torqueing mains and treads came out. now what?

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alsdemon

alsdemon

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we had assmembled my short block last november but my torque whench was not right so we waited . i finnaly brought home a differant whench home to finish up when i went to do 3th or 4 cap one bolt did not tighten up so i removed that bolt and the treads came out with the bolt. now what/ can i run a heily coil or do i need a new block? :angry2:
 
I don't know what engine you have but if you have enough material around the cap you could tap it to the next larger size? Other than that you may want to contact a machine shop about the Heli coil, In all my years I've never encountered this problem.
 
I've never, ever done that. Not even using an impact gun. Are you sure the bolt was the right one? A heli-coil could work i think. But I'd be VERY concerned using it in htat position and running the engine hard at all. In any event, I'd call it a machine shop repair. Might be better to drill and tap to the next size bolt...
 
i would think if you were to drill/tap it you probably should have the mains line bored/honed, or whatever the hell it is called.....
 
I'd imagine you could have it welded and re-taped to be the same size. Using a helicoil would scare the hell out of me! I get nervous just using them on a trans pan lol.
 
never heard of or seen this before....

I would get a new block.

I would also talk to the machine shop who did the work to that block.
One thing a lot of machine shops DO NOT do... is check over the piece BEFORE doing the work. I've seen blocks done down to the line bore process and then find that the caps are the wrong ones and end up being miles off. they think 'oh I'll just mag it and if no cracks, it's perfect'...no
And last but not least is did the guy know what he was doing with the line hone.
then how most shops don't tap out all the holes, like when you get your heads back with a stud broke off in every end hole....
 
I can't even imagine pulling the threads out of a cast iron block. Was it fished out of a lake?

Not only do you have a problem with the one bolt but I would be suspect of the others.
 
My thought, take it to a machine shop. I wouldnt trust a Helicoil on a main bolt.

My assumption is that you werent dry-torquing it. Thats the only time I've ever heard of this happening.

Have you run 1/2 inch tap up it to see if it was truly the block and not the bolt?
 
if i remember right i tap all the bolts hole my self before i took it to have hot tanked/ was a running motor when i got it/ it was a wendage tray bolt hole and they are shorter then the other main bolts/ not a high hp motor mostly stock. it had been over hauled before/ the bolt when in another hole and was fine/ yes click type whench mac i think/ there was no line bore done old bearing looked fine just whened to freshen it up before it was installed/ may have had a heil coil in there already and thats what came out/ will have to rethink what i,m going to do with it time is running out we will have to move soon not much money left. i had head bolt break off before but not this
 
Next size bolt or helicoil, either one will work.
 
Helicoil will work just fine and be stronger than the original threads were. However, the hole will need to be drilled perpendicular to the block so I'd have a machine shop set it up in a Bridgeport or something similar to have it drilled. If it's a little off it will either move the main cap or change the clamping load so I'd want to be sure with that.
 
I think youre right Guitar but i would never trust it myself unless i had it splayed or redrilled for 4 bolt caps but this is just my scared self. And I am not a machinist.
 
Guitar Jones said:
Helicoil will work just fine and be stronger than the original threads were. However, the hole will need to be drilled perpendicular to the block so I'd have a machine shop set it up in a Bridgeport or something similar to have it drilled. If it's a little off it will either move the main cap or change the clamping load so I'd want to be sure with that.
Click to expand...


I agree... That's why I said it's a machinist's repair regardless or whic option gets used. The new thread or hole must be perfectly placed.
 
Guitar Jones is right. It needs to be heli-coiled on a Bridgeport to ensure that it is perfectly perpendicular to the mating surface of the block.

As far as everyone's concerns about the strength of a heli-coil, they are much stronger than the original bolt hole. I'm shocked at some of the responses here suggesting to get a new block or tapping it oversize.

Too much mis-information being thrown around here.

I have personally done helicoils on main bolts IN THE CAR. Not my first choice, but I was trying to bail out a dumbass mechanic that didn't want to pull the engine out. It sucked to do it, but it worked.
 
Just a thought on this he said the threads came out with the bolt could this block already have a heil coil in it and just need a new one
 
I have several head bolt holes heli coiled, each time I tear it down it needs another, its a 1969 block and has been torn down numerous times, at least 20. You can only squeeze so much blood out of a turnip before its time for another. To heli coil a main bolt its gonna have to be drilled perfectly straight to avoid any side loading on the main cap and I would go ahead and line bore it after. The block is like the foundation on a house, if its not straight your gonna have a crooked house.
 
Personally I wouldn't do a Toyota style of repair. I would get another undamaged block. How many more holes are on the verge of having the threads pulled? This is just my opinion and what I would do.


http://www.emhart.com/products/helicoil.asp

I would look at the helicoil website and see what you actually need. Keep in mind that there are plenty of foreign made trash around so you need to make sure that you get a real part.


Heli-Coil On-Line Tech Talk

Wire Insert Length Selection

Heli-Coil screw-thread wire inserts are available in 5 standard lengths. Insert availability in 1,1- ½, 2, 2 -1/2, and 3 times the nominal thread diameter provide thread length combinations to fit most every application.

To properly choose an insert length, several factors must be considered. Knowledge of the parent material strength, bolt material and strength as well as the specific load requirements of the application must be weighed to insure the integrity of the threaded joint.

To assist in this choice, Heli-Coil publishes a Tensile Strength Bulletin, Bulletin 68-2 which provides tensile strength information for the various thread sizes and lengths of inserts available as installed in a variety of common parent materials.

For most general applications, a 1-1/2 or 2 diameter length of engagement is adequate. For critical applications or limited engagement areas, it is important that the items discussed above be reviewed closely.

For further technical assistance, please contact the Applications Engineering Group.
 
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