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Old 11-20-2019, 05:17 PM
Dragncar Dragncar is offline
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Default OT, air compressor head bolt tq ?

I have a Craftsman 5 HP twin cylinder air compressor. It is all aluminum. It blew the head gasket so I bought 2 new ones. Anyone know the tq specs on something like that ? I bet I could get by with "feel" but if I can get the actual number I would appreciate it.
Thanks for any help.

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Old 11-20-2019, 09:41 PM
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67drake 67drake is offline
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I couldn’t find the specs when I put a new gasket on mine either. I just kind of snugged em. Well the gasket blew out again a few months later, Argh! So I snugged them then let it run and cool down for a few cycles and found them to be pretty loose again. So I resnugged them. That did the trick as they haven’t given me a problem since.
Sorry , I know “snug” isn’t too helpful though!

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Old 11-20-2019, 11:15 PM
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You can go by feel. Also it's a good idea to snug them up every so often.

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Old 11-21-2019, 12:54 PM
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ftwmlp ftwmlp is offline
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I found a parts lists for a Craftsman 106-175180 5 HP compressor. The scanned drawings were not very clear, but it looks like the head bolts are 3/8-16 (UNC). Standard torque for a grade 5 bolt of that spec would be 23-25 ft/lbs. Might be a place to start.

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Old 11-21-2019, 06:50 PM
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68lemans462 68lemans462 is offline
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I'd suggest the german torque spec: gutentight

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Old 11-21-2019, 07:25 PM
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Boogy Boogy is offline
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I agree with head bolt torque at 25-30 ft-lbs (multiply by 12 to get in lbs). And also agree you must go back and re-check this after running a few cycles hot/cold after replacement. Or you can just say "click" out loud after tightening each bolt snuggly and let her buck.

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Old 11-22-2019, 03:17 AM
Schurkey Schurkey is offline
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Quote:
Originally Posted by ftwmlp View Post
I found a parts lists for a Craftsman 106-175180 5 HP compressor. The scanned drawings were not very clear, but it looks like the head bolts are 3/8-16 (UNC). Standard torque for a grade 5 bolt of that spec would be 23-25 ft/lbs. Might be a place to start.
Provided the bolts are Grade 5, and actually 3/8-16, of course.

"I" would drop the torque by ~20%, and coat the threads with antiseize, and the underside of the bolt heads with moly-based lube. Yes, retorque after heat cycling.

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