Valve insert exhaust??

[Gary WA]

Never seen this what are they Insert type Exhaust only on two valves?

[Russ/40]

Looks to be a valve seat in a seat. Odd, but clearly been there a long time. I wouldn't worry about it, unless the interior seat can't be sufficiently dressed. Then I'd pull it all out and start over.

[Kurt in NJ]

There was a tool that peined the metal around the top of the valve seat,it leaves a mark like that

[George Miller]

Yes the edge was rolled in over the seat. There is a tool for that. Most of the time when you only have two seats replaced there was a crack going to the cylinder wall. Number 3 and 4 are bad for that.

[Russ/40]

OK, I can accept that something is peined, but looks like the seat is peined outward. Still not a big deal, but I would sure like to learn more about the technique and the tool.

[BRENT in 10-uh-C]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by Russ/40

OK, I can accept that something is peined, but looks like the seat is peined outward. Still not a big deal, but I would sure like to learn more about the technique and the tool.

The technique is simple. The valve seat is set with a size plus graduated thousandths beginning with 0.001 thru about 0.004 inch oversized. A cutter is either set, -or a specific size can be purchased that will cut the counter-bore in the block. Generally this is done in a size that allows for 0.001" interference fit. The cutter pilots off of a mandrel that pilots off of the valve guide. This allows for concentricity.


Now everyone's methods are different but the way I do it is cut the seat bore about 0.002" below the deck surface with the seat installed. To prep for installing the seat, I chill the seats and use a propane torch to warm the counterbored seat area. Generally the seat drops right into place, but if not, I have a driver that sets it. Then a pilot is reinserted into the guide which will pilot the peening tool. You rotate the tool around the edge of the seat insert on the block surface and strike it lightly with a hammer which compacts the area up against the seat. I have included some pics of a peening tool so you can see what it is.


.
.

[Russ/40]

Thank You Brent for your explanation. Would you please give me your read on Gary's picture 2 above. What was peined, the seat or the block. The outermost circle looks too clean to be the peined edge.

[Tom Wesenberg]

The block should be lightly rolled over the OD of the new seat. This one appears to have been done with a tool that gives it a smooth line all the way around. I never had that tool, and had to peen the lip by hand when I installed seats.

[George Miller]

Yes there is a tool that goes in the holder for the cutter. I have put many in the last 60 years. We did a lot of cars in my Dads shop. I still have the same tool used it on the engine that I,m working on now.