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Torque wrenches. Engine failures, Don't go off Half torqued.

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Torque wrenches. Engine failures, Don't go off Half torqued.

wayne712222 wayne712222
I watched NASCAR once | Posts: 17 | Joined: 10/13
Posted: 12/09/13
11:15 AM

when was the last time your torque wrench was checked for calibration..

a well written article..

something that is not mentioned.. if you are a racer.. at a national event.. and you see the ARP trailer there.. they usually show up at NHRA national events. but they might make it to Nascar events.

the have a torque wrench tester with them usually.. to check the torque readings on your wrench verses what your ARP fasteners should be torqued to..

you know what you have torqued your head bolt/studs to..  the main cap bolts.. the rod bolts or nuts..  write those numbers down and they will check it at that setting to see how far it is off..  or what it takes to get to that setting...

i have not talked to ARP about this.. but i did talk to them and got them to bring the torque wrench tester in their trailer.

testing your calibration.. do not readjust your torque wrench handle . that should be done at a repair station..

pick up that 15 mm 1/2" drive socket  in 12 point..  that will allow you to connect two 1/2" torque wrenches together for a quick check..

if you have a beam type torque wrench.. like that old craftsman beam that's been sitting in the bottom drawer..   place some tape at ... say 65 foot pounds.. hook it to your click type with it set to 65 foot pounds..   see if the click type clicks at 65 foot pounds..

or a little under or a little over.. do this in the air.. not clamped in a vice..

how far off is your torque wrench.

if its more than  a few foot pounds off.. you may want to contact the manufacturer and see if they have a calibration service available.. all the major tool suppliers have that available.. snap on.. mac.. cornwell.. and craftsman.. yes.. you can send your torque wrench to sears. usually via one of their home stores/parts centers to get it inspected, estimated for your approval.. repaired and calibrated..

now that you have dusted off the beam type torque wrench.. put it to use after a blow up... or failure..  use it to loosen at least some of the bolts on each component.. to see what the break away torque is..   or attempt to torque the existing fasteners a little more to see where they were tightened too..

its a great step to avoid repeated engine failures.


let me describe where i came to this position.

in the early 90s i worked at a small production engine rebuilder.

there were small numbers of engines coming back with blown head gaskets..

as a lark.. the bosses son who was shop foreman tore this engine down himself..

he used a beam type torque wrench and found the head bolts on the small block chevy were only torqued to around 45 foot pounds.  the next morning as i got in hours before everybody else..  i checked the torque wrenches with my personal brand new craftsman click type..  the 3 torque wrenches were off.. one was 10 pounds low at 65, the next was 15 pounds low.. the third was 20 pounds low..  i found that one had been left at 110 foot pounds over the weekend..

the owner let me purchase a wall mounted dial type torque wrench tester... so they could just set the torque wrenches off the wall mounted unit..  simple fix right..

the employees removed it from the wall and tossed it on my parts counter..  said.. its not accurate.. as each one of the torque wrenches reads differently..  and they know their torque wrenches.. they have used them for years and years.. they know they are accurate..  i think i lasted about 3 more days at that job that i loved..

that was the place that i came up with  one of my best jokes..

the exxon valdez had run aground in alaska only a few weeks before and exxon had an oily taste in everybodies mouth right then..   the boss returned from the parts store and started tossing cases of exxon motor oil on the counter for me to put away.  the 3 or 4 engine customers at the counter all said together in a groan..

exxon motor oil.. ugh....  i looked at them and replied..  whats wrong with it.. its good enough to lubricate the gulf of alaska.

these bolts were identical before one was overtorqued..