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I've got a problem on some very expensive cast iron small block Ford heads I need some advice with. The boss that is cracked holds the intake manifold down. Only torqued to 20ft lbs so not a tremendous amount of force. Not sure what caused the problem in the first place or how long its been like this? Maybe bolts too short? maybe over tightened at some point in its life? All I know is its my problem now.

There is still a fair bit of good threads to grab and I can go with longer bolts that extend all the way through. The bolt holes are tapped all the way through. The bolts that were in there only grabbed a few threads.

One thought is to put studs in the two holes instead of bolts. Thinking being less chance to screw up whats left over the years putting bolts in and out of the damaged hole. The other is taking the heads off and having them repaired. I don't have a lot of experience welding cast iron so my thoughts are to find someone that does rather than me learning on expensive parts. Looks like plenty of meat for the stud to hold but there could be some stress risers or cracks in what's left of the boss that I'm not seeing that concerns me.

I'll post pics here as soon as I can get them uploaded.

So the question is do I try the studs and risk some more metal breaking off or do I remove the heads and attempt to have them welded or brazed?

pics

The stub idea sounds like the way to go.

Do the studs/bolts point straight up so you can actually put the manifold on with the studs in place? If so you could add a nut or a flange nut to the bottom of the boss for that much more strength. If not you can get long set screws so you can easily install the stud with the manifold in place but a nut on the bottom would be a challenge, but I guess jb weld or even rtv would hold it while you screw the stud in.

Thanks, The studs do go straight up. Some of the raceteams used to put in 4 studs to make it easier to drop the manifold on straight. Not really period correct for this car but don't want to take a chance on screwing up the heads anymore than they are. Thought about getting long enough studs to put a nylock on the bottom? Don't know if that would help or not?

Any good ideas for a source for studs?

Also anyone with a lot of experience repairing cast iron have any thoughts?

I think a nut on the bottom will add some strength because it will help distribute the load a bit.

A nylok is fine but not needed, any nut will do because you can snug it against the bottom of the boss.

Since you're using a jam nut, you don't need a proper stud, just a high quality threaded rod would do fine and this you can get from mcmaster. Or as I suggested a long set screw is also a good option. On my engine I replaced almost all the factory studs with 8-18 SS thread rod and red loctited them in place.

Why the head broke I don't know, but it looks liek you have plenty of metal left. I'd do the stud and go. If this brakes, and I don't think it will, to can still get it welded /brazed and haven't lost anything.

^^^^^^^
What he said.

If the heads were angle milled, a trick to raise compression on cast iron american stuff. Then the bolt hole will be slightly miss-aligned and break out the top edge. Even if the intake flange was milled to match, the bolt hole will be off.
If this is the case, then spot face the intake to match the angle of the bolt/stud hole.

_________________
Wade Williams
Master Ferrari Tech
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Engine Machinist
Fabricator
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I'll bet that's the answer. I couldn't figure out how it broke the way it broke....like the bolt was pulling sideways. Doh!

Interesting thought. I don't have a lot of faith in the last guy that rebuit the motor.

What would be the best way to check with the engine in the car? Last time the guy had the motor was to replace the block. I don't know if he did anything with the heads other than valve job but I do know it was a new block he machined for it. We had a problem that leaned the motor durning a race and burned a channel between cyl 7 and 8 in the block. Come to think of it the head was damaged and welded and he had to mill it flat again.

I guess just put in 4 studs and try to drop the manifold on and see if the studs are all straight up and down?