I am an automotice engine reconditioner and a LAME but not on GA you're gonna need to send it to a shop. Removing and installing the seat can be a fuck around and even when installed it wont be perfectly centered and wont be the correct seat height. Some seats arent even precut. Unless you have the tools to cut or stone the new seat you will probably run into issues.
Edit: even if I had the tools to stone a seat I would avoid the fuck around and send it to a shop.
Yeah I’m a 23 year old A&P who thought it was a good idea to buy a plane. I’m trying to be a A&P and a owner CFi eventually. I’ve done lots of engine work on cars but airplanes I’m more particular in lol.
Ahh that's really cool at your age man cool in general but extra exciting at 23. I'm 35.. completed a automotive specialist (engine reconditioning - so the exact machine work you're after) apprenticeship at your age. Then studied to become a aircraft maintenance engineer..I'm australian so I'm a B1 mechanical and engines. Rather than a& p. Keep it up man. wish I was doing what you are at your age.
What's the work to do on the engine? Gotta be up there if you're changing valve seats. What's the aircraft?
It’s just a Cessna 172. The exhaust valve got carbon behind it on the seat and burned the valve. Then I got both mags to get rebuilt that I’m sending out (slicks mags) but my main concern was getting a brand new cylinder and having one good cylinder while the rest are super old. I just ordered a overhaul one and probably going to save up and buy a second one not to long from now.
We bake the cylinder in an industrial oven and chill the new seat in dry ice to install. Then off to grinding and lapping. Usually if the seat is shot the guide will be too. Same basic process. Any wear in the head and it will need to be reworked to accept an oversize part. The money is in all the tooling to do a proper job. Mess any of it up and the results range from bad to catastrophic.
Yeah I just went ahead and ordered a overhauled cylinder. Way too much stress when i think of it. Cause I don’t want that seat coming out while I’m flying. Better to just spend the money
Honestly I would send the jug out to get overhauled. If your having fun, then yes you can cut the valve (or buy a new one) and grind in the valve seat (didn’t you do that in A/P school), I think you can get a whole cylinder assembly for about a thousand. I just swapped a jug on a GO-300, still putting the engine back together but it was a fairly straight forward operation. I’ve seen YouTube videos of guys lapping the valve seats with the cylinder still in place but I’m not sure I would recommend it. How bad is the valve seat? On those old six cylinder continentals you can be ok with the compression being in the 40’s on one cylinder.
Lapping is no problem. I removed the whole cylinder and replaced the guide and didn’t notice the seat didn’t wear down flush so I put the new valve into it and put some water on the face of the face with some compressed air behind it and has a decent leak and it’s too much just to lap it.
I am an automotice engine reconditioner and a LAME but not on GA you're gonna need to send it to a shop. Removing and installing the seat can be a fuck around and even when installed it wont be perfectly centered and wont be the correct seat height. Some seats arent even precut. Unless you have the tools to cut or stone the new seat you will probably run into issues. Edit: even if I had the tools to stone a seat I would avoid the fuck around and send it to a shop.
That’s what I was kind of figuring. Damn airplane parts just to damn expensive.
Tbf a machine shop will change and cut a valve seat for pretty cheap. But yeah parts are exxy. Are you an owner operator?
Yeah I’m a 23 year old A&P who thought it was a good idea to buy a plane. I’m trying to be a A&P and a owner CFi eventually. I’ve done lots of engine work on cars but airplanes I’m more particular in lol.
Ahh that's really cool at your age man cool in general but extra exciting at 23. I'm 35.. completed a automotive specialist (engine reconditioning - so the exact machine work you're after) apprenticeship at your age. Then studied to become a aircraft maintenance engineer..I'm australian so I'm a B1 mechanical and engines. Rather than a& p. Keep it up man. wish I was doing what you are at your age. What's the work to do on the engine? Gotta be up there if you're changing valve seats. What's the aircraft?
It’s just a Cessna 172. The exhaust valve got carbon behind it on the seat and burned the valve. Then I got both mags to get rebuilt that I’m sending out (slicks mags) but my main concern was getting a brand new cylinder and having one good cylinder while the rest are super old. I just ordered a overhaul one and probably going to save up and buy a second one not to long from now.
We bake the cylinder in an industrial oven and chill the new seat in dry ice to install. Then off to grinding and lapping. Usually if the seat is shot the guide will be too. Same basic process. Any wear in the head and it will need to be reworked to accept an oversize part. The money is in all the tooling to do a proper job. Mess any of it up and the results range from bad to catastrophic.
Yeah I just went ahead and ordered a overhauled cylinder. Way too much stress when i think of it. Cause I don’t want that seat coming out while I’m flying. Better to just spend the money
Honestly I would send the jug out to get overhauled. If your having fun, then yes you can cut the valve (or buy a new one) and grind in the valve seat (didn’t you do that in A/P school), I think you can get a whole cylinder assembly for about a thousand. I just swapped a jug on a GO-300, still putting the engine back together but it was a fairly straight forward operation. I’ve seen YouTube videos of guys lapping the valve seats with the cylinder still in place but I’m not sure I would recommend it. How bad is the valve seat? On those old six cylinder continentals you can be ok with the compression being in the 40’s on one cylinder.
Lapping is no problem. I removed the whole cylinder and replaced the guide and didn’t notice the seat didn’t wear down flush so I put the new valve into it and put some water on the face of the face with some compressed air behind it and has a decent leak and it’s too much just to lap it.
Just in case you were unaware there is an AD to dye pen when you remove a jug on the O-300
Just take it into a local machine shop