Titanium Retainers

[Beej '86 325es]

Need some input on this. I have a partially complete - performance built S50 head. It's got s.s. valves, ti retainers, heated keepers, port/polish job, & performance v.s.

I was reading a letter in Roundel that Turner Motorsports replied to. They had said not to use titanium retainers unless it was a track car because they wear out fast and would need to be replaced. I plan on using the car as an autocrosser, little track, and sometimes around town when I get the S50 in.

Can someone explain just how these wear out? :?

[Alex Mc]

Ti retainers are no good on 4-valve street motors for the same reason Turner said not to use them - they wear out quickly. The use of Ti retainers is clearly cut valvetrain weight, but the cost you pay is that titanium is simply not as hard or strong as heat-treated steel - especially from Motorsport (note: early production retainers had metallurgical issues, so the new retainers must be fitted if its an older head - these should be replaced anyway though on a rebuild). The accelerated wear is simply unacceptable on a street application, which is why at our shop we will NOT install them on a street car.

If they do fail? Valve stem keeper pulls through the worn retainer surface, thus seperating the valve from the spring. The valve proceeds into the chamber while the piston is charging up the cylinder, and the kaboom - valve gets TKO'd by the piston head, and for every revolution thereafter (at 6000rpm thats 100 times per second). Its simply not worth the risk for a few extra grams off the already light valvetrain.

[Beej '86 325es]

Thank you, Alex. That was very helpful. Since you obviously know a lot about this type of stuff, do you see anything wrong with using the stainless steel valves that are in the head since it will be partially a street car?
Thanks!