Valve Seats


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By Rudder2fly - 15 Years Ago
Is there anyway to tell if valve seats have been upgraded to hard seats? Thanks.
By Ol'ford nut - 15 Years Ago
You need to give us more-

Engine together in car? Heads off but together? Heads off with valves out? Can you see if the seats have been replaced?

Only way "I" can tell is when grinding seats. Unless it is a recent job.

By mctim64 - 15 Years Ago
If you have the head off you can see that the steel seat is a bit shinier than the cast around it.  Sometimes with the head on the engine you can look down the exhaust port and see where the seat stops and the cast head starts but if the engine has been run you usually can't see this.

I like the Pitts in your avitar, I might post a pic of my "Flyin' Fool" Smile

By Rudder2fly - 15 Years Ago
Heads are together and on a shelf. They were run so I don't know if I can see a difference in the metal. I am about to start to work with them and just wondered if there was some test to find out the seat material. The engine was rebuilt but don't know when? I'm just trying to keep costs down. No sense replacing something if it is already there. Block is ready to go to the machine shop. I have been into model planes for 34 years. Hence the handle rudder2fly. My Dad had a shirt with that on and I liked it. The Pitts was a favorite of his also. Love to see your plane Tim. I just love this site for all the info thats available. Thanks to everyone!!!!!!
By oldcarmark - 15 Years Ago
I just got my heads redone with hard seats on the exhaust valves.The inserts can be seen clearly outside the the circumference of the valve heads.In other words they are not hidden under the valve heads and if yours have been redone you will be able to see the inserts.
By mctim64 - 15 Years Ago
If you have the heads off just pop one of the exhaust valves out you should be able to see a line where the seat meets the head.  Not all shops will put so big a seat in that you can tell it's there with the valve in, we don't, and Ford machined their heads so to the untrained eye it may look as if there is a seat installed.

This head has a hard seat but it is not easy to see under the valve.

This head you can clearly see the seat and the different shade of metal.

this head has no hard exhaust seat insert.

And this is the "Flying Fool" Wink

I do C/L  not R/C, I wasn't very good with radio so I just went out and got my private ticket so I could fly the real thing. Tongue

By Rono - 15 Years Ago
My machinist told me that there are about 3 grades of hardened seats. I think the better shops can determine the hardness.

Rono.

By mctim64 - 15 Years Ago
Rono (2/15/2010)
My machinist told me that there are about 3 grades of hardened seats. I think the better shops can determine the hardness.

Rono.

There are different hardness seats for different fuels (gas, LPG, ect) they also make cast iron seats, if these are installed you are no better off than before.

By Rudder2fly - 15 Years Ago
Thanks for the great pics Tim. I should be able to tell the metal type now.Your plane looks to be a stunt type and with Mcoy power, looks great. Thanks to everyone who replied.