Ci head repair?

Hi Folks
While performing a minor valve job we discovered cracks in the seats of 3 intake valves . The pic is typical of all three. My machinist said he can replace the seat but feels the crack is in the head as well.
Cast iron Indy 440-1c .

Why did this happen?

Has anyone had any luck repairing this ?

Does anyone know the depth of the original valve seat on this head

Thanks for looking

Happens with Dart SBC heads all the time.
Really hot on one side, much cooler incoming air and fuel on the other side.

If it doesn’t leak on a pressure test, put some seats in them and run it(or not).

We’ve had guys run the Dart heads in oval track cars with the cracks opened up way more than that for years..... without putting seats in.

Thanks for that info.

Spoke to a machinist that said about the same thing, but added to try and get a 1/4” depth seat into it. I’m just concerned that may go to deep and into a water passage?

Anybody been there ?

G

If it pressure tested good...... I’d just run it.

If it’s leaking already, then it’s time for welding or pinning.

Do you mean pressure test on the coolant side or valve to valve seat seal?

I think he's referring to the coolant side. Many heads crack like that but never leak water. Like Dwayne said, if it doesn't leak, cut the seats and run it.
The magnum era small block heads were bad for this.

In my experience, pressure checking a cast iron head will only show a leak if the crack is pretty bad. I have pressure checked cast iron heads that didn't leak when checked, but did leak when they got hot when running. Just saying if you weren't having any leaking issues when they were ran last, and they check good, then run em.

Putting a seat in it would be good only if the relief cut for the seat cut out all of the original crack.

Thanks for the reply and sharing Your experience.

I spoke with a gentleman at Indy today who (contrary to my past experiences) was really helpful. Said about the same as both of you. Happens all the time, Pressure check and re-seat.
What about heating the crack while under pressure ?

I didnt notice any performance issues and only had them apart for inspection due to a possible valve geometry issue, BUT now that I think of it the water may have been a little low when I pulled the radiator.

Do not heat that crack. If it wasn’t cracked through before, it will be after doing that.

Indy has new owners

I don’t understand? If I only got to 150 or so why would it be different than operating temp.
Thanks for your reply
G

Yes that’s what I heard