Goodson Gazette

Posts in the Tech Notes category

Getting a Grip on Dowel Pin Pullers

Getting a Grip on Dowel Pin Pullers

I have a confession to make. I’m addicted to social media. That means I watch a lot of how-to videos on YouTube. Some of them are great, but some of them … not so much. I was watching one the other night when the guy used a pair of vise-grips to pull a dowel pin. I wanted to reach through the screen and rip those pliers out of his hands. Yes, he got the dowel out. But he also crushed it (and not in a good way). Let me be clear, you don’t use vise-grips to pull dowels. You use a dowel puller.

That’s what we’re going to talk about today. Dowel Pin Pullers. What your options are and how to use them.

There are a couple types of Dowel Pin Pullers, both of which incorporate a slide hammer.

Goodson Pin Pal PullerI’ll start with the Goodson Pin Pal Puller since it is the closest in design to vise-grips. Now, before you say I’m contradicting myself, you need to know that these locking pliers have been modified with special, replaceable jaws to stop you from destroying the dowel pins.

Before we look at how to use this tool, let’s talk safety. First of all, always use safety goggles or safety glasses when removing dowels with this or any other impact tool. Second, do not use this tool on hardened dowel pins; you’ll damage the tool. If you’re not sure if the pin is hardened, run a file across the top of the pin. If no metal is removed, don’t use this tool.

To remove dowel pins with the Pin Pal Puller, position the jaws over the pin to be removed and tighten them firmly. Do not over-tighten. You will be embedding the jaws into the pin slightly but you don’t want to crush the pin. Maintaining your grip on the pliers, grasp the slide hammer firmly with your other hand. Be sure your fingers are not between the top of the shaft and the top of the slide hammer (If you’ve ever slammed your finger in a door, you’ll understand why). Using short, fast upward strokes, impact the pin out.

If you plan to reuse the pin, you can file all of the high spots before reinstalling. In some cases, the pin is the same diameter from top to bottom so you can flip it over and reinstall the pin. No one will ever know you pulled the pin.

Goodson's Dowel Pin Puller and ColletsNow let’s move on to the Goodson Dowel Puller. This tool is available as individual pieces or sets. This dowel removal method uses gripping collets and a slide hammer to do its work.

The first step in using this puller is to select the correct size gripping collet. They are available with IDs from .1575” to .8000” so you’re pretty likely to find the size you need. We can’t stress this enough. Too small or too large of a collet won’t grasp the dowel pin sufficiently to work safely.

Proper assembly of the Goodson Dowel Pin PullerTo assemble this tool, you will put the slide hammer (GAO-2) onto the slide shaft (GAO-1), followed by the tightening sleeve (GAO-3). It is essential when installing the tightening sleeve on the shaft that the flared end is toward the collet end of the shaft. Last you will thread the collet onto the shaft as far as it will go.

Place the fully assembled tool over the dowel you want to remove. To lock the collet onto the dowel, grip the slide hammer and strike it against the tightening sleeve, forcing it over the top of collet compressing it tightly on the dowel. When you’re satisfied that the collet is tight on the dowel, use an upward motion with the slide hammer to pull the dowel. Again, be careful of your hand position so you don’t hurt yourself.

Now that the dowel is out, you need to release it from the collet. To do this, place the complete assembly on the removal basin (GAO-21) and sharply strike the top of the shaft with a hammer. This will release the tightening sleeve from the collet allowing you to access the dowel pin. You can now repeat the procedure on the remaining dowels.

For best results regardless of the dowel puller you are using it is important to only remove dowels when they are clean and dry. Oils, lubes, grease, etc. will get in the way of the tool’s operation and should be removed before trying to pull the dowels. Use a grease remover, carb cleaner or the like to remove any grease or oil then compressed air to dry the surface.

As always, if you have any questions about how to remove dowel pins, contact the Goodson Techxperts by email or phone (1-800-533-8010).

Goodson/Vizard ‘HOW TO BUILD HORSEPOWER’ Seminar


Where:-  Vizard personal shop – 109 Mistywood Drive, Mount Holly, NC 28120. (This is just 10 miles west of Charlotte).

When:-Sept 8-9-10 for attendees to the full seminar and Sat 9th at 5:30 for Cam and Flow Bench program presentation.

Cost: For full three day seminar - $500.

For attendees to the Saturday evening:- free but only a limited number can be accommodated. Please call in to reserve a spot. 1-865-850-0666

Seminar highlights:- Erson Cams Dick Boyer will be on hand Friday and Saturday and will be giving a 30 minute ‘how to’ on hybrid SB Chevy/LS builds.

Also on Saturday evening there will be some well-known ProStock Cylinder head experts as well as experts in other areas of power production in the upper echelons of motor sport.

Saturday evening’s presentation will be accompanied with a cookout by three skilled barbecue chefs.

Attendee’s for the full three day seminar will receive a copy of the Torqemaster cam program and the IOP flow bench program. This has a value of not less than $600!

Subject Material: Way more than we have room for here so go to the seminar web-site

What will the two programs do for professional engine building shops?

1ST here is what the ‘TorqueMaster cam selection program will do:-


  • With just 7 inputs (bore, stroke, CR, intake and exhaust valve sizes, rocker ratios and peak power rpm) it will deliver hyper accurate answers for cam LCA, duration of intake & exhaust, cam advance, required minimum valve lifts, idle vacuum, dynamic CR, cranking pressure, torque output, hp output, required cfm of head flow to meet power level, & port cc for best results. NO OTHER PROGRAM ON THE MARKET WILL DELIVER THIS COMPREHENSIVE INFO.
  • Once the cam specs are calculated the user can search a data bank of profiles to select a cam that matches the selection within a degree or so. Currently this selection has a combined flat and roller plus hydraulic and solid selection of OVER 2200 PROFILES. The required profile can be identified in about 30 SECONDS!
  • Unlike cam catalogues the data bank not only delivers the LCA and duration figures you find in a typical cam catalogue but also lobe area in inch/degrees plus (and this is a first) absolute intensity.
  • Again unlike other cam catalogues TorqueMaster will also make a cylinder head recommendation for the most compatible match between cam and heads – in about 30 seconds. But it does not stop there. You can also find the best rockers for the application – also in about 30 seconds and the same goes for the rest of the valve train. After that you can apply ‘Torquemaster to figure the best intake and carb by part number, again in almost no time flat.
  • How effective is TorqueMaster at producing power? Very - those who have tried it so far have seen big gains in power while the cost of the build has decreased but customer value has not.
  • With this program it is possible for the engine shop to sell a cam to a customer who will pay via credit card. The part # then tells which cam company to email the order to. The cam company then drop ships to the customer and bills the engine shop. That’s profit without any human interaction. The engine shop could be selling cams at midnight!


The IOP flow program.


The advantages of IOP over any program available are:-

  • Apart from delivering the port flow numbers (imperial or metric) IOP calculates many other factors including:-
  • Mean port velocity
  • Port flow efficiency
  • Calculated Mach #
  • Expected torque & HP
  • Port energy
  • Specific port energy density
  • Port area at the minimum point
  • Valve area
  • Port to valve area ratio’s (pop-up gives target range)
  • There are numerous pop-up comment boxes that steer the user to the optimum port characteristics. No other program will do this. Follow the recommendations and the user will produce top performing heads without having to make any judgement calls. This is what it takes to turn a beginner into a top pro.


Marvin @ 865-850-0666

Reluctor Ring Removal and Installation

If you deal with late model engines, you, no doubt, have dealt with a Reluctor Ring. So what is a reluctor ring? It's a multi-toothed timing ring press-fit on a crankshaft which works with a magnetic sensor to identify crankshaft position. Quite the mouthful, huh?

There are two common configurations of reluctor rings – 24 tooth and 58 tooth. They are generally two plates that are welded together, though Callies Crankshaft makes single-piece models (available through Goodson). Reluctor Rings are also called tone rings or timing plates.

In this article, we’re going to look at the procedure for removing and installing the reluctor ring using the Goodson Reluctor Ring Jig (RRJ-350).

Let’s start with removal. It’s not as easy as it may sound since there isn’t a key or other registering device. Before beginning removal, make witness marks on both the reluctor wheel and the crankshaft rear flange. Proper position of the wheel is essential.

To avoid bending or distorting the reluctor wheel, DO NOT use a puller when removing the reluctor. We recommend heating the wheel with a torch to about 200ºF. Like all metal, the wheel will expand and you should be able to slip it off easily. Be sure to wear heat resistant gloves.

First, let‘s take a look at the tool and the reluctor ring in a little more detail.

Reluctor Ring Detail

 [powr-photo-gallery id=808e0470_1502290877]

The Reluctor Ring Jig is designed specifically to fit Generation III (LS1 and LS6) and Generation IV (LS2, LS3 and LS7) GM motors. 

Now, let’s get the reluctor wheel installed.

Chamfer the entry edge of the reluctor ring to ease installation. Be sure that you have thoroughly deburred the edges. Any sharp edges may cause the reluctor ring to catch on the casting, making installation impossible.

Heat the reluctor ring to approximately 450ºF (232ºC) using a torch or in your cleaning oven. Line up the 8mm indexing dowel with the 8mm indexing hole and slip the reluctor ring onto the jig. Now, slip the reluctor ring onto the crankshaft. In his Engine Professional article, Mike Mavrigian says, "I heated the the wheel's ID lip with a torch, slipped the wheel onto the Goodson jig, and the wheel slid onto the crank as easily as a rock drops into water."

A couple of final thoughts:

  1. DO NOT try to bang the reluctor ring into place; you'll only end up damaging it and having to start all over.
  2. Cold pressing the ring into place can easily warp it, leaving it useless.

As always, if you have any questions about this or any other technical topic, contact the Goodson Techxperts by phone (800-533-8010) or email.


Decimal Conversion At a Glance

Why hunt for a calculator to convert fractions to decimal and back again when we've done all the work for you?
Goodson Decimal Chart

Crank Polishing Belts Are NOT All The Same

Assortment of Crankshaft Polishing BeltsThe variety of crankshaft polishing belts can seem overwhelming at times. After all, you have straight edged, scalloped edged, premium, micro polishing, fine polishing, super-micro polishing, cork, grit, grain, backing material, bond and the list goes on. 

Today, we're going to explain some of the differences and how to choose the right belt for the crankshaft you're polishing.

Grit : This is probably the element you're the most familiar with. Grit is representative of the size and number of grains per square inch. The higher the number, the finer the abrasive grains and the less material will be removed. 

Grain : Also known as abrasive, this is the type of material the abrasive grains are made of. Most common abrasives are Aluminum-Oxide or Silicon-Carbide. Which one you choose is dependent to what material you are polishing and personal preference. Aluminum-Oxide tends to be more aggressive for use on harder materials while Silicon-Carbide is used on softer materials as it isn't as aggressive.

Backing : The abrasive grains must be bonded onto some sort of backing. It is usually a woven cloth to allow flexibility when polishing. Most Goodson belts have a "J-Weight" backing which means it's about the weight of blue jeans. "J-Weight" = jean weight.

Shape : You can choose from straight-edge or scalloped-edge belts. We recommend using the scalloped-edge belts for radius polishing. The scallop yields into and polishes the radius without the chance of leaving a line on the finished crankshaft.

Now, let's take a quick look at the crankshaft polishing belt options available from Goodson:

Standard Polishing Belts are the backbone of the Goodson product line. These belts are Aluminum-Oxide and are available in 240, 320 and 400 grit. Sizes range from 60" to 91" long and 3/4" to 2" wide. Standard Scalloped-Edge belts are available in 64", 72" and 91" long and 1" wide only in 320 grit.

Goodson Fine Finish Polishing BeltsFine Finish Polishing Belts are a very aggressive belt that many customers call "the blue-backed belt." They are Aluminum-Oxide with a flexible woven back and 2-layer resin bond. These belts are available in 320 and 400 grit; 60" to 91" long and 1" wide.

Goodson Scotch-Brite Style Micro Crankshaft Polishing BeltsNext up are Scotch-Brite Style Micro and Super-Micro Finish Belts. These belts give a non-direction finish and both feature a resin bold. The Micro Finish belts are Aluminum-Oxide while the Super-Micro Finish belts are Silicon-Carbide. Both are available in lengths from 60" to 91" and widths of 3/4" or 1". They're generally used for a final finish.

Goodson Abrasive Cork Super-Fine Finish Crankshaft Polishing BeltsIf you prefer a Satin Finish, try the Goodson Abrasive Cork Super-Fine Finish Belts. These belts won't disturb polished radii. The Silicon-Carbide belts are available from 64" to 91" long and 3/4" or 1" wide.

A few years ago, Goodson added a line of Premium Aluminum-Oxide Crankshaft Polishing Belts. These belts have a very flexible j-weight cloth backing with a high strength joint. They are available in the standard 60" to 91" lengths, 3/4 or 1" wide in 600 and 800 grit for an exceptional finish.

Goodson Premium Ceramic Scalloped Micro Polishing BeltLast but not least is another premium belt available from Goodson - the Premium Ceramic Micro Polishing Belt. This scalloped belt features a structured abrasive specifically designed to be used with polishing rouge (CPR-16). This belt is only available in a 1" width from 60" up to 77" long.

As always, if you have any additional questions about these or any Goodson products, contact the Goodson Techxperts by email or call 1-800-533-8010.

Leveling Your Machinists Level

Calibrating and Maintaining Your Precision Machinists Level
Maintaining the Machinists Level : Replacing the Vial
Maintaining the Machinists Level : Replacing The Vial pt. 2
Maintaining the Machinists Level : Replacing the Vial - 3
Maintaining the Machinists Level : Replacing the Vial - 4
Maintaining Your Machinists Level : Replacing the Vial - 5
Maintaining Your Machinists Level : Replacing the Vial - 6
Maintaining Your Machinists Level : Replacing the Vial - 7
Maintaining Your Machinists Level : Calibrating the Level
Maintaining Your Machinists Level : Calibrating the Level - 2
Maintaining Your Machinists Level : Calibrating the Level - 3
Maintaining Your Machinists Level : Calibrating the Level - 4
Maintaining Your Machinists Level : Calibrating the Level - 6
Maintaining Your Machinists Level : Calibrating the Level - 6
Maintaining Your Machinists Level : Calibrating the Level - 7
Maintaining Your Machinists Level : Calibrating the Level - 8
Maintaining Your Machinists Level : You're Ready to Level Your Work

Taking the Grind Out of Piston Ring Fitting

By Dave Monyhan

We're getting close to the end of our series on  Rod & Piston Work. So far we've talked about Connecting Rod Basics, MeasuringMachining and Removing & Installing Pins and Bushings. In this edition of Tech Notes, we'll be looking at Piston Ring Fitting. A lot of science goes into the design and manufacture of piston rings. We don't have the time (or room) for that in this post. We will, however, try to get a piston ring expert to share some of his knowledge with us in the near future.

Okay, we all know that piston rings and pistons have always been a part of the internal combustion since its inception way back in the 1800s. We also know that piston rings are designed to seal the cylinder to create compression so the ignition can light the air fuel mixture. And we know that the piston and the cylinder wall must have a specific clearance for oil.

But what about the piston ring? Why can’t you just take them out of the box and put them on the piston and finish assembling the engine? Well actually you can take the piston ring right out of the box and yes, you can install them on the pistons and yes, you can then finish assembling the engine and for the standard “stock” or “grocery getter” engine you will probably be just fine. However that theory will only work for the older style cast iron engines with standard oversize bores. For example, a Small Block Chevy has a 4” bore. If you bore and hone to .030” oversize, the out of the box ring and piston set will not have to be end-gapped. I do recommend, though, that with every engine job you check everything including ring gap even for a stock or grocery getting engine.

But, if you are doing any kind of performance work or adding custom pistons with file-to-fit rings or varying bore sizes you must file to fit. Also if you are changing the fuel delivery system from carburetion to fuel injection, adding nitrous, blowers or turbos then YES, you need to file to fit the piston rings. It is essential that you follow the ring gap directions supplied with your piston and ring packs when you buy them.

What about piston ring gap?

The standing theory is that the piston ring gap is supposed to be .004” for every inch of cylinder bore diameter. We all knew that from high school auto shop.

So how do you file a piston ring to the proper gap?

Recommended Piston Ring End Gap courtesy of Mahle-Clevite

Chart courtesty of Mahle-Clevite.

Goodson PRF-500 Manual Piston Ring GrinderGoodson PRF-250 Manual Piston Ring FilerGoodson PRF-812DW Powered Piston Ring Filer

Left to Right: Goodson Manual Piston Ring Grinder (PRF-500), Goodson Manual Piston Ring Grinder (PRF-250), Goodson Powered Piston Ring Filer (PRF-812DW)

At Goodson we offer both manual and electric piston ring filers. But, before you can gap the ring you need to first…..square the ring in the bore. I recommend our newest Ring Squaring ToolThe squaring tools come in a variety of bore sizes and have a range of .300” of an inch per tool.

Goodson Ring Squaring ToolMeasuring Ring Gap with the Goodson Ring Squaring Tool Goodson Ring Squaring Tool In Bore

Once the ring is squared in the bore and you have the correctly measured how much material you need to remove from the gap, it’s time to load the piston ring into the ring filer. 

We also need to deal with any “burrs left on the ring gap by using the de-burring wheel on the right side of the PRF-812DW

So as you can see piston ring gaping is very straight forward and actual pretty simple with the correct tools.

Like any procedure there can and will be exceptions so if you get in a bind just call the Goodson Tech Department (800-533-8010) and they will help you fully understand this A to Z procedure.

The Ins and Outs of Pressing Piston Pins and Bushings

We’ve spent the past few weeks talking about measuring and machining connecting rods but we may have put the cart before the horse. This week we’re going to correct that by talking about removing and installing piston pins and bushings.

Old Hydraulic Shop PressIn order to prep your con rods for machining, you will need to have a few items. First, you’ll need a shop press. Goodson Tech Services Manager, Erik Shepard, recommends when looking to add a shop press ask yourself a few questions.

  1. What’s your budget?
  2. What do you plan to do with the press?
    Erik said, “Usually when someone gets a press, they find all kinds of things to use it for. From pressing out pins and bushings to straightening pieces, etc.”
  3. How strong of a ram do you need?
    For pressing piston pins and bushings, you’ll need a minimum of 5 tons of pressure, but you’ll probably want to go up to 20 to 30 tons if not higher, depending on what you plan to do with it.
  4. How much room do you have for a press?
    Presses are available in lots of sizes from bench-top units to large free-standing ones. Depending on what you plan to do with the press, you will also need room around the unit so keep that in mind when choosing a press.
  5. What’s your power source? Is it hydraulic or air over hydraulic? Both have their advantages and disadvantages.

For pressing piston pins and bushings, you’ll need a minimum of 5 tons of pressure, In our experience, most pins should break loose at 1800 to 2200 PSI. If you’re still running into resistance at this point, you have other problems. If all you’re going to do with the press is work on con rods, you can use a bench-top model but as Erik said before, you’ll probably find all kinds of uses for a press.  He also added that you need be sure it is rigid and durable. Look for quality welded joints and heavy gauge metal. When deciding which press to add to your shop, you will also want to check out the machine’s warranty. Remember, a shop press is as important an investment in your business as any of the other shop machines you use.

Now that you have the press, you’ll need some fixtures and tooling with which to work. Goodson offers several units for piston pin pressing and for pressing pin bushings, particularly tapered pin bushings. We’ll look at each one separately.


Piston Pin Removal & Installation Fixture (PPE-7082)

This fixture is composed of several parts that combine to take some of the guess-work out of removing and installing interference fit piston pins. It  was designed to protect high dollar pistons from damage since the piston itself is NEVER under pressure. One of the key features is a series of support inserts that you use to keep the connecting rod aligned properly. Several standard sizes are available, plus one that is ready to be machined to your exact needs.  For a complete run down on how to use the Piston Pin Removal and Installation Fixture, check out the product instructions.

In addition to the standard instructions, Goodson Techxpert, Chris Jensen gives these key tips:

  1. Use the fixture with the press plates that came with your press
  2. Always select the proper insert. Be sure it fits the piston and pin properly
  3. Always use Press-Fit Lube (Goodson PFL-200) during the removal and installation process
  4. Verify alignment, verify alignment and verify alignment
  5. The piston must float during installation
  6. The rod must be centered on the pin for proper installation

One last warning that applies with all of these operations: If you run into excessive resistance, do NOT keep applying pressure. You can easily cause damage.

Universal Piston Pin Press-Out Tool (PPE-1)

Cross-section of correct Press-out tool set up

A universal tool set to use with your shop press, this tool is made of high quality steel and is sized to work with most applications. This set is for basic removal of pins without damage to the piston. Using the Piston Pin Press-Out Tool is pretty self-explanatory, but you can check out the product instructions for more details.

As with the Piston Pin Removal and Installation Tool, always be sure to use correctly sized support fixtures, use press-fit lube and verify your alignment to avoid damage to the work piece.

Tapered Pin Bushing Press Kit from Goodson

Universal Tapered Pin Bushing Press Kit (TB-KIT)

One of our newer additions to this class of tooling, the Universal Tapered Pin Bushing Press Kit is designed to work on common light to medium duty diesel applications. It can be used to remove and install tapered pin bushings.

When asked why a shop should invest in the Universal Tapered Pin Bushing Press Kit, Erik Shepard gave these five points:

  1. It’s the best tool for removal and installation for tapered connecting rod bushings up to 2″ in diameter.
  2. The tool is designed to prevent piston damage during use
  3. With the number of bushing drivers included in the kit, it can accommodate many sizes of tapered rods
  4. Specially sized bushing drivers can be made to order
  5. You never have to make-do with different methods when installing or removing tapered bushings.

For more specific information, check out the product use instructions.

As always, if you have any additional questions about these or any Goodson products, contact the Goodson Techxperts by email or call 1-800-533-8010.

Connecting Rod Honing Basics

Sunnen's Complete Cylinder Head and Engine Rebuilding HandbookOver the past few weeks we’ve been talking about Connecting Rod Reconditioning in Tech Notes. Thanks to our friends at Sunnen® Products Company, we’ve been able to share material from their book, Sunnen’s Complete Cylinder Head and Engine Rebuilding Handbook. Unfortunately, this book is now out of print. If you’re looking for a copy of the book, they’re pretty scarce but you might be able to find one on Amazon or eBay. We also did a short search and found that it is available as an e-book, but a membership is required in order to read or download the text.

As we move into our last section on Connecting Rod Reconditioning there’s a lot to cover. If you’ve been working on engines for any length of time, you already know most of it. With that in mind, we’re just going to cover a few basics here and give you some links to additional resources.

Cap and Rod Cutting

Face and side view of connecting rodAs we’ve talked about in previous articles, all connecting rods have a parting edge. Most are flat surfaces machined into the cap and rod sections. These surfaces must be straight and perpendicular to the rod sides. If they aren’t, cap misalignment can reduce clearance between the rod and the crankshaft journal.

In most rebuilding cases, you will remove .003” (0.08mm) from each mating surface for a total of .006” (0.15mm). This small of an amount of reduced center-to-center distance won’t interfere with the compression ratio significantly and general doesn’t compromise the deck-to-piston clearance; even when the deck is resurfaced.

You will, of course, need to remove rod bolts when getting ready to work on the mating surfaces. To do this, you will probably need a press and disassembly fixture. Be sure the surfaces are clean as well before doing any machining.

A Few Important Tips

  1. Be sure to identify the type of parting edge you’re dealing with as each is handled differently. More on this later.
  2. When machining your rod(s), be sure to clamp them into the machine firmly. If they are at all loose, the grinding wheel may push the rod up so that you are removing less material than you planned.
  3. Always machine the full set of rods and caps the same.
  4. When finished grinding, clean bolt holes to remove any chips or debris that may have accumulated then install new bolts.

Parting Edges

Fractured Parting illustrationAs stated before, most of the connecting rods you will deal with have a straight parting edge. You may also come across rods with Tongue & Groove (T&G), Serrated or Fractured parting edges. Due to the many irregular edges common in serrated and fractured parting edges, there isn’t much you can do to machine these.

Tongue & Groove Parting EdgeTongue & Groove (T&G) parting edges can be machined but there is a very specific way in which to work. First off, it’s essential to note that most manufacturers incorporate a slight clearance between the tongue and bottom of the groove. When grinding these rods, be sure the amount of material removed does not exceed the amount clearance or you will need to grind the tongue to restore proper clearance.

Tongue & Groove Parting Edge Grinding“To grind tongue, place parting edge of gauge rod so tongue surface DOES NOT rest in any of the grooves of the gauge rod and place a shim under the groove surface approximately equal to the thickness of the tongue. Clamp tightly, remove shim and grind as normal.” – page 301-302

Rod Honing

The most common way to recondition connecting rod housing bores is through honing. Machines can be set up quickly and produce a round straight bore that is often equal to or better than the OE manufacturer’s. Interchangeable mandrels of various sizes reduce set-up time so you can produce more in less time. Connecting rod mandrels use a double-wide stone arrangement designed to increase the stone surface area to better alignment and faster material removal.

Rod Honing OilAs with most honing operations, be sure to use enough honing oil. Always use a honing oil that is specifically formulated for this type of honing such as Goodson’s Rod Honing Oil (RHO-10 or RHO-50) or Sunnen’s Mineral Based Honing Oil (MAN-845). Also, keep your supply of honing oil clean by filtering it and changing it regularly. This will enhance its performance and improve your finished product.

Most rod honing is performed with a horizontal honing machine. These are available in manual, power-stroked or CNC options.

“Let’s examine some of the capabilities of manual horizontal honing machines. They can be used to size connecting rod housing and pin bores, small engines and motorcycle cylinder assemblies, and to fit steering king-pins, just to name a few. Any bored hole used for a bearing surface or alignment purposes can benefit greatly from honing. Closer tolerances can be maintained with greater ease and productivity.” – page 303

Common Bore Errors

There are ten common bore errors associated with machining, heat treating or holding the part. These include:

  • 10 Common Bore Errorsout of round
  • bellmouth
  • waviness
  • undersize
  • barrel
  • taper
  • boring marks
  • reamer chatter
  • rainbow
  • misalignment

Honing can correct all ten of these errors. Honing is characterized by “large areas of abrasive contact; low cutting pressure, low velocity, floating tool or part and automatic centering of the tool by expansion inside the bore.” – page 303.

Key considerations when Rod Honing:


Select the proper stone composition. There are generally four stone compositions from which to choose; roughing, general purpose, finishing and for steel. Both Goodson and Sunnen stones use the same numbering system. Roughing stones are 5s (for example: Sunnen’s KL-5 or Goodson’s HK-5), General Purpose stones are 7s, Finishing are 13s and Steel at 14s).

Select the correct housing unit. Honing mandrels are available in a wide range of bores. Depending on the part you’re honing, select the most suitable mandrel size. Follow the manufacturer’s directions for assembly and set-up.

One final thought

A final step when reconditioning connecting rods that is often overlooked is demagnetizing the parts before you start putting the engine back together. This is critical to prevent premature engine failure. Heat and friction from engine operation and the machining process can induce magnetism which must be removed. Check out this previous post on the importance of demagnetizing.

This has been a brief overview of connecting rod reconditioning. For more information, check out Engine Builder Magazine’s “Back to Basics: Reconditioning Connecting Rods” and “Connecting Rod Reconditioning: More To It Than You Might Think”. You can also read the entire section from the Sunnen Engine Rebuilding Handbook here.

As usual, if you have any additional questions about this topic, contact the Goodson Techxperts by email or phone at 1-800-533-8010.

Inspecting & Measuring the Pistons, Pins & Connecting Rods

Inspecting & Measuring the Pistons, Pins & Connecting Rods

Pistons should be inspected and measured at several locations including the skirt, top, middle and bottom ring lands and the pin bore.

The skirt should always be measured exactly 90º from the pin bore. The actual height location may vary from manufacturer to manufacturer, but most specify a location the same height as the pin bore location.

After inspecting the ring lands, check each with a new ring. It is important to use new rings for the measuring procedure because wear will reduce the width of the old rings. A feeler gauge is placed between the ring and the top of the land. Under no circumstances should the ring-to-land clearance exceed .006” (0.15mm). Worn out ring lands do not let the rings seal in the explosive pressures of the burning air-fuel charge. It is not advisable to reuse pistons during a rebuild and rings should never be reused.

The pin bore must be gauged with the AG-300 Precision Gauge. Bores should be round and straight, showing no signs of taper or out-of-round. Those exceeding .0005” (.013mm) should be fitted with oversize pins.  The following procedure is used to measure the piston:

  1. Select an appropriate sized micrometer and measure the piston skirt 90º from the pin hole location, as per manufacturer specifications. Record this measurement. Remember that the piston skirts are cam-ground (see image above).
  2. Measure the skirt just below the bottom ring groove and then measure the lowest part of the skirt. Record both measurements. Use them to determine the amount of taper found on the skirt. The bottom part of the skirt will always be larger than the top.
  3. Install a new piston ring backwards into the top ring groove. Insert the largest thickness feeler gauge that fits between the ring and groove. If the thickness exceeds .006” (0.15mm), replace the piston.
  4. Measure the pin bore for size and out-of-round, as per manufacturer’s specifications. Any deviation over .0005” (.002mm) is unacceptable and may require the installation of an oversize pin.

 Piston Pins

Inspect your piston pins for damage. Complete failure (breakage) of the piston pin is a very rare occurrence in engines. Damage caused from incorrect fit or detonation, however, are commonplace. Improper installation of the pin can cause galling of the pin, rod and piston. If left uncorrected, the piston pin bore will quickly fail. Oversize pins can often be fitted to the piston and rod to salvage the assembly.

Detonation damage to the piston pin can also lead to early pin failure. Over-advanced ignition timing is the likely cause. Another common problem you’ll see is pin damage due to inadequate use of assembly lube.

Connecting Rods

Today’s connecting rods strain under 3,000+ HP in racing engines or as few as 50 to 300 HP in a passenger car. Regardless of the vehicle’s use, the connecting rod must be free of defects, straight and on-size. If the connecting rod is overlooked during an engine rebuild, the result is shortened engine life.

The tunnel or housing bore of the rod plays a significant role in engine operation. It must be round and parallel to the piston pin bore. Surface finish must be quite low in order to efficiently transfer heat away from the bearing inserts.

After many hours of operation the housing bore can become out-of-round. The majority of the out-of-round condition can be measured where the cap and rod mate (the parting edge). Measurements at the parting edge tend to be larger than when the rod is measured end-to-end. Out-of-round is what we call the condition when one measurement location is larger than another 90º away. A limited amount of out-of-round is acceptable.

Connecting Rod Measurement

The connecting rod must be measured for alignment. In addition, it must be measured at the rod journal bearing housing (tunnel) bore, the piston pin (tunnel) bore and the center-to-center distance. The bearing housing and pin bores are measured with a Sunnen AG-300 precision gauge or dial bore gauge for size and out-of-round. Center-to-center distance can be measured with a vernier caliper.


The center-to-center distance between the large and small ends of the connecting rod must be maintained within .005” (0.13mm); in most cars, less is better. Diesel engines often require a maximum variation of .002” (0.05mm). The large and small ends of the rod should be measured for out-of-round, taper and barrel, and should not exceed a variation of .0005” (0.002mm). Measurements are performed with the Sunnen AG-300 Precision Gauge or with a Dial Bore Gauge. A snap gauge or inside micrometer is NOT advised.

Here’s how to measure the connecting rod with the AG-300:

  1. Set your micrometer to the minimum or maximum housing bore diameter.
  2. Install the appropriate gauge points onto the gauge fingers (see chart). Adjust the AG-300 precision gauge indicator needle to zero and lock into place.
  3. Place the rod onto the measurement points near the parting edge (beam facing 12 o’clock or 6 o’clock position) so that the thrust surface of the rod lays flat against the face of the AG-300. Next, rotate the rod until you obtain a minimum reading (rod beam will be located at or around the 3 o’clock or 9 0’clock position on the indicator). Any deviation from the maximum bore means that the rod should be resized by honing or boring.
  4. Place a pair of the appropriate-diameter piston pins into the setting block and clamp into place. Adjust the AG-300 Precision Gauge (zero the indicator needle) and lock into place.
  5. Place the pin end of the connecting rod onto the measuring points and rotate until you obtain the maximum size. If the size exceeds the manufacturer’s specifications the rod will need to be reconditioned.
Midget .375” (9.53mm) .750” (19.05mm)
Standard .720” (18.29mm) 1.530” (38.86mm)
Medium 1.500” (38.10mm) 2.250” (57.15mm)
Large 1.940” (49.28mm) 2.690” (68.33mm)
X-Large 2.625” (66.68mm) 3.375” (85.73mm)

One last warning; the area from 2 o’clock to 8 o’clock and 3 o’clock to 9 o’clock positions will experience the most out-of-round condition.

The rod is considered acceptable if the parting edge location does not entirely clean up during the reconditioning process. This small area allows a small pool of oil to form and provides increased oil wedge during lubrication. To promote this same effect, some bearing manufacturers make a “Delta-wall” bearing where the edges of the insert are thinned. By thinning the edges you promote the formation of an oil pool.

Connecting rods stretch slightly at the parting line during extreme operating conditions. The housing bore pulls in toward the journal, while the center-to-center length increases. Over long periods of time, the housing bore is forced out-of-round to a point that it never returns to a round shape.

Rods having “gone to metal” (housing bore making physical contact with the crankshaft) must be inspected very closely during non-destructive testing (NDT). Metal build-up on the housing bore interior should be removed with a file before reconditioning. It is imperative that these rods be resized before returning them to service. Should cracks or fractures be found during NDT, replace the rod without hesitation.

The press-fit piston pin retention system is used on most engines. It is important to measure the pin bore for size. Press-fit pin bores are made slightly smaller (approx. 0.0008” to 0.0012” or 0.02 to 0.03mm) than the diameter of the pin. CAUTION: Always measure the pin bore before the pin is installed. Excessive material in the pin bore will cause the pin to seize half-way through during installation and cause the pin to become loose. Oversize pins are available for most applications to correct loose fitting or out-of-specification pins. In the majority of cases, press-fit pin bores do not require reconditioning. If a press-fit pin must be resized for an oversize piston, so too will the piston pin bore.

On rods fitted with free-floating pins, bronze bushings are used to support the pin. There are two methods used for their repair: Fit an oversize pin to the rod and piston; or remove and replace and fit a new pin bushing for the same (stock) size pin.

The housing the pin bores must be perpendicular to one another. Misalignment can cause rubbing or the piston skirts on the cylinders and cause edge-loading on the bearing by the crankshaft. Both problems will result in early engine failure. Measurement of the rod for twist, bend and center-to-center distances are made with sophisticated rod alignment machines.

Goodson thanks Sunnen Products Company for permission to use this information from Sunnen’s Complete Cylinder Head and Engine Building Handbook.

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