Best valve guide material?
 

Doing a quick search of several vendors it looks like phosphorus bronze is the commonly used material for 911 valve guides. I have heard that manganese bronze are also available and better. What's the material of choice among top builders and what is the difference between these two materials?

We use manganese bronze on normally aspirated street engines and phosphorus bronze on turbo and race engines.
MB is more durable and PB transfers heat better.

Beware of claims of magic/ propitiatory materials. Most are just advertizing gimmicks.
Bronzonium comes to mind as a perfect example.

Sounds like MB is the way to go for a mostly stock 3.2 that will see the occasional DE event. Thanks Henry.

The Heat Transfer Coefficient of Phosphor Bronze is strongly affected by its alloy content.

A 5% Tin PB material would have a typical Heat Transfer Coefficient of about 69 Wm^-1.degK^-1

An alloy with 10% Tin would have a significantly lower value of around 50Wm^-1.degK^-1

Maganese Bronze is quite different and is much more consistent at about
105 Wm^-1.degK^-1

The materials that have been designed for high performance valve guides such as Colsibro and Hidurel are Precipitation Hardening Nickel-Silicon Bronzes and have Heat Transfer Coefficient of about 190 Wm^-1.degK^-1

This is around 4 times that of the high Tin content Phosphor Bronzes.

The Colsibro and Hidurel materials have excellent strength and relatively high modulus values but possibly lower lubricity than Phosphor Bronzes.

I have priced up Colsibro in the last couple of weeks and it would be about $3.00 per guide before machining.

Great info Chris and Henry. Thanks..

valve job
 

Henry,

Do you send your heads out for a valve job or is it done in house?

Thanks,
Harry

Sorry...

just went to your website...in house!


h