The Stovebolt Site Forums The Shop Area Engine Shop snapped head bolt

yesterday I was tightening my head bolts down and snapped one off at 80ft. lbs. of torque, i was going by this and was trying to reach 90 at least http://1954advance-design.com/Stovebolt-engine/head-bolt.html I don't know if it snapped off in the block very deep or if there is a little bit sticking out that i might be able to get hold of. i am going to look at it later, but my question is how do I remove this bolt if it did break off in the engine, and where can i get new head bolts?


thanks in advance, Indy

Many times, once the stress on the bolt (i.e. the head snaps off) is relieved the shaft will simply unscrew. The bolts are available from several vendors and perhaps at your local FLAPS.

took the head off, and tried to get the bolt to unscrew, but it is stuck tight..... now what?



Indy

using vice grips, a pipe wrench, or a welded on nut?

vice grips and a pipe wrench, I don't have access to a welder or I would try it.



Indy

Rereading the first post I guess these questions come up

Were the threads chased?
What if anything was used as a lube?
Original bolt, but how were they coming out?

How much of the bolt is exposed now that the head is off?

Personally this is where the cheap HF wire feed is worth it.
110V.
You don't have to worry about how well it works for a real welding session. Your filling a hole.

It's small and lite enough to get inside or underneath...

Don't be in a rush here. Do you have any machinist friends nearby? The last thing you want to try is an easy-out which can make things much worse. When this is cleared up, you need to examine all your head bolts. If any did not thread nicely, they could be stretched and distorted too.

How much of the broken broken bolt is above the deck surface? I have good luck using a left hand drill bit to get broken bolts out.

I second Don's suggestion on left handed drill bit. They tend to heat the bolt a bit while drilling and then they may grab the bolt and turn it out.

Where do you buy these left hand drills? I would like some.

I see the left handers at the local Marine and Industrial supply house.

Many local parts stores are keeping them now. NAPA should keep them.

I get them from the local Ace Hardware store. I have also got them from the Snap On dealer.

Same shelf as the left-handed monkey wrenches, yuk, yuk, yuk. (We need to learn to laugh when things go bad.) Left hand bits are great except when you are trying to drill a hole right handed because you didn't pay attention to what box you pulled the bit out of. I wrote "LEFT HAND, STUPID!" on mine.

There are a lot of them listed on eBay, Here is one example.

Regarding the method of welding a nut to it, isn't there a risk of welding the bolt to the threads in the block? The current has to pass through there.

i used engine oil as a lube, but i am afraid I don't understand your other two questions . I have a little welder but it will hardly weld sheet metal,so it probably won't do the job real well. also the bolt is sticking out of the block about 1/8 of an inch. I probably will just replace all of the head bolts so I hopefully won't have to deal with this again




Indy

sadly, I don't have any machinist friends near me, or even a machine shop within a 50 mile radius.

Indy

Were the threads chased?
As in did you run a tap down them to clean up the threads and make sure the bottoms of the holes are clean and free of anything that may cause the bolt to bottom out before intended.

How much oil was used to lube the bolts.
Look up "Hydrolock".

A small welder will do the job.
Get it out a practice welding a similar size bolt, washer and nut together.

A washer over/around the broken bolt shank will keep the block protected some and give the nut a little support. A large fender washer might give room to tac to outside the nut as well as the center. (make sure you can still get a wrench or socket on it)

Welding the threads to the block would take some effort with a small welder I think, but that's why I suggest the washer first.

I'd try using some wax as soon as the nut is welded on to take advantage of the heat cycle generated from welding. I haven't tried that technique but this would be a place to give it a shot if it were me.

Another hot tip: use canned biscuit dough around the weld area to prevent metal splatter on the block.

Woah... you just blew my mind

What about thick pancake batter?

And if you use a tig welder, you won't have any splatter and you can eat the now cooked biscuit.

With the head off you should have enough head bolt length remaining to use a stud retractor. They are available at most auto parts store or even Sears. And EBay. Google Stud Retractor for an image.

"the bolt is sticking out of the block about 1/8 of an inch."

Above is the information given by the trucks owner. Seems that most guys prefer to weld a nut to the broken bolt and have given good advise how to do it. I suggested a using a left handed drill bit to drill the center of the broken bolt, usually drilling this way will spin the broken bolt out. Another method is to use a sharp punch or small chisel and slowly try to spin the broken bolt out, it takes patience and you have to be careful not to damage the metal around the bolt.

A method that has worked well on bolts not rusted solid.

use a Dremel tool with a cut off wheel and cut a slot across the bolt to fit a large screwdriver. You could do the same thing with a hacksaw blade but not around a sealing surface.

If your screwdriver has a hex on the shaft, great, or clamp a vice grip to it.

All the above suggestions assume the thread is in good shape and not galled or otherwise compromised. If the thread is seized, it's probably going to be necessary to drill the bolt out a little at a time after getting a center punch dimple in the exact middle of the bolt. I'd suggest renting a magnetic-base drill press that holds itself to the top of the block for that operation, since even a slight misalignment of the drill bit will result in a junk block. Drill the bolt out about 1/32" at a time until you get to the minor diameter of the thread, then use a tap to clear the remaining residue.

If the thread in the block is severely damaged, drill and tap the hole for a heli-coil while you're set up with the drill press. Good luck!
Jerry

Indy when you get it out PM me and I'll send you a bolt there are 2 lengths .....

If the remaining thread in the block was a concern, would using a stud help?

It would depend on the amount of damage to the thread. I tend to err on the side of caution where head attachment is concerned as there's very little room for error. One of my racing competitors had a flaky torque wrench and stripped one head bolt thread as he was assembling his engine. He kept going, and ended up with 6 stripped threads and damage to several others. I salvaged his VERY expensive race block with a lot of prep work done to it by making up a drill guide jig and putting HeliCoil inserts in all the head bolt holes.

Did I mention he had a bad case of Budweiser fever while he was building that engine?

Jerry

update....... i finally got it out!!! sorry for the delay, been busy. thankfully i had a spare bolt lying around that i had forgot about to replace it with.

thank you all for your help,

Indy

Yeah.... but we want to know HOW you got it out

inquiring minds wanna know.....How did you get it out?

yes, don't do this to us...

sorry, got busy again.....



i first cut a flat side on both sides of the remaining bolt with a dremel cut off tool, then got the biggest crescent wrench i coul find and presto!!!! it turned!!!!!



Indy

Wait just a gall durn minutes here....
No one suggested that!!!

i know!! ain't I so smart!!!!!



Indy

Irwin makes them, try lowes. and home depot, or order off the internet.

Materman: A Crescent wrench? Nice! I don't have to buy a new tool...got me some already. Good fix.