c5z16z

why would you run bronze valve guides if the material is softer and would wear faster than the powdered metal guides ?

and what grade of bronze is used for valve guides ?

and what carbon grade is used for the powdered metal guides ?

A.R. Shale Targa

iTrader: (2)

Bronze is more porous, lubricates better, and runs cooler but wears faster
as it is softer.

machinistone

With the high quality lubricant impregnated powdered metal guides we have now, the only advantage a bronze guide has is not shattering should a valve bend.

c5z16z

what grade/type of metal do the powdered metal guides consist of ?

and same for the bronze what kind/grade of bronze is used for valve guides ?

lets say you go with a set of heads that have bronze valve guides, if i was to go with titanium intake valves and stainless steel exhaust valves what type of coating would you go with on the valve stems to live on a street car ( of course using roller tip rocker arms ) ?

and why dont i see people running titanium valves for the exhaust side for weight reduction over stainless steel valves ?

Exidous

iTrader: (11)

The smaller size of the exhaust valve makes the weight reduction less significant that an intake valve so most don't fine the juice worth the squeeze. Unless the motor is spinning a LOT of RPM's and every aspec of valvetrain stability is being scrutinized it's just not worth it.

Some may run an iconel valve for turbo applications to beat the heat.

c5z16z

are inconel valves more expensive than titanium valves ?



what grade/type of metal do the powdered metal guides consist of ?

and same for the bronze what kind/grade of bronze is used for valve guides ?

c5z16z

come on, somebody educate me more and valve guides and valves ....

A.R. Shale Targa

iTrader: (2)

check this out..........http://www.sbintl.com/KLine.html

v8pwr

iTrader: (19)

Titanium valves will live fine on the street. A coating helps but will not prevent the problem, usually it's valve control. The user also has to make sure there is sufficient lubrication. There are people that are losing valves but Ti valves have been used for a while. There are a lot of coatings depending on how much you want to spend. The DLC coating is generally considered the premium coating but valve manufacturers can and will specify a coating for the particular application. Bronze guides are made in different alloys depending on use and cost. The most common are phosphorus bronze and manganese bronze. One is better for exhaust applications but I can't remember. Powdered metals are relatively new and they bring some very interesting possibilities with them. These materials can be made with some very nice improvements over commonly available materials and affordable to manufacture in mass quantities, just take a look at stock connecting rods. Titanium is used for exhaust valves but they require beryllium copper valve seats because titanium is a very poor conductor of heat and the copper seat pulls the heat out.

SSCamaro99_3

iTrader: (1)

Beryllium is also fairly toxic when inhaled. I think F1 banned it a few years ago. When the valve seat struck the head repeatedly it would vaporize small bits of the berrylium-copper and they would go out the exhaust. It may be hard to find that type of valve for an application.

driver56

Also check out CHE Precision Inc. for guide and seat information.

machinistone

Ti valves are more expensive - inconel valves are less than half the cost. That does not though mean that should money be no object, that Ti is a better choice than inconel. As was said, the inconel valves can handle very high heat which is why we use them in extreme turbo and marine applications. The Ti valves are great on the intake side where you have a larger valve and want to reduce weight. You can get good valve control at a cheaper price by using a hollow stem intake valve with the proper cam lobe for the application.

Powdered metal guide formulations are somewhat proprietary, and to be honest I don't know the exact combination used, but the important thing is that they're able to mix metals in powder form in the sinter forging process, that would normally not be able to form a proper casting together. So now you get the strength and long life of a hardened cast iron guide with the lubricity of a bronze guide. Iron would be the primary component, zinc for lubricity, nickel for strength, copper, bronze, etc...

For full replacement bronze guides we typically use a manganese bronze guide, or in high heat applications, a phosphor-bronze guide - each manufacturer will have their own proprietary makup.

I've never heard of CuBe seats blowing toxins out the tailpipe, but you do need to wear a facemask when machining them as the dust can cause harm.

c5z16z

thanks for the help fellas

SSCamaro99_3

iTrader: (1)

I read an article about their use in F1 and it being an issue. F1 is a pretty extreme setup, may not be an issue in a different application. That is about the extent that I have on it.