ThomasC2

A friend of mine is about to replace his valves. Stock/OEM valves was the main option. But know he found a company that sells custom made valves in titanium for the same cost as stock.

The benefit would be less weight. But are there any known down sides, or is this the future?

Any comments about this?

Thomas

Strega(UK)

Can only comment from my days owning 4 stroke motocross bikes with titanium valves. They tend to literally wear out! I had to have them adjusted frequently until they were like tooth picks. In the end I went stainless. Not sure if used in a car they would suffer the same fate!

robt964

The valves wouldn't be made of pure titanium but instead an alloy. Anything can be made to a price. It would be impossible to make the comparison without knowing the grades. My personal thoughts would be that the 964 motor doesn't rev hard enough to benefit much here. I'd be inclined to stick with stock or a KNOWN entity. It's not like 964s chew through stock valves.

pu911rsr

Folks run titty valves in 2L race motors that they rev very high (9k) they don't last long but they are light.
Phil

ALEX P

Just go with 993 valves - they are readily available from multiple suppliers, have a smaller dia stem and weigh less.

Steve Weiner-Rennsport Systems

Phil is correct;Ti valves afford very high revs due to light weight and their shape, assuming the rest of the engine has been suitably prepared, however these do not last long and are quite expensive.

In addition, Ti valves require beryillium-copper seats which are not cheap and hazardous (toxic) to machine.

For race engines that require very high revs to make power, its all part of the 'recipe', but not needed in all but the highest output race engines.

ThomasC2

Ok, a big thank you guys. In 6 hours I've got the answers I needed! Stock valves it is!

During this weekend I'll pull out the starter from my own car. Time for an overhaul after 24 years.

Have a nice weekend guys!

Thomas

Goughary

We went with 993 valves in mine when I did the top end, ti retainers and aasco springs. The 993 valves are lighter than the stock 964 valves. It's not a performance upgrade , but the lighter valve train makes me worry less at the redline.

Ti valves unless you are building a much higher revving performance motor, are too expensive and too much an overkill.