85camaro350

My starter bolt broke in half when i was tightiening it. Its in the block, no way i can touch it so do i heli coil it? and where do you buy these heli coils?

84 Z28 5.0 HO

A heli coil is used to repair damaged threads. First you have to get whats left of the bolt out by using an easy out or drilling it out. Depending on the method you may not need the heli coil

ede

i'd start with a left hand drill. since you broke it going in there'sa very good chance it isn't really stuck and may come out as you drill it. if not use the tap drill, left hand if you can find it, and drill and tap. there's no need to spend 50 dollars on a heli coil kit.

85camaro350

what if i drilled it out...then used a tap from sears and re tap the hole....would that work and would it be easy?

84 Z-28 350

get an EZ out, we use them in the air force, all you have to do is drill a small indention in the broken fastner, and it has these taps I guess you could call them that are twisted in the wrong direction and have a sharp edge on them that digs into the indentation and let's you turn it out, there great, and I've seen them in the civilian world, in my old collage auto class, so I know you can get them.

RB83L69

I wouldn't use an Easy-Out in anything.... I have yet to see one actually work on genuinely stuck hardware. They usually break off in the fastener. Then you have to drill that out too, and it's even harder then the bolt; so you end up with a situation that's about like having to drill steel out of wood that's lodged in butter.

I'd do what ede suggested instead. The hardest thing is going to be keeping the drill centered on the broken bolt, and not wandering off sideways and ruining the hole. Start with a very small bit, like 1/8" or smaller get is absolutely centered and straight, so the hole will guide succeedingly larger ones in, and DON"T BREAK IT OFF IN THE HOLE; then a larger size, like 3/16"; then the left-hand bit in a size slightly smaller than the 3/8" bolt, like about a 5/16" one.

If you remove the threads from the hole in the process, a tap won't help..... if there's no metal there to cut threads out of, it's pretty hard to cut threads..... if you damage the threads, a Heli-Coil is probably going to be necessary. Chances are the bolt will come out easily.

If you ruin the hole, about all you can do, is to drill it out much larger; put a steel pipe plug in it; and re-drill and tap the hole. But then, you have to get the hole accurately located; not a trivial matter. If it comes to that you'd probably be better off pulling the motor out and taking it to a machine shop.

Next time be more careful about lining everything up straight before cranking down on the bolts.

84 Z-28 350

I've seen EZ outs work on everything from 3/16 alumnium skin screws to 1 1/16 hardend steel wing attach bolts in which were broken off because the skin shifted, sheetmetal and machine shop swear by them

RB83L69

also aluminum

Big difference between sheet aluminum (or even airframe forgings) and rusted cast iron. They work fine in a low-force situaation like that, but if the bolt is really stuck (rusted), they just break, and then you've got an even worse mess on your hands.

I would recommend skipping the EZ Out stage, it has very low odds of success in the application at hand.

84 Z-28 350

the wing attach bolts are defenitly steel, there slighlightly magnetic- if you put the washers next to them it will pick them up, and we were changing the wing because 2 layers of skin shifted and the bolts were jamed in, we got the nut off one end, and we were trying to turn out the bolt and it broke off, and we coulden't swing a hamer in the fuse due to room. we called machine shop down and they pulled a huge EZ out out and preceded to drill a small pilot hole and twist the bolt out.

ede

i'll second the skip ez outs. cause more problems than they solve

EvilCartman

iTrader: (1)

Hehe, that's funny... The machine shop I'm at always ends up machining broken EZ outs, out.

85camaro350

so what if i wanted to skip all this, and take it somewhere...should i get it towed or take the engine out...? And what kind of a place should i take it too

85camaro350

anyone???

RB83L69

If it was me, I'd take the engine out myself; and take it to an auto machine shop. I doubt anybody will be willing to attempt it and guarantee that they won't destroy the block, with the motor in the car. I can't imagine getting everything done with the motor in the car, working from underneath up in between everything in there, with sufficient precision so as not to end up with the drill missing the bolt and going into the cast iron, which will move the hole, which would be fatal.

This is not a good place to try to take a short cut.

85camaro350

well i can get it towed for free...and if i towed it to a machine shop, wouldnt they take the engine out to do it?

RB83L69

Of course they would. And then you would pay them for doing it.

Pull it yourself, it'll cost you A WHOLE LOT less, if you can.