Let’s talk about the valve refacer. I mean you all have one. Some of you have two. My question today, is what is the program in your shop to maintain that piece of equipment? It is one of the more critical machines you have. Without a concentric and properly ground valve, your whole valve job will be compromised. So how do you keep your machine in tip-top running condition? Well that’s what I am going to talk about today.
Whether you have a Rottler, Kwik-Way, Sioux, IDL, Sunnen, Van Norman, Black & Decker, Thor, KO-LEE, Skill, Snap-On, Comec, or SERDI, they all will need daily and weekly tender loving care to ensure the machine will continue to provide the necessary accuracy and durability you require for you and your customers.
First, start with a clean machine. There is nothing worse than trying to grind valves with a dirty, non-maintained machine. Take a little time at the end of each day to ensure your valve refacer is wiped down and ready to use when you come to work the next day. Start by using a shop towel to wipe off all excess oil, grease and grit from all surfaces. Then get the heavy-duty cleaner and wipe down all surfaces again.
On at least a monthly basis, empty the coolant/oil reservoir and wipe out the sludge. If your machine is equipped with a strainer or filter for the oil make sure that gets cleaned out as well. Turn your machine on its side and clean all of the surfaces to remove the buildup from underneath.
Next, go through and make sure your drive belts are in good shape. Look at them as you would a fan belt on your car. If you see cracking or flat spots it’s time to replace the belt. Look at the pulley grooves. Are they clean? Make sure the pulleys are running true and don’t have chips in them. If it’s a cog-type belt, make sure the cogs are clean. Double-check the set screws that hold the pulleys to the drive shafts. They will have Allen screws that can loosen up. Tighten as necessary.
Now, check the slides (or gibbs, as they are often called). These are critical to the proper operation of your machine. Most of these slides are designed to be adjusted periodically. They do wear, and if you don’t keep them adjusted they will not provide the smooth movement you need for grinding, compromising the accuracy of your machine.
Check for bearing noise. Start the motors one at a time and listen using a mechanic’s stethoscope for minute noises associated with bearing failure. Replace questionable bearings before your machine breaks down during an important job.
You should listen to your valve chuck as well. It will talk to you when it needs service. Each manufacturer has a very specific procedure for this adjustment. Make sure you consult the manual for the proper method for your model. Put a piece of drill stock in the chuck and get out your dial indicator to check the degree of run out you have. If it’s excessive, readjust your chuck to the correct specification. If the run out does not improve, it’s time to replace the chuck. Always consult the manufacturer’s manual to ensure this procedure is done properly.
There may be times when you need to work on very small-stemmed valves. Most of the later multi-valve overhead cam cylinder heads have extremely small stem valves as small as 4mm. When this job comes in don’t turn it away, you can add a chuck adaptor that is designed to accommodate these smaller valves.
Now that everything is clean, repaired and adjusted you can start grinding valves. Start by putting in real valve grinding oil. Keep in mind there are some machines designed to run synthetic, water-based coolant.
Mount the stones according to the procedure in your instruction manual. Remember: ARROW UP.
In today’s world, one wheel will not be effective on the all of the different material valves are being made from. You need to make sure you have the correct wheel for the material you will be grinding. The most popular is the standard go-to called the “general purpose” or GP wheel. This wheel is your day-to-day wheel for Chevys and Fords with standard iron and steel valves.
Stellite is the wheel you will need to grind the Stellite material found in the diesel or industrial type of engine valve.
Titanium is for the total “Go Fast” engine crowd out there. These valves can cost over $100 each and you’d better make sure you have the correct abrasive or you can actually ruin these high dollar valves. I also want to take a second and encourage you to keep a very sharp diamond for dressing as we really need to open up the face of the wheel for titanium, which can be a smeary material.
Valve Grinding Oil
A pet peeve of mine is using transmission oil in your valve refacer instead of valve grinding oil. You should not use transmission oil to grind valves. Yes it is an oil, and yes, it is cheap. However, transmission oil will actually attack the bond that holds the grains together, decreasing the life of your abrasive dramatically. It will also not prevent the buildup of valve material into the abrasive wheel.
Use premium valve grinding oil in your valve refacer. Make sure it is designed specifically for grinding valves. Also make sure that your operators are aware that not all oil will serve all applications for the various material valves are made from. Just like having the correct valve grinding abrasive wheel you need to match it to the correct oil for that material. Grinding valves made from steel or iron using good, high-quality valve grind oil is key to success. However, when you grind the valves made from titanium or Stellite you need to change the oil to a type that is designed and enhanced to grind these types of materials. Titanium is a very smeary material when ground and oil designed for titanium will prevent stone loading and you’ll actually be able to grind more valves between dressings.
Diamonds are not just a “girl’s best friend” they are also an engine builder’s best friend. Diamonds are very hard, but dressing diamonds need tender loving care and need to be inspected daily or at least weekly. The inspection should include a good look through a strong magnifying glass to see if there are any fractures in the structure of the diamond. Look closely to ensure the diamond still has a point. If a flat has been ground into the diamond face it will actually close off the grinding ability of the abrasive. You always need to have a sharp diamond for dressing any abrasive.
Keep in mind that you can affect how an abrasive wheel grinds by adjusting the speed in which you draw the diamond across the face of the abrasive wheel. To dress an abrasive wheel properly you draw the diamond across at a medium speed. If you increase the speed in which a diamond dresses the abrasive wheel you will open up the structure of the wheel and make it grind faster. If you slow down the speed in which the diamond dresses the wheel you will close off the structure and make the wheel act like a finishing or polishing wheel. Find the speed you like and ensure you dress the abrasive wheel in the same manner each and every time.
Dressing the butt stone is critical as well. First, check to ensure the butt grinding attachment is true to the wheel using a dial indicator. Sweep the surface – if it is not 90 degrees adjust it until it is. Again, use a sharp diamond and dress this stone as you would the valve face stone.
Remember, it’s the shop that keeps its equipment tuned and ready to take on jobs your customers are relying on. Your customers will appreciate you providing them with a clean, quality product, mirrored by the organized and well-maintained shop you keep.
See ya in the shop!