjusting the rods, I guess that's the only part that is possible to adjust to get that kind of change?

I was told there are some kind of "hat" to place on top of the valve to get a bigger surface for the roller? Anything you recommend or not?

Thanks all!

Henrik



-----Ursprungligt meddelande-----
Från: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] För JDeRyke at aol.com
Skickat: den 17 maj 2010 19:50
Till: detomaso at realbig.com
Ämne: Re: [DeTomaso] Rocker installation

Rocker geometry changes with aftermarket parts is common,and its very 
important to get it right before running the engine hard. Complete engine failure 
sometimes results. Head thickness, gasket thickness, valve stem lengths, 
rocker type and what cam you use all influence the geometry. FWIW, as Tomas 
said, intake and exhaust valve stems are usually different lengths. Note that 
this happens with all-stock parts if the heads have been at all machined, 
even for a simple valve grind.

Get one adjustable pushrod to check the lengths you need. Adjustable 
pushrods are not for running in an engine; ther usually aren't stiff enough and 
are always too heavy. Use a felt pen on a valve stem tip, assemble that 
cylinder and roll the engine thru two complete revolutions; the tip will scrub off 
the marking ink and you'll clearly see the contact area. Then you can order 
the correct length pushrods. or have some made up locally. Remember, they 
must still be hardened on the upper ends. There are lots of cam tech sites 
that explain whats going on here, and how to correct it by varying pushrod or 
valve stem length. Good luck- J Deryke
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