I know it's a dealer, but can't Dean Caterpillar help? Although, I'll bet the labor would probably kill the deal.
alan627b

They are bound to others with a lot more "head" experience than me, but I don't remember 3T's as having removeable valve seats. ....and I don't remember them as being such that one was able to cut them out and press in new valve seats. I don't think the head was thick enough in that area to allow for machining before the water jacket got to thin.

Checked the parts books and Old 3T is correct. The 3T series never did use valve seat inserts.....and the "meat" in that area appears pretty thin. Inserts did not come along until later on the D339.

You guys are seldom wrong, and my parts book doesn't show them either, but Dean Cat and others show the valve seats are replaceable. The part numbers are 7F8922 for the exhaust valve seat and 7F8923 for the intake valve seat.

You can pretty clearly see a ring aroung the valve seat inserts in the head and when I lay my new inserts on top of them they line up.

I have tried TIG welding a bead around the insert to shrink it and have ground down a valve and welded it to the insert. The insert is really hard compared to the cast iron head around it and it just breaks chunks out of the insert when you try to drive it out with the valve welded to it. I even built a heavy duty "valve surrogate" with a 3/4 inch steel shaft that I TIG welded to the insert with stainless steel rod (seems to stick better) but this still won't drive the insert out.

If I had a mill I could reference it to the center of the valve guide and use an end mill to cut the old insert just shy of the exact depth and width of the new inserts I have. I am sure that it would then be weak enough to drive out.

Any other ideas would be appreciated.

Thanks,
KansasD7

There was a repair seat insert process used years ago that called for peening iron over the edge of the seat ring. A piloted cutter was used to cut back this peened metal before the seat could be pulled. Could you perhaps have run into some of these seats? I have no idea if they were ever used in Cat repairs. I have never seen one, only read about them in service books. I think it was Waukesha engine or perhaps Herculese that referred to them.

Just a long shot idea, probably not worth a thing but there it is. Good luck!

Probably stellite seats.
If you have a steady hand take a die grinder to the seat in a couple of spots and grind as far as you dare to weaken the grip and try your weld/heat/beat process again. Hopefully you only have a few to do:)

At the dealer the heads that had no seats were bored out with a boring tool we had and seats were then installed.Boy I can,t just remember how the seats were removed now to replace with new ones but it seems the welder would run a small bead around them and they would come out but I,ll see if I can get in touch with the guy that always did our heads and get back.

SJ is right about running a small bead around whatever you're trying to get out. Works well with bearings too. Just let it cool totally before you try to pry or beat the part out. A little dry ice (if you can get it) applied to the part for will also help.

What happens is the part will expand from the heat and as there's no place for the material to go, it'll actually shrink when it cools.