Don Terrill’s Speed-Talk

My monster air compressor has developed a knocking noise, sounds like a rod is on its way out. Its a Ingersoll Rand 2545, 10hp, 120 gallon horizontal. I was looking online to see if this has a one or two piece connecting rod but I keep finding different answers.

I'm afraid if it is a one piece rod than I would have to press the crank apart to replace the rod, and not sure about indexing the crank to put it back together.

Does anyone know if these large IR compressors use a one or two piece rod? Anyone else heard of this problem before? Does anyone have one of these compressors or maybe the pump I'm looking at to replace this one, a IR 71T2?

Just thinking this through a little before I tear into it and loose my air supply.

Thanks very much!

Mm

check http://www.ecompressedair.com for ir parts my compressor blew up 2 weeks ago and i found a allmost new 10hp in town used at a body shop i believe that the rods are two piece because you have to take the rods off to get the crank out of the case if you have a rod knock i don't knon if the rods have bearings in them or if they are able to be gotten in undersizes either case its not hard to to do yourself if yor are an engine builder

I've been looking around everywhere online to see if someone can tell me for sure what type rod this compressor uses. Some say one piece, some say two piece. If your right and the rods have to come off the crank in order to get it out of the case, and that makes total sense. I just didn't think of it I guess. I'm going to tear into it and see what I see. I now have a small back up compressor so I won't be without air in the shop. Can't use the bead blaster for more than about 30 seconds before the pressure drops below 100, and keeps dropping!

Shop is pretty much dead without air!

Thanks for your response!

Mm

I finally found what I believe is accurate info on this compressor pump. It seems to have one piece rods. Easy enough to take apart, pull the front cover and slide the rods off the crank. Pull the rear cover and remove the crank out the back. I wish it had two piece rods so I could resize them on the rod machine instead of spending the money to replace them.

Ingersoll Rand probably designs these with that in mind.

Thanks very much!

Mm

so the crank is 2 piece???? and comes apart??? i can tell you that this new compressor spins the pump much faster then my old one but it takes a lot less time to recover to 150lbs i would guess that when it comes apart it really tears up a lot of stuff but IR says the pump is good for like 15000 hrs with maintance and oil changes did you ghet your apart yet??

I have a pump apart from a 7.5 V type 2 stage, the rods are 1 piece alum , the journal is just a sleeve that fits over the crank pin --perhaps they sell them in oversize ---this pump had a main bearing failure --sounded like a rod knock then seized, common ball bearings, I repaired it with an old model A Ford trans bearing, the inner race of the original bearing was so tight I had to cut it off. I won't put many hours on it, I figure it failed with about 12,000 hours, I am using it as a standby for high volume, most time my 3hp is enough.

I like the old slow moving pumps, not as much air but they don't break much,now the same pump is spun 2X faster to make more air at the expense of long life

Perhaps the rod can be bored out and a suitable cam bearing installed

FWIW my compressor started knocking , thouhgt it was a rod, turns out it was the valves! was a simple fix after I found it.

Hey sorry guys I've been gone for awhile. I have not got this pump apart yet. I have not had the time lately to do anything except work.

I'm fairly sure as stated it has a one piece rod and the throw on the crank is just a sleeve. Sounds like its going to be very easy to take apart.

Mm

donc wrote:FWIW my compressor started knocking , thouhgt it was a rod, turns out it was the valves! was a simple fix after I found it.

I actually wondered if that was possible. Listening to the knock its not the speed of a rod, I don't think, probably more main bearing or possible a valve problem????

Any body heard a noisy valve on a compressor, what's it sound like?

Thanks

Mm

jred wrote:so the crank is 2 piece???? and comes apart??? i can tell you that this new compressor spins the pump much faster then my old one but it takes a lot less time to recover to 150lbs i would guess that when it comes apart it really tears up a lot of stuff but IR says the pump is good for like 15000 hrs with maintance and oil changes did you ghet your apart yet??

I've read a few times now that the newer compressor's are not as good as the older ones in that they are built cheaper, spin way faster, nosier and just don't last a long. This IR I've got is less than two years old and it spins I believe just about 900 rpm's at the pump. That's with the 10 hp driving it. 7.5 hp I think spins faster, not sure about that. I think for a bigger compressor, bigger than most cool home shop compressors, its fairly quiet. You can actually talk over it only several feet away. A lot of compressor's I've had you need to be twenty or thirty feet away before you can talk over the noise of the compressor.

I don't know how many hours are on this unit but most certainly it was supposed to last longer than it did.

Back to they don't build them like they used too!!!

Mm

Check the intercooler brackets. I have used three different IR compressors and one of them cracked a bracket about midway through its life. As was mentioned, it could also be a valve -- problems with mine came later.

In my 1980's vintage single cylinder upright compressor, the aluminum rod is one piece with no bushing or sleeve. The crank is single sided so in the event of damage, the front cover comes off and the rod slips off the open end of the crankpin. These things run at constant speed with little variance in load, so any rod damage is usually from lack of oil. Sometimes you get lucky: mine got noisy and began to seize up when the oil level got a little low; it uses a primitive splash/dipper oiling system. I disassembled, honed the swollen & blackened big end of the rod back to a slip-fit on the cleaned crankpin and reassembled. So far, so good....3 yrs since teardown and counting. I'd thought I was going to have to make a new rod or at least add an insert!