Diesel Engine Repair Quality Control Procedures

[KBasson]

Good Day Gents

I will really appreciate any feedback with regards the following. We carry out frequent diesel engine overhauls ourselves. We have quite a large fleet of earthmoving equipment which we utilise in the mining industry. My problem however, is the fact that basically every repair job has some or other comeback. The quality of the repair procedures are just not up to scratch. I have taken the issue up with the relevant manager and he just always seems to have some or other excuse. I obviously just cannot carry on like this. I woulod really appreciate any pointers or guidelines in this area. I have thought of putting together a quality control matrix, where the craftsman is forced to systematically follow strict guidelines in the form of a checklist or matrix.

Any assistance or help will really be appreciated.

Thank You
Ken
South Africa

 

[patprimmer]

I think your Quality Manual could simply say, "follow Workshop Manual procedures".

Maybe you need a new manager, or maybe he needs the appropriate resources.

Regards
pat pprimmer@acay.com.au
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[franzh]

As my illustrious colleague states, maybe you need a new manager.
In many engineering courses, a segment is taught about quality control. We call it "accountability".
Consider how the equipment performs when new. “Proper” repair procedures, following the original manufacturers manual or guidelines, should not encounter any more comebacks then a new piece of equipment. Note the emphasis on the word “proper”!
It is the service or maintenance managers responsibility to balance the cost of repairs (rebuild or replace), assigning the proper skill level technician to the appropriate task, and providing the necessary training and other resources to the technicians to allow them to do their job properly.
Now, to be totally fair, a comeback is when the original repair failed, or was not properly diagnosed or repaired according to manufacturers specs. Secondary failures should not be considered a comeback. Replacing a waterpump and then encountering connected hose failure should be considered a comeback. Repairing a radiator after a flat tire is not, unless the flat tire caused the radiator to fail (object impact).
Engine failures caused by improper machining is relatively easy to backtrace, as are failures caused by failed air or oil filtration, which is not related to comeback, unless the rebuilding procedure was faulty.
Is your equipment totally remanufactured or refurbished to like new condition or is only the failed component serviced?
Franz


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[KBasson]

Hi Chaps

Thanks for your response. I thank you for your valuable input. The problem I am faced with is, the fact that when we experience engine, transmission failiures etc. we do not generally ascertain the root cause of the problem in the first place. I attribute this to a lack of skill and management skills. I have just been given the responsibility of the maintenance of our entire plant fleet operation of mining & earthmoving equipment. My first task in the new position was to generate an Asset Management Strategy for the division. The problem I am faced with now, i.e. engine repair & diagnostic effeciveness, is a typical area that needs to be improved dramatically. Any technical references or websites that could possibly assist me in this regard will highly appreciated. I do take your points that the plant manager could be the problem, as I tend to agree with the possible suggestion that he indeed might be the problem. It is however not that simple, to just replace him. Skill shortages are quite prevalent in this area and effective leadreship & management is definitely required on my behalf.

 

[patprimmer]

Unfortunately, a certain level of experience is needed to identify root causes for problems. There are plenty of references as to how to repair damaged parts, but nothing I know of that teaches how to be aware to look into a piece of equipment to identify where a problem may have started.

For example, engine bearings may be giving short life. Basic cause might be insufficient lubrication.
Root cause might be a damaged oil pick up that also sucks air with the oil, or a change in oil quality, or a dirty oil cooler or the bearing crush might be wrong or the bearing quality might have changed or or.

I can only recommend tight control of procedures, if in doubt replace part worn or near spec parts as well as damaged parts. Specify first class parts and materials.

Regards
pat pprimmer@acay.com.au
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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[enginebob]

I would tend to guess that is a problem that many companys have. Even major engine rebuild shops that specialize. These days there is a lack of the good old skills, and too much pushing to get a job out fast. I think one place to start, is "SLOW DOWN" it would be better to take twice as long as normal to do the job than you have to "REDO" the job. A redo job will cost way more because of having to Remove the componet again. More new gaskets and other parts and maybe even major catastrophic failed parts. Another area that can cause even the best people to fail, is lack of sleep and rest. Why does everyone look forward to a day off?????? Yeah so they can go on a schedual their bodies like. And "sleep in", maybe you should poll the people doing the work and ask if they are rested enough.
And what shift they could work and not be so worn out on.

 

[Warpspeed]

There may well also be an economical level of repair. To completely rebuild a whole engine or transmission "by the book" just to fix a cosmetic oil leak is just not going to be economical. Only the military can afford that level of perfection. A small number of repair jobs that bounce back is also going to be inevitable and should be acceptable.

As others have already said you need supervisory staff that have the required skills and experience to make the correct decisions. It is not simply a matter of laying down set procedures, supervisors need to be able to make correct value judgments on the spot.

Fixed written procedures only seem to work where the work is fairly repetitive and somewhat routine, as in perhaps routine maintenance. Breakdown repairs can be quite an adventure in comparison, because of the inability to plan ahead. As a first step I wold look towards the qualifications, experience and suitability of key people.

 

[leroi]

Read with interest your problems. From my experience as a mechanic, I'd like to make some suggestions thgat might help things. First, don't do any major work out in the field if you can help it. Get a tow vehicle if you don't have one--some of the old east bloc trucks can tow a US M-1 tank (70T) and they are cheap. Use it to get the vehicle back in the shop, out of the sun, wind, rain, dark, sandstorms, all of it. Second, spend some bucks on the shop facilities themselves. First order of business is sufficient cleaning equipment and procedures. DON'T EVER OPEN UP AN ENGINE UNTIL IT IS THOROUGHLY CLEAN ON THE OUTSIDE!!!!! There really is a four-step cleaning procedure on major engine work--1)pressure wash engine in vehicle prior to removal (I always hated wrenching on filthy engines) 2) pressure wash engine once it is out of the vehicle, using whatever necessary additional cleaners to get it spotless 3) clean all the engine parts once the engine is completely dismantled, using solvent, before you send them to the machine shop and 4) clean, I like using the local hand-held carwash with lots of hot soapy water, all the engine parts that went to the machine shop before you put them back on the bench to go into the engine. If you aren't doing this, well, you are going to have engines fail from dirt. Also necessary is spending sufficient bucks on necessary shop building for proper engine assembly. Just because the British car industry used to build engines on dirt floors thru the '60's doesn't make it a good idea. Clean, WELL LIT (Basically, operating-room light levels, particularly for someone like me who is over 40), good workbenches, and there in SA, I'm sure, air conditioned, at least in part. No point in trying to build a clean engine in a dusty part of the world with a fan blowing all that dust around as the mechanic tries to keep cool. Spend bucks on regular housecleaning, and if you've got a crew of mechanics who can't pick up after themselves, well, dammit, you are going to have to get rid of at least some of them and get some who will. Spend bucks on a good hardware assortment for the shop--get a good assortment of SAE GR-8 hardware--no point in anything less--good assortment of electrical wiring pieces, hydraulic pieces, to where your mechanics aren't coldcocked by lack of one lousy nut or bolt or fitting. From my experience, there's a lot of major engine problems also caused by bad machine work. Here in the USA there's a shortage of good automotive machinists and shops, on account of the decline in automotive engine rebuilding. Make sure that you've got a good machinist, doubt it makes sense to do the work in-house on account of the capital expenditures necessary and lack of return on investment, but depending on where you are, it is worth a look. Make sure you've got a good relationship with all your parts suppliers--if they've been jerked around in the past, you've got to get right with them however they want you to. Can't do things without the help of good parts people. Long enough post--contact me if you want to hear more/more details. Best of luck--Dan White

 

[Majik]

I run a diesel engine rebuilding facility and would be glad to go over any questions you have about what determines a "rebuild" and what is a "fix". I would also go over proper work enviroment and what is considered proper and what isn't. We've been in business for 30 years and have done diesel engine contracts for the army so we've seen times when farmers rebuild engines in the middle of a corn field to extremely tight mil spec rebuilds. Much of what dan white said is true and the decline in machine shops is due to the fact most people haven't upgraded to these new standards of cleanlyness and overhead swallows them whole. There are also other factors including measuring equipment. You can't spec an engine with a harbor freight digitial caliper and some plastigauge (don't get me started on that crap). my email is khengineering at gmail.com if you need to get in touch.