It's likely that we will only offer Ampco45 seats in the future after doing some further research, similar thermal conductivity without the health hazards!

 

Can anyone tell me why using an Ampco 45 seat with a steel valve may not be a good idea if longevity is a concern?

 

I'm guessing this is a rhetorical question with the answer involving the hardness of the material. I would agree that this isn't something I would recommend for a daily driver, but I think the costs involved would rule that out for most people anyways. These guys seem to be successfully using them with SS valves on the 2JZ platform, and Kibblewhite's website outlines teams utilizing the Ampco 45 to reduce wear on SS valves...

 

+1 for not using Beryllium.

We are currently investigating how to identify and get rid of Beryllium in TONS of different places in the aerospace industry.

 

I wholeheartedly agree, and this single caveat needs to be emphasized to the masses more than anything else in this discussion.

Using a soft metal seat is fine, so long as one is prepared to change seats more frequently than he typically would, simply because steel valves will put a punishing on them. OEMs realized this consequence when tetraethyl lead was eliminated from gasoline and took a toll on the Rc 20 iron seats. Of course, if one is facing the replacement of Ti valves at $100+ apiece, better to let the seats take the beating and spare the valves.

IF there was a sceneario whereby one was truly interested in developing a seat with superior thermal conductivity and OE-like longevity with steel alloy valves, the best bet (IMO) would be something with superior thermal properties and hardness in the range of Rc 35-40. There are CuBe alloys that fit the bill, and maybe some newer ones, but in either case they won't be cheap.

 

+1 on that as well, we have had tons and tons of training on Beryllium in the Navy... it is nasty stuff, however a few workcenters still use beryllium tools when working on Magnetic Assemblies...

 

Are you sure that AMPCO 45 is so soft?

http://www.ampcometal.com/common/dat...45_EX_E_US.pdf

98 HRB so it seems to be in the range of the softest OEM iron seat!

Also, Be-Cu valve seat are generally in the range of 20 to 41 HRC (More Ni, less hard).

 

Iron seats in the days of leaded fuels were soft (like Ampco 45), but the introduction of unleaded fuels caused them to wear out prematurely.

Harder ductile iron seats are used today, and are suitable for the unleaded fuels we use. I've not personally subjected an OEM seat to a Rockwell Hardness test, but the consensus of info I find says that will show at least 32 Rc, with aftermarket induction hardened tool steel seats being upward of Rc 60.

Of course, this applies to steel valves. When one uses Ti valves (e.g. Spyros), the picture changes considerably.

 

What about the MoldStar material like MoldStar 90? Many places have switched to this from the CuBe seats.

 

It's ~Rc 30 - a harder material than Ampco 45.

 

I've heard the moldstar90 is tough to get, but haven't actually looked into it myself.

 

 

 

 

Looking good!!!