Are engine parts such as valves and other valvetrain parts, bearings, pistons, rings, cams and lifters called "hard parts" because they are harder to sell than other parts? Well, lately, maybe.
Engine hard parts are slower moving parts than many other items such as filters, ignition parts, gaskets, belts, hoses, water pumps, fuel pumps, alternators and so on. Because of this, many parts stores don’t even stock engine hard parts and rely on their warehouses to provide these parts when a customer needs a set of bearings, rings or pistons. Parts for the more popular applications, such as Chevy and Ford, are usually available, but parts for less-common engines may have to be shipped in from a regional or national warehouse – and sometimes that can take days. And what if an engine is considered obsolete? Then the only source of supply may be a specialty warehouse that deals in older stock or custom-made components.
Engine hard parts do require a higher level of product knowledge to accurately identify applications and to look up the right parts for a particular engine. So with that in mind, let’s look at some of the things you need to know to sell these kind of parts.
When a customer needs engine parts, chances are he needs a lot of parts. In many instances, the parts are being replaced because an engine is being rebuilt or overhauled. If it needs bearings, chances are it also needs rings too – and maybe pistons, valve guides, valve springs, a new timing chain and gear set, a new oil pump, maybe a camshaft, lifters and pushrods. If the engine has "torque-to-yield" head bolts, your customer will need to replace those, too. Also needed will be new gaskets as well as filters, oil, antifreeze, spark plugs, maybe some belts and hoses, a new oxygen sensor (recommended for high-mileage engines) and maybe even motor mounts. It’s a laundry list of sales opportunities that shouldn’t be overlooked.
If the cylinders in the engine are worn and have to be bored to oversize, the engine will need new oversized pistons and rings. This will raise compression somewhat, which may require installing a thicker head gasket to maintain the original compression ratio. Resurfacing the head or block will also raise compression. When compression goes up, so does the risk of engine-damaging spark knock (detonation). The knock sensor in most late-model engines can compensate for this by retarding ignition timing a few degrees if the engine starts to ping. But retarding the timing hurts fuel economy and performance. The only other alternative is to burn more expensive high-octane premium gasoline. Considering how expensive gasoline is these days, it’s cheaper to maintain the engine’s original compression ratio by installing a thicker head gasket or even a head gasket shim in conjunction with a stock head gasket (this can also save the cost of having to replace an overhead cam cylinder head if the head has to be milled to restore flatness).
Kits are a convenient way to provide most of the commonly replaced engine hard parts in one box under one part number. It takes much of the guesswork out of looking up and matching parts for a particular engine. Once you’ve identified the year, make, model and engine (which often requires the engine code and/or VIN number), you only have to look up a single number for the kit.
Kits are like a fast food menu. The most popular applications and parts combinations are offered as single numbers to save time and effort – which makes selling engine hard parts a lot easier. It also makes it easier to get all the parts because the kit is packaged by a single supplier (though they may use a variety of brand name parts within the kit). Dealing with a single supplier also makes it easier to resolve any warranty issues that may arise later.
Installers like engine kits because the kit includes everything they need in one box – including some of the "small stuff" they may have forgotten about or might have overlooked.
Kits may even save your customer money if the kit price is less than the sum of the individual parts (which it typically is).
TYPES OF KITS
Kits are packaged to cover various types of repairs:
Master kits include most of the commonly replaced parts for doing a complete overhaul such as pistons and rings, rod & main bearings, camshaft, lifters, timing chain and gears, oil pump, oil plugs, freeze plugs, gaskets and seals. Pistons and rings are usually available in up to 0.060 oversizes, and bearings in up to 0.030 undersizes. A choice of ring types (plain, chrome or moly) may also be offered.
Re-ring kits include rings, rod bearings and gaskets.
Block kits contain new piston rings, cam bearings and gaskets (with a choice of ring sizes and types).
Cam and lifter kits with a new standard camshaft and lifters. Some contain cam and lifters only. Others also include a timing chain and gear set and/or gaskets.
Short block kits, which contains a new oil pump, head and pan gasket set, camshaft and valve lifters.
Performance engine kits that have high-performance versions of most of the same parts included in a master kit (higher compression or hypereutectic or forged pistons, premium rings, premium bearings, hotter cam, stiffer valve springs, etc.).
Choosing the right kit involves talking with your customers to find out what they really need and want. If they’re doing a complete overhaul, a master kit would be the best choice. You’ll also have to determine if the cylinders are worn and are being being bored to oversize, and if the crankshaft journals are stock sized or undersized. Once you’re nailed down the particulars, you can specify the correct kit.
WHICH PARTS WEAR OUT AND WHY
The most wear-prone parts in an engine are probably the valve guides, followed by the rings, bearings, oil pump, camshaft and lifters. A lot depends on how well the engine has been maintained, the operating environment and how it has been used (or abused).
Worn valve guides is the number-one cause of increased oil consumption in high mileage engines. The intake guides are exposed to vacuum every time the intake valve opens, so if the guides are worn oil will suck through the guides into the combustion chamber. Here, the oil can foul spark plugs and form carbon deposits that increase compression and increase the risk of detonation and preignition.
Worn valve guides in aluminum cylinder heads and some cast-iron heads can be pressed out and replaced with new ones. Other repair options including reaming the worn valve guides to oversize and installing new valves with oversized valve stems, or reaming and sleeving the worn guides with bronze liners to restore proper valve guide to valve stem clearances.
Worn rings and cylinders can increase oil burning, too. Cylinders wear most at the top because that’s where the loads are the highest. Ring wear is inevitable as the miles add up, but can also occur when dirt gets past the air filter. When the rings lose their ability to seal, combustion gases blowby into the crankcase and dilute the oil. Over time, this can accelerate bearing wear and lead to premature bearing failure.
Bearing wear also adds up with mileage, but can be greatly accelerated by poor maintenance (not changing the oil often enough) or by contaminants that enter the crankcase (dirt, unburned fuel or coolant). As bearing clearances increase, oil pressure drops. This increases the risk of metal-to-metal contact, especially when the engine is working hard under load and eventually results in bearing fatigue or scuffing and failure.
Bearings are cooled primarily by oil flow between the bearing and journal. Anything that disrupts or reduces the flow of oil not only raises bearing temperatures but also increases the risk of scoring or wiping the bearing. Conditions that can reduce oil flow and cause the bearings to run hot include a worn oil pump, restricted oil pickup screen, internal oil leaks, a low oil level in the crankcase or aerated oil (oil level too high).
Dilution of the oil with raw fuel (from piston blowby or an overly rich fuel condition) can break down the lubricant and cause the bearings to fail. Oil contamination by antifreeze is another problem that can wipe out a set of bearings. Antifreeze can enter the crankcase through a leaky head gasket, a poor seal between the head and block (usually the result of undetected head or deck warpage, improper head resurfacing, loss of head bolt torque or a poor head gasket seal), or through cracks in the head or block water jackets.
Pistons typically suffer the most wear on their sides, and can be scuffed or seize if the engine overheats. Piston slap is a classic symptom of too much clearance between the pistons and cylinder bores. Piston slap is most audible when a cold engine is first started because clearances are greatest then.
Pistons can also be damaged by detonation and preignition. Detonation can crack ring lands while preignition creates hot spots that can literally burn a hole right through the top of a piston. Common causes of detonation and/or preignition include a lean fuel mixture (dirty injectors or an air leak), overadvanced ignition timing, a buildup of carbon deposits in the combustion chamber (from worn valve guides and/or rings) and cooling problems.
Camshafts wear out too, and experience the most wear on their lobes. The pressure on the lobes is extremely high, especially with flat bottom lifters, and can wear down lobes if the oil is in poor condition or oil pressure is lost. A rounded cam lobe will cause a loss of compression, misfire and loss of power.
Valve springs are another item that weaken with accumulated mileage and should be replaced. Heat and constant flexing cause the springs to lose tension over time. Weak valve springs can allow the valves to float or bounce at high RPM, causing the engine to misfire or worse. If the valve springs can’t keep up with the RPMs, a valve may hit a piston. Or, a spring may break causing a loss of compression and a steady miss. New valve springs should always be recommended when an engine is being overhauled or given a valve job. New valve springs are also recommended if the cam and lifters are being replaced. Stronger valve springs (and pushrods) are usually required with performance cams.
Exhaust valves are another item that usually need to be replaced in high mileage engines. Exhaust valves run hundreds of degrees hotter than intake valves, and consequently suffer the most wear. If a valve gets too hot, it may "burn" and lose its ability to seal the combustion chamber. This can result in a compression leak, misfire, loss of performance and power, and a huge increase in emissions. Most engine builders will automatically replace all of the exhaust valves when overhauling an engine or giving it a valve job.
In engines with aluminum heads, the valve seats are inserts rather than part of the head. If worn, cracked or loose, the seats will have to be replaced. A damaged integral valve seat in a cast iron head can often be machined out and replaced with a seat insert to save the head.
Engine hard parts are not hard to sell if you know how to sell them, and what to sell. The only hard part is making the most of the sales opportunity so your customer gets everything he needs – including the soft parts that go with the hard parts.