12L14 for valve seat cage

[borna]

Hello all,
Is 12L14 a good material for valve cage?

Thanks
Borna

 

[steamer]

Most of the Callouts I've seen have been for bronze.....

Dave

 

[GailInNM]

Borna,
It will work --- for a little while. 12L14 rusts quickly from the water in the products of combustion. Then it will leak with almost no recourse except to replace it.
As Dave mentioned bronze is much better.
Gail in NM

 

[borna]

Does it matter what kind ob bronze to use?

Thanks

 

[GailInNM]

SAE660 (CDA932 - CDA93200) is easily available from most metal suppliers and from machine tool suppliers such as Enco and MSC. Normally comes in 13 inch long bars that are oversize from the nominal diameter.
It machines easily with a good finish. It is what I like to use.

Other bronzes are suitable also and some people prefer them.
Gail in NM

 

[stevehuckss396]

Brass will also work if you are working with small cages. I used brass for 1/4 inch valves and they still work some 3 years later. I have also used drill rod if you can believe it. O1 i believe. Worked well but I prefer brass.

 

[borna]

Thanks all for the info. How about CAM, can I use 12L14 for CAM or too soft?

 

[Swede]

For valve seats, try aluminum bronze. It is a really interesting material. Very strong, harder than most bronzes, and not as easy to machine - hard to describe, at least in my lathe, it tends to make weird noises when cut, but it finishes up nicely.

12L14 is not suitable cam material unless case hardened later, and the case hardening process comes with troubles of its own. I'd go with a medium carbon steel like 4140 or 4340, and for any significant running, it needs to be through-hardened and then tempered.

 

[Ed T]

Yes, aluminum bronze makes excellent valve seats, but it is an absolute bugger to machine especially if it has to be tapped. I wrestled with it for many years and it would not be my material of choice for anything unless there was no other choice. One issue is that the bars are often cast and the center of the bar can be "pulpy" from the effects of shrinking during cooling. In simple machining operations, the center of the bar is often where the part is found and the results can be unfortunate. IMHO, pick something easier to machine as suggested above.

 

[Rustkolector]

I have successfully used 12L14 and phosphor bronze for valve cages. My prefernce is the harder phosphor bronze. It machines very well, the guides and seats wear well, and the cages won't corrode.

Gail brought up a topic related issue that should be considered when building, BUT more often when operating model engines. Upper cylinder corrosion is quite common in model IC engines using ferrous cylinders, heads, valves, and valve cages. It is especially prevalent in engines that are run for short periods that don't reach optimum internal temperatures. If the engine gets good'n hot, then not much of a problem. However, most model engine demo runs don't let the engine get warm enough to keep it free of internal moisture, even when a fuel/oil mix is used. After all runs (long or short), my practice now is to pull the plugs and fog (not flood) the cylinders with WD-40, then replace the plugs.

Jeff

 

[Swede]

Yes, aluminum bronze makes excellent valve seats, but it is an absolute bugger to machine especially if it has to be tapped. I wrestled with it for many years and it would not be my material of choice for anything unless there was no other choice. One issue is that the bars are often cast and the center of the bar can be "pulpy" from the effects of shrinking during cooling. In simple machining operations, the center of the bar is often where the part is found and the results can be unfortunate. IMHO, pick something easier to machine as suggested above.

This is interesting, Ed. I'll agree that it doesn't machine like 360 brass or 12L14, but I haven't had it present any great difficulty. For machinability, I'd put it somewhere between cold-roll 1018 steel and tool steel. Definitely easier that any stainless, probably on par with a medium steel like 4140.

Maybe we have different alloys, considering the wild variety of bronzes out there. Not all aluminum bronze is the same.

A sharp tool with neutral to negative rake is a must. Drilling can be tricky as unmodified drills definitely grab and pull like they do with other copper alloys.

 

[Ed T]

Swede, Maybe there are different flavors. I don't recall the alloy number of the material we were using, but I certainly recall the issues we had with machining it and with the variability of the results which were difficult to detect. The issue may be somewhat associated with the original group of parts being made from plate stock that was cut into blocks and then machined into parts while the production parts were made on bar feed machines and, of course, started with bar stock. Anyhow, I'm glad you're having good luck with it, but I'll continue to avoid it if I can.