Question from reading in severial places By 89newbie (Read 494 times)

[89newbie]

Valve seats? are there seats in some of the engines or are they all just valve to aluminum heads as I have read?

[silverfox96]

Valve seats are steel inserts.

[Bashan]

Nov 9, 2011 10:56:08 GMT -6 silverfox96 said:

Valve seats are steel inserts.

Yes, they can be. But if you read this Wikipedia article you can see that they can also simply be the area where the valve makes contact with the actual head metal. This often occurs in inexpensively made engines like the Chinese GY6. If you'll look in the Arrow and Tank manuals in our Library there's sections on how to use tools to cut the head material to match the valve and then lap the valve to seat it. I suspect that many of the more sophisticated engines that are coming out now in the high end scooters will have valve seat inserts of some exotic metals. Rich

[89newbie]

Nov 9, 2011 10:56:08 GMT -6 silverfox96 said:

Valve seats are steel inserts.

LOL qauite farmilar with them used to ne an aircraft engine tech always pullin jugs to send to the shop to have new seats installed from compression loss broken valves etc. Question arose because I read some Mfg are not installing seats.

[89newbie]

Nov 9, 2011 13:36:14 GMT -6 Bashan said:

Nov 9, 2011 10:56:08 GMT -6 silverfox96 said:

Valve seats are steel inserts.

Yes, they can be. But if you read this Wikipedia article you can see that they can also simply be the area where the valve makes contact with the actual head metal. This often occurs in inexpensively made engines like the Chinese GY6. If you'll look in the Arrow and Tank manuals in our Library there's sections on how to use tools to cut the head material to match the valve and then lap the valve to seat it. I suspect that many of the more sophisticated engines that are coming out now in the high end scooters will have valve seat inserts of some exotic metals. Rich

Thats where I was coming from. No seat, - - head, steel valves, non anoized valve top. Results China Mfg set valves close to get them to run. Heat and run time causes valves to seat further in the -- head and the constant strike from the tappet combined with the heat of running anneals the stem head. All this causes valves to need adjustment. LOL the good thing is once broken in your not going to drop a seat on the highway. Now the thought of the fast breakin as opposed to the slow one probably causes a deeper seat in the -- head faster, while giving a slower annealing of the valve stem head.