ABQ99TA

iTrader: (17)

Well I was in the middle of my cam swap and everything was going great. I have all the springs in and was getting ready to pull the pulley off. When I was trying to get the crank bolt out it snapped. There looks to be about 5/8 of the bolt still in the crank. I compared the new bolt to the new one that is how I came up with the 5/8 number. I'm thinking I have to start with a small drill bit and move my way up but any suggestions would be great. I think I'm FUC*** for the weekend at least.

matt94z

iTrader: (49)

Drill the bolt as center as possible and get an easy out. Good luck!

ABQ99TA

iTrader: (17)

Well i got the pulley off and it looks like what is left of the bolt is right at the end of the threds in the crank. I can not see any threds on the inside of the crank. I hoping I twont be that bad. Or any worse than it already is.

StevieZ

iTrader: (3)

Kind of deep for an extractor (easy out). He'll need some kind of extension for it.

3.4camaro

iTrader: (1)

consult a local machine shop. They will know what to do. You may have to pull the engine.

Next time, get an ARP crank bolt. I love mine. No need to TTY, just torque and you're good to go.

ABQ99TA

iTrader: (17)

Thanks for the advise. But it was the stock bolt from the factory I was taking it out of the engine for the first time. I will be buying a ARP for reinstallation after what just happend.

68chevypu

iTrader: (18)

I know it sounds dumb but I've heard of some people just putting a finger on it and twisting and it comes out. I mean you should only be fighting the drag of the threads, not actual torque.

But I could be wrong

Websy21

iTrader: (34)

No, doesn't sound dumb at all, I once was in this situation. I was only doing a pulley swap and on a different engine but same pile of Thought I was fucked and immediately got on the horn with a machine shop. After some thought, I went back and had another good look at it. Thankfully b/c of my superhuman strength I spun it out by hand Lucky bastard

ABQ99TA

iTrader: (17)

I wish it is to deep to get a finger on it. Thanks anyway maybe I'll hit up my girl to see if her fingers are small enough to get back there. On my way to the liquor store right now!!!!!!!!

ABQ99TA

iTrader: (17)

If I need to pull the motor is there somewere I can find directions for this?

Tainted

iTrader: (9)

drop the entire k frame as a whole, its the easiest way. takes about 4 hours

THE_PROFESSOR

Reach in there with a screwdriver, see if you can catch an edge.

Don't force it to the point that the threads are in danger..............

Take your time before you go pulling that engine.

vettenuts

iTrader: (4)

Are you sure this is the first time it has been out? Never heard of this happening unless someone had already buggered the threads using a bolt for removal/installation of the pulley (very bad practice) or someone used a **** load of red Loctite.

uncle ray

if you can get to it weld up a bead on it of very short and small tacks. then weld the bolt together and turn it out very slowly. same thing happened to me with a header bolt. i think its cause they are grade 10 which is just brittle as hell

DCx

iTrader: (12)

yikes! im glad i got an ARP crank bolt for my swap.

jermzz

iTrader: (18)

+1....

eallanboggs

iTrader: (1)

If you are going to try this repair yourself you need a sleeve to insert into the bolt hole to "guide" the twist drill bit as you drill the hole for the easy out. There is no way you are going to get the drill be dead center doing it freehand. If you're that lucky you should play the powerball and junk this engine and buy a new one with your winnings. The O.D. of the sleeve must match the I.D. of the bolt hole. The I.D. of the sleeve will be the size of the hole you choose to drill. You can then use a drill bit extender to hold your screw extractor as you remove the broken portion. The threads don't extend all the way to the crank snout. You should be able to perform this operation with the engine installed. This is highly unusual if what you say is true about the bolt never having been removed. You're best to chase those threads after the piece is removed. You going to flush the bolt hole and blow it out with compressed air once the stubby portion is out, right?

nesikachad

I'm a machinist and have pulled a sheared bolt or two.

First, I'd get a bottle of Kroil and a hot air gun.

Next, get yourself a center drill Probably a #1 from a machine tool supply center. Don't buy carbide, get High speed steel.

Buy a set of transfer punches. They are cheap and have many other uses around a garage.

Use a transfer punch that has the closest matching OD to the bolt hole's ID.

Example: a typical 3/8-16 bolt hole has a minor dimension (the tap size) of 5/16ths.

You would use a 5/16th's transfer punch.

Now, tap the transfer punch while attempting to keep it pointing right down the center of the crank snout.

It will leave a center mark for your center drill.

Chuck up your center drill and start your hole. You may want to use a bit of oil on the drill to control chips and (more importantly) to lubricate the cutting surfaces of the tool.

Don't spin your drill at a gazillion Rpm. You'll only burn up the tool. Use moderate pressure and rpm and allow the tool to do the work. Don't rush or force it. Drills are typically in the upper 60's on the rockwell C scale. You'll have a hell of a time getting that material cleared out if you break the tool off inside the hole it's forming.

Ok, drill no more than about an 1/8th to 3/16ths deep. Just eye ball it.

Now, get the largest drill you can use with confidence that does not exceed the minor pitch diameter of the hole.

---Side note. I know the LS1/2 uses metric fasteners. You don't need a tap drill chart to find the minor hole diameter. Metric stuff is easy to figure in your head. It's major diameter minus the thread pitch. Here's an example.

6mm bolt with a .75 thread pitch. the bolt measures 6mm in diameter and the thread climbs .75mm per revolution. Subtract .75 from 6mm and you get what? 5.25 right?

You would not want to use a drill any larger than 5.25mm otherwise you'd permanently ruin the screw hole because you drilled out all the inside threads.

Measure the OD of your bolt with calipers (if you don't know the pitch already) and then multiply by 25.4 to get the metric equivelant)

Example:
.375 X 25.4 ='s 9.5mm

If the bolt has a pitch of .5 then subtract the .5 from 9.5. You'd not want to use a drill bigger than 9mm.

You'd be better down in the 6's or 7's. Much easier to drill bigger than it is to fill in a hole.

Now that you have your drill selected, start your hole. Again, make sure you don't run too much rpm and burn it up.

Periodically pull the drill out of the hole so that the chips have a chance to evacuate from the flutes. this is important because if they get jammed into the hole, the tool will break.

Lubricate the drill with oil also. While your at the machine tool supply shop, ask for a small bottle of moly based tapping/cutting fluid. Nasty smelling chit that works great for this sort of thing.

Hopefully you will be able to drill through the bolt and have a space behind it.

Once your are all the way through, squirt Kroil into the hole and then start on it with the hot air gun. Heat the crank evenly and get that Kroil smoking good.

then let it sit and allow the capilary action to draw it up into the threads.

Now, you can try and Easy out, but I have had better luck with good ol Torx bits from Sears. Just don't use a cheap tool because chances are it's not heat treated properly and is liable to break or twist off inside the hole. Craftsman stuff is decent enough quality for this chore.

Find one that is just a bit too large for the hole you drilled and then drive it in with a ball peen hammer. If you look at the face of the torx bit you'll notice it has a star shape. Use some common sense. the center portion that makes up the meat of the tool cannot be larger than the hole. It just won't fit. but the outer flutes will drive into the hole and provide the bite for the tool to latch onto the bolt.

Using a progressive and deliberate force attempt to remove the broken off fastener.

If it comes out, great.

If not, warm it up again and see if it works then.

If not, remove the torx bit and try the easy out. As a last resort you can try with a left handed tap and bolt with a spacer.

This is more risky because you risk shearing the smaller bolt inside the larger one. It'll stress the outside threads of the larger bolt even more and make it a bigger pain to remove. Do this only as a last resort.

I know this sounds a bit intimidating, but a little patience and a few bucks in good tooling will make this an easy task.

Buy split point drills and they won't walk all over the place on you. Drills come in two lengths. Stub length and Jobber. Always use the shortest tool possible for any machine operation. Short, Rigid tools don't wander or deflect nearly as much as long ones.

The hot air gun won't screw up your crank. a torch might. It'll take longer to heat up, but it won't hurt anything. Maybe put a wet rag around your front seal to avoid too much heat transfer to the rubber. That'd be my only concern.

I've removed a ton of broken off screws and bolts in my day using this practice. It works.

When you are done, get a tap that is the same size as the threaded hole in the crank and chase the threads. Blow the hole out or flush with brake cleaner afterwards so that you know there is no debris left in it.

A better tool might be to use a thread chaser. It'll form and reshape any goofed up threads rather than cut through them the way a tap will.

I hope this helps and gets you out of your bind.

Best of luck.

Mike454SS

iTrader: (4)

Advice from a pro is the best advice...good luck man.

For what it's worth, I've found that the DeWalt drill index at home depot are actually really nice drills. They're HSS, coated, split point, and seem to do an awesome job drilling harder materials. They only had fractional indexes...but a 7/32 is only 0.010 smaller than the #1 suggested above and should still work out fine.

vettenuts

iTrader: (4)

Sounds like where it broke is just at the entrance to the threaded section of the crank, which is recessed about 1-1/2" with a fairly large ID. Having said that, follow above advice and hopefully you will have a successful ending.