Cracked valve seats

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flipper

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Dropped a set of 360 J heads off at my machinist broke them down found 3 cracks all on spark plug threads running in the direction of the intake seats only one runs into the actual seat, machinist says they (the other two)are not deep and can probably be blended there is a small ridge between the plug well and the seat this is where the beginning of the cracks are.Hate to give up these heads as they are in good condition except for the cracking,anyone run into this before if so what's a good fix.Should I just press in a new seat?
 
how much to fix them? usually the proper way to fix a crack is drill the ends and pin them. then you need to blend in the fix. shop time adds up.

i'm also wondering why they cracked...
 
Very common problem with all Mopar heads unfortunately . Usually cheaper to start with another set of good cores. Good luck
 
Unfortunately this is the second set of cores have one more set,its not into water (yet)and I'm a cheap bastard.
 
You can find any 340/360 head for next to nothing in core form. If you're cheap, this will be the cheapest way to address the issue and they are all basically the same thing. Otherwise you have probable guide work in order to install new hardened seats, possibly new valves, and valve job to fix them.
 
Well, you can always try to run them. Once i know there's a potential problem I hate leaving it - but it comes down to your decision: cut the loss and move on, or roll the dice.
 
moper said:
Well, you can always try to run them. Once i know there's a potential problem I hate leaving it - but it comes down to your decision: cut the loss and move on, or roll the dice.
Click to expand...

If you are going to roll the dice anyway, why not try fillin the cracks with JB Weld? I once patched a cracked water pump housing with and it held for years. But it wasn't on any kind of a performance engine.
 
I was thinking more of fusing with a tig torch,before pressing a new seat in.Not sure if this will work,being it's the intake side it won't see as much heat as the exhaust,but it is in line with the plug.
 
jabdusty57 said:
If you are going to roll the dice anyway, why not try fillin the cracks with JB Weld? I once patched a cracked water pump housing with and it held for years. But it wasn't on any kind of a performance engine.
Click to expand...

Big difference between a water pump housing and the inside of the combustion chamber.
 
flipper said:
I was thinking more of fusing with a tig torch,before pressing a new seat in.Not sure if this will work,being it's the intake side it won't see as much heat as the exhaust,but it is in line with the plug.
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Cast iron doesn't ''fuse'' well.
Don't use a ''brass'' rod either.
If you are going to attempt to weld it, grind the crack out with a small ''V'' and then heat it up to a dull red in the area, and then arc or tig weld with a nickel based rod about 1/2'' at a time, and pean the weld. Keep it hot and repeat.
Then after you are finished welding and peaning, heat up the whole area one last time and then wrap the head in insulation and let it cool slowly over night.
I am a journeyman welder and did this several times over the years.
Pinning would work well too, i've heard of good success with the procedure but i haven't personally tried it.
There is probably something on you tube showing how to do this.
Just my 2 cents.......
 
Dartnut said:
Cast iron doesn't ''fuse'' well.
Don't use a ''brass'' rod either.
If you are going to attempt to weld it, grind the crack out with a small ''V'' and then heat it up to a dull red in the area, and then arc or tig weld with a nickel based rod about 1/2'' at a time, and pean the weld. Keep it hot and repeat.
Then after you are finished welding and peaning, heat up the whole area one last time and then wrap the head in insulation and let it cool slowly over night.
I am a journeyman welder and did this several times over the years.
Pinning would work well too, i've heard of good success with the procedure but i haven't personally tried it.
There is probably something on you tube showing how to do this.
Just my 2 cents.......
Click to expand...
Thanks for the reply,Not sure what I'm going to do yet I have a good friend who is a very seasoned welder(worked for toshiba turbines)now works with me in Fort Mac I haven;t run it by him yet but may just try this for curiosity anyway,we've done some pretty unique stuff on pumps, gearboxes,and turbines so who knows.
 
There is a place in Fairmont WV called J & C Enterprises.
All they do is repair cracked cylinder heads 304-366-4536.
It may cost prohibited for you for shipping reasons, but it would be worth at least a phone call.
 
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