iron head seat replacement

[dsvracer]

looking to replace the valve seats in an iron head sportster.  what would be  good interference fit ?? done plenty of seats on the aluminum heads but this is new to me on cast iron.  thanks for the help.  dsv

[Ohio HD]

Aren't the valve seats in an Iron Head cut from the head casting?

[JW113]

Mine are.

-JW

[SP33DY]

looking to replace the valve seats in an iron head sportster.  what would be  good interference fit ?? done plenty of seats on the aluminum heads but this is new to me on cast iron.  thanks for the help.  dsv

Counterbore the head for 0.004" to 0.005" interference fit.

 You need to be careful about seat thickness in these heads because the short side doesn't have much material under the seat. AV&V AV1757S is good for 900 and 1000 exhausts. AV&V AV2068 or Goodson HVS2068 is good for 1000 intakes, but too big for the 900 intake unless you decide to go to the larger 1000 valve. These seats are 0.315" thick. Many years ago, I had Martin-Wells make me a couple of boxes of special seats for the 900's  and 1000's but I can't find them to give you the dimensions. I think they were 0.250" thick.

[SP33DY]

Aren't the valve seats in an Iron Head cut from the head casting?

Yes they are, from the factory. After a few top end overhauls, refinishing the seats eventually sinks them to the point that the head needs to be counterbored to install new seat rings.

[dsvracer]

Thank you so much for the information. have a great new year.  dsv

[Buglet]

   Years ago Harley use to sell replacement seats for the Iron heads. 

[JW113]

I think another reason to add seats is to make the heads compatible with unleaded gas. The cast iron heads as from the factory, ain't...

-JW