today i was pulling my stock studs and tapping and installing new screw in studs the hexless ones with the little shoulder. well seems to me i overtightened one and the stud boss has a hairline crack thats a total length of 1 cm starting at the stud to the edge of the face of the boss which is 1/2 of it then the other half goes down the side of the boss. its not long nor is it wide its about a think as a piece of hair. can i stick jb weld in there or quiksteel? would it even effect it?

 

I don't think you'll get away with JB weld.

You'll likely need to grind out the crack, and then weld and file down.

Failing that, the crack will continue to spread.

 

Yeah, that would probably have me looking for another head.

 

Yikes!
How the heck did you overtighten those? You're using double jam nuts right? I could barely get that up in the 30ftlbs range before the nuts just kept wanting to turn.

Personally i'd just braze it up. Get your local machine shop to do it for you, or leave it in your BBQ at max heat for 2hrs or so, then grab a little MAPP/Propane setup (or oxy/propane) and get some brazing rod. I think cast iron can be brazed pretty easily.

Welding it is a PITA, but that's another choice. If you've got a lot of work/money into the heads then I wouldn't be looking into new ones. But if these are 416's and you're just starting then by all means grab a new one.

 

Why didn't you just drill and roll pin the rocker studs.
There is no way to repair a cracked stud boss.

 

i feel dumb. i dont know i just found them for a good deal and figured i dont know what. but these are 601 casting and the head is fully ported with a new valve job and i dont wanna give it up. i can braze i have all the tools for it down at my work but will that hold? i used 2 jamnuts and i honestly didnt think i used a lot of pressure but i checked after and it looks like the shoulder that it jams on went a little into the boss more than all the others. again

 

If it's trashed, it's trashed... wishing and wanting won't un-break the metal.

Brazing won't hold. Welding probably would, if you can find somebody that can weld cast iron without warping it.

Makes a pretty good argument for cutting those bosses down and using the right hardware, and not trying to rig it somehow with either the "repair" studs or with pins, which are just about as likely to crack one.

But, as common and plentiful as those heads are, your least-cost and highest probability of success, is to simply replace the casting. Cut your losses now. "Sunk costs" are not recoverable, not with any amount of wailing and gnashing of teeth.

 

ahh i guess you guys are right guess its time to do it all over again. this sucks.

 

If you want a set of 416's pay the shipping and they are yours

 

thanks but no im just gonna buy another 601 since i still have a redone one sitting around uncracked.

 

ok since this crack doesnt go far down the boss at all what if i just have it cut down the appropriate height for the hex head screw in stud since i already have it tapped for it. i think how much that has to be taken off is further down than the crack. do you think thatd work and just leave all the others alone?

 

Maybe if you can be sure you're getting rid of the entire crack, since cracks like to grow.

 

Sure, if the crack is less than about 3/8" deep; that's about how far the bosses have to be cut down. As long as you can machine down to undamaged metal.

 

Get the machine shop to magnaflux it. That'll tell you how far it is.
Get their opinion.
I think the way the stresses effect that part of the cylinder head, brazing or welding is a perfectly acceptable method of fixing it. It's on the boss, so you won't warp the mating surface or anything. Personally i'd just v-grind it and weld it with a torch or TIG and 99-ni rod.

 

The stress from the stud flexing back and forth is going to open it back up if it's brazed. Brazing doesn't fix the problem, it just covers it with a lump of different-colored metal.

 

I'd have to disagree Chris. If he can heat up the cast iron enough, it'll wick it's way into the crack like crazy. Cast iron LOVES to be brazed. It's just like gluing metal together, with very very tight fitup.
Plus the braze has a lot more ductility than the iron, so it shouldn't cause any problems.
I'd still prefer to weld it myself. If he's got a lot of time and $$ into the heads I think i'd at least try to get it welded up. Worst thing that can happen is the stud breaks off and the rocker takes a jump. It'll run on 7 cylinders and tick like crazy until you get it fixed. :shrug:

 

well the crack i see is way less than 3/8" going down the side of the boss. so im gonna find a hex head screw in stud have the boss ground down and make sure there is no crack then use that stud for that hole. ive brazed steel before but it was kinda weak but i dont know how it is on the cast iron so i couldnt really say.