Does anyone have any experience with using Dry Film Lubricants on engine parts. I'm going to be going with a ported head/cam change and was thinking of having the cam, valve stems, valve springs and retainers,and rocker arms done. Any thoughts?
Thanks!
Jim

 

I used some on pistons including the pin holes so the machine shop charged me to hone them so the pins would go in

A dry film coating would probably just add weight to the retainers (most such coatings hold more oil too) and there is some controversy on whether they may reduce heat transfer out of the springs to the oil. If the springs are a single coil without a damper then there's no friction there anyway, and if there is a damper spring then friction is what lets it work. Definitely a good idea on the cam lobes/rockers but you may find doing the valve stems can result in valves that no longer fit...

Most people who use such coatings use specific thermal barrier coatings on the piston tops and thermal dispersing/oil shedding coatings on the valvesprings. Dry film lubricants are usually reserved for high friction areas like cam lobes, bearings and piston skirts.

 

we have a roller cam, so you don't really need them there. The clearence issues are real, so any on the valve stems would have to be taken into account for guide clearence. Springs it won't do much, but I was reading a Mustang mag that pointed out making sure the flat ends are nice and smooth (no burrs and the like) will help with the twisting that the springs do under compression, but that's more careful prep work. The valve ends of the rockers are a bit funky (I think they're miniature hydrolics) but the contact point there is tiney. Maybe there it would help.... I honestly don't know as I'm not up on the little thinggys....

Matt

 

To digress slightly, that's not the only mode of operation for double valve springs—maybe not oven the principal one, depending on the application. A single spring often has to have a higher than desirable rate in order to raise its resonant frequency above the normal range of operation. (Resonance can cause loss of valve seat pressure.) Use of a suitably chosen double spring setup can attenuate that resonance.

The valve spring listing on this page claims specific benefits for an anti-friction coating on double valve springs and gives data to support that:
http://www.hpcoatings.com/products/lubritic.aspx

A stock MCS head has single valve springs, so I can't see much benefit to an anti-friction coating in this application.

Neil
05 MCS
96 M3