Pump Magazine On-Line






Article 50: Cars and Pumps ?!

(How Much Real Help Can We Get?)


I am a pump guy, not a car man. I mean, I know enough about cars to have a conversation, but ask me about details of the engine, and you will know the cars are not my forte. Besides, I drive what I consider a cross between a convenient car and a transport vehicle - an Isuzu Subaru 1998. My company does repair of pumps, blowers, compressors, mixers, and similar types of rotating machinery. We use heavy duty trucks to pick up the equipment from the power plants, paper mills, chemical plants, water and wastewater plants and so on. For that, a heavy duty rugged truck is what one needs:


But for normal visits to our customers, my SUV works just one, - gets me there, moves fast, and yet should I need to pick up a relatively small or mid-size pump to repair, on emergency,  - if needs be, I can easily fit it to my Isuzu:


So, when my friends started to ask me when will I be getting a new car, my question to them was - why?


Well, gas mileage, that's why. You see, since 1998 and about 180,000 miles, my mileage went down from original 25-something to now 15-something. Why? Well, the car is getting old, my wife told me. Why?! - I still would not settle for such answer. What makes car mileage go down? I don't know, - but a qualified mechanic, a car professional - should. But would he?


So, on the next trip for an oil change, I asked the mechanical at my local shop nearby this question. Well, he said, you need a tune up, changed sparks, this and that. Then, he said, fill up with Super-93 a couple of times, and it will clean up the left over junk - and your mileage will be as good as new!


Yeah. I did all that, and after hundreds of dollars - no difference.


Now I was getting frustrated. Does anyone know? Is this the engine block wearing out, cylinders clog up? - whatever?


Let's ask the real professionals, I decided. Since I drive Isuzu - I need to speak to - who? - the Isuzu dealer, their repair shop. I am sure, I thought, their mechanics, with combined, as they say, "hundreds years of experience" would know. And so I happened to get a promotional card in the mail - guess from who? - from the Isuzu shop, inviting me to partake from the wonders of their professional repairs! Thanks, I thought, - now I will get the answer - and have my mileage restore - it may cost money, of course, - but first, let's see, I was hoping, if they tell me what wrong. With all this years of car experience... If THEY do not know, who does?! So what is wrong, Mister Car Specialist?



So I called them and spoke to the repair manager. I want, I said, to bring my car to you, as you are inviting per your marketing card. I know my problem - low gas mileage, 15 miles-to-the-gallon. Why is it, and can you fix it? - and I will pay for that, gladly - just tell me if you can?


Well, she said, - it could be many things...

- Low tire pressure (no, I said, I keep it at the 30 psi as you manual recommends)

- Bad spark plugs (no, I said, I just changed them, with no difference)

- Bad oil changes (no, I said, I change it every 3,000 miles)


Well, she said, what's wrong is that you should have been using our service all along, and would not have this problem. And with that - she hung up the phone.


And so it goes - how much Real Help can we get? What is happening to the American Service - do we still have a zeal, a professional pride, a desire to get things done, to find out what the true problem is, and fix it? Is it all about making money first, regardless whether a mechanic truly knows what he or she is doing - or just pretends he does?


Well, some may wonder, - what kind of answer did you expect? Let me illustrate by example in the area I am more familiar, as compared to cars. Let's use a pump analogy. For my car, my original mileage decreased from 25 to 15 mpg, i.e. 40% drop. Suppose one of my customers would experience a similar 40% decrease in pump efficiency over time and would like me tell him, first - why?, and secondly - is there anything I can possibly do to fix it? How would I answer his question?


Just as a car repair shop asked me about my car, I would ask the pump owner some basic information about his pump. Let's assume he has a 16x18-30 double suction pump (16" discharge, 18" suction, 30" impeller OD). At 1200 rpm, such pump typically produces 10,000 gpm, and develops 400 feet of head. To keep this head (pressure) from leaking out flow back to the suction, clearances need to be tight, about 0.028", which allows roughly 320 gpm, i.e. a small fraction of flow (320/10,000 = 3%) as compared to the main flow of 10,000 gpm.


With time, wear ring wear out, and typically, in a few (2-3) years, clearance doubles, thus passing 640 gpm. While many repair shops would recommend pump overhauls when clearances double, a more fair answer is to let the user, not a repair shop, decide. After all, if efficiency is decreased by 3%, is it really worthwhile to yank the pump out for repair? Certainly, a good business for a repair shop, - but not so wise for the pump owner, unless he is spending someone else's else, not his, money.


But, say the pump becomes older, and after 7-9 years clearances develops to a gaping 1/2 opening"!? Perhaps a part of a ring is entirely washed away, or worn away? Now, we get:


320 x ( 0.50" / 0.028") = 5714 gpm, or 5714/10,000 = 57% drop in efficiency! Now we are talking numbers!


And that is what I would answer to my client. Perhaps he would be interested to know how I did these calculations,  - perhaps not. By in either case, my answer would be based on some reasonable expectations,  knowledge, based on professional experience, of what causes (or at least may cause) pumps to loose performance. Had I just told my client: "It depends on many things, you better bring the pump to the shop for us to look at", - that would be either covering ignorance of not really knowing what is going on, or blatant dishonesty. I think most people would feel the same way.


Which of these two scenarios (answers) would you prefer?


I wonder what would the car service manager, that brushed me off with ignorance, tell her dentist if hearing this: "Hmmm... This tooth does not look great. Let me pull it and see what is going on there... And, while I am at it, let's pull a couple more teeth just to see how the gums look under there..." (And that is as a response on her question: "Doctor, my tooth hurts a little, what do you think might be a problem?").


All I wanted is to have an answer to a simple question: what are some possible causes of such dramatic drop in a car (any car!) performance, from this service manager's experience? I do not expect her to know the "thermodynamic of the combustion cycle", but, if she has been in car service business for any length of time, she should have told me at least some reasonable, possible, causes, for such problem, based on her, hopefully extended, experience.  Without such answer, I have to assume she really does not know, and if so, can I trust her with my car? Or, if she did not know, could she ask some other, perhaps a more experienced, mechanic at her shop?


Perhaps migration of American Industry from the

e US shores somewhere else, took this professionalism and knowledge how to "fix things" with it? Perhaps in our move toward service-oriented society we strayed into so much focused on counting the profits -  that are forgetting the responsibility and importance of customer satisfaction, work ethics and long hours, burning mid-night oil when a job needs to be done.


If that is a trend, I, for one, refuse to be part of it. When it comes to pumps, our company priority will remain focused on what I believe it needs to be: do the job honestly and professionally, do what needs to be done, do not do what does not need to be done. Hire qualified professionals, with true knowledge, - not someone who "saw" others do things, but themselves can only "describe" the job, but not really actually "do" it.


Long live the hard work! Long live pump professionals!


P.S. By the way, if I ever find out (from who?) what made my car mileage go down so drastically, - I will let you know!


The Saga continues...


Norman Rice, a Technical Director with RealServices spoke with me about this issue, and offered an oil analysis. According to Norman, he suspected that gasoline in the cylinder chamber of the engine does not fully compress, but blows-by, back to the crank-case, and possibly also back thru the valves, similar to a "mitro-valve prolapse" of the human heart issues. Products of combustion may also leak back to the crank-case. To find out more, he recommended an oil analysis, which is attached here for those interested: My_Oil_Analysis . Norm also suggested to check the compression on the cylinders by the car mechanic, which is what I intend to do in the near future - and will keep you posted!


For those interested, Mr. Rice can be contacted at:


Norman Rice, Technical Director

Voice:    330-630-3700

Fax:       330-630-3733


Dr. Lev Nelik, P.E., APICS

Editor, Pump Magazine

October 2009