'90 MM 2.4L FI Build

[BradMph]

Hey that is fixable! absolutely 100% fixable. And if you get it fixed at the right place it shouldn't ever crack there again. I have seen many heads exactly like yours, this is the nature of the older cast heads for some reason. But do not throw that away. A good shop will grind a little in and fill it like a filling on a tooth. It will bond those egdes back into one if the welder knows his technique. After welding you probably do not want to grind it to smooth it out. Leave it as the welder has. Unless he piled a 1/2in of molten metal on it. If you grind on it, you will probably crack it again.
When I got my head from a place that repairs them, I was chatting with them and just mentioned that I was going to clean it up and do a little work to smooth the weld out. He friggin responded instantly, saying no no no, leave it alone or it will not keep it's strength. So far he has been correct and I have had the temps in a hot range a few times after installation.

Thanks for those images. It's always the same place I see these cracks, or the MCA jet housing.

You can almost do your own valve grind also. Unless the valves are tweaked bad. Just replace the guides and seals, install new valve and get the wooden dowel tool with two rubber ends and some compound and go to it. Might as well replace the valve springs also since your there. I think $45 was what I paid for high performance Schneider springs.
Or let the machine shop do it all and if it F*ks up, drive it into his shop's front window. lol

He only has to replace the valves that are bent. If they are really bent and not just wobbling. Save them also so we can see if there are severe wobble marks on the stems. Bent valves usually happen on a timing belt snap and they hit the pistons. If that hasn't happen, most the time they are just carbon wobble marks on the stem. You always want to replace the seals also. Its a super easy job to do. guides are a little tougher but backyard mechanic can do it. Tools are simple and I have listed them in my thread when I reseated my valves and replace seals and springs for the first time.

Valves that are bent usually wobble around in the guides. The stems will kind of look like this image sort of.
wobblevalve.jpg