so im pretty pissed right now. I got my rotating assy back from the machine shop and i was installing my crank and mains, well while "Q"ing them the number 3 main bolt snapped of in my f***ing block now im going to have to drill and easy out it out of the damn block or take the block to the shop and have them do it.

 

if the threads were ok in the block you should be able to just unscrew it after you get the cap back off. if it broke low enough that you cant grab it with your fingers you should just get a reversed drill bit. like i said, if the threads were clean and in good condition the thread stretch would have ben released when the bolt broke. it "should" just unscrew. i know in the real world things don't always work out the way they are supposed to so this may not be as easy as i say. be very careful with the drill and east out if this is the way you go. i call them maybe outs.

 

BUMMER! Hopefully there will be enough of the bolt to grab onto with a pair of vise grips. I wouldn't use an EZ out. I would rather pay $15 for a machine shop to get it out without damaging the threads than running the chance of breaking off an EZ out in the block. If those threads are damaged it could ruin the block. Once you get the main cap off soak that bad boy with PB blaster for a week straight. That should help "loosen" the bolt before trying to get it out. Of course, a main cap bolt probably shouldn't be seized in like an exhaust manifold bolt. Good luck!

 

Were they new bolts ? If so I would be sending the maker a email. If they were the originals I have heard they can get brittle from being under pressure for many years and not to reuse them.

 

Sounds like your reusing bolts and that asking for BIG problems,Just think if it didnt snap off and the first time you revved it to 5k the bolt broke.............NEW BOLTS EVERY TIME........Shoot thats the cheap stuff anyways..............Jerr

 

Tough break ,sounds like my luck.That does however convince me to get new fasteners.Do you guys use bolts or studs for the mains?later,BO

 

i-dont-think-so.jpg


Norm

 

Couldnt wait to use that one,could ya,norm?Nice photo of you though!Later,BO

 

yes i was reusing the old bolts. but now that im going through this i will buy new main bolts every time. it cant hurts since a new set of ARP bots are less then 35 bucks huh. ya live ya learn huh. Oh its going to the machine shop i dont want to break and easy out in it i know how reliable those shitty things are. I am a helicopter crew chief in the USAF and we use those sometime but most of the time they dont work

 

Good thinking.

Norm

 

BTW- it's not being under pressure that will necessarily make a bolt brittle, it's the heat cycles.

 

In the 80's Ford V6 head bolts popped off. It's a great thing to have happen. Would the heat cycles do that?

 

Heat cycles from ambient to above 1200° then returning it to ambient within seconds?

Not something that normally happens in an engine block.

Norm

 

Most likely, the bolt was too soft for the application.

Norm

 

You know it all Norm!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Hardly.

Norm

 

Norm, your just so dog gone humble.

 

In this case, Norm's correct. There is a lot of misinformation out there about how metals behave. High strength fasteners such as main cap bolts do not just "get brittle". They may have internal flaws from manufacturing. They may have been nicked. They can get fatigued, but that would require hundreds of thousands, if not millions of torque cycles. They may have been overtorqued at some point. To change the heat treat on the material and cause brittleness, however, is not something that can happen in normal use.

 

Now this is an honest question Joe, I would like to know. So a "good" bolt,properly taken care of will last forever? Heating and cooling cycles won't affect them? But then you did say normal use didn't you? OK, then I have to ask how many perfect pieces are found in a production run of anything? (That includes aftermarket pieces).

Thanks

 

I did over torque the #3 main. i torqued it to 110- ft lbs it should of only been 80 ft lbs. So for the good news i talked to my dad and he said that it should back right out if i was to hit it with a chisel or a screw driver and turn it out as im doing it so i did it and since there was no tension on the bolt any more it back right now out i had it out in less then two minutes. So back to putting my engine together. I ordered some new ARP main bolts from summit today so they should be here this week. I was worried i would have to take it back to the machine shop but nope its all good now and i am a man again.

 

Check the installation instructions on the ARP bolts...I believe, without having them in front of me, that it requires that they be torqued, loosened then retourqued a few times to break them in so to speak...an important proceedure easily overlooked...

Dont ask me how I know that...

 

Joe, these were legitimate questions that I would like to know the answers. I promise not to argue with you.

 

I'm thinking too hard Norm. If it was soft it would stretch.
JMO

 

Yes it would. Think a little harder.

Norm

 

No one said anything about "forever".

No one said they would, or would not, as it is not part of anything that was being discussed.

He did. Perfectly understandable, since nine second bracket cars are not being discussed.

Impossible to say, due to the many factors involved.

Not at all.

If they were "legitimate" they would have been far more specific, and far less argumentative.

OP stated the cause and his solution, so I see no reason for this thread to continue.

Norm

 

close the thread, i see no reason for an argument to happen over a subject like this. I simply over torqued the bolt and get it out pretty easily. Thanks guys

 

Norm stop trying to answer questions you weren't asked and don't know the answers. I asked Joe because I wanted the correct answers. Plain and simple.

 

Thread closed at posters request

 

Sorry, I didn't mean to blow you off. I meant to respond and had a senior moment...

Let me start by saying that there are two types of failures in metal parts, ductile and brittle.

Ductile failures involve stretching of the metal and almost always result from exceeding the yield and ultimate strengths of the material (metals have a yield strength, where loads exceed the elastic range and go into plastic - permanent - deformation, and an ultimate strength, where they break). A bolt that breaks from overtorquing usually exhibits a ductile failure.

Brittle failures involve failure of the metal without stretching or yielding. These most often occur as fatigue failures. The interesting thing about fatigue failures is that given enough cycles, they can occur at stresses below even the yield limit.

Fatigue failures are a science unto themselves. Every metal has what is known as an S-N curve, which plots cyclic load level against number of cycles to failure. The higher the load, the fewer cycles required to fail. Conversely, some metals actually have a load limit below which they will not fail, even at an infinite number of cycles. This long-winded explanation gets back to your original question. Yes, it IS possible for a bolt, when properly designed and installed, to last indefinitely.

Of course, there are a lot of variables in this. Does the head of the bolt fit flat against the bearing surface? Is the hole perfectly aligned? Are the threads clean and properly lubed? Was it torqued correctly? Etc, etc...

Newer motors incorporate single-use torque-to-yield bolts. This is done to maximize the strength of the bolt - stretching it work hardens the material - but the precise amount of stretch must be used. Too much and the bolt fails, too little and the joint is not strong enough. Over torquing a normal bolt will have the same effect - stretching it once will render it unsuitable to reuse.

And you are correct, mass produced parts tend to have variability, but bolts, particularly high strength fasteners, are perhaps the least variable mass produced parts around. Centuries of experience has produced precision screw machines that can repeatably manufacture precision fasteners.