I've done many internet searches on BeCu and I've seen contradictory information on Beryllium Copper Valve seats.

Are they fine to run for a 99% street car with coated Titanium intake and SS exhaust valves (using pump gas)? Any pit falls? Can they survive high mile street usage?

Do any of you use them on the street? Can you offer your experience w/them?

Thanks

 

The longevity of the valve job will be reduced compared to a cast iron or powdered metal seat. Why do you want to run the copper seats?

 

The beryllium copper transfers heat much more efficient through the cylinder heads it work great in a nitrous or boosted app. were a lot of heat is generated.

 

My heads already have the beryllium copper seats installed. I've heard they are better for Titanium valves, but I want to make sure they would last driven on the street.

Some info on the Net says it's about the best thing going for Tit valves and endurance racing, and would last very long w/proper setup on the street. Other info says, I wouldn't last 5k miles. I was hoping to get some real world 1st hand feedback?

 

They install those cause the Ti. valves would beat up other type of seats?

 

I talked to DelWest about these seats for use in a high exhaust temp industrial application, and they said "No" on using these seats with a stainless valve. They said it wasn't the material of the valve but the WEIGHT of the valve. The heavy weight of a stainless valve would hammer the seats in. The softer material of the copper-based seat needs the light weight of a titanium valve to help it keep its shape.

 

Your setup can live on the street if you pay close attention to it . Those seats are intended for Ti valves . The BeCu seats conduct heat alot better than iron seats . Titanium does not dissipate heat very well so this helps them live longer . The BeCu seats are softer and will not live as long as iron seats and they're less tolerant of an unstable valvetrain . If you're able to gently put the valve on the seat it'll live a decent life but don't expect 20k-30k miles . The valve job has a major role in this . Find someone who can put a quality valve job and tell them what you're trying to achieve .

 

Interesting...

I was told by the guys who did my heads that the copper-berrylium seats are harder than cast iron seats and will beat up the valves. The main reason they are used with Ti valves is because Ti is not as heat resistant as stainless. The Ti needs to have the heat conducted away from the valve or its life will be reduced significantly-especially on the exhaust valve. The CB seats, because they have copper as a component, conduct heat far better than cast iron so it will be drawn out of the valve once it makes contact. It isn't as necessary on intake valve seats when using Ti valves as it is on the exhaust valve seat. Where copper is very soft, I understand berrylium to be very rather hard making the overall alloy of the two harder than than cast iron.

 

Titanium is very resistant to heat , it just doesn't conduct it very well . When they alloy copper with Be it becomes much stronger while maintaining it's original property of conductivity . While the addition of Be does improve copper it does not make it harder than cast iron . The sintered metals are showing excellent options in a lot of areas . Another reason Ti works well with BeCu seats is reduced valve bounce on the seat from the reduction in inertia .

 

What?

I wonder where you guys on here get your information sometimes? Do you people make this stuff up?

 

What's wrong with it?

I don't know how heat resistant titanium is, but he is correct that titanium is not very efficient at dissipating heat. That's half the reason Be-Cu seats are popular with Ti valves, because it's very good at absorbing the heat out of the titanium.

As for the second part, I don't know about reduced valvebounce, but it surely makes sense that the titanium would have less inertia than a comparable stainless (heavier) or even inconel (much heavier) valve, so it wouldn't be far fetched to assume there could be less valve bounce either.

I don't see what's so suspicious about his comments.

 

I get my information from many sources , including my life . If you ever weld Ti you'll see it reacts violently with oxygen when heated . If you do not have a large enough gas envelope the material will oxidize . That's why when welding Ti tubing you'll need to run a trailing cup and do a back purge . The material just doesn't conduct heat well , check out the physical properties and it'll show you .

 

For what it's worth, gm does not use CB seats in the ls7 head, and it has ti valves. Also, have u looked into the cost of the CB seats? Good enough for GM, good enough for me. We are having some ls7 heads repaired right now and the seats are iron.

 

Titanium is fatigued by heat far more quickly than stainless steel which is why the CB seats are used- to draw the heat out of the Ti valves at a higher rate. I disagreed that Ti is as good at resisting heat and I would say does not dissapate heat as well as stainless. If it did, then CB seats would not be a necessary consideration.

As far as the valve bounce comment, his post reads as though the CB seats have something to do with reducing valve bounce which doesn't make any sense. If that is not what he meant, then I am sorry for the comment. The Ti being a lighter material will reduce valve bounce and valve lofting because the spring is not stressed as much as it would be with a heavier stainless valve. It has nothing to do with CB seats.

The cylinder head guys that put CB seats in my SB2.2 castings informed me they are harder than cast iron seats and are also toxic among other things... I dunno. They told me not to put a lot of street miles on the engine because the valves would not last. They would beat themselves to death against the CB seat. They are race car only type of stuff. (Like an SB2.2 is a great idea in a pro street car anyway...)

I believe the stock GM valves are coated which makes the Ti alloy more resistant to heat so the CB seats are not necessarily an essential at than point- although I doubt it would hurt.

I would agree with v8pwr that Ti does not conduct as well. It seems to "absorb" or hold the heat (for a lack of better terms).

 

They use a sintered iron, or powdered metal, which I believe have similar characteristics to Be-Cu. The old process of alloying metals by melting them down prevented a number of mixtures, or alloys, because they wouldn't mix (like water and oil, I believe). The powdered metal process doesn't have that complication, so manufacturers, such as GM, can design alloys with properties that were impossible with older processes.

Not to mention, I don't think the valve/seat meterial combination was designed for the same stresses that a Be-Cu seat is normally used in. If you cracked open the engine in any 9000RPM smallblock in a NMRA/NMCA pro stock type class, I don't think you'd find any seat material other than Be-Cu, or something similar like AMPCO 45, which is a non-toxic alternative.

 

I believe the copper berrylium material is called Alloy 25 manufactured by Xceldyne and Del West for valve seats and spring seats.

 

Thanks for all of the replies. I've recently heard first hand from 2 highly regarded cylinder head experts, and they both said the seats will live fine on the street as long as valve train is properly matched and stable. So I feel much more comfortable running them on the street now.

 

As far as costs go, the ones I priced to fit a 1.65 diameter ex. valve were less than $14 each, but that was shop cost.

 

Negative. I don't understand where people are saying that a steel seat is softer than a copper beryllium seat. The reason that people say that a copper beryllium seat will not last long on the street is because it will lose it's valve job. Why would it lose it's valve job so quickly as to where a standard steel seated valve job can run for XX,XXX miles?

The reason being is that copper beryllium seats are much softer than steel seats. Think about it this way. With a lighter material being smashed into it (titanium) a copper beryllium seat can not last as long compared to a heavier (stainless) valve being smashed into a steel seat. Why would a larger force being smashed into the same sized item cause it to last longer than a comparably sized, but less weight (thus less force) object being smashed into the same sized object made out of copper beryllium not last as long? We've already covered that copper beryllium seats dissipate heat much better so that is out of the question as a stressor. The answer is simply material strength.

 

Exactly, the titanium valve is much softer than a comparable stainless steel valve. Even for a titanium valve, the Be-Cu seat is the "sacrificial lamb" so to speak, mainly because it is easier and cheaper to do a new valvejob rather than to replace an entire set of titanium valves, especially in the upper eschelons of racing where the valves are custom and would usually take months to replace. Now we're talking a stainless steel valve is going to be beating on the Be-Cu seat? Probably not a good idea.