The Stovebolt Site Forums The Shop Area Engine Shop Broken valve cover bolt

Well, jr was putting the valve cover back on the 235 and one of the bolts sheared as he was tightening. He said it wasn't even all the way down yet. Regardless of how it happened, any ideas on how to get the broken part out?

I've used some of those broken bolt tools in the past with mixed results. I really don't like the thought of drilling on the head.

Any suggestions would be greatly appreciated.

Signed....There goes my Sunday....

1/4 inch bolt I am guessing. Right on top lots of room if it is not sticking up and you can't get any thing to grip it then I would try to drill in the exact centre . Maybe try a easy out if that fails then drill bigger and tap usually when you tap the origional threads will follow the tap and cut the old bolt threads out .Has to be drilled in the exact centre .

Thanks. Yeah, it's a pretty small diameter bolt. I've used those "broken bolt" removers in the past. A few times with success, a few other times where things got worse. Kinda worried about trying to drill into it and get in the exact center when it's pretty difficult to get at it from above and ensure that you are not only in the exact center but also going straight down.

We are going to try JB Weld for now. We found a couple of small washers to contain the weld and keep the broken top piece sitting level. He said it broke without being tight so maybe, just maybe, there will be enough bite to unscrew it. Chances are slim, but we'll see what happens.

You probably can't grab it with Vice Grips or you would have tried that.

If the JBWeld doesn't work, you might try using a Dremel with a cut-off wheel to slot the broken end and then try a screwdriver. I've had good luck with that technique. Depends on if any of the bolt is exposed.

Since it wasn't torqued down, another technique is to try to catch the broken lip with a sharp punch and then unscrew it by gently tapping the punch counterclockwise until enough is exposed to grab it with Vice Grips.

If you resort to drilling or using the Dremel, be sure to mask off the head to keep grit and metal shavings from getting into it.

Good luck,

Matt

Thanks Matt. Yeah, when he first came in the house and said what happened, I figured we could get some vice grips on it and get it out no problem. It is broken flush with the surface if not a little below. Since it's such a small diameter bolt, I don't think a Dremel will work since I would end up cutting into the head also.

Hoping the cash in a karma point with the JB weld. Now I just have let it sit and be patient. Yeah, that's never gone well for me after 52 years either.

Bolts that snap when tightening usually aren't seized in the threads. Most of the time it's bolt that,s been brittled by age. The punch and hammer trick usually works. If not, then Sears sells a kit called "Bolt-Out" that are a variation of the left hand twist drills. Unless the bolt end was spotless and oil-free, then the JB Weld probably won't hold, but worth a try.

We tried to clean both but I just went out and tested it and it came right off with little no effort so it didn't bond to either surface. So much for cashing in some karma. Will look into punch next. It's just such a small surface, I have my doubts I will be able to get it to work.

If all else fails and you have a wire feed welder you can put a blob on the bolt and twist it out. The heat will probably help too. "A little dab will do ya". If you are worried about getting weld on the head drill a hole slightly smaller than the bolt in a piece of copper and use that as a shield. Grease on the head around the bolt might also shield it.

Mig weld a 1/4 nut on the broken portion of the bolt and carefully loosen.

Well, we got it out. I went to Home Depot and bought a small punch set. I tried with that but just couldn't get it to bite into anything. Going through my drawerss, I found a Speed Out kit. We attempted to punch a center hole but it ended up off center. Used the drilling end of the Speed Out and removed some material. Then tried the bolt removal end. It just removed more material. Tried a few iterations of that and threw the hands up in the air. Ryan had to get back to school. so I started messing around with it some more. I used a regular drill bit and started removing more material. I then tried sticking various things in and hoping something would grab on. Finally, I drilled out some more and took the bolt removal end of the Speed Out and hammered down into the hole I drilled. I then took a box wrench and ever so slightly, started applying some pressure. Seemed like it was digging in but then felt like if popped free. Thankfully, I didn't do my normal range of motions when I'm fed up and continued to turn. Sure enough, the broken part was coming along also.

So, next question, and I think this leads back to why this happened in the first place. I bought a new gasket which seems about as think as the other one. The valve cover is an after market chrome one. When the valve cover bolts are "snug" the valve cover still can be wiggled around. It seems the bolt are seating before coming in complete contact with the valve cover. It is just that the after market cover is thinner than the original? The bolts only appear to be about 1/2 long. Would it be ok to put a washer under the bolt head so that the cover can be tighten down? Also, this particular cover has vents on top of it. That just doesn't seen right to me. Thoughts?

It does sound like the bolts are bottoming out in the holes. What I'd do is buzz some length off the ends of the bolts instead of using washers, but that would work as well.

The valve cover bolts should have some football shaped washers under them.

Thanks for the pic Tim. Like I said, there is an after market chrome cover on there now. Definitely not enough room for that type of washer. But it's good to know that they came with them. That explains the bottoming out.

I'll start looking around for a possible stock valve cover.

Ron & Ryan,

Might this work with your valve cover?

Those long load spreaders lower down on that page were original equipment on Corvair engines, but they certainly help slow down the leaks from the cheap repop chrome valve covers for a stovebolt engine!
Jerry

Thanks Tim. Yes, that would definitely do the trick. Never heard of them before. Good to deal with?

I have had good experiences with Danchuck, but I have only purchased a few parts from them.

The simple, permanent fix would be to install some 1/4-20 studs about 3/4" long in the holes in the head with blue Loctite. They not only eliminate bottoming out another bolt and breaking it off, but they also give you guide pins to retain the gasket in the proper place as you install the cover. Filing or grinding them to the right length will also allow for the use of chrome acorn nuts if you decide to dress things up a bit.
Jerry

Great idea! Thank you!