headbolts from NAPA====bad batch????????????

Brian Love · Mar 3, 2012

working on a 350 or now known as 5.7 bought new bolts with gasket set then broke 1 long 1 off on first tourque sequence 35 lbs. then on other side broke a short 1 at 65 lbs.wow!!I threaded em in by hand no resistance like dirt or anything.just wondering if anyone else has had trouble like this.and this is the first time I ever bought new bolts instead of cleaning old ones never had a problem til now

retired farmer · Mar 3, 2012

Probably made from some of that good chinese steel from the World Trade Center.

buickanddeere · Mar 3, 2012

Counterfeit fasteners, filters and lube oil are a real and widespread problem. You should hear all the problems in the Nuclear and Military caused by the lowest bid.
Try FastenAll or similar vendor.Even the local JD dealer has a very extensive selection of nuts and bolts.

Jon Hagen · Mar 3, 2012

Not really, but I have not bought head bolts from NAPA. Are you using a "clicker" type torque wrench ? I have had them fail and still not click at 4X the torque setting. Might want to check that on a junker engine with known good bolts. That might help tell if the problem is bad bolts or bad torque wrench.

Brian Love · Mar 3, 2012

thanks!!I did 2 different wrenches

RandyB(MI) · Mar 3, 2012

Few yrs ago I did a few heads on Dodge 2.2 4cyl and bought bolts from Car Quest (DANA brand) and 3 out of the batch wobbled badly when rolled on flat counter. Wouldn't even hand thread in block because they were so warped. I work at a factory and I see where their priorities lie! Quallity is just a game , a collateral coincidence , but numbers and departmental at-a-boys take center spotlight. The " FAT " at the top calls the shots. " NEW" doesn't mean $hit anymore!

Anonymous-0 · Mar 3, 2012

Alright, this is a first for me. Since when did GM require the head bolts to be changed? I've always re-used the head bolts in the old 350s and they seem to be holding up fine so far.

I do know on certain engines where the bolts are marginal at best, like certain 4 cylinders and some Kohler engines. And they should not be re-used. Usually the bolts come with the head gasket.

You did put lube (or sealer if open to water) on the threads, didn't you? Lack of lube should not have been a problem at 35 ft. lb. but may have been at 65 ft. lb.

oldtanker · Mar 3, 2012

Most torque values are clean, dry threads only. If they are lubed they are actually over tightened unless it calls for lubing the threads in the specs.

Also there are a lot of engines out there today that use "torque to yield" specs. That means the bolts are tightened till they stretch. Those bolts are not supposed to be reused because they have already been stretched and can break if stretched again even more.

Rick

headbolts from NAPA====bad batch????????????

Brian Love

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retired farmer

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buickanddeere

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Jon Hagen

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Brian Love

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RandyB(MI)

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Anonymous-0

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oldtanker

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