Broke a head bolt, Now I'm really ticked off!

[Into Tractors]

Well, normally we break a head bolt when we are "Removing" the head, not putting it back on Just have to vent and as this has put me behind schedule as the other two tractors I just finished over-hauling for 2 folks just left yesterday.

I don't consider myself an newbie to engines and such, I've restored over 12 tractors for myself over the last 12+ yrs, plus I do work for other folks, but this is the first time I've broken a head bolt while putting it back on

The bolt was brand new, it was even a Grade 8 bolt too, didn't buy from a hardware store either, it was designed for use for an IH cub head too which really bothers me, was carefully going thru the torque sequence, and I was only at 25lbs when it broke. Broke it off just at the surface too, so I couldn't weld a nut onto it. Prior to re-installing the head, I ran a tap thru all the threads, nothing unusual there, sprayed copper-cote on the gasket as I normally do, set it in place, installed the head, and went to town on snugging down the bolts.

Man that just made me cuss like no end. I even scratched paint on the head when I tossed down the torque wrench.

So, now I'm out a head bolt, a head gasket, need to clean the residue off everything, repaint the head that I scratched the paint on, etc. and start all over

The good news is I did manage to drill out the bolt. Thankfully George Willer (Thanks Teacher) posted awhile back about having to drill out a broken head bolt. He used the head as a guide, and went at it that way. So I used his approach and it worked for me.

I broke 2 left hand drill bits, and beat the heck out of myself, but 3 hrs later I got it done.

Still not happy though, my guess is the bolt was defective in either the tempering of perhaps bad threads? I'll never know I guess.

Hopefully I can tighten it down the next time with no problems Now this means I have to mow tomorrow using the other mower with the 46" deck, man that stinks

So with that being said, I have a 18 yr old single malt and a decent cigar, so I'm going to sit out on the back porch and cry myself to sleep.

[BigBill]

Are the bolts too long or is it a shallow hole? I never broke a G8 bolt yet. I use grade 8bolts all the time from TSC and I hope there not from China we seem to be there toxic waste dump here the states lately today its crayons for the kids.

Be happy the block is ok thats all that matters the broken bolt will come out.
The only thing this strange i ever seen break is 3/8" tow chain with my log truck.

[bob in CT]

methinks I smell China. Or it could be hydrogen embrittlement which could happen anywhere. When parts are plated, it works like our electrolysis tanks. Hydrogen gas is given off in the bath and it can become trapped by the plating. If the parts are not baked off properly or they are cooled too slowly, the hydrogen can actually creep inbetween the metal grains and the parts get very weak. It is a issue for 300 series stainless and I have seen bad parts crumble like crackers under a rolling pin.

Once in a while a hardened bot falls on the floor and someone tosses into the basket of tempered parts. or the material is wrong. lots of things could happen and do but you sure dont want that bolt somewhere where you life depended upon it.

I don't have access to a lab anymore, otherwise I could run a failure analysis. Do you have a Rockwell machine on the base? A Rockwell A test could give a clue.

Bob

[TexCub]

Depending on where you got those left-hand bits, that hurts by itself!! Glad it's out and behind you though!

[Into Tractors]

Are the bolts too long or is it a shallow hole?

Bill, checked that. This was one of the long bolts, and it was in the correct place for installation. The bolt never bottomed out, so I'd have to guess that there were bad threads on the bolt itself, or it was weak to begin with? I ran a tap thru all the holes prior to putting the head back on, and the tap went in with no problems. Double checked the hole after drilling out the bolt, to make sure there is nothing in the hole, and you could drop a pencil thru it, so there was anything in the hole that the bolt could have hit.

Or it could be hydrogen embrittlement

Bob, you taught me a new word today! I'm thinking along that line. I looked at the bolt and the metal doesn't look right to me. It looks awfully "porous" to me. The metal of the bolt where it snapped just looks really "grainey"

Oh well, chalk it up to experience, anything that can go wrong will go wrong. I'm hoping the Case/IH dealership "might" have a gasket in stock (that's wishful thinking) so I'm going to call them as soon as they open. They can at least order it and have it by Saturday, as for the bolt, not sure which route I'll take. Might go over to Fastenal and pick up a complete new set from them, as these bolts have put a scare in me.

[bob in CT]

save the bolt, don't touch the fracture and send it to me.
I may be able to get a "G Job" done.

Bob

[magnumpi]

Mike: When you wrote a paragraph above starting with "The good news is......" I figured you for "I stayed at a Holiday Inn Express last night" !! Sorry, couldn't resist, plus I figure you need a laugh at these moments. It's stories like this that make hesitant to tear into mine - you know in your heart of hearts its inevitable. Stay calm.....perhaps an adult beverage. Craig

[Into Tractors]

I may be able to get a "G Job" done.

Bob, you must by psychic? I brought the bolt to the office, to show the guys at the other end of the building. AT&T also does "Aging Aircraft" studies and such, as we develop things that test and analyze the different components for the aircraft systems and such at the base.

Anyway, showed the bolt to one of the managers, and he saw that the head was marked to be a Grade-8, he then looked at the metal of the break and scratched his head. He too say's it look's odd.

So, he's going to do me a favor and take it over to one of the labs and check it. Only thing now, is he wants a "Second" undamaged bolt to test as well He want's to compare 2 against one another. So I have to give up another one to be broken on purpose now.

Good thing the Case/IH dealer has bolts in stock I guess, the ordered the gasket, won't be here until tomorrow morning though.

[Lance Leitzel]

Mike no offense, just a chance for me to learn. Do you really have to replace a head gasket that has never been used? Lance

[Into Tractors]

Well, I wouldn't recommend re-using one. In this case, I had already sprayed it with copper-coat, which sets up and get's tacky. When I pulled the head back off, the gasket stuck to the engine, so I had to peel it off. I had already torqued the bolts down to 25lbs at that point, so the gasket had already been depressed, so there's no way I could re-use it as it had already been compressed some.

One thing I'll do for now on, is to "trial" run all my bolts in the future. Like I said in my original post, I've never had this happen. I'm really leaning towards that one bolt had bad threads, and may also be a faulty bolt, and it seized up when I was installing it. I didn't inspect the bolts really, they were brand new and still in the package.

[magnumpi]

Mike: I'm no engine builder, but wouldn't a "dry run" pre-stretch the bolts. Then torqueing down the head stretches them a second time, followed by a retorque for their 3rd stretch. I raise the issue as Saab (roll your eyes on cue) had head bolt issues 6-7 yrs ago - a factory automated machine incorrectly torqued the head bolts (only every engine built for 18 months !! Nice QC - thanks again GM) such that ultinmately head gaskets blew etc etc. The factory TSB calls for new bolts !! Maybe this is just another way to sell product - who knows. Craig

[Into Tractors]

Mike: I'm no engine builder, but wouldn't a "dry run" pre-stretch the bolts.

I guess I should have worded that more carefully, what I should have said is I'm planning on checking the bolts next time to be sure they thread in without binding/seizing. I'm just planning on doing a "sanity" check the second go around, my temper can't afford another melt down like last night.

Sorry, couldn't resist, plus I figure you need a laugh at these moments. It's stories like this that make hesitant to tear into mine - you know in your heart of hearts its inevitable.

Believe me, I can appreciate the humor. When this happened last night, my neighbor just happened to be outside his barn, doing an oil change. When the bolt broke and I started yelling out a few choice words, threw a few things across the room of the barn. My neighbor came running over as he thought something might have fallen on me or something, as the last time he was over there, I had a tractor suspended in mid-air hanging from a gantry.

When he showed up, he found me walking/pacing in circles in the middle of the barn, and I was still muttering and yelling some choice words. Once I calmed down and told him what happened, he asked if he could throw something too as he was ticked off. He saw the chipped paint on the engine head, and knew I spent a lot of time on it, as I had actually polished up the porting on it, and painted it with black high-temp paint. My new paint scheme was looking good. The head will be black, but the bolt heads will be red. Thought the contrast would look good

I was "really" looking forward to getting it back together. I spent a lot of "extra" time as I just rebuilt the entire front axle assembly and such, as I replaced a busted bolster, etc.

Oh well, I keep telling myself that this is just a hobby, and the world isn't going to end.

[magnumpi]

Mike: Obviously, you've done enough of these restorations that this is a temporary setback at worst. What is the protocol on useage/torqueing of bolts in general and head bolts in particular. C

[bob in CT]

Craig you are right.

Head bolts that are designed to stretch are one-time use. This is common with aluminum heads and iron blocks because of the different rates of expansion of the metals. All iron usually don't use this design of head bolts and/or studs and they can be reused.

Mcmaster-Carr has grade 9 which has an extra-deep head. Not sure if the head bolt size is available. What size are they? The manual does not specify this, just "short" and "long".

[magnumpi]

Thanks Bob - to carry it one step further, does this then suggest that Mike should not reuse his head bolts in a perfect world as they've been torqued to 25 ft/lbs once already ?? C