a fella after a while knows your in the "ballpark" with out a torque wrench..but you have to work around the mechanical trade quite a bit
I broke some Head bolts
- Thread starter Dootimes2
- Start date
Agreed. The 'ol calibrated wrist or elbow, as the case may be.
In my past life I had a drawer full of preset torque wrenches and drivers that ranged from in/oz to ft/lbs.
Having done it about 50 or 60 thousand times over 20 years I'm confident I'll be able to tighten a panhead screw to 4-6 in/lbs until they put me in the box.
get factory bolts....when the motor was engineered a certain type of bolt is called for..too hard(such as grade 8) of a bolt could lead to issues with it coming looose or worse yet...pulling the cylinders out of round...a lot of thought and science is put into head bolts to make sure they have the right amount of strength, stretch and give to do the job they need to do...just not worth the the risk to throw a fastner store bolt in there...still think the torque wrench was out of cal...and yes M-8 and fourth wolf...turn a wrench long enough..yeah you can get a feel for whats tight...
Fixed!
Making Sure there is not Anti-Freeze in the Bolt Holes! This causing it to hydo lock and strip a thread.. FYI!
The Head Bolts Thread in to the Cylinder! Go Through the Head! fyi!
Making Sure there is not Anti-Freeze in the Bolt Holes! This causing it to hydo lock and strip a thread.. FYI!
The Head Bolts Thread in to the Cylinder! Go Through the Head! fyi!
DO NOT PUT ANY LUBE ON THE THREADS BEFORE TORKING BOLTS OR NUTS. Clean the threads of the bolt/nut before.
Like the guys above, you can feel a bolt or nut yielding after a few hundred tries. If you can't feel yielding, stuff breaks. For head bolts, a short Craftsman or Snap-On ratchet almost as tight as you can get it without using body weight is about right, assuming you have normal strength. A long combination wrench applied the same way should net the same result.
Got a pic of the broken bolts?
Something more is going on than a bad wrench and maybe it's by design. Let's say his wrench is total crap and he put 50lbs on that bolt. It still shouldn't break, should it? 25lbs is not very tight. When someone said "about as tight as you can get with a short wrench" I hope they mean a 3" handle. Normal 6-7" handle wrench pulled that hard for me is WAY over 25lbs. Bolt stretch is a way better measure of tight but much harder to do than using a torque wrench. So... do you guys think these bolts are designed to break like this at not much more than factory torque? Seems like they would be under a LOT more stress when that motor is at 8000rpm than twisting them into a soft aluminum cylinder. Prolly a good idea to get a new set plus 2 or 3 if you are installing new heads.
G
gman086
Well-known member
Whenever I hear these stories (breaking head bolts with low torque) it almost ALWAYS gets traced back to this because the novice pulls the stock head off before draining the coolant all the way down. I'd bet my paycheck that's what happened. Make darn sure those bolt holes are free from coolant!!!
Have FUN!
G MAN
R
Rev Kev
Well-known member
X3 As a Mechaniac for the Past 26 years, My money is on Antifreeze in the bolt holes, OR, with the aftermarket head, Now the bolts are too long, (Head is thinner) and bottomed out before clamping the head down.
Really easy check here:
Torque it with another wrench at the same torque and then use yours, is it still turning the bolt?
I would lean toward a bad wrench long before I buy three separate bolts corroding to the point they fail, all without any signs of physical damage while you were removing then then reinstalling them.
The ONLY other thing I could suggest is that the new head isn't thick enough and the bolt is bottoming well before the head is seated.
Torque it with another wrench at the same torque and then use yours, is it still turning the bolt?
I would lean toward a bad wrench long before I buy three separate bolts corroding to the point they fail, all without any signs of physical damage while you were removing then then reinstalling them.
The ONLY other thing I could suggest is that the new head isn't thick enough and the bolt is bottoming well before the head is seated.
I can see this being an issue, but if the torque wrench was functioning correctly, he would have a loose head, not broken bolts.
Well it went back together last night. The broblem was the torque wrench. It does not work properly at the low setting. I bought a new one and bolts torqued just fine.Still made me a bit nervous, but everything went well. There was no antifeeze in the holes ( guarenteed ). Also the bolts were not bottomed out. The one I had to remove from the cylinder was a good 1/4"+ from the bottom. In fact once I put the easy out in it I unscrewed it with my fingers, which means it had no pressure on it from the cylinder. IT WAS THE WRENCH. I am not worried about swapping out the head on the wifs sled at all.
G
gman086
Well-known member
WRONG. I will send you my address for that check. I hope it's big.
I'm unemployed - HA!
Glad you got her fixed.Have FUN!
G MAN
