Titanium Valves

[Big Jay]

The upside;
Lighter, which allows you to run less spring pressure, which makes a tad more power. ( Titanium is about 9/16th the weight of steel or stainless)

The valve head can be flat instead of dished which raises cylinder pressure.

Downside:

Expensive

Soft, so lash caps must be used.

Must use bronze seats. Soft titanium won't last long closing on a steel seat. Many of the new bikes from Japan have titanium valves with steel seats and are having much problems.

Jay

[Addy Leung]

may I have few questions here,
What type of stainless steel to be used for valve materials? 302, 316, 304 or something esle?
Could we ask the machine shop to tailor make the valves for replacement?
any heat treament requied to be done for the new valaves?

[Big Jay]

Why would you want to have a shop make stainless valves from scratch, when they are an off the shelf item?

http://www.gszone.biz/valves.html

Jay

[Addy Leung]

BJ, yes, thanks for your information. But I am living at Hong Kong and there is a lot of good machine shops. So I just think whether I can make some of these valves by them.

[Addy Leung]

Hi BJ,
I did some research and found following: It seems making a valve is not a simple job.

http://www.federal-mogul.com/fmeconnect/technicalservices/downloads/1108.pdf

http://www.supertechperformance.com/technology.htm

These materials are selected to meet specific engine requirements. The definition of ?stainless steel? is generally
accepted to be a steel alloy containing at least 10% chromium in its composition. As can be seen below, Sil 1
approaches this level while maintaining many of the favorable characteristics and lower costs associated with the
inexpensive carbon steel alloys. Sil XB, 422, 21-2N, and 21-4N are true stainless alloys.
1541: Carbon steel with added manganese for improved corrosion resistance
8440: Medium to heavy duty steel alloy with a higher chromium content to enhance high temperature
strength.
Sil 1: Heavy duty steel alloy with an 8.5% chromium content for excellent high temperature performance.
Used for many factory high performance intake valves.
Sil XB: A ferritic stainless steel alloy, with 20% chromium content and 1.3% nickel. Used in heavy duty
intake valves.
422: A stainless steel alloy specified for high performance intake valve usage. This specialty type of
stainless is designed with the temperature ranges and characteristics of intake valves usage in
mind, and is different from the more common exhaust valve stainless materials. Our 422 stainless
valves are easily equal to any of the ?severe use? valves on the market.
Ti-6: Titanium is a lightweight, nonferrous material used in high RPM racing applications. It is 40%
lighter than steel and maintains its strength at high temperatures. Normally used for the larger
intake valves, although there are limited uses for titanium exhaust valves as well.
21-2N: Austenitic stainless steel with 21% chromium and 25 NICKEL. As the most popular exhaust valve
material, it has excellent performance characteristics at elevated temperatures. With additional heat
treating and manufacturing processes, this material can be upgraded to become the ultimate choice
for exhaust usage. With different processes, it makes for a good quality, inexpensive intake valve
as well.
21-4N: An Austenitic stainless steel similar to 21-2N, except for a greater nickel content (4%), used as an
alternate to 21-2N.

[mark m]

But I am living at Hong Kong and there is a lot of good machine shops. So I just think whether I can make some of these valves by them.

It is virtually impossible to do a one-off job cheaper or better than someone setup to do a production run of the same item. Economy of scale simply defeats you in this endeavor. For something you can buy as cheaply as valves, it is not worth considering. A valve is a finely machined and finish ground piece with a very sophisticated profile to allow for max performance and a long life in a very hostile environment. It would likely cost as much for a shop to do one custom valve as for an entire set of production valves from a performance shop.


Mark

[Big Jay]

But I am living at Hong Kong and there is a lot of good machine shops. So I just think whether I can make some of these valves by them.

It is virtually impossible to do a one-off job cheaper or better than someone setup to do a production run of the same item. Economy of scale simply defeats you in this endeavor. For something you can buy as cheaply as valves, it is not worth considering. A valve is a finely machined and finish ground piece with a very sophisticated profile to allow for max performance and a long life in a very hostile environment. It would likely cost as much for a shop to do one custom valve as for an entire set of production valves from a performance shop.


Mark

Not to mention that the stems are hard chrome plated then ground to size.

Valves are not machined from large bar stock. A 36 mm valve with a 7 mm stem doesn't start with a piece of stainless over 36 mm. It starts with a piece of material a little over 7mm and the head is forged ( smashed flat) then machined into the proper shape.

Jay