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Your premier source for information on the Turbo KA: KA24E-T and KA24DE-T (KA with aftermarket turbo kit)!
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mrbean
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Ok, I need a little help defining terms regarding work on the engine block/components. If you can define any of them that would be great. It'd be even greater if you could tell me which ones are really vital, and which are luxuries:

shot-peened?glass-beaded?magnafluxed?hone?hot-tanked?

I've been trying to do research on what exactly is needed for a KA-T project, and there just seems to be too many areas to sink money into, especially when it comes to engine work. Since I'm a complete newb to this area, when these terms get thrown around, I have no sense of the cost and value of each, so any help would be appreciated. Thanks!

Feel free to add any additional terms if I've left anything important out...


RMiller
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They're all luxeries, really. If you want to build a motor with better internals, you can get the block hot tanked, which cleans it. Then you can ask the machine shop if you need the block re-decked, which is where they use a planer to level the top of the block. Then you might ask them if your cylinder walls look good. If not, they may need to be honed, or they may need to be bored to a larger diameter, then honed. Leaving the block alone still offers lots of potential. If your engine has really high mileage or doesn't run properly, a better route to take would be to buy a lower mileage and better running ka, single or twin cam. It is possible to get 400 whp out of the stock dual cam also.

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try askjeves.com that's how i figured out what shot peened was. im sure the rest of the terms are on there also.

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Shot-peening:Crank, Con-rods, and Pistons

The standard equipment these days is of a pretty high quality, and most probably the only part you'll need to change is the pistons (maybe) and perhaps con-rod bolts. The crank is often best left 'as is', with the only modifications really needed are a general cleaning up of casting/forging dags, etc, and a polishing of the bearing surfaces. While it's out of the engine, however, it's often worth looking to see if any weight can be removed safely and to get it shot peened after a careful balancing. By the way, it's a common myth that shot peening increases the strength of a component. Wrong! All it does is give the surface of the component a tough skin and tends to remove any stress points on the surface that could possibly be a crack starter. So - If two identical cranks, with one shot peened and the other not, were revved until they broke, the untreated one would break first, thus giving the illusion of lesser strength than the treated one, when in fact the untreated one simply broke from a unnecessary stress crack, the metal in it being every bit as good as the other treated crank. Perhaps a better view of shot-peening is to think that it stops the crank or whatever from being weak. ;) For really high revs, the counterweights on the crank should be knife-edged to reduce wind drag and drag when the crank hits the sump oil. It's also well worth checking the crank for straightness, though you may get an unpleasant surprise, and have to get the crank straightened. The same process for con-rods, but they must be balanced end-for-end and also made equal weights to each other. The con-rod bolts are much better these days than in past, but if there's any doubt go out and get a set of ARP (or equivalent) rod bolts for your engine. If the correct bolts aren't available, you might consider a set that's got a slightly larger diameter and reaming the con-rods to suit. The important thing with con-rod bolts are snugness of fit, ie, no matter which end the bolt goes through (Some come up through the cap), it must have a slight interference fit (0.0005" or so) and that interference must continue through to the other side of the con-rod so the cap (or main part) fits very accurately on the other half. The head of the bolt must fill the available area as much as possible, and the threaded part of the bolt must only be just long enough to cover the retaining nut. Every time you strip down the engine, replace the bolts - DO NOT REUSE THEM!! (Put them to good use - Give them to someone you want to beat!) Shot peen after balancing, etc

Sourced from Bill Sherwood's Engine page

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fiznat
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magnafluxed?

This is a process to check the integrity of the peices you want to re-use (block, rods, etc). What they do is treat the block with some sort of magnetic process (sorry I'm not sure exactly how it works), and then basically dust the entire thing with tiny metal shavings. What you look for is places where the shavings pile up more than other places. If there is an internal crack or weakness in the block (or whatever), it will attract more metal than anywhere else. What you will have is basically an x-ray of any unseen cracks or weaknesses.

hone?

This is a polishing of the cylinders that is done after boring, Usually when you pay for a block to be bored, honing is included in the cost as a necessary process.

hot-tanked?

Its a bath for your block. To make assembly easier and cleaner, the block can be basically dipped into a hot cleaning solution that will get all the gunk/carbon/oil and crap off of it so you can have fresh surfaces to work with. After this is done a lot of people get the block painted as well.

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Glass-beading (and the importance of proper cleaning)Glass beads are an abrasive media used for fine blast cleaning of parts. If left in your engine they will destroy it through abrasion. It is just like having sand in your eyes. Besides it hurting, if you don’t get it out it will eventually destroy your eye. This too applies to your engine. However just by flushing your engine out when it is together will not remove the glass bead. Over a period of time there has been an increase in premature engine failures due to glass beads being present in the engine. Most of these failures have shown up in rapid wear in piston rings, pistons and cylinder bores, in some cases in less than 200 miles. We will limit the scope of this article to the engine but the same applies to the transmission and primary drive. The photos of the failed parts (piston and rings) have been analyzed to determine what the cause of the failure was. It is easy enough for many people to guess why something failed but by digging deeper and doing analysis one turns up the real facts rather than just ideas or theories. Hastings Rings Company has been kind enough to conduct tests and supply the 2 highly magnified super duper photos of the glass bead and rings for us. The other photos are ones that we have taken of the same parts but not so magnified. During our discussions with Hastings they have mentioned that they are seeing an alarming rate of engine failures (auto engines) due to improper cleaning of glass beads. For most people glass beading is a cheap and inexpensive way to clean internal parts like flywheels, conrods, cams, etc as well as crankcases and cam cover. The problem is in the lack of proper cleaning of parts after glass beading and prior to installation. Most people replace their old parts with new parts so glass beading of surfaces won’t apply however way too many times we see used parts glass beaded and then assembled into an engine. In some cases it is necessary to glass bead some internal parts however it is not necessary just for the sake to remove the oil discoloration and make them “look” pretty. For general cleaning of internal parts(on non glass beaded parts), solvent and good old fashioned hand scrubbing with a stiff brush is best and then a final high pressure clean water blast (garden hose is ok) to rinse away any contaminants left in the solvent. In general it is recommended not to glass bead internal parts and here are a few reasons: 1/ On machined surfaces like, cam and pinion shaft gears, cam shafts, cam bushings, lower end shafts and housings, valve stems, etc, these parts are manufactured with a specific surface finish which is destroyed by glass beading. The worst of it is that the nice polished surface finish has now been destroyed and we have introduced a rough textured surface finish which now acts as an abrasive on each of its mating surfaces. 2/ When glass beading cases with cam bushings, drive and pinion housings, pushrod guides, rod races, etc still installed, the glass beads have plenty of places to lodge itself in and hide out and miss even thorough cleaning. Bushings have flanges on them that the bead can become lodged behind, likewise with the drive housing flange plus it also has an oil hole that glass beads can hide down in and pushrod guide underside area in the cam chest just to name a few spots. Valve ports with valve guides installed will allow glass beads to become lodged between the valve guide and port and enter the combustion chamber. Cylinder head combustion chambers can also hide glass bead in their pores due to their porous castings. If cases or cylinders need to be glass beading, make sure all parts like bushings, housings, cylinder base studs, pushrod guides, etc are removed first. So as you can see there are many places that glass bead can be hiding in. At times it may become necessary to glass bead cases especially the exterior as we all want our cases to look like new. Here are a few ways to minimize the risk of glass bead to inside parts: 1/ Remove exterior parts like cylinder base studs from the cases 2/ Use ductape to mask all the inside areas. After glass beading, give parts a blast off with air and then a blast off with water from the garden hose. Tap out ALL threaded holes. Use dish washing detergent on the tap. This will aid as a lubricant and a cleaning agent. We don’t need a cutting compound as all we are doing is cleaning out an existing thread. After the threading process, pressure blast the hole with the garden hose. Thorough and final cleaning of your parts from glass beads can only be achieved by using very hot soapy water (solvent does absolutely nothing for glass bead cleaning). The most ideal way to handle this is to use the kitchen sink. My wife Carolyn has come to accept this however some of you may want to wait for your Mrs to be out shopping or way out of town. This depends on the consequences if she unexpectedly stops back home and catches you at it. Dish washing liquid (plenty of it) is ideal to use in the hot water. Use a firm scrubbing brush as well as a small hole brush and don’t forget to stick the hole brush down all the threaded holes and twist the brush around. Repeat this process (the cleaning process) several times. Drain all the water out and rinse the parts and sink each time. The final step is to blast each part off with the garden hose with the nozzle on jet stream. We want to blast every little nook, cranny, blind and threaded hole, etc. We know this water is clean so it’s a slam dunk deal. Blow dry parts with compressed air. As a final step paint all inside casting surfaces with an epoxy high heat internal engine paint. This will become your insurance policy. Do not paint gasket surfaces. If you have still not been convinced to remove the bushings and housings, etc, make sure the paint gets between the flanges and the casting as this is where the glass bead will be just hanging out. Once all these steps have been, done don’t leave your nice clean parts out in the open if it will be a while before you get around to assembling them. Wrap them in a nice new clean plastic bag. Of course there are other associated parts that also have to be looked at for cleanliness. It is worthless if you have thoroughly cleaned your engine but not your oil tank, lines, pump, carb, etc.

Sourced from Virtual Indian by Mike Tomas

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Rex
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Magnaflux (brand name)

Benefits Our magnetic particles are designed to hold up better and do not break down during agitation. This avoids having to change the bath as often and insures consistent performance during inspection.

The only requirement from an inspectability standpoint is that the component being inspected must be made of a ferromagnetic material such iron, nickel or cobalt, or some of their alloys. Ferromagnetic materials are materials that can be magnetized to a level that will allow the inspection to be effective.

The MAGNAGLO product line is our fluorescent (requires a black light) wet method magnetic particle materials used in Magnetic Particle Inspection to locate surface and subsurface flaws in ferrous parts.

The MAGNAFLUX product line is our dry method, non-fluorescent magnetic particles materials used in Magnetic Particle Inspection to detect surface and subsurface flaws in ferrous parts.

Sourced from Magnaflux's web site

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Balance & Blueprint (this is from an MG/Austin-Healey/Triumph site)

Ten Reasons to Blueprint and Balance Your Engine

While a rebuilt engine may be within factory tolerances and cost less, a blueprinted engine will actually perform better and last up to twice as long. The difference is that while the factory gave an allowable range of clearances in the factory manual, it actually manufactured all of its engines using the same clearance for each similar component with a minimal tolerance of two tenths of a thousandth of an inch. A blueprinted engine duplicates the clearances and tolerances the factory used. In other words, a blueprinted engine reduces the potential tolerance buildup of a rebuilt engine to two ten thousandths of an inch. How is this done? Read on.

1. CRANKSHAFT

The reconditioning of the crankshaft is the most critical part on an engine overhaul. First, the crankshaft is inspected for wear on both the bearing journals and the thrust faces. Next, it is magnafluxed for cracks which may render it useless. Cracks are more likely to occur in long-stroke three or four-main bearing engines (such as Spitfire, Midget 1500, MGA and early MGB, TR-3 & 4, TR-250, and TR-6) which consistently use high rpms. When the crank is reground, the factory normally allows a tolerance of up to .001" for the bearing journal diameters. Thus, the rod journal diameters could be different by as much as .001", likewise the main journals. This causes great variation in the bearing clearances and causes premature bearing failure. In a blueprinted engine, the desired tolerance is specified to a reputable crankshaft grinder ensuring that all rod journal diameters are within .002" and all the mains are within .0002". While the welding of a thrust face is acceptable, it is not recommended that a bearing journal be welded in order to bring it up to size. Since the weld is usually a harder material than the crankshaft, it may develop surface cracks during severe temperature cycles, eliminating all bearing clearance and causing catastrophic bearing failure.

2. CONNECTING RODS

In a blueprinted engine, the rods are magnafluxed and checked for straightness. Floating wrist pin rods are then rebushed and sized to each individual wrist pin within a narrow tolerance to eliminate wrist pin knock and increase life. Unlike V-8 engines, which normally operate below 3000 rpm, the smaller engines are usually revved higher which produces higher stresses. As a result, the big-ends of the rods actually stretch to an out-of-round condition which must be reconditioned to prevent failure. Since bearings from different manufacturers differ in shell thickness, the bearings to be used in the engine are assembled in the rods, and the rod bolts are retorqued. The inside diameter is measured with a highly accurate micrometer and the bearing clearance to the crankshaft is determined. Next, the rods are reassembled without the bearing shells and the inside diameter is measured. Finally, the inside diameter required for the desired bearing clearance is what each rod is reconditioned to. Large clearances will result in low oil pressure and premature bearing failure while tight clearances can cause catastrophic failures. "Plastigage" is never used because of its inherent inaccuracy due to age, bolt torque, and difficulty of precise measurement. After rechecking bearing clearances, the rod bolts are replaced during final assembly.If the rod big-ends are reconditioned in a rebuilt engine, they are usually done without regard for the reground crankshaft dimensions and have a relatively large factory tolerance. This tolerance buildup can result in grossly inaccurate bearing clearances.

3. CAMSHAFT

In blueprinted engines the camshafts are reground to either stock specifications or a grind with a slightly higher lift which improves midrange performance without sacrificing idle. All lifters (tappets) are replaced and cam bearings are replaced and resized in engines so equipped. Block cam journals are measured in engines without bearings and are modified to accept bearings if necessary.

4. ENGINE BLOCK

In all blueprinted engines, the block is completely stripped and boiled out, oil gallery plugs replaced, core plugs replaced, and head gasket surface checked for flatness and milled if necessary. Since the main journals in the block stretch the same way the rods do, due to age or high stresses, the main journals are reconditioned (line honed) using the same methods used to determine the correct rod big-end diameters.

5. PISTONS AND BORES

One of the most common fallacies among engine rebuilders is that pistons with 60,000 miles on them can be reused in small, highly stressed engines. As an engine wears, a taper is worn into each cylinder by the rings in addition to the skirts of the pistons being worn. This taper causes ring failure, piston wear in the ring lands (grooves), and accelerates wear on the cylinder walls. Another result is excessive piston-to-cylinder wall clearance which causes piston slap and excessive blowby. Unless the block is bored out to fit new oversize pistons, a rebuilt engine could start burning oil with 500 miles of use. In all blueprinted engines, the pistons and wrist pins are replaced with new, original equipment, "oversized" pistons. The pistons are zygloed (magnafluxing for aluminum) and the cylinders are bored and honed to provide the proper clearance for each individual piston. The new rings are then fitted to each piston and cylinder for proper gap. Thus, the block tapers are removed, and the piston-to-wall clearance is reduced to the original factory dimension allowing maximum mileage to be obtained from the blueprinted engine.

6. CYLINDER HEAD

The cylinder head in each blueprinted engine is boiled out, magnafluxed, checked for flatness and milled if necessary, and has all the valve guides replaced. Valves are replaced as necessary and the guides are resized to the valves. Valve springs are checked for correct tension. If a head is cracked in a critical area where it cannot be repaired, it is replaced. If a head is cracked in the valve seats, sometimes the crack can be eliminated by replacing the affected valve seats. In any case, the valve seats are inspected and replaced with steel seats if necessary. Another common fallacy is that stellite valve seats are necessary for use with unleaded gas. Think of it this way: your engine has run for the last 17+ years on unleaded fuel with cast iron or steel seats, even the late Spitfires and MGBs which were designed to run on unleaded fuel. Steel seats are far stronger than cast iron but much less expensive and damaging than stellite, which are much harder than steel seats and accelerate wear on the valve face. Stellite seats were developed by the automotive industry so they could increase efficiency and gas mileage of their engines by running them at designed temperatures of 205-215 degrees F. If your British engine is run that hot for long, worn valve seats will be the least of your problems. The primary problem with unleaded gas in British engines is the lack of octane which can be compensated for by lowering the compression ratio or retarding the ignition timing by a few degrees.

7. ROCKER ASSEMBLY

Each rocker in a blueprinted engine is reconditioned and fitted to a new rocker shaft to insure accurate valve clearances.

8. DISTRIBUTOR

The distributor in a blueprinted engine is complete disassembled, cleaned, and the mechanical advance curve is checked. Points, condensors, and pickup wires are renewed if applicable. In addition, vacuum advance or retard units are checked to be fully functional or replaced.

9. FINAL ASSEMBLY

Two primary rules to follow in final assembly are "Cleanliness is next to Godliness" and "Pay close attention to detail". All parts are spotlessly cleaned and all threads are "retapped or died". Oil pumps are replaced with new original pumps or high capacity pumps, if available. Timing chains, tensioners, seals, and gaskets are replaced and thoroughly sealed. Marginally worn parts such as crank pulley seal surfaces and timing gears are reconditioned or replaced. New hardware is used as much as possible and the engine is painted the original color or semi-gloss black, whichever the customer prefers.

10. BALANCING

Balancing, which can enhance performance, is an option on blueprinted engines . The rotating mass, including the crank pulley, timing gear, crankshaft, flywheel, and clutch pressure plate, are balanced dynamically. The piston and pin assemblies are statically balanced within a tolerance of 0.2 gram, and the connecting rods are balanced end-for-end to the same tolerance. This means that all the small ends weigh the same and all the big ends weigh the same. It is highly recommended that balancing be performed because the reconditioning process removes varied amounts of metal from each part, thus changing the balance. Also, since the factory tolerances are in the magnitude of 10 grams, your engine will run smoother, longer, and rev higher than when it was new from the factory if it is balanced to tighter tolerances.

Sourced from Bob's Foreign Auto Service Web Page

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Cylinder Honing

The Smooth Science of Cylinder Honing

The basics of honing cylinder blocks hasn’t changed much in recent years, but what has changed are the type of abrasives being used by many engine builders.

Silicon carbide and aluminum oxide honing stones of various grits have long been used in power honing machines and portable hones to finish cylinder bores. These types of abrasives are popular with engine builders because of their flexibility and low cost.

But in recent years, a growing number of performance engine builders and custom engine builders have started using the same type of honing stones that production engine rebuilders and OEMs use: diamond abrasives.

Conventional vitrified abrasives cut cleanly and do an excellent job of finishing cylinders – provided the right honing procedure is used to achieve a bore finish that meets OEM specs or the ring manufacturer’s requirements. But as the stones work the surface, they experience a lot of wear. In fact, the stones wear almost as much as the metal surface in the bore. Consequently, the honing machine operator has to constantly monitor the honing process and compensate for stone wear to keep the bores round and straight.

Tim Mera of Sunnen Products Co. in St. Louis, MO, says conventional abrasives require a balance between cutting action and stone life. As a rule, harder metals require softer stones. A softer stone requires less honing pressure, produces less heat and causes less bore distortion. So the bond that’s used in conventional abrasives is designed to wear quickly and expose the abrasives for good cutting action.

OEMs and production engine builders, on the other hand, don’t have the luxury of being able to baby-sit their honing equipment. Because of their higher production volumes, OEMs and PERs have to run their honing operations at higher speeds and with less operator supervision – which means diamond honing stones in most cases.

Diamond has long been the material of choice for high speed, high volume honing applications because of its excellent wear characteristics. Stone life depends on the hardness of the abrasive, the hardness of the substrate that holds the abrasives, the hardness of the engine block, honing speed, load and the amount of metal that’s removed. Diamond is the hardest natural substance known, so it can hold a cutting edge much longer than a conventional abrasive. This means the bond that holds the diamonds can also be harder because it doesn’t have to wear away as quickly to expose fresh stones on the surface.

Typically, a set of conventional vitrified honing stones might do up to 30 V8 blocks (240 to 260 cylinder bores) before they’re worn out and have to be replaced. A set of metal bond diamond honing stones, on the other hand, might do as many as 1500 V8 engine blocks (12,000 cylinder bores) before they have to be replaced. That’s a huge difference.

However, diamonds require a sizable up-front investment. A set of stones can cost $600 to $700 – which is a big jump from $15 to $35 for a set of conventional honing stones. Consequently, many small custom engine builders say diamonds are too expensive for their purposes. They also say they can’t afford to buy several sets of diamond stones to cover all the different bore sizes they do.

Even so, when the longer life of diamond stones is compared to that of conventional abrasives, diamonds may be more economical in the long run, even for a small shop (assuming an operator doesn’t overstroke a bore and break a stone!).

Pim van den Bergh of K-Line Industries, Holland, MI, says he sees more and more shops switching to diamond for a variety of reasons. "We were one of the first to offer diamond for honing machines because we saw its many advantages." He says it gives very consistent results with minimal stone wear.

Pros & Cons Of DiamondsBecause diamond is a harder material and wears more slowly than conventional abrasives, it cuts differently and requires more pressure. Diamond tends to plow through a metal surface rather than cut through it. This can generate heat and distortion in the cylinder bore if the wrong type of equipment, pressure settings or lubrication is used in the honing process. When done correctly, though, it can actually improve bore geometry by producing a rounder, straighter hole.

Diamond is also good for rough honing cylinders to oversize because it can remove a lot of metal fast. But finishing requires at least a two-step procedure. Otherwise, the surface will be too rough.

If you’re switching from conventional stones to diamond, you’ll generally have to use a higher grit to achieve the same Ra (roughness average) when finishing a cylinder. For example, if you have been using #220 grit conventional stones to finish cylinders for chrome rings, the equivalent diamond stones might be a #325 grit. If you have been using #280 grit conventional stones to hone for moly rings, the diamond equivalent might be #550 grit stones. The actual numbers will vary somewhat depending on the brand and grade of the stones.

A cylinder bore must have a certain amount of cross hatch and valley depth to retain oil. However, it must also provide a relatively flat surface area to support the piston rings. Ring manufacturers typically specify a surface finish of at least 28 to 35 Ra for chrome rings, and 16 to 25 Ra for moly faced rings. These numbers can be easily obtained with diamond stones and brushing, say those who use this honing technique.

One rebuilder we spoke to says he uses #325 grit diamond stones to end up with an Ra finish in the 20 to 25 range, which he feels is about right for moly rings. For some applications, though, he uses a #500 grit diamond to achieve a smoother finish in the 15 to 20 Ra range.

Final FinishSomething else that’s different when honing with diamond is what diamond does to the bore surface. Diamond tends to leave a lot of torn and folded metal on the surface, causing sort of a smeared appearance that doesn’t make a very good bore finish. Consequently, finishing the cylinder requires a second step to remove the damaged material.

One way to get rid of this material is to plateau the surface with a fine grit conventional abrasive (like a #400 or #600 grit stone). All that’s needed are a few strokes to shave off the tops of the peaks. But, the most popular method for finishing the bores when using diamond stones is to sweep the bores with a flexible brush or a nylon bristle plateau-honing tool. Brushing helps remove the torn and folded debris while improving the overall surface finish.

Chris Jensen of Goodson Tools & Supplies in Winona, MN, says, "there’s a lot of confusion about how to finish cylinder bores when using diamond. Since diamond leaves a lot of folded and torn metal on the surface, the bores need to be brushed to remove the debris. Many different names are given to the same tool and process. Some call it a plateau hone, a soft hone, a whisker hone or an ultra-fine hone. But they all do the same thing: they sweep across the surface to remove jagged peaks, folded and torn material."

Bristle style soft hones consist of mono-filament strands that are extrude-molded with a fine abrasive material embedded in the strands. The filaments can be mounted in different types of holders or brushes that can be used with portable or automatic honing equipment.

When finishing the cylinders with a brush, only light pressure is required. The rpm of the brush should be similar to that which the cylinder was originally honed, and no more than 16 to 18 strokes should be applied (some say 8 to 10 strokes are about right). Too many strokes with a brush may produce too smooth a finish that doesn’t hold oil.

Reversing the direction of rotation while brushing helps to remove the unwanted material on the surface. The end result should be a cylinder that provides immediate ring seal with little if any wear on the cylinder wall or rings when the engine is first started.

Sunnen’s Mera says, "brushing the bore after honing makes a huge improvement in the surface finish, whether diamonds or conventional honing stones were used to hone the bore. You can get the overall Ra down to 8 to 12, with RPK (relative peak height) numbers in the 5 to 15 range, and RVK (relative valley depth) numbers in the 15 to 30 range."

Equipment RequirementsSomething else to keep in mind about diamond is that it works best in power honing equipment that has been designed to take maximum advantage of diamond’s honing properties. There are a number of companies that make diamond honing heads for use with various honing machines: Rottler, K-Line, Kwik-Way, Peterson, Winona Van Norman, Sunnen and others. But because of the increased loads, diamond may overtax some older power honing machines and increase the risk of stripped gears. It may be better to buy a new honing machine that has more horsepower and rigidity to handle diamonds.

"Most of our customers who hone with diamonds use a CK21 machine," says Sunnen’s Mera.

As for portable honing equipment, conventional abrasives are the better choice for this type of application. Most of those we spoke with say diamonds require too much pressure for portable honing equipment.

Another difference with diamond is the type of lubricant that’s required. A synthetic water-based lubricant is usually recommended instead of honing oil.

K-Line’s van den Bergh says, "water-based lubricants are easier and cheaper to dispose of than oil-based lubricants because they can be evaporated down to reduce their bulk. On the other hand, they occasionally require make-up water and have to be monitored to prevent bacterial growth.

"The type of lubricant you choose is very important because it can make quite a difference in honing performance. With conventional abrasives, you want a good quality honing oil. A lot of people run into honing problems because they’ve diluted their honing oil or tried to use something else like diesel oil or kerosene," says van den Bergh.

Anthony Usher of Rottler Mfg. in Kent, WA, says the OEMs all use long-lasting superabrasives with metal bonded honing stones. But the equipment and controls they use are very expensive, which makes it difficult to bring the same technology into a typical aftermarket job shop.

"About 12 years ago, we decided to change that. If new engines are originally honed with diamonds, why can’t we develop the same technology? So we set about developing honing equipment, controls and stones that would put the same technology into the hands of a job shop," says Usher.

"Diamonds last a long, long time. Because the stones don’t wear away, you can control the size of the bore more accurately," Usher explains. "This allowed us to build an automatic control system that allows us to size bores exactly the same every time."

Usher says for under $30,000, a job shop can buy a diamond honing machine that substantially reduces running costs and gives better results.

"The HP6A power stroking automatic honing machine is our newest product. It runs with diamond abrasives and has a programmable load control for both rough honing and finish honing. When it is finishing the cylinder, it automatically reduces the load because some cylinders have very thin areas that may distort if the load isn’t changed. The HP6A has a base price of $23,900 and a fully equipped unit goes for $28,000 to $35,000."

Plateau Finish Is BestRegardless of what type of honing equipment or abrasives are used to finish cylinder bores, more and more shops are finding a plateau finish provides the ultimate finish.

A plateau finish is one that closely resembles a broken-in cylinder bore. When the bore is honed, the surface of the metal will have microscopic peaks and valleys. Peaks don’t provide much ring support, so as soon as the engine is started the piston rings start to scrub up and down and shear off the tallest peaks. As the engine continues to run, the peaks will be gradually shaved down until the cylinder bores are relatively smooth and flat (except for the valleys in the crosshatch that must be there to hold oil).

The normal engine break-in procedure will eventually produce a plateau finish anyway. But until it does, the rings and cylinders will experience unnecessary wear and the engine will experience increased blowby, oil consumption and emissions until the rings have seated – which might take several hundred or even several thousand miles to complete.

A better approach is to precondition the bore surface so the rings don’t have to "hone" the cylinders. A plateau finish will provide maximum compression right from the start, and eliminate most ring seating and sealing problems.

One recipe for achieving a plateau finish is to bore or hone to within .003½ of final size. Then finish to final dimensions with a #220 or #280 grit conventional abrasive and follow up with half a dozen strokes of a #600 grit stone, cork, or a flexible brush or nylon bristle plateau honing tool.

If diamond stones are used, bore or rough hone to within .005½ of final size. Then hone the cylinder to final dimensions with #325 to #500 grit diamonds, followed by six to eight strokes with a flexible brush or plateau honing tool. Many experts recommend leaving a little extra metal in the bore for final finishing if diamonds have been used to rough hone the cylinder. This is because rough honing with diamond leaves a very rough finish (over 100 RA depending on the grit of stone used).

Honing Hard MaterialsIn recent years, Nikasil coatings have provided a challenge for engine builders. Nikasil is a hard coating of nickel and silicon carbide about .0025½ to .003½ thick that is applied to cylinder bores to improve wear resistance. Invented by the German firm Mahle, Nikasil was originally developed for the Mercedes Wankel rotary engine. It has been used by BMW and Porsche in some of their engines, and is also used in many chain saw engines, some motorcycle and marine engines, and even many NASCAR Winston Cup engines.

Goodson’s Jensen says PERs have had success honing Nikasil treated cylinders with diamond. But for smaller shops that have only portable honing equipment, you can’t exert enough pressure with diamond to hone Nikasil. The best advice here is to use #220 silicone carbine and just do a couple of strokes to deglaze the cylinder. If a cylinder has to be bored to oversize, cut it out with a boring bar and then hone in the usual manner to achieve the desired dimensions and finish.

Ed Kiebler of Winona Van Norman in Wichita, KS, says new harder coatings on cylinder walls are forcing shops to change to diamond honing and to upgrade their equipment.

"I see a lot of shops who are interested in diamond but who don’t fully realize what’s involved in the diamond honing process. Diamond takes a lot of pressure to cut. Some people use diamond on portable hones, but realistically you can’t get enough pressure to make the diamonds perform well. Having said that, I truly believe the new harder cylinder coating materials are going to force people to go to diamonds," says Kiebler.

"The two-cycle stuff is all Nikasil. Now the outboard engines are going to Nikasil, too. All the NASCAR Winston Cup shops are using Nikasil cylinders. If it’s good for NASCAR, it’s not going to be long before you start seeing it in OEM engines," Kiebler explains. "The time is coming when you’re going to have to use diamonds if you’re going to hone Nikasil cylinders."

Kiebler says all most shops do is slightly roughen Nikasil cylinders. "You don’t really remove much material. The Winston Cup shops are running some of these motors five races before they redo the cylinders. The Nikasil coating really extends ring life and cuts down on ring wear."

OEM TRENDSDave Riley of Gehring L.P. in Farmington Hills, MI, a supplier of honing equipment to original equipment manufacturers, says almost all OEM internal combustion gasoline engines in North America today are being rough honed with diamond abrasives.

Riley says the OEM focus is on using water soluble synthetic honing coolants, which means diamond abrasives because vitrified conventional abrasives require honing oil. The other industry trend he sees is that cylinder bores are being respecified to smoother finishes.

"We’re talking 0.15 to 0.3 Ra finishes that are extremely smooth," says Riley. "They’re doing this to further reduce emissions. A lot of this is being driven by ring technology because rings can now survive in conditions that provide much less oil. However, in my opinion these new surface finish specifications are reaching the limits of technology."

One of the things that the OEMs do to achieve high quality bore finishes is to use computer numerically controlled (CNC) honing machines. The cutting speeds of these machines are 50 to 75 percent faster than what was used 10 years ago. Faster cutting speeds allows the abrasives to cut smoother, and finer abrasives can be used for a smoother finish without sacrificing cycle time.

Riley says there’s a dramatic difference in the amount of time the OEMs allow to hone a cylinder versus what a typical aftermarket engine builder or production engine rebuilder spends on the same process. He says OEMs typically spend only about 15 to 20 seconds to hone a bore with automated honing equipment. By comparison, it can take up to several minutes to manually hone a bore using a power honing machine.

"The OEM machines are completely automated and automatically control bore size and shape. They also measure and inspect 100 percent of the bores, and can sort by bore size if they run bore grades," he says.

"As the need to reproduce OEM finishes in the aftermarket grows, so too will the demand for honing equipment that can meet these specifications. This will obviously have an impact on honing costs," Riley explains. "We are developing a low cost, CNC-controlled single spindle honing machine for the aftermarket. The operator would load the block and the machine would automatically hone the bores to OEM tolerances."

Riley says Gehring also offers custom honing services for low volume engine prototype development and performance engines.

Cylinder bore quality plays a huge role in reducing friction and blowby for improved engine performance and durability. Better bore geometry also contributes to better sealing and more usable power. Riley says a lot of performance engine builders are hot honing their blocks to more accurately simulate actual running conditions. They also use torque plates when honing (some with simulated manifolds to further stress the block), and may even bolt a bellhousing to the block to reproduce the stresses and loads the block will experience in a vehicle.

"For OEM production applications, we have developed clamping and other methods to stress the block while it is being honed," says Riley. This is done to further improve bore geometry and sealing.

Aluminum Engines SoonRiley says another OEM trend is the development of future engines that use various types of bore surface coatings in aluminum blocks. The coatings are sprayed-on powder metal or steel wire alloys that create the surface characteristics of a traditional iron bore.

"Last year, about 15 percent of the prototype engines we saw had some type of coated aluminum bores. This year, the percentage is up to 67 percent. So there has been a dramatic shift toward aluminum blocks with coated bores."

Coated aluminum bores have a number of advantages, one of which is better thermal conductivity between the cylinders and water jacket. Another is less heat distortion for better sealing. The coating provides wear resistance and allows the use of larger bores within a given block size for more total displacement.

Riley says the OEMs are currently acid etching the bores to finish them. But acid is environmentally unfriendly so the OEMs are developing alternative ways to finish coated aluminum bores that do not require acid etching. Diamond honing is used for roughing, but the finishing step is being done with nonmetallic bonded abrasives such as vitrified abrasives, rubber or brushes. The goal is to come up with a process that will work using water-based honing fluid.

How will the aftermarket refinish coated bores in aluminum engines? Riley says the most likely approach will be to hone away the original bore finish, then reapply the surface coating and refinish it back to OEM specifications.

Laser StructuringA number of years ago, Gehring developed a unique process called "laser structuring" to enhance engine durability. The process uses a laser to burn small pits into areas of the cylinder bore surface where ring loading and wear are highest. The pits improve oil retention and ring lubrication, and significantly reduces ring and bore wear.

Riley says the new laser structuring process is now being used in Europe on diesel engines. "At 150,000 kilometers, the bores are showing almost no measurable wear (only 1 to 2 microns) and the emissions performance is the same as new," he says.

Riley says the laser structuring process can be used to create almost any kind of pattern imaginable in the bore surface. Typically, a series of dots or dashes 25 to 60 microns deep and 40 microns wide are burned into the top third of the cylinder by the laser after the bore has been semi-finished. A final honing step is then done using fine stones to remove any buildup of material around the pits and to finish the bore.

The laser part of the process takes about 9 to 15 seconds per cylinder and uses a special machine that rotates and lowers the laser beam as it is projected onto the surface of each cylinder.

Riley says the laser structuring process is ideal for hard blocks or those with special surface coatings that make them difficult to finish with conventional honing techniques. "It’s a perfect application for high performance, diesel and aircraft engines," he says.

Remember To Clean The BoresAs we wrap up this article on honing abrasives, one final point to remember is the importance of cleaning the bores after honing. Honing leaves a lot of metallic and abrasive debris in the bores – which must be removed before the engine is assembled. Washing and scrubbing with warm soapy water will remove most of the loose debris. Some engine builders follow up by wiping out the cylinders with automatic transmission fluid. The point is get the cylinders clean so there are no contaminants to damage the rings or to get into the oil.

Sourced from Larry Carley

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fiznat
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damn. I've been totally outdone!

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Rex
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Once people have read through the above and validated it's accuracy, someone (cough Nick, Article manager) should build an article/sticky using those. I can get the rest (assuming I missed something) later.

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mrbean
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Wow, That's awesome, guys! Thanks everyone. I feel like I've been in a class...

This really should be a sticky :)

nab911
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Im just gonna do a home self Hone, polish what i can with sandpaper and throw it all together and see how high it revs ;)

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TrunkMonkey
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Rex wrote:Once people have read through the above and validated it's accuracy, someone (cough Nick, Article manager) should build an article/sticky using those. I can get the rest (assuming I missed something) later.
i only scanned it, but for the most part everything looks good. i did notice a couple of things i don't agree with, but i've learned that when it comes to engine building, lots of "fact" is is more or less personal preference.

just in case this does get archived, make sure you give credit to whoever you stole this info from ;) .

-demetrius

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Rex
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demcj wrote: ... just in case this does get archived, make sure you give credit to whoever you stole this info from ;) .

-demetrius


I've added links to the sources and references to them as well at the bottom of each post.

SloS13
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what about scattered, smothered, covered, chunked and diced?


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