In the last couple of years we have discussed the various maintenance requirements for your big machines – surface grinders, crank grinders, cleaning machines, etc. Let’s not forget those other devices that play a pretty important part in your continued effort to build the best engines you and your employees can offer to your valued customers.
Air compressor: We generally take this unit for granted, due to its place in the shop. Let’s face it; all it does is supply compressed air to all of our machines and the various departments. If we allow this machine to go down all is lost until we get air back into the system. Trust me, blowing into the end of your air impact wrench ain’t gonna get it done.
When was the last time you changed the oil in your air compressor? This oil change needs to be done at least every year using non-detergent 30-weight oil. As always check your owner’s manual and conform to the manufacturer’s recommendations for the proper oil for your compressor. There is a “compressor cool” additive that helps to keep the compressor oil cooler and minimizes condensation in the pump.
Next inspect the drive belts for wear. Always replace them in matched sets to keep balanced tension from drive to driven pulley. Also, make sure your belt guard is doing its job; if it’s barely hanging on, take a few minutes to affix it properly.
Look under your air storage tank and you’ll see a water drain valve. Compressed air creates condensation and condensation is water. During the summer you may need to drain this reservoir daily, during cooler months at least once a week. I recommend an in-line water separator and automatic oilier attached no less than 10 to 12 feet from the air compressor. This distance allows the air to semi-cool prior to going through the filter and allows the filter to do its job better. Keep in mind some of your high-dollar machines need air to run; we don’t want any water to create rust or contamination in those air systems.
Now follow all of your air lines through the shop. Are there any leaks? If you have leaks you’re wasting money in electricity to replenish the air supply. Take the time to repair all air leaks in the shop.
I like to see automatic oilers at the air stations that feed your hand operated air tools. Most of your big machines come standard with filters and oilers. Water and grit in your airlines will shorten the life of your air tools. There are little caps available that are used to cover the nipple of your air tools when not in use to keep any debris from getting inside your air tools.
Hydraulic press or H-frame press: Most shops have a hydraulic press for the pressing jobs that come through the shop. Change the hydraulic oil in the press at least every two years with high quality non-foaming hydraulic oil.
Does your press have a tonnage gauge? Does it work? It’s important to know how much pressure you are putting on a part. If the gauge isn’t working properly, replace it. Some presses use air over hydraulic to create the necessary pressure. Again, make sure there is an oilier and water separator on the press and periodically clean and add fresh oil. Inspect your pressing tools for nicks, burrs, mushrooming, etc. If your tools are mushroomed, accidents will happen. Replace your worn tools. Always wear eye and face protection during any pressing job.
Bench grinder: Inspect the grinding wheels and dress them to ensure they are straight and true. Look at the wire brush for any missing wire. Replace the whole brush as needed. Inspect the bearing for noise and replace as required. Make sure your safety shields are in place and always wear eye protection and face protection.
Seat grinding kit: A seat grinding kit is a must-have tool for single combustion chamber jobs, as well as small displacement or very large valve jobs that don’t mount easily to your cylinder head machining center. Inspect your dresser diamond to make sure it has a point. Make sure the threads the diamond screws into are clean and re-tap as required. Check the stone holder pilot in the dresser: over time it will wear and needs to be replaced. Measure the ID of the stone holders for wear. You can simply put a brand new pilot into the stone holder, and pull it out and listen for a popping sound, this popping sounds tells you that the clearance is tight, however we are machinists and I still recommend that you measure that ID to eliminate any guess work. Spin the stone holder and listen for any bearing noise or grit contamination noise to see if it needs to be replaced.
Now organize your pilots according to size. Measure the top portion of the pilots at the top and the bottom and note the difference. If you have more than .001” in wear that pilot is junk and needs to be replaced. If the tops of your pilots are worn, your valve seat concentricity is compromised. If you use an air grinder, clean and lubricate daily. If you use an electric grinder, pay attention to the trigger assembly. See any sparks when you press the trigger? Replace that switch, before somebody gets shocked. On either unit the nose bearing assembly will wear and replacements are available.
One last thing; use bounce springs when grinding your valve seats. These springs allow the stone to automatically lift off the seat and actually leaves a nicer finish, while controlling chatter.
See you in the Shop!