Broken valve cover bolt removal is next on my agenda.

[Plyrr471]

So my work continues with my winter project shown here:

Winter off season project engine compartment “clean up” and engine repaint.

The previous owner left me this broken bolt to deal with. Drivers side valve cover bolt, luckily right in the front of the head. It appears to be broken off on an angle, or he tried to drill and remove. I can’t tell. My plan is to try to attack it with a left hand twist drill bit and an ez out, which should be to me by next weekend. It’s soaking in Liquid Wrench now and will be for the next week. Any other suggestions guys?

 

[RemCharger]

I would weld , if a mig was available.

 

[Plyrr471]

Thanks for the quick response Rem. That would be wishful thinking on my part. No tools or talent to do that, plus car is not mobile at this time, and won’t be until spring.

 

[69Bee]

It already looks like someone tried to drill it (2 circles), and you will not likely be successful and could make it worse. The smaller circle (darker one) is the drill bit that broke and is harder than the bolt. Bolts rarely break evenly, so unless center punched/drilled, the drill bit will walk. When I get something like this is, I start with a carbide endmill to flatten it out, center drill, then drill out progressively with lefthand bits. All of this in the Seat & Guide machine as it is easier and maintains alignment, not to mention, carbide is brittle (HARD) and easily broken used by hand.

 

[69Bee]

I would weld , if a mig was available.

Two items not concentric so they will not spin out, kind of like intersecting crack repair pins.

 

[pnora]

That is going to be a bugger to remove. What ever is along side the broken bolt is pinning it to the head. No left drill bit is going to get it out. I would center punch it and try to drill the original bolt out first.

 

[RemCharger]

Two items not concentric so they will not spin out, kind of like intersecting crack repair pins.

Ah, I thought it was a drill hole beside it.

 

[Plyrr471]

The original hole looks a little oblong. I was/am, going to try to come in on a slight angle in order to drill where the drill bit (presumably) and bolt meet. Something like in this illustration:

 

[69Bee]

One problem you will encounter is that the broken drill bit is harder than the original bolt and will push your drill bit off center towards the old bolt. This is why I use the carbide endmill to get it flat and get to virgin OE bolt, then center drill to establish a center point. If you are extremely careful, a 3/16" or 1/4" carbide endmill will work. Make sure you do not enter at an angle; it needs to go in at 0 degrees (or 90 degrees mathematically)...

 

[Plyrr471]

@69Bee until a second ago I didn’t know what an end mill was, not that I do there are lots of offerings. Which end would you suggest? Something like this, although doubtful, can I drive it with a handheld drill? I have no machining capability.

 

[sam dupont]

are you sure that is a broken drill bit? The raised ridge in the middle also looks like stretched metal. Two very different challenges. If you have a Dremel end grinder, they make small end mill bits like 69bee referred to. Cleaned up, it should be obvious what you are dealing with.

 

[Plyrr471]

@sam dupont that’s just my assumption at this time. It could just very well be a broken stud and drilled and failed attempt at removal.

 

[sam dupont]

I would be hoping for a stretched and broken bolt as it's mild steel and much easier to deal with

 

[QuickBpBp]

So my work continues with my winter project shown here:

Winter off season project engine compartment “clean up” and engine repaint.

The previous owner left me this broken bolt to deal with. Drivers side valve cover bolt, luckily right in the front of the head. It appears to be broken off on an angle, or he tried to drill and remove. I can’t tell. My plan is to try to attack it with a left hand twist drill bit and an ez out, which should be to me by next weekend. It’s soaking in Liquid Wrench now and will be for the next week. Any other suggestions guys?

View attachment 1982694

View attachment 1982697

If you don't have an easy way. Just pull the head and take it to a machine shop. You need to get a head gasket and an intake gasket which are not expensive. Have them drill it and put a Heli-coil in it. No worries about leaking then. Looking at the amount of crap and paint on the valve spring alone I would not be buttoning up that engine anytime soon...

 

[Plyrr471]

Thanks Quick. Hopefully it doesn’t come to that. I’ll clean the paint flakes that have landed in the rocker area but that over spray has been there for about 30k miles since the engine was built, it hasn’t been an issue so far.

 

[Virg464]

"69Bee" is on it. I've used carbide a bunch of times. Yes you can use a drill motor, the only issue you will have is keeping it steady. the carbide will most likely chip due to excessive movement, but it'll keep cutting (it's that hard). However it will cut anything, be careful if you go that route to keep it away from the head/threads (as best as possible) because the carbide will cut that just like anything else. I normally try to use a "ballend" mill, it creates a natural concave surface which centers the next bit. Good luck, and go slow.

 

[Plyrr471]

Thanks Virg, we’ll see how it goes.