I am in the process of changing a timing belt for a friend. The f$$king crank bolt won't come off with the girly 250 ft-lb wrench, and lot of swearing, breaker bars and sweat. So I figure I would get a bigger tool I found a 3/4 inch from sears for $206 with 700 glorious lbs of torque

Sears doesn't have parts in 3/4 size. Not even a converter to 1/2 I wanted to complete this job tonight, but I don't know if I can. Where can I find this part if it exists?

 

The wrench itself won't make a bit of difference if the compressor isn't up to snuff.

I've tried it before and my electric impact wrench put out more effort than the 120psi compressor I rented.

3/4" drive impacts require huge compressors to use...big enough that you have to tow them is what the guy told me.

 

Sears lists 7.5 cfm at 90 psi as the requirements. Looks like the compressor capable of motivating this gun is 600 bucks. I don't think my friends 200 dollar compressor is up to that.

The 1/2 inch that does 600 ft-lb is 4.8 cfm at 90.

I will have to do some research on this. I never realized that cfm's in compressors can vary so widely. There are some that you do not have to tow, but you will pay the price definately. Strangest thing is there is no correlation between cfm and hp of the motor. This does not make since.

 

I never got to understanding the correlations and critical stats for compressors b/c I reduced it down to not having enough money or space to put all that stuff, so I stopped trying to understand.

I did remember reading in the Sears catalog that the hp isn't really that important b/c of the design of newer compressors. Higher hp might help with transient high loads (like busting off the crank pulley bolt) to keep the cfm's consistent and the pressure up.

Also, electric compressors handle sharp loads better without pressure loss, but are also bigger and heavier.

I'm still not sure what would meet our requirements tho.

 

Well tomorrow I will know if my newest addition to my tool chest worked. I bought the 1/2 inch wrench. My friends compressor is 5hp and rated at 5.5 cfm at 90.

Now I have a $170 air tool and no compressor. Time for more tools.

I know that hp determines work, but what about the efficiency of the motor in pumping. At home depot, my friends AC is going for 200. Another with a 3 hp motor is going for 250, but has higher cfm at 40 and 90. CFM at 90 was about 6.6. I thought this was odd, until I look at the motors. The motor on the 3 hp AC seemed much larger than the one on my friends AC. Of course this was an electric to electric comparison.

PS, Am I the only one that caresses their new tools

 

..... think about all those poor kittens

 

Have you considered using an electric impact wrench. I have heard some good things about those.

 

Is that Ingersol-Rand (sp?)? Campbell-Hausfield is pretty good too right?

 

IR is Ingersol. I think the Campbell is descent for shade tree mechanics. My friend has a 250 ft-lb that he has had for a few years. Cost him like 30 bucks. It has gotten off everything except this crank pulley bolt.