My Pneumatic air wrench is around 375ft/lb and wouldnt take off the crankshaft nut. Any idea how much is needed to get that thing off?

would the one below work?

https://www.amazon.com/AEROPRO-TOOLS-2-Inch-Composite-1000FT-LB/dp/B08KF9SP3J/ref=sr_1_1_sspa?dchild=1&keywords=1%2F2+In.+Composite+Air+Impact+Wrench&qid=1613222206&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyOTZKTzRBWTBZUEpMJmVuY3J5cHRlZElkPUEwNDk3OTIyMTJCS0tMNUMwRDFOSCZlbmNyeXB0ZWRBZElkPUExMDE5NzI4SFVRUEQ1QzVSSVBBJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==#customerReviews

I have this one.  It's removed L28 crank pulley bolts among others.  The one you specified claims a breakaway torque spec of 1200 lbs.  The one I have claims 1190 lbs so the one you are looking at should work going by those parameters.

 

https://www.harborfreight.com/12-in-composite-xtreme-torque-air-impact-wrench-62891.html

Edited February 13, 20214 yr by Reptoid Overlords

What impact did you already try? What size hose? How much air pressure and volume?

I sent an email to a friend who gave another friend some suggestions on this same topic about a year ago. I'll let you know what he says.

thanks. below is a cheap air wrench i have and tried. as for hose its a 300psi campbell hausfeld. air compressor is little small but POrter & Cable, i think from Lowes or Home Depot....The PSI yesterday was at 120PSI and bolt wasnt budging

https://www.walmart.com/ip/Hyper-Tough-1-2-Aluminum-Impact-Wrench/751983391

Engine still in the car? Put long handled socket handle with 27mm socket on said nut, and rest arm against left frame rail. Engage starter for 1.46 seconds. Nut will be loose. 

Air driven impact wrenches need sufficient air volume to reach their potential. 1000 psi doesn’t matter if it just wheezes out of a small 500 foot long hose... 

its out of the car. air hose is about 15' long. Gonna Wait and see what SteveJ says but maybe i will go with an electric wrench like

https://www.harborfreight.com/85-amp-corded-12-in-heavy-duty-extreme-torque-impact-wrench-64120.html

24 minutes ago, Wally said:

thanks. below is a cheap air wrench i have and tried. as for hose its a 300psi campbell hausfeld. air compressor is little small but POrter & Cable, i think from Lowes or Home Depot....The PSI yesterday was at 120PSI and bolt wasnt budging

https://www.walmart.com/ip/Hyper-Tough-1-2-Aluminum-Impact-Wrench/751983391

My point was what Zkars said, hose diameter is what matters for air tools, not PSI rating. A small diameter hose doesn't feed a sufficient volume of air for an impact wrench. Sort of like breathing through a straw. 250 Ft/Lbs is probably optimistic. Probably need a better impact. If the engines in the car try Zkars idea

1 hour ago, zKars said:

Engine still in the car? Put long handled socket handle with 27mm socket on said nut, and rest arm against left frame rail. Engage starter for 1.46 seconds. Nut will be loose. 

Air driven impact wrenches need sufficient air volume to reach their potential. 1000 psi doesn’t matter if it just wheezes out of a small 500 foot long hose... 

I think this is what my friend suggested.

Otherwise, it's probably a matter of bolting the engine to something very solid and getting a four foot pipe to put over the end of a wrench (800 ft-lbs).

You could also use a planetary gear torque multiplier. Most can be used to tighten and loosen. Be sure not to exceed the rated input torque. Thirty years later I still remember the loud bang when I was helping to tighten a large taper hub fastener on a tire shredder to 2000 ft-lbs and we blew up the torque multiplier using a long handled breaker bar on the input.

I just got my friend's reply:

"Fill the air inlet of the impact with air tool oil, connect the air and then blast away at the nut. The oil prevents air from going out of the vanes of the impact, and will produce significantly more torque than just air."

4 hours ago, Wally said:

My Pneumatic air wrench is around 375ft/lb and wouldnt take off the crankshaft nut. Any idea how much is needed to get that thing off?

would the one below work?

https://www.amazon.com/AEROPRO-TOOLS-2-Inch-Composite-1000FT-LB/dp/B08KF9SP3J/ref=sr_1_1_sspa?dchild=1&keywords=1%2F2+In.+Composite+Air+Impact+Wrench&qid=1613222206&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyOTZKTzRBWTBZUEpMJmVuY3J5cHRlZElkPUEwNDk3OTIyMTJCS0tMNUMwRDFOSCZlbmNyeXB0ZWRBZElkPUExMDE5NzI4SFVRUEQ1QzVSSVBBJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==#customerReviews

You can try to shock the threads loose. Place a large brass drift on the center of the bolt head, and smack it sharply with a 3 pound drill hammer.  Sometimes two or three raps may be needed.

Then hit it with the impact gun.