Tech Solutions: Tips for Engine Performance Builders

May 1, 2009

Tech Solutions is a new section that will run in select issues of Hotrod & Restoration throughout 2009. The page is an opportunity for our readers who are professional performance engine builders to share their expertise with other builders. To submit a Tech Solution, email Mike Mavrigian at Tech Solutions is sponsored by MAHLE.

Close to Home

Since most of us don’t own an engine dyno, we end up farming this out to a shop that does have a dyno. Here’s a tip for those engine builders who haven’t dyno-run an engine before: try to find a dyno that is as close to your shop as possible. The reason is that things rarely go as planned. You might run into setup problems or you might need to run around trying to find a carburetor part, etc. Also, you may run into an oil, vacuum or coolant leak that will need to be addressed before making the final pulls. All sorts of things can happen that will require more time. It’s always best to find a dyno as close to your home base as possible to avoid spending a night in a motel. Plus, the closer you are to the dyno, the better chance you have of running back to your shop to grab a part. Plan ahead and keep the trip as short as possible.   Jody Holtrey Medina Mountain Motors Creston, Ohio

Don’t Guess on Torque

If you’re faced with trying to torque a bolt head or nut in a difficult-to-access location, an offset wrench might do the trick. Snap-on (and probably some other tool makers) offers a 2-in.-long offset flat wrench that features a 12-point box wrench at one end and a square drive at the other end. Attach this to your torque wrench and tighten away. Because of the 2-in. extension length, you’ll need to compensate for the torque setting by reducing it. The formula to follow is to take the length of the torque wrench (head to grip) plus the length of the extension, then divide the length of the torque wrench alone by the new total wrench and extension length, then multiply that by the desired torque value. So, if the desired torque is, say, 65 lbs./ft. and the torque wrench plus the extension is, say, 16.5 inches, you’d set the torque wrench to 57 lbs./ft. Using this extension along with your torque wrench is a lot more accurate than just using your arm as the gauge. The Snap-on dealer might have to special order the extension, but it’s worth it. Jeff Lance Allan-M&S Auto Machine Wadsworth, Ohio

Nitrogen Saves Tools

If you’re faced with working a race, either on your own racecar or a customer’s car, make sure you have a compressed nitrogen bottle on hand to run any pneumatic tools. Compressed nitrogen is commonly used to inflate race tires because nitrogen doesn’t carry moisture (which helps keep tire inflation more consistent as the tires heat up). But using nitrogen for your air tools also saves the tools from moisture contamination, bearings on your tools will last longer. Be sure to fit a regulator to the bottle, since nitrogen is compressed at about 2,000 psi. Mark McMahan McMahan Autosports Akron, Ohio

Aluminum versus Iron Heads

When a customer wants to switch from iron to aluminum heads it’s often because they think that the advantage is the reduction of engine weight. Make them aware that because aluminum dissipates heat much faster than iron, the use of aluminum heads will likely require more timing, since the reduction of heat and chance of detonation has about the same effect as running almost one full point in compression ratio. This is why you can run a bit more compression with aluminum heads. Rick Gable Gable Machine & Engine Akron, Ohio