CLEVITE CLINIC

[Music] [Music] [Applause] [Music] like any business automobile repair has its own special problems [Music] and like any business automobile repair has its headaches [Music] but one great blessing it has over other careers only one thing is required to go straight to the top whether it's in a large shop or a small garage that's knowing how to fix that car and fix it well and where the mechanic knows major engine repair a stream of cars will beat a path to this shop no matter where he's located or how he parts his hair working for him are too powerful factors one the world's automobile population is exploding like the human population yet we are only producing a small increase in the number of really skilled career-type master mechanics ones capable of handling major work [Music] this means the advanced mechanic or garage owner who devotes a little time to regular study in Russia finds himself in an increasingly favorable position [Music] [Applause] [Music] [Applause] [Music] at the heart of major engine repair lies the science of bearing replacement which reaches into all systems of the engine therefore many engine repairs either begin or end with bearings bearing replacement is easy if you give it a little study and a lot of care the bearing must take the full power impulse of the engine and save the expensive shaft it's subjected to unbelievable destructive power and it's got to take it without failure because when bearing failure does occur the customers got big problems and sometimes so does the mechanic one customer knows all about it and is ready and willing to tell us which half of which bearing has failed [Music] another not always a woman thinks her engine knocking needs only a couple of turns of a screwdriver and that a bearing is something a sea captain takes with his compass [Music] but the experienced mechanic thinks of worn bearings when he sees and hears three things engine knock excessive oil consumption indicated by smoke or the customers story or low oil pressure once you confirm that the bearings are worn the problem is not to merely replace them we'll get to that later first find out what caused the wear and correct that repeat find out what caused the wear and correct that a little selling involved because if our customer needs bearings he wants to buy bearings only he doesn't know that a failed bearing is only a clue that something else is wrong nor does he know that our first job is a detective job and one of our suspects is himself and his driving habits another is the character and work habits of the last mechanic to work on the car but neither are too hard to track down they leave very explicit fingerprints on the bearings themselves your first move is to read these prints now complete bearing failure destroys the fingerprints and won't reveal its story but adjacent bearings may provide the clue to the cause of failure of this bearing for example this bearing surface reports fatigue and overloading it happens this way extreme operating loads and heat often caused by unwise driving habits such as lugging crack the bearing metal very minutely as he'd and loads continue the cracks drive for the bond line with more loads more heat the cracks change direction just this side of the bond line the small particles of bearing material which now flake off proud the shaft overheat melt disintegration begins take another look at the culprit or rather this one about all you can do to correct this is explain overloading to him and be sure his engine is repaired with high duty bearings next set of fingerprints this one tells of foreign particles on the bearing surface you can see and feel them now the bearing is designed to absorb a certain number of small particles so they won't score the expensive crankshaft but what a great many small particles build up within the bearing metal or particles too large for absorption find their way into the oil clearance trouble occurs under load when the oil clearance normally becomes smaller the bearing with the embedded dirt particles becomes a grinding wheel grinding down the crankshaft but what do you do to correct this well see if the owner is changing oil filters regularly the oil is meant to carry off foreign particles see also that the air filter is cleaned regularly properly seated connected and working properly that in the future the owner uses a careful competent mechanic because those foreign particles could have been left there by the man who ground the valves or hold the cylinder scraps of hard steel or birds the fight against dirt and metal shavings in the closed tolerance parts of the engine is half the battle next case what do these three tell you well this time the culprit is not the owner all three tell you about a mechanic each time he made the same mistake in three different ways improper seating of the bearing take this first one notice the place where the Babbitt's surface has actually flaked off now let's take a look at the back see that spot that means a piece of dirt between the back of the bearing and the seat you lose your roundness of bearing seat and looking at it the other way obviously it's going to pinch the shaft where in one spot on the bearing overheat in one spot melt now the second bearing tells a different story if we turn it over you'll notice it's very shiny on the back why because it's been moving within its bore why did it move here's our answer and the culprit during installation the mechanic saw the bearing projecting above the bearing cap thinking to make a better fit he filed down the parting faces it's easier now but it throws away the whole advantage of bearing crush and makes a loose fit the bearing can spin in its bore that projection was designed for a tight fit when the bearing is assembled next the bearing at the top these fingerprints point to filed bearing caps that mechanic loves the file he wanted less oil clearance this time so he took out his trusty file and effect too much crush result site pinch and you can see where the bearing wear will occur never file bearing caps next case now here are two halves of the same bearing notice how they're worn on opposite sides let's take a few seconds to guess what problem this type of wear points to [Music] connecting-rod misalignment a banter or twisted rod does this you can see the bearing has no chance the same effect would result if the bearing caps had shifted which happens if too large a socket is used to tighten the bearing caps so that it crowds against the cap causing a shift next what caused this type of wear let's take another guess well the correct answer is out of ground bearing seat obviously any new bearing will also quickly conform to this out of round seat creating metal to metal contact and terrific wear in the area of the parting line so you see we've stolen the man's money unless we first correct the bearing seat all right next the fingerprints on this bearing you won't always be able to trace hard to read it's trying to tell you of crankcase distortion caused by alternation of extreme heat and cooling and if you look at them as a group this is the way bearings marked by crankshaft or crankcase distortion will look its best to always check the crankshaft alignment before replacing bearings now here's a common one this bearing is yelling for oil simple but completely fatal check the whole oil flow system to find flood passages oil leaks broken oil pump blocked suction screen or you may find the owner as your problem but don't put in you bearings until you've caught the culprit now what does this bearing say well everyone is to be congratulated just plain normal where the owner and the mechanics have kept this car in top-notch shape for 150,000 miles everything on it but the reputation has worn them so that when it goes it will probably disintegrate all at once into thin air meanwhile check all friction points in the engine because each will have been subjected to the same where as the bearings there we have an introduction to the detective work of bearing replacement now let's see how the theory works out in actual workbench practice believe it or not the most important part of a bearing replacement job is cleanliness over half the failures are from dirt you know the kind of minut tolerances we're talking about they can be wiped out by dirt let's avoid that with clean tools a clean bench everything as clean as possible for example when the oil pan is removed to be clean be careful that the open crankcase isn't subjected to blasts of dust then right at the outset check to see if the oil suction screen needs replacing and before we get too deep into the work let's talk for just a moment about parts identification in some engines the position of parts is identified by steel stamped numbers that appear on the valve or camshaft side of the engine mixed or reversed caps can cause misalignment and excessive bearing where when identification marks cannot be found stabbed or prick punch the parts yourself so they'll be put back in the same position next check the crankshaft for scored out of round or tapered journals when any of these conditions are found the shaft must be reground for best results grind against the engine shaft rotation toward the high tolerance and polish the journals with the shaft rotation to a 20 micro inch finish or better be sure the oil holes are blended into the journal surface if regrinding is not required record the largest diameters of main journals and crank pins this is important it will determine what bearing you select for proper oil clearance after removing any crankshaft oil plugs thoroughly clean all oil passages then check the connecting rods the rod bearing bore and the piston pin pushing bore should be parallel within one thousandth of an inch in six inches of pin length [Music] if rods are not parallel misalignment and bearing failure will result therefore out of parallel rod should be replaced with new or reconditioned ones the rod bore should be round within one thousandth of an inch less roundness than that will reduce oil clearance at the parting line the rod bore finish should be smooth enough to make good bearing contact and transfer heat away from the friction surface check your valve stems and guides heavy carbon below the head can mean worn valve guides if any machining was done in the block clean it meticulously don't forget to remove any chip prevention plugs in the oil holes swab and flush all oil passages [Music] air hose yes but be careful you don't blow dirt in now how to select your replacement bearings if you have a choice lien every time in favor of bearings equal to the quantity of original equipment a special chapter on the important procedure of selecting under sizes is found in the cleveite mechanics engine bearing reference manual compare to see if the old and the new are the same in all respects if not remember there may have been a design improvement check your parts distributor until you're ready keep the bearings clean and don't touch the bearing surfaces if possible so you don't undo your good work so far double check for cleanliness in all your work areas then check your saddle bore finish for nicks and scratches clean and install the main bearings and crankshaft for an alignment check if your shop uses the Prussian blue alignment method be sure to keep the coating of blue ink very very thin to prevent the ink from using auto parts not actually touched and misleading you after torquing down the main bearing caps and rotating the shaft remove the crank in this manner and examine it 75% covered with blue is acceptable 85% is excellent [Music] now check your bearing clearance put plastic gauge the length of the bearing insert or the journal be sure it won't be in the oil hole in the journal be sure the crankcase is upside-down so the weight of the crank won't influence your reading unless you're making a frame overhaul in which case relieve the weight of the crank with a jack measure at the widest point of plastic age and read it here this works equally well on main or rod bearings as long as you have the engine down check the camshaft bearings use a diagonal four gauge for size roundness and taper measure three diameters 120 degrees apart at the front and rear of each bore check York levite manual for tolerances page 64 the cooling system passages are they clean of course the radiator should be checked before disassembling pistons clean them inside and out including the grooves then decide whether they should be used or replaced also check the vacuum booster pump the oil filter air filter and crankcase ventilation before reassembly check all parts for absolute cleanliness inspect all bearing caps and rods for any burrs or nicks that might interfere with bearing seating wipe off all bearing banks crankcase and rod boards and seat of the bearing caps be sure that the oil holes in the bearing register with those in the bearing seat remember do not file bearing party faces for any reason whatsoever the bearings as received are precise and need no further operations what about shins well only if the original manufacturer used shims if so be careful to duplicate exactly the original installation noting whether the manufacturers shim extended over the parting faces or just to them front and rear main bearing oil seals are an important part don't throw away a good job by brushing off this operation a tight or poorly lubricated oil seal has often burned out an otherwise good bearing job be careful not to reverse upper and lower main bearing inserts coat the bearing surfaces and journals with heavy oil but don't get any on the bearing backs [Music] use a torque wrench to draw up the bearing caps and follow faithfully the recommended torque shown in the bearing shop manual use new bolts on the main bearings alternate your wrench from one ball to the other instead of fully torquing one first Wenlock nuts are used get new ones and don't draw them up too tight on end clearances check York Levite mechanics reference manual section 8 to check end clearances pry the crankshaft as far forward as possible and insert feelers between the front flange of the bearing and the mating surface of the crankshaft check both front and rear what if the end play is greater than the book allows use a thrust main bearing with oversized flanges with this bearing you can machine the flange faces to obtain proper and play work toward the lower limit of n play tolerance [Music] double check to see that all the rods main and rod caps did not get accidentally reversed during installation also check your connecting rod and clearance though it should not change [Music] now for a final check on the entire job your oil pressure loss indicator has some advantages though it's only four pressure lubed engines this method checks the oil clearance but it also shows up oil leaks it pre loops the engine before it is turned over on its own power a job well done yes indeed and why not he's a factory trained highly experienced mechanic with a great deal of both theoretical and practical knowledge but what he did here you can do too with a little study a great deal of cleanliness and lots of care and these procedures can pay off for you with more customers and more satisfied customers automobile repair is a pressure business when the customers got troubles he acts as if you had been driving his car he wants it fixed and half the time at half the cost but when you know your stuff the customer somehow knows you know it he doesn't talk he listens he brags about his mechanic like he does his doctor which is why no matter where he's located or how he parts his hair the automotive world will beat a path to the door of the man who's got his Baron [Music] [Applause] [Music]