Dave's "Blah, Blah Blog"

By David P. Monyhan, ASE-Certified Cylinder Head Specialist
As seen in Engine Builder, March 2004

This article is not here to teach you how to properly hone a cylinder bore. It is here to keep you informed on how to maintain your honing machine so when you do hone your machine is ready to hone and not moan!

Let’s start with one of the main ingredients of honing, the honing oil. Automotive type transmission fluid is NOT honing oil. Period! Don’t let me catch you using trany fluid in your honing machine. Honing oils are not all alike either. Always use the highest quality honing oil from a supplier you can trust.

It is essential that you keep your honing oil clean from debris as well as try to minimize the actual content of swarf. Swarf is the combination of honing oil, broken down honing stone abrasive from and severed material you are honing. Your first line of defense against swarf entering your filters is honing filter paper. This filter paper comes in a variety of sizes and can be easily cut to fit your machine. Your next step is to replace your filter. Most machines have a cartridge-type filter while some use a spin on oil filter like you have on your car engine. These filters will clog and need to be changed on a regular basis. If your machine doesn’t have a filter, you can always rig one yourself. I saw a shop that had incorporated a remote type spin on oil filter from an automotive application and put it in line with the coolant pump. Keep in mind that an automotive oil filter might be too fine to flow your honing oil properly. Keep experimenting until you find one to suit your needs.

Univeral Coolant Magnet shown above on Flywheel Grinder can be cut or shaped to fit machine bases or return ways.

I recommend adding a magnet to the equation to remove the metal particles from the honing oil. Something as simple as a horseshoe magnet, or better yet, a magnetic type strip will greatly improve the removal of metal from your honing oil and prolong the oil life, resulting in faster, honing with less stone loading.

Okay, let’s take a look at honing stones.

Stones are made from a variety of abrasive types, designed for the material you are honing. They are designed to breakdown and, if used properly, you should see even wear throughout their life. However at times they will become loaded, clogged or glazed over. You can use a special diamond dresser or you can use one honing stone against another to unload the pores of the grain to make them more free cutting. In the event they become worn unevenly you must re-true them with a hardened truing sleeve.

Truing sleeves are readily available for 1″to 6″ diameters, and every shop should have one for the 3-1/2″ to 4″ range, however you may need to fabricate your own for the larger diameters. Clamp the truing sleeve into your fixture and expand your stones to work the taper out of your honing stones. It sometimes will take a while, but it will be worth the effort to save that set of honing stones. Never use cleaning solvent to clean your honing stones, solvent will attack the bond of the stone making the bond harder and affecting the result of the stone’s finish.

Once in a while or at least twice a year you should drain out all of your honing oil and scrape out the goo that forms over time. Use a degreaser to thoroughly clean the entire reservoir of your machine. Replace your filters and add new, fresh honing oil.

Also, look over your machine to insure any grease zerts are greased. Oil the traversing bar that allows the left and right movement of the honing head. Some of these machines hone heads are direct-drive with a gearbox and others are belt driven. For the gearbox change the fluid according to the manufacturer and for the belt driven machine, clean the belts and pulleys and adjust the belt tension according to the manufacturer’s recommendations. Look at the cover of your drive motor and fan, and clean if necessary.

Wipe down your dial bore gauge and make sure it is calibrated accurately. Spray electrical contact cleaner into the spindle movement of your dial indicator. This will also flush out the indicator so it moves freely. Another tip is to rotate the carbide contact balls and contact centralizer rings. Always store your dial bore gauge back in its case or in a drawer when not in use.

Remember honing is the final machining operation prior to installing the pistons into the cylinders. If your machine is clean, accurate and always tuned up, your end result will be what you wish it be.

Remember, if you have more questions, contact the Goodson Tech Department at 1-800-533-8010 (customers outside the US & Canada, please call 507-452-1830).

Lightweight block castings have become very prevalent in our market. Since the overall mass has been reduced, the controlled stresses have become an important factor in the block’s integrity. To ensure integrity, we must recreate that stress by using a Torque Plate when boring and honing.

Always begin by torquing your main caps in place to correct specifications. Next, install a torque plate and torque in place using final assembly torque specifications. Also, we recommend using correct length bolts. If they are too long or too short, they may abnormally stress the block. The future will even dictate correctly torquing all external motor mounts and related accessory brackets.

Allow .003″ minimum material in the cylinder bore. Remove broken and partially severed material by honing after the boring operation.

Plateau hone, soft hone, whisker hone and ultra-finish hone. Confused? Don’t feel bad… there are many machinists out there who are uncertain about this new honing method. In fact, it’s one of the most frequently asked questions on the Goodson Technical Service hotline.

For years, we have been honing cylinders with a coarse stone followed by a finishing stone. Then ring materials changed, requiring an additional very fine finishing stone to follow. Now current technology demands an added step to create an even cleaner, burr-free finish.

However, even with these conventional honing techniques, peaks of folded and torn metal still remain in bores. No amount of washing with an ordinary brush could remove this material. A too-rough bore results in scuffing and rapid wear of components, poor ring sealing, reduced component life and oil consumption. This is especially a problem with today’s thinner, low-tension piston rings. Piston ring manufacturers now lap the rings to replicate seating. With the use of ultra-finish hones, cylinder wall technology has also been elevated to pre-seated quality.

Confusion about this hone tool arises from the many different names given to the same tool and process; Plateau hones, soft hones, whisker hones and ultra-finish hones all do the same thing. Without enlarging the bore, they sweep across the surface to remove jagged peaks, folded and torn material.

The ultra-finish hone consists of a mono-filament strand that is extrude-molded with a fine abrasive material. This abrasive filament can be mounted to different types of holders, but usage and performance is identical. Goodson offers this product in holders and brush-type tools, for use with many of the current hones – portable or automatic. We also offer a selection of small diameter ultra-finish hones that can be used with a simple, pistol-grip drill.

During use, the ultra-finish hone will travel at a light load pressure, closely simulating RPM at which the cylinder was initially honed. Rotation can be reversed when using a portable hone. It’s purpose is to slightly deburr the edges of and to remove folded and partially severed material from the cylinder face, the area piston rings actually ride on. The ultra-finish hone is not designed to clean out grooves established by coarse honing or to deglaze cylinders. By design, the ultra-finish hone is used to prepare the cylinder bore for immediate ring seal with little, if any, material loss from cylinder wall on initial engine start-up. This minimizes ring abrasion and broken cylinder wall material migrating to our oiling system. Now we have a near perfect situation, a lapped ring passing over a fully prepared cylinder.

CAUTION: Don’t over do the cylinder with a ultra-finish hone. Sixteen to eighteen strokes are the maximum. Strokes beyond this can produce a finish too smooth to retain adequate lubrication for wear resistance and infinite cylinder pressure sealing.

For those of us that are not yet equipped with a profilometer, here is a slick little test that illustrates the effect of ultra-finish honing. After finishing a cylinder with conventional finishing techniques, dry the cylinder surface area. Take a cotton ball and lightly contact the cylinder rotating around 2 or 3 surface inches. Cotton strands can be seen hanging, snagged on the wall. Now use the ultra-finish hone on the cylinder with liberal amounts of honing oil. Repeat the cotton ball test after using the ultra-finish hone and see the difference. A very noticeable difference should occur with the number of cotton strands, almost no retention! Not a very scientific test, but a good indication of what type of finish has been established in that cylinder. This same finish can be achieved in many other applications, valve guides, lifter bores and piston pin bushings.

Adding this step in your honing procedure will finalize the plateau finish. Rings will seal without abrasion, compression is maximized, and better oil control will lower emissions. Ends scuffing and scratching, prevents premature wear of valve guides, stems, lifters, etc. You now have the tools and knowledge, add the ultra-finish hones to your honing process to completely finish the job. If you have any additional questions regarding this topic, feel free to call (1-800-533-8010) or e-mail me jim@goodson.com.

PROBLEM: Hone is not cutting

• If stones are loading, you need to apply more honing oil to properly flush stones. We recommend our HO-10 Honing Oil. Filtered oil is preferred.
• Make sure that your guide blocks are not too tight. Honing stones should contact the cylinder first. You should put the hone in the cylinder and then expand. The guide blocks should have about .010″ to .030″ clearance.
• Try narrowing your stones, this will put more pressure on the abrasive. Use an old file or dressing stone to narrow the face of the hone stone. Along the entire length of the stone, take approximately 1/3 off the leading edge. This produces more effective pressure on the stone without changing the pressure setting of the hone.

PROBLEM: Hone is chattering

• To eliminate chatter, try varying the stroke rate as you hone.
• Try some of the tips listed above for troubleshooting if the “hone is not cutting” usually any of those suggestions will also help overcome chatter.

PROBLEM: Stones and guides are wearing unevenly

• This is most commonly the result of light honing pressure. To remedy this problem, increase pressure and vary stroke rate momentarily.

PROBLEM: Taper in cylinders with limited access

• Taper will develop while honing a cylinder that doesn’t permit equal overstroking at both ends. There is a tendency for the hone to dwell at the open end of the cylinder and remove too much material. Dwelling at the web end is not a solution because it removes too much material from the center and causes a barrel-shaped cylinder. Goodson offer special honing stones that prevent taper in these cylinders. They have shorter stones that exert more pressure at the bottom and are specially designed for use in short or blind holes. Please call our Techxperts for more information on these stones.

By Jim Tapp, Tech Services Manager

Originally published in Talkin’ Tech, June 2008

In the tech training classes we hold here at Goodson, we were talking recently about crack detection and I thought, “Hey, that’d be a good topic for Talkin’ Tech.” Of course, I could probably write a book about crack detection, but an overview is all we have room for here.

First, let’s talk about why we check for cracks in heads and blocks. The obvious reason is that you can’t fix what you don’t know is there. Cracks and pinholes in heads and blocks can lead to a loss of power in the engine, resulting in poor performance.  That, unfortunately, is the best-case scenario. Cracks or pinholes can also lead to overheating and complete engine failure, not to mention dissatisfied customers returning again and again in search of that elusive leak.

My recommendation is when a customer brings in a head or a block for you to work on, before you even take the piece, ask him a few questions. Ask if he’s had any coolant leaks. If he has, and the deck checks flat you’re probably going to be dealing with cracks and/or pinholes. Ask him where he got the head. If it came from a “core specialist” (a.k.a. the junkyard), you have to think the worst. You have no history so you’ll need to check every inch of the core. Okay, you get my drift. If your customer wants you to diagnose a problem with the head or block, you’ll probably want to use one or more methods of crack detection to determine where the problems are.

That brings us to the inspection methods. There are four inspection methods that you can use, each of which has its applications. These methods are:

• Dry magnetic particle inspection (use for cast iron)
• Wet magnetic particle inspection (rarely used for heads or blocks; very messy)
• Dye penetrant inspection (ideal for aluminum castings)
• Pressure (or vacuum) testing (use to find pin holes in aluminum or cast iron)

You may find yourself using more than one inspection method on a single work piece to diagnose and fix some problems.

Let’s take a closer look at each method.

Dry Magnetic Particle Inspection

As the name implies, this inspection method uses a magnetic field and dry magnetic crack detection powder. Both the dry and wet magnetic particle inspection methods will work only on ferrous materials (cast iron, for instance).  With this method, a magnetic field is applied to the piece being tested. Where there is a crack in the surface (or near the surface) a break in the magnetic field will show when crack detection powder is applied. The break or crack sets up a secondary magnetic field, attracting the powder to the casting flaw.

Dry magnetic powder is a fine cast iron dust with dye added to make visual identification easier. Commonly available colors are red, white and yellow. There’s no difference in the colors; they don’t work differently. But you’ll want a powder color that will provide contrast with the casting so you can see it easily.

Wet Magnetic Particle Inspection

This inspection method is VERY closely related to the Dry Particle Inspection. The only difference is that in this method, the magnetic powder is mixed with a carrier that you can spray onto the piece you’re testing. This method uses fluorescent powder that glows under a black light. The biggest advantage that Wet Particle Inspection has over Dry Particle Inspection is that the carrier will flow into very small cracks, making them easier to see.

Magnaflux Magnetic Inspection Devices

Y-6 Yoke with AC Magnetization

Y-7 Yoke with AC/DC Magnetization

L-10 Inspection coil

This leads me to the biggest disadvantage of wet magnetic testing. It is MESSY. Not only will you need to clean the casting thoroughly before testing it, once you’re done testing, you’ll have another clean-up job ahead of you. The carrier is usually an oil-based product and you will need to get that off of the casting before you start on your repairs.

In both inspection methods, the magnetic field is applied in a variety of ways – through a permanent magnet, an electromagnet or hand-held “yokes” or coils. Most machine shops that I’ve had experience with use a hand-held device like the Y-6 and Y-7 Yokes from Magnaflux®. These are pretty versatile dry units that you can take to the work piece. I, for one, would much rather take a tool that weighs about 7-1/2 pounds to a head or block than the other way around as in wet testing.

Once you’ve decided to use Magnetic Particle Inspection, you have another decision to make; which magnetic field generator (electromagnet) to use. Goodson carries the Magnaflux® brand and it’s pretty much the standard in the industry so those are the units I’m most familiar with. The Y-6 and Y-7 Yokes are versatile, as I said before. They’re hand-held and both have legs that you can bend into almost any shape to fit securely against most objects. The biggest difference between them is that the Y-6 is AC only and the Y-7 can be operated in both AC and DC. The DC mode makes near-surface cracks show. Both of these units can be used with either Wet or Dry Particle Inspection.

Your other option from Goodson and Magnaflux is an inspection coil. This unit is used with wet particle inspection and is most often used with small parts such as valve stems, rocker arms, etc. In this case, you bring the part to the coil and pass it through the field being generated.

One final tip on magnetic particle inspection – always test an area from two directions. If the crack lines up with the magnetic field it won’t show. To be sure that you’ve tested the area fully, turn the field generator 90º and test again.

GLO-KIT is an example
of a Dye Penetrant Kit

Dye Penetrant Inspection

Again, the name says it all. Dye Penetrant Inspection (or DPI) uses a penetrating dye that shows where cracks and pinholes exist. Some of these penetrating dyes are visible under a black (or ultraviolet) light, while others don’t need a light source to be seen. Fluorescent penetrants are more sensitive than the visual dyes, but the down side is that they have to be viewed in a dark area, which may not be entirely practical in the shop.

The biggest advantage that this inspection method has over the magnetic methods is that it will also find pinholes – something magnetic particle inspection cannot do. Dye Penetrant Inspection can also be used on aluminum heads and non-metallic materials.  Another advantage of DPI is the lower initial cost. You can get a complete kit for DPI for anywhere from about $45 up to $750 while the starting point for the Magnetic Inspection units is $700.

DPI is basically a three-step process:

• Clean the surface to be tested thoroughly to remove all traces of dirt, grease and carbon-based material.
• Apply the dye penetrant liberally to the surface and allow it to soak in for at least 20 minutes. One of the most common mistakes is not letting the dye set long enough.
• Remove the excess dye and apply the developer. The developer helps to draw the dye out of the crack allowing you to see it, either with the naked eye or with a black light, depending on the type of dye used.

A few words to the wise; these dyes will stain skin, cloth and other porous surfaces. So don’t grab your wife’s new white towels to clean off the excess dye. You might find yourself sleeping in the shop for a while if you make that mistake, along with a few others we won’t talk about here.

Pressure Testing

The last method of crack detection we’ll talk about here is pressure testing. This method is often used along with one of those listed above as a final check that all of the cracks or pinholes have been repaired. Of course, it can’t be totally simple; there are two ways to perform pressure testing – wet or dry. Procedures are essentially the same regardless of which method you choose.

First of all, the head being tested needs to be completely clean. You will attach a special block-off plate to the head to seal off the water passages, then pump pressurized air into the head through an air line inserted into a water port. Some sources will tell you to use about 60 psi, but in my experience, 20 to 25 psi is adequate. Some heads have core plugs pressed into them and these will blow out at 60 psi. It’s not only an inconvenience, it’s a safety hazard.

Here’s where the methods differ. With the wet method, you’ll lower the head into a water tank until it’s completely submerged. If you have holes or cracks, the escaping air bubbles will show you where. The dry method is similar. Instead of taking the head to the water, you’re bringing the water to the head. Once the head is pressurized, you’ll spray it with a soapy solution (bubble fluid or a little dish soap in water). If there are cracks or holes, the solution will bubble up and you’ll know where you need to repair.

Pressure testing is one of the easiest of the crack detection methods available A drawback is that pressure testing can’t identify all cracks. Surface cracks that don’t connect to a water passage won’t show any leakage so you could miss those if you just use pressure testing.

Vacuum Testing

One last testing method we’ll talk about is vacuum testing. It’s most often used to test valve-to-seat seals on cylinder heads. Vacuum testing is easier than pressure testing, but it has one major down side. Vacuum testing can tell you that there is a leak, but it won’t locate it for you.

To perform vacuum testing, you’ll need a vacuum pump, a work surface with a rubber top and plugs that will close off the water passages. Once the holes are plugged, pull about 25″ Hg vacuum and watch what happens. If there are leaks, the vacuum will drop or not hold steady.

Whew! That was a lot of information in a small space. Probably more than you ever wanted to know about crack detection, but this is really just scratching the surface on the topic. For more information, we recommend the book, Engine Service Automotive Machining and Engine Repair by Gary Lewis or Sunnen’s Complete Cylinder Head and Engine Rebuilding Handbook by John Edwards. Unfortunately the Sunnen book is no longer in print, but you can probably find a used copy on e-bay or Amazon. There are also a lot of resources out there on the web. Just enter the search terms “magnetic particle inspection” and “dye penetrant inspection” and you’ll get lots of pages to check out.

by David P. Monyhan

There are a lot of ways to disassemble a cylinder head. You’ve probably used the old hammer and socket method many times for the standard Chevy and Fords. Don’t do it! Assembly of the cylinder head is compromised and will create a whole new set of problems.

The C-frame style of valve spring compressor has become the preferred tool for disassembly and re-assembly of the standard applications like Chevy and Ford. These compressors work with air and a special jaw presses on the retainer, allowing you to remove the keepers quickly and safely. There are also manual versions of the C-frame compressor that utilize an over-center cam clamp for compressing the spring. This style was the basis for adding the air cylinder to do the work of compressing the retainer. Both units come in a variety of sizes and have optional jaws for the various diameters of retainers. These types of spring compressors are good for stock springs up about 300 to 350 lbs.

The “killer” springs of the high performance world need a killer, heavy-duty type of air spring compressor. These springs can have as much as 900 pounds of pressure and if you’re not using the proper tools, you can be seriously injured or worse. These heavy-duty spring compressors are made from T-6 aluminum so they won’t flex during the compression of the retainer but are still light enough to handle easily. I strongly recommend using a solid jaw rather than an adjustable one when working on high-performance heads. With a solid jaw there is no chance of flexing or twisting keeping the retainer from shooting off into space or possibly hitting you in the face.

There is another way to take these killer springs off safely. It’s to use a tool that looks like a C-Clamp. They’re not real fancy, require a little arm strength but still get the job done. These modified C-clamps units have a specially designed receiver or jaw, so you can remove and install keepers safely. I’ve watched the Top Fuel guys using both air and manual compressors on very hot heads right after a 330 mph run and both work well.   However, when it comes to the multi-valve overhead cam cylinder heads, the hammer and socket definitely need to be put in the tool box and the C-frame compressor is compromised due to the very small diameter and sometimes very deep lifter bores that we need to go through to get at the retainers and keepers. You need a tool designed specially for this job.

Spring benches came into the market several years ago, and are available in either a manual or pneumatic style, from a variety of manufacturers. I like the spring bench for a couple of reasons: 1) you have a dedicated workspace and 2) all of your tools stay in one place. One thing all spring benches have in common is that they protect the lifter bore from damage. It is very important to not damage the lifter bore during disassembly or assembly.

Spring benches also support or hold the valve securely. Valve stems on multi-valve OHC cylinder heads are getting down to 4mm and manufacturers are putting not two, not three   but up to four or five valves into the combustion chamber. With these small sizes, there is potential for bending the valve, which you naturally want to avoid. What makes the spring bench ideally suited for these heads is that a support holds the valve in place by pushing up on the valve head while an open-design pressing foot compresses the spring allowing access to the keepers and retainers.

Putting the keepers back into the retainer is the next challenge. I’ve seen a guy who could do it with a screwdriver and a little bit of grease but I’ve also witnessed group efforts that were anything but successful. There are some spring-loaded keeper tools that are fast and do the trick every time. To use these keeper installers you’ll need a vertically open pressing foot. An added benefit of the spring bench is that they make the entire re-assembly process much faster. You can ensure your valve stem seals are positioned properly and on the higher end benches you even have the ability to install the cam and set the lifters.

The Keeper-Eeze is another really cool tool that’s relatively new and uses only the strength in your arm for the assembly or disassembly process. Note how this tool keeps the lifter bore from damage by using a nylon protector.

Another way to get these multi-valve overhead cam cylinder heads apart is to use an arbor press or your seat and guide machine. These machines can act as your assembly and disassembly bench using adapters. Keep in mind you still need to have a way to keep the valve from opening during the pressing operation. You can use a piece of wood or small bags filled with shot placed in the combustion chamber. This will prevent the valve from opening during the pressing process. Be careful to not damage the lifter bore or bend the valve.

Ok, now you have the springs off, what about the valve stem seals? Some of these valve stem seals seem like they are welded to the guide, they are so darn tough to remove. What  do you do? You can try pliers but the clamping action actually makes the seal tighter. You need to get under the seal and use a slide hammer to get the seal off the guide.

Some of these steel jacketed seals make the job even more difficult because you can’t get under the seal to remove it. I found a seal puller that actually pierces the metal seal, allow the tool to grip the seal and then using a slide hammer you can remove the seal very easily.

Installing the new seals is easier than removing them. There are tools made specifically for this job and they incorporate a sleeve that is installed over the valve. This sleeve does two things; 1) it enlarges the ID of seal during the installation and 2) it stops the keeper grooves in the valve stem from tearing the ID of the valve stem seal.

Taking the OHC cylinder head apart and putting it back together is one thing. But during the cleaning (you knew I’d get to this eventually), inspection and machining process it’s a challenge to keep track of all of these components. Get yourself a cylinder head organizer. These organizers have compartments to keep everything in order and all in one place. Now you can keep all of these components in an organized manner. This is very important when its time to put everything back together again.

Remember you can’t clean it or machine it until you take it apart. Do it right and you make money and satisfy your customers at the same time!

See you in the shop!

Q: What is the proper way to angle mill? Should I change the intake side or the head or change the intake?

Common practice is to do all work to the cylinder head. Then if the manifolds are changed or heads are changed, they don’t have to be done as sets (2 heads and a manifold). Manifolds can be changed at will without modification when all the work is completed on the heads.

Q: What is the formula for this?

Different heads have different requirements. Check out the chart below for more information.

Carbides are more brittle than high speed steel, so it is very important that they be used with care. There are three things to remember when using carbide cutting tools:

1. Avoid making intermittent cuts
2. Do not turn tool in reverse of normal rotation
3. Avoid cutting out valve seats with counterbore seat cutters

When in use, always keep carbide tools stored separately, cased in wood or plastic. If they happen to bump into other tools or machine surfaces, the carbide could chip, thus destroying the integrity of the tool. Tool Boards can esily help revent tool damage. Your Tool Board will enable you to organize and separate your tools for quick selection and safe storage. Some machines are already equipped with a Tool Board. If not, take some time to construct your own. Your productivity will automatically increase and your carbide tools will be stored safely and properly.

Goodson has developed new products that make your 3-angle cutting system more versatile than ever. We now offer special holders and blades to create new bowl profiles and custom size spring pads. If you have an existing system or are thinking about investing in one, keep on reading to learn more.

Start with our 3-D Fast Cut or similar 3-angle cutting system. 3-D Fast Cut is a precise and affordable valve seat refacing method. No special pilots are needed and ball heads are available to fit most popular pilots. Formtools are economical and available in many different profiles.

To upgrade to a Bowl Profiler, all you need to purchase is different tool holders and blades! The profiler tool holders use the same ball head body as in your 3-angle system. With this tooling you can machine seats and bowls on a pair of V8 heads in about 40 minutes. More economical than bowl hogs, the bowl profiler also gives you a variety of different angles to choose from. Special radius blades are also available for unshrouding valves in combustion chambers.

Our new Adjustable Spring Pad Cutters also use the same ball head body in your 3-angle system. Create a custom size spring pad by cutting ID, OD, and depth with one carbide blade. For a single spring or import use .375″ blade and for multiple springs or hi-performance use the .500″ blade. Set cutters with a micrometer (Order No. MGA-MIC) and your existing .375″ pilot to acheive a more precise sizing.

Our new Lift Clip is a must when using the Bowl Profiler or Spring Pad Cutter. It allows you to work in areas that will not accommodate bounce springs. Use with a bounce spring to reduce chatter and enhance seat cutting and finishing.

Dry Method Magnetic Particle Inspection
When “Magnafluxing” a casting, never blast with media prior to testing. Blast media peens the surface and can move metal, possibly closing the very cracks or flaws that you are trying to identify. When very coarse wire brushes are used roughly, they can also mask these areas.

Usually the casting itself, without cleaning, is the best indication of leakage. Check the casting by visually examining its entire surface to see if there is an area that looks exceptionally clean. Usually one or two combustion chambers or piston tops are free of carbon. Leaking coolant in an operating engine is an excellent carbon remover.

In diesel chambers, look for pitting on the casting or piston top. If we are in an area that has oil, but no combustion (such as the lifter or rocker arm area) look for anti-freeze “jelly”. This is the result of coolant weeping into hot oil. A cracked area with poor-quality coolant or even just water in the system, would usually show rust along the crack.

Remember — these tips are not methods of crack detection, they are simply quick checks to speed up crack identification.

To help identify cracks quickly and easily while “Magnafluxing”, choose a colored powder that stands out the most. For example, darker colors on bright parts and lighter colors (white or yellow) on dark castings.

Goodson’s Magnaflux powders are almost twice as “active” as other private label powders. In other words, using the same amount of powder and light source, you’ll find almost twice the amount of Goodson Magnaflux powder collected at the crack instead of laying about on the casting.

Alumni-Chek Method
When using this method, we need to chemically clean the area to be tested with Goodson’s AC-1 Cleaner, then dry the area. When AC-2 Penetrant is applied, let it stand for 2-3 minutes to penetrate into any cracks or flaws. Now the tricky part… removing the excess dye. Do not flood the entire area with chemical cleaner or water. Do not dry with compressed air. Use a damp shop towel (be sure to wring it out well) or a shop towel with just a light spray of cleaner applied to it, not the casting. Cleaning excess dye with this method will leave the dye in the flaws for the last step. AC-3 Developer can now be applied. This fluid will lift the dye from the casting and present it on a contrasting white background.

Leak Detection Plates
When using pressure or vacuum plates, give them a light coating of automatic transmission fluid. This cleans and seals for a better test. When testing is complete, apply another coat of ATF to clean and store the plates. This will keep them soft by helping to prevent oxidation.