Ingersoll Rand Model A compressor 1968 – advice please

[julianm]

I’’ve had this for 4 years now & it has been very useful for tyre inflation & as a blow gun for cleaning up parts etc. I’m thinking it should be capable of running an impact wrench to save my wrists a bit & hope you may be able to offer some advice:

It takes 13 mins to run up to 150psi, will then cut in if the pressure drops by about 15psi. If left alone it doesn’t seem to leak down within an hour or so, but overnight will go down to about 30psi. The tank is about 600 litres. I don't know what the CFM might be.
Does that sound OK?

I’ve got an adjustable reducer on it at the moment (it’s been swung down for a photo of the plate) but for an impact wrench I expect I’ll need to tee off a connector straight from the tank.

Do you reckon it would work out OK for what would be ‘hobby’ use?

Also , I’m not sure if a ½ or 3/8 gun would suit best – it would need to cope with wheel nuts at 100ftlb but I think I’ve had enough of doing any heavy suspension work where a ½ gun might be essential & perhaps a 3/8 gun would be more useful in confined spaces.

Many thanks if you can offer any guidance, Julian.

 

[Rig Pig]

I doubt that you would get much run time out of that, windy guns eat air. The tank looks more like 60l than 600!

 

[julianm]

Oh heck - out by a factor of 10!
I`ll see f I can borrow one for a practice.

 

[Turbo]

If there's no plate on the pump what hp is the motor, that will give you an idea of the pump output. It looks like a single cylinder pump but a better photo would help.
Either way it sound like you have an air leak somewhere. There's a good parts backup from IR so I would suggest you remove the cylinder head & have a look. There's a good chance there could be a build up of dirt in the valves after 50 years. Before you do that check the inlet air filter.
To check for leakage past the piston rings let the compressor fill up & cut out, remove the oil filler/dipstick & listen/feel for air escaping.

 

[julianm]

Thanks for the comments Turbo - I`ve had a look at the motor & it`s 0.5hp, 1425 rpm. I`ve checked all the unions & they are free of leaks. There is some blowback through the air inlet/filter (which is nice & clean) so maybe the valves are dirty or they may be a gasket problem? Would the be the reed type in there? I can`t find any diags or refernces to this model with several online search attempts.
Thanks again, Julian

 

[Turbo]

With just a 0.5hp motor it's not going to have a large output, maybe 5cfm and will struggle to feed an air wrench. If you have the cyl head off you can measure the piston diameter & stroke, from that calculate the swept volume, calculate the pump rpm & from those figures work out the theoretical cfm of the pump.

 

[MattF]

Whip the top plate off the head and you'll see the valve plate under there.

 

[julianm]

Hello & thanks for the ideas - I`ve taken a look & removed some rusty muck from the head, cleaned up the reeds & put a little more tension on the inlet side with a very slight bend at the `hinge` end & now have less blowback through the intake. I`m hopefully teating a gun next week & will report back.

 

[dannyp]

my bet is about 2 cfm going on that a compressor with 3hp motor usally gives about 12 cfm

 

[HughF]

These are great compressors, I have the v twin version, quiet, pump to 150 as you know.

 

[postie jon]

These are great compressors, I have the v twin version, quiet, pump to 150 as you know.

snap same as mine.

 

[eyresy]

As a rule of thumb, multiply the horsepower by 4, this will give you the approx output at 7 bar (102psi) - at 10 bar this will drop by about 30% - so 1.5cfm if you're lucky. This will not run an impact wrench, or rather it will but you will be waiting for long periods in between removing nuts for the pressure to build back up

 

[julianm]

I`ve picked up a 1/2" impact wrench, have put a tee straight into the tank to bypass the regulator & had a go - with 150psi in the tank it's whizzed off each of the wheel nuts on my Subaru in about 2 seconds, with the wrench set at '2' of 4 settings. They're torqued at 95ftlbs & all 5 were off without the compressor cutting back in.
It`s an old impact wrench, a Desoutter 2W40-P which seems to be in first class order even though I think it must be at least 25 years old. I think they have a reputation for being well engineered - it weighs a ton & the L/R lever is brass!
For any work I`m involved in I reckon it will be very helpful - I`d like to give it a go on a crankshaft nut but no need at present - I might try a hub nut for fun when I`ve got a wheel off.
Thanks again for the suggestions & advice.

 

[HughF]

Desoutter make great tools, should give you plenty of service that impact.