Broken tap

M

maxparplus

Member
I unfortunately broke off a tap in the valve cover retaining bolt hole in my cylinder head. It's broken off flush so I can't grab it from the sides. Any advice on how to get the broken tap piece out without removing the head?

Thanks,
Max
 
Those little bolts usually are not under pressure after they break. I used a dental pick to back one out. Otherwise, you can buy drill bits with a reverse twist. Put it in the drill and run the drill backwards, they back right out.
 
If its a tap that's broken off and not a bolt its a bit harder, the last one I broke off I had to take a sharp chisel and slowly chip it away.
 
There are extractors made for removing broken taps. Try a good machine shop supply house (like Grainger's).
 
The flutes that are along the sides of taps offer an access to get them out. I think I saw extractors offered in the Enco catalogue.
 
The two ways that I would use to take out the broken off tape would be: First, chip away at it with a very small chisel and break the tap apart. The second and the quickest, is to blow it out with a cutting torch. The cast iron head won't be phased by the torch. Chase the threads with a tap afterwards to get the slag cleaned out of them. If you had a small set of needle nose plyers and the tap was big enough, one could unscrew the broken tap with the plyers.
 
maxparplus said:
I unfortunately broke off a tap in the valve cover retaining bolt hole in my cylinder head. It's broken off flush so I can't grab it from the sides. Any advice on how to get the broken tap piece out without removing the head?

Thanks,
Max
Click to expand...

Pay attention to "40 Deluxe" here, get the tap extractor. If not, I can almost guarantee you'l be opening the proverbial "can-of-worms"?

We do this for a living here, if it's a "clean" break the extractor will remove it!

You don't say a 2, 3, or 4 flute, but the correct tools work really good! Most likely the remaining threads will be OK also! It can be done with the torch, but it is somewhat "messy" on the car!

Thanks, Gary in N.Y.

P.S. If you choose the punch, chisel, and hammer method make sure you have another head available beforehand. That's a fairly small tap with little extra room to work.
 
the taps are high carbon and very hard, if you get a torch with a very small welding tip and put the flame on the tap(last resort) it will turn to slag which will be easy to get out with a dental pick, i have had to do that on several engines with broken taps, they got stuck and were broke because of to much torque applied
 
There is a place near me that uses Electric Discharge Machining that disintegrates broken taps and drills. From what I understand you don't even have to remove the head. http://www.brokentap.com/index.html. Maybe someone near you can do the same.
I have never had to use them, but it is another option for ya.
 
a company called walden makes a set of inexpensive extractors. i bought a set years ago and they have never failed me yet. it was well worth the forty dollars i spent buying them. good luck with what ever you do.
 
I bout a tap extractor from ENCO and it worked like a charm with little effort. It broke it loose and i literally turned it out with my fingers. Thanks so much for the help guys. It had been bothering me for weeks and I had tried drilling on it multiple times. THANKS 46yBlock for the ENCO referral.
 
Many years ago I had to replace a broken exhaust manifold on the Dodge 413 engine in my motor home, during the removal process two bolts broke off flush with the head..
I tried a couple of 'easy-out' bolt extractors after first drilling a hole into the broken bolts. The first type of 'easy-out' would not get a good purchase on the bolt so I had to try others, finally found one that got a good bite into the bolt, however, it snapped when I put pressure to it.... Now I had a real problem, broken bolt with a broken bolt extractor stuck in the bolt.
I checked with several people for a solution, the common solution was remove the head and take it to a machine shop.
I tried one last hope, an old time mechanic that I knew.. "Ken" asked me if I had a torch, oxy/acet, I told him I did.. He suggested that I use a small tip, about an '0', set the flame to a neutral flame, put on goggles and heat the bolt extractor to the melt point, at which time the bolt extractor would blow out of the hole.
I had a hard time bringing myself to use a torch on the head, I finally mustered up the courage and lite the torch, following Ken's instructions.
Just as Ken said, when the bolt extractor started to reach the melt point it exploded out of the hole. Using a cobalt drill bit, I drilled out the remainder of the bolt, re-tapped the hole.. I then drilled out the other broken bolt, re-tapped the hole and installed the new manifold. I have never had much luck with most of the bolt extractors I have tried.
 
blucar said:
Many years ago I had to replace a broken exhaust manifold on the Dodge 413 engine in my motor home, during the removal process two bolts broke off flush with the head..
I tried a couple of 'easy-out' bolt extractors after first drilling a hole into the broken bolts. The first type of 'easy-out' would not get a good purchase on the bolt so I had to try others, finally found one that got a good bite into the bolt, however, it snapped when I put pressure to it.... Now I had a real problem, broken bolt with a broken bolt extractor stuck in the bolt.
I checked with several people for a solution, the common solution was remove the head and take it to a machine shop.
I tried one last hope, an old time mechanic that I knew.. "Ken" asked me if I had a torch, oxy/acet, I told him I did.. He suggested that I use a small tip, about an '0', set the flame to a neutral flame, put on goggles and heat the bolt extractor to the melt point, at which time the bolt extractor would blow out of the hole.
I had a hard time bringing myself to use a torch on the head, I finally mustered up the courage and lite the torch, following Ken's instructions.
Just as Ken said, when the bolt extractor started to reach the melt point it exploded out of the hole. Using a cobalt drill bit, I drilled out the remainder of the bolt, re-tapped the hole.. I then drilled out the other broken bolt, re-tapped the hole and installed the new manifold. I have never had much luck with most of the bolt extractors I have tried.
Click to expand...

I had a similar incident with a 312 block. One engine mount bolt was broken flush. It probably happened during the car wreck that sent everything to the salvage yard decades before, as the engine ended up in a CocaCola COE truck, and then after that a 1 ton pickup. When I got it the crankshaft still had the COE fan bolted to it's snout, the setup which was never changed by the 1 ton owner.

I finally blew the bolt out with a torch. The block fluxing didnt show any cracks.
 
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