Cracked Valve Seats

[74-StreetMachine]

  A few months ago my brother picked up a pair of 440 heads from a 77 Dodge motorhome.  We were cleaning them up and getting ready to do a home porting job and noticed cracks in the two valve seats near the center. Both heads had cracks in the same place. The don't look to go too far. We were thinking about having the seats ground out and new hardened ones pressed in. They only have 25,000 miles on them.

Is this a common thing ?
Are these heads worth saving ?
The heads have extra steam vent holes in them, are they that much better than regular heads ?

Thanks, Randy

[squeakfinder]

I have set a of 452 heads at the machinist wright now. One of the exhaust valve's was burnt. It actually had 1/4 inch chunk missing from the valve. Although its not the exact same problem as yours its a common problem if the fuel mixture is to lean.

[is_it_EVER_done?]

Wow, those are good pics. I personally have never seen a cracked seat on a 452, and to see two cracked in the same place is really odd. I can't venture a guess as to why, but the 452 heads are good stock heads, so they are worth fixing if it's not too expensive.

You might want to check around first, as I've seen them for sale for around $50.00 a pair, but as with everything, they probably aren't available when you need a set.

As for the steam holes, standard "car type" blocks don't have provisions for them, and standard head gaskets will block them, so they're irrelevant as they're just something some motorhomes had, but make no difference for car use.

Check to make sure that the heads use a standard type "car" sparkplug as I have heard of some motorhome/industrial heads using a small specialized plug, though I have never run across a set that did.

[AKcharger]

I'd be thinking what made that happen? perhaps there's more suprises waiting for you? I'd go with another set of heads

[Chryco Psycho]

they can be easily fixed if the machinist cares to do it , or just get another set 

[MOPARHOUND!]

Two exhaust valves next to each other, a heavy motor home, and mountain climbing is hard on a gas engine.

Also, note the lack of the triangular shaped water passage between these two cylinders, compared to the end cylinders.

Just an inherent weak spot in the design, that is exposed under tremondous stress, IMO.   I'd have the heads checked and fixed.

[74-StreetMachine]

Thanks for all of the input. This engine is in excellent shape and well worth saving with only 25000 original miles. Still has crosshatch visible in the cylinders. Next stop - the machine shop.

[Carl1]

Get some uncracked cores. To repair these heads properly is expensive, and can't be done just anywhere, no matter what the local guy says he's done before. Put hard seats in the new heads they will handle the heat and the lead free fuel.
For your information a crack in cast iron goes all the way through. Sorry to piss on your parade, there is no easy fix.

[Rayzor]

I would bet that if you magnufluxed those heads, alot more cracking would show up that your not seeing. I would pass on them and get another pair.

[Steve P.]

Are you doing anything with the block or just a refresh??  I have a set of the same heads out in the shop. They are really nothing special. If you are doing a performance build you are going to block off the steam ports anyway. Unless you are going back into a motor home or something requiring heavy use constantly go to a set of 452's to keep it on the cheap. You won't need to add hardened seats. If you are going to build a higher HP motor just buy the Eddy's now and don't wast any more time screwing around...