What epoxy would you use?

[boostjunkie]

Okay, so here's my problem. There's a bolt in the camshaft assembly that has separated. So the tip of the bolt (part of it is still threaded into the rocker shaft) is stuck in the rocker shaft. The TSB that's out lists a VERY involved process where you need to take out the camshaft and slide the rocker shaft out of the camshaft assembly to get the piece out.

Instead, I'm going to try and take a paper clip width piece of metal, place some sort of epoxy on the tip, and GINGERLY unscrew the tip of the broken bolt out. The torque on the bolt is about 7ft/lbs, so I wouldn't need that much twisting force to get it out, but I'd need some sort of epoxy that I could put on the tip of the extractor piece, that wouldn't dry until it contacted the separated bolt tip.

Any ideas on what to use?

[BAC5.2]

JB weld? How easy is the bolt to access?

What caused the seperation?

[vrg3]

Once the head of a bolt has snapped off, all the tension in the fastener's gone, so all that's holding it in is friction/siezedness between the threads.

So I'd start by trying to back the bolt out with a chisel. With epoxy I'd be afraid of getting some on the internal threads which could ruin the chances of getting it out at all.

If the chisel fails, I'd next try a small left-handed drill bit, and maybe an easy-out.

But if you really want to use epoxy, I think you'd want to use some very quick-setting stuff to minimize the amount of time it has to flow. And use some kind of gel/putty stuff rather than the liquidy stuff.

[boostjunkie]

Here's a link to the TSB. I changed the exhaust bolt to the "new style," but left the old one out:

http://k6kid.tripod.com/files/liftbolts.pdf

Not sure if the chisel will fit in the bolt hole. I thought about using a bolt extractor, but I don't think they make one that small.

[vrg3]

You can get very small chisels, but, yeah, that'll probably be hard.

So these are, what, 6mm bolts? A 1/4" chisel might barely fit, and should be fairly easy to find. You can find smaller chisels if you look hard enough, but you probably don't have that much time.

Hmm... My opinion is that a left-handed drill bit is worth a try.

The bolt should have been exposed to motor oil for its whole life, so it shouldn't be seized at all. And it's probably a class 8.8 fastener, so it wouldn't be too hardened. Just the grip of the cutting tip of the drill bit might be enough to back it off without even drilling a hole.

If you're worried about keeping the drill bit centered, a quick tap with a center punch could help.

I realize all of this is much easier said than done.

[boostjunkie]

These are 5-6mm bolts, yes. As for hardness, I know it has the standard markings of three hashmarks on the head. Not sure what that means in terms of hardness.

In all honesty, I wouldn't mind trying to do it the TSB way, however, I can't really spare the downtime right now I am a little worried about the bolt eventually dislodging and falling thru the rocker shaft assembly... and then *gasp* lodging itself in maybe the camshaft gear

[FG!!]

easy-out

or if any part of the screw is sticking out you can use a dremel with the thin cutoff wheel to put a little groove in the screw, and then use a flathead screwdriver to get it out.

[vrg3]

Three hash marks? Isn't that an SAE designation for grade 5?

Yeah, a bolt with nothing other than thread-to-thread friction holding it in place isn't gonna stay very long in an environment that has so much vibration. You definitely want to deal with this now.

[evolutionmovement]

I bet it will come right out - I can't see it being seized. We torched the rusted manifold bolt heads off two badly sea water-leaking engines and the bolts came out by hand easily once the heads were melted off. If those weren't seized these shouldn't be.

Steve

[boostjunkie]

Unfortunately, the tip of the bolt is deep within the rocker shaft assembly, so there's no way I can dremel a slot in it

Do they even make an easy out that small? I looked at Sears and couldn't find one that would work. Also, when drilling into the bolt tip, how do I keep the shards from falling into the rocker shaft assembly?

Not sure where the three hash marks fall in terms of overall strength but I do know the more hash marks it has the stronger the bolt.

I have no doubt the bolt tip isn't seized. The problem is getting a good hold on it so I can turn it on the threading. Makes things really tough when the diameter of the remaining piece (and the orifice I have to work with) is only 5mm wide

[evolutionmovement]

What about the paperclip bent like a 'U' with the two wire ends sticking into opposite sides of the bolt's diameter? The friction of the wire ends may be enough to move it.

Steve

[boostjunkie]

This is what I had in mind. Except I was going to use two jumper pins. We'll see.

I'd like to try to get this out of the way tomorrow, but it looks like we might be getting some snow around here.

[FG!!]

Yeah, they make ezouts that small.

Can you just mess up the threads so it doesn't back out?

[vrg3]

I haven't seen an easy-out that small which is why I suggested the left-handed drill bit instead.

If you're lucky, you wouldn't actually have to drill. The sharp edge of the drill bit might be enough to turn the bolt. It'd probably grip better than the jumper pins/paper clip thing. But that's certainly worth trying too.

If you can find a cold chisel that will fit, it should be able to make a slot that a flathead screwdriver could use.

[Binford]

Just wanted to say they DO make easyouts that small-I have one. But I also agree that you shouldn't need it if you try a left handed drill bit. Three marks on the head means grade 5, which is tensile(pulling) strength. Grade 8(five marks) is shear strength. You can drill a hole in it if need be, but it definately helps if you've got a really good drill bit.

[206er]

I would only go to JB weld as a last resort because it needs a really clean surface to bond very well. since the bolt is down in the threads, cleaning it wont be very easy, not to mention getting some JB on the threads like Vikash said. try taking a small enough flathead screwdriver to fit in the hole, sharpen the blade, tap the bolt a little to make a small groove(this might be futile), squirt some oil in there to help a little, and try to turn it out. I put my money on the EZ out to work the best, good luck.

[professor]

www.mcmaster.com page 2673

ez out for 5-6mm bolts, uses a 5/16" drill bit $1.65 you might be able to find this locally at a very good, professional auto mechanics supply (maybe)

If you are worried about drill chips this small (not an issue IMO), use a vacuum cleaner to vaccum them up while you drill, maybe an extra set of hands might help.