Cam Tower Torque - Shoulda Checked Here FIRST

[DeesZ]

Lesson learned: I should have checked here first. My head is hung low and my tail is between my legs. I picked up a really nice E88 head the other day. I was checking the torque for the cam towers. I couldn't find specs in the FSM, so I checked Tom Monroe book "How to Rebuild..." and found the torque listed at 33 ft-lb. Need I say more? Well the first one snapped the bolt; I guess I am fortunate that it didn't strip the head. Of course, now a search here tells me that 15 ft-lbs would have been much more proper. The other bolts were much tighter than 15 ft-lb, too, so I backed them off and retorqued to 15 ft-lb. Like I said - should have checked here first - I know. I feel bad.

Anyway, bottom line here, is the head salvageable? What do you think, will a good machine shop pull me out of this mess or is this head sunk?

Thanks for your help and advice.

John

p.s.

I guess I gotta also ask; to what degree is the Monroe book in error? Is this the only bad info in there and I was lucky enough to find it and dumb enough to believe it.... or should I discount it as a reference?

[earlyzman]

I'm sure you can get that broken bolt out fairly easily. I got fooled the same way, but mine started to strip. I wasn't too worried since those bolts in combination with the locating dowells are only for the initial cam alignment. Since the head bolts go through the cam towers, they are the ones doing all the work after that. You might be able to drill that bolt and use an easy out with the cam tower in place, otherwise you'll have to pull the cam again. Good luck.

[JimmyZ]

Drilling through high strength bolts is next to impossible. A carbide drill bit in a milling machine might get it. Ease of removal really depends on where the bolt sheared at. (Above, at or below the surface) Any drilling on something like this should be done in a machine and not by hand so as to avoid skipping and damaging the threads. The cam tower mating surface must not be marred unless you want to have the top of the head milled.

I just had a head bolt snap in an L24 block. Fortunately it had enough protrusion to allow me to weld a head on it. This welding apporach was a last resort because the bolt had begun to fracture. It came off easily once the head was welded on. The heat helped to break the Loctite/rust bond.

In aluminum removing bolts is much easier. In your case heating the head will help during removal. If the wife agrees clean the head and bake it in the oven for an hour at 350-400. Wrap the head in aluminum foil to keep everything you cook from being cylinder head flavored. Place it on something clean and flat so that the head surface isn't damaged. (Cookie sheet) The aluminum will be softer and easier to scratch when it's hot. Take a drift or punch and tap the edge of the bolt to loosen it. Work fast while the aluminum is hot. Little taps are all that's needed.

If this doesn't get it then EDM (electrical discharge machining) can.

Of course it would be easiest to drop it by a head shop and let them take it out.