tappets and metallurgy

[avantey]

I am missing the tappets for a 1916 Hupp engine and considering making them. I am not sure what stock and hardening to use though.

Option 1 is a CRS and either case or pack case harden. This would give a case of near to .100" deep or almost all the way thru the 3/8-24 thread.

Option 2 is either an A2 or S7 tool steel and a Rockwell of 60-60C. I have been told this is better as it leaves a 'soft' core that will take the repeated pounding of the valve beeter than the more brittle case hardened part.

Any thoughts on this from a metallurgy point of view? Thanks- Bill

[Peter J.Heizmann]

Hello, Bill.

Will discuss your query with our Metallurgical Director at work tomorrow for his input.

I have some thoughts tonight that lean towards Choice #2, however, do not want to steer you in the wrong direction.

Regards,

Peter J... <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[nearchoclatetown]

It's just a guess, but 60-62C sounds pretty hard for something like a tappet. I'd borrow one, there has to be someone with an extra one, and Rockwell it. The S-7 is excellant steel to machine, very stabile, only goes to about 58C. Do you have a picture? My opinion would be to not case harden them, but through harden whatever flavor steel you use.

[Peter J.Heizmann]

Hi, Bill...

Discussed your query with our metallurgical staff.

First, agree with Doug (nearchocolatetown)that 60-62C is an extreme.

Second, agree with Doug, again, that a sample of a worn out tappet could be checked in a few minutes. If there is one available, the door is open for you to send it to me and we could perform a "destructive" microstructure analysis "non-gratis". At least you would know for certain which route to go.

Back in 1916, they certainly did not have the technology of available metallurgical properties of today.

Case hardening is like flame hardening in the sense of what is the desired depth one wishes to attain? We produce castings (Gear blanks, for example) that spec out .125 flame hardening of the O.D. gear teeth area.

Again, if you can find a used tappet, I will have our guys do a microstructure analysis.

Send an e-mail (below) and I will provide an address if you are interested.

Regards,

Peter J... <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[avantey]

Hi Pete- thanks for the ofer to help and info. I believe all of you that the 60-62C is too hard now.

I actually have an entire extra assembled engine that came with the car but it is a big pile of rust! I was at at it again just now- took off the chamber side cover and can see eight complete tappet sets, just can't get them out......

The large plugs that screw in the top of the jugs are rusted in quite badly and quite rusty too. I could not make a pipe wrench stay on them to try and loosen one. If I could loosen one I could get the valve outand then the tappet. I really don't want to gt this engine for parts just yet as it is a great reference for reassembling the engine. This car came home in two truckloads and a trailer full so the extra assemblies are worth a lot to me as refernces! (I also have a frot and rear axle assembly)

Any idea how to loosen the top plug? It appears to be about a 1 1/2" socket size but the rust would make it hard to stay on.

thanks for the help- Bill

avantey@excite.com

[nearchoclatetown]

Heat and your favorite rust juice.