Snapped girdle studs below block line

[Murdock]

I bought this engine used with less than 1000 miles per previous owner. I noticed I have to snapped girdle studs when I went to remove the oil pan. I ordered the replacements and went to work. To make a long story short. When I removed the girdle from the block I found four studs snapped below the block. I don't believe there is a viable solution to getting these out. If anyone has suggestions please chime in. I would assume at this point the girdle is not an option for this engine if I cannot reach those studs. Should I just to the 2 and 3 mains and get away with it then drill and tap new holes near the snapped ones so I can secure the oil pan? What are some thoughts on this?

 

[mikestertwo]

You should be able to drill the broken studs on center and use an easy out to remove them.

 

[bison]

Attempt to back them out with a sharp pic. They shouldn't have been bottomed out if installed correctly and now that they are broken off there's no load on the threads. I wouldn't attempt to drill them unless you can get a good center punch. If drilled an extractor should work since the studs shouldn't be seized. If getting a good center punch and drill isn't going to work or risk of breaking extraction tool off it's best to mill them out in a Bridgeport. A competent machinist could have them out in under an hr. Typical cost for 4 studs extracted would be $100. $50-60 for the first one and $15 for the additional ones if the setup is the same which it will be. If you break a drill or extractor off expect the bill to at least double.


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[Murdock]

Thanks for the advice. I was uner the impression this was hardened steel on the studs and wouldn't drill out very well. I do have all these tools. I may try it on one and see. If I cant seem to get it, them off to the machine shop. I have never had a stub broken off in that location before. Thanks again for the help !!

 

[cbird77]

I've used a metal etcher for writing my name on tools to get out lots of broken off allen head bolts. As long as the threads are ok and the broken off part can be reached with the point of the etcher, they usually spin right out of the hole.

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[charlief1]

If you do try and drill them out start with the smallest left hand drill bit you can find. Just barely start it so you can see if it's centered. If it is then step up 1 size on a slow speed and the piece may just back out.

 

[earlbrown]

Yep. Left handed drills are the ticket. You won't risk leaving a hardened extractor in there, they don't swedge the workpiece in place and the instant the fastener decides to back out, you know it.

 

[ijames]

x2 on the left hand bit - like Bison said there shouldn't be any real resistance on the threads so start with a sharp pick and try to just work them out. If that doesn't work, then center punch and touch with a left hand drill bit. If you are lucky the friction from bit to stud will back it right out. If you suspect loctite use a heatgun and get it over 250F - wet your finger and get a quiet sizzle but not a burn from a brief touch, then try the pick or left hand drill again. If you have to seriously drill then the best setup is in a mill but if you have to do it in place there is a cutter/bit called the rescue bit that is pretty amazing. See http://www.theoriginalrescuebit.com/ for the sales pitch. A friend used one to extract four broken exhaust manifold bolts from a Ford 460 in a motorhome and it cut just like in the video. He ordered from amazon.com since it was in stock there.

 

[earlbrown]

I wonder how the price of a 'rescue bit' compares to a carbide end mill?

 

[Murdock]

DONE!! Thanks for the advice. I used a center punch on two, then drilled it out with left hand drill bit. Two backed out while drilling and the other came out when I put the extractor bit on it. The 4th one came out by using a pick and spinning it back out. The whole process took about an hour. Now I get to put it back together with the ARP studs. The left hand drill bits are great.

 

[m233roller]

The most common reason for those breaking off is TO MUCH torque and guys those are NOT studs, they are just set screws.

 

[Razor]

Those are 1/4 inch bolts.. any kind of TQ on them and they'll snap.

Had a shop one time assemble a short block and when I went to put the pan on... 4 where busted

 

[ijames]

I wonder how the price of a 'rescue bit' compares to a carbide end mill?

Sorry, didn't see this. Yes, the rescue bit is 2-4 times more than a same-size carbide end mill, but if you have ever tried using a carbide end mill in a hand-held die grinder you know that the carbide will shatter the first time it touches anything, while the rescue bit lasts and lasts even in my friend's hands. Even regular HSS end mills chip and break in a die grinder after not much use, and they won't cut through anything really hard. The rescue bit feels pretty heavy for the size. I don't know the actual composition but my guess is some kind of high-molybdenum tool steel.

 

[earlbrown]

Odd, I use 1/8" end mills in high speed tools all the time. I had no idea they were supposed to shatter. Perhaps it's some sort of inconel type material.

 

[Murdock]

SO then, what is the difference between the "set screw" and a stud? Would it be torque or the lack there of or material? Or is it the design to which the material would be used for? It is holding down the girdle and then the pan. Do you not torque the girdle down on the stud or set screw? If this is the case it would seem to me that the set screw or stud would also need to meet a specified torque value. I only ask this question because I do not know the answer,not to be an jerk or anything.

 

[earlbrown]

They're studs. Just from the context they don't seem to be a touch as one would normally expect.