Hardened seats coming loose

[duffeycycles]

Thats what Delcron said...& half of them fell out in the first 2,500 miles

[T. Cotten]

The amount of press fit is dependent on the diameter.
The larger diameter the larger the press
Think about the press fit on a valve guide for Harley flat heads.
Diameter is between .5625 & .5937.
Press fit is .0025 / .0015
Now think about a valve seat that is about 2.000 dia. or larger (4 times the diameter of the guide).

Wow Bruce!

So you mean the press on something really big, like a cylinder sleeve, should be really really big?

I'm sure you realize that if the seat's expansion closely matches the matrix casting, then no extreme press is needed.

That's why an OEM bronze seat within the original bronze is easy.
When you start cutting into the aluminum it gets complicated, particularly with all the worms in half-century-old hardware.

....Cotten

[moldthread]

Tom,
Go back and reread what I said about installing them.
With the dry ice and heat they fall in.

Also if you have a MACHINERY HANDBOOK look at it.
It has been the resource for machining since 1914.
You can find the expansion and contraction for metals at -194 F. and 250 F.

[T. Cotten]

With all respect, Bruce,

Please review my posts too.

Its not just about getting them in;
I've heard an early head crack under blankets in the next room, and it is a sickening sound indeed.

...Cotten