October '17

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44 THE SHOP OCTOBER 2017 SHOP TOOLS & EQUIPMENT either before you leave the shop or when you arrive home—drain water from the engine block. Depending on the quality of the dyno shop's local water supply, leaving water in the block's cooling jackets can promote rust. Once the engine is installed to the vehicle, fill the cooling system with a 50/50 mix of quality antifreeze and distilled water. CHECK FOR LEAKS BEFOREHAND In order to avoid unnecessary delays at the dyno, do your best to check for oil, water and vacuum leaks. By finding leaks before the trip, you'll avoid extended downtime on the dyno. Since dyno time is precious (generally charged by the hour), you need to try to avoid spending extra time and money. The better the prep, the more efficient and eco- nomical the dyno session will be. There are several ways to check for leaks before the trip. Try plugging the coolant outlet while sending water through the cooling system with a garden hose. This allows you to check for water leaks at the water pump and the block's water jacket plugs. A smoke machine is invaluable. It uses a liquid (essentially baby oil) under mild heat, which turns it to a steam vapor, which will not harm any engine parts. For instance, you can connect a smoke machine to the block's oil pressure gauge port. Escaping smoke may indicate a leak area (oil pan, rear seal, front seal, valve covers, etc.). A smoke machine's hose nozzle can be connected to vacuum ports, oil ports or coolant ports. Although not necessary, using an ultraviolet light may aid in detecting and pinpointing leak areas. It's not uncommon to have a few leaks at areas such as valve covers, oil pans, water pumps, possibly freeze plugs, etc. Finding and repairing leaks early will save time and money once you're at the dyno. OIL LEVEL It may seem obvious, but remember to add oil to the engine. The type of oil selection should be discussed with the dyno shop prior to your trip. Choosing the correct oil might be based on the specific type of engine, type of camshaft, oil recommended by the lifter manufacturer, and/or the experience of the engine builder and/or dyno shop operator. In addition to having the correct amount of oil for your sump capacity and filter size, key concerns may relate to piston ring break-in and camshaft break-in. If running a flat-tappet cam, the oil must contain the necessary amount of high-pres- sure friction modifier ZDDP (zinc dialkyl dithiophosphate) in order to allow lobe and lifter break-in. This is available as an additive or already contained in quarts of specialty oils/break-in oils. Even if you're running a roller cam, this additive will serve to protect valve tips if running high-pressure valve springs. Do not run a synthetic oil for break-in, as this may reduce friction to the point where the rings won't seat properly. Running a synthetic oil can also result in external oil leaks on older-vintage engines Prepping Your Engine for the Dyno Exhaust headers will get very hot during dyno pulls. If you supply your own headers, avoid those that are chrome-plated or specialty- coated, as they may become discolored, especially if fuel mixture is on the lean side during initial runs. Once the engine is "broken-in," you can install the headers of your choice in the vehicle. (Photo taken at Koffel's Place, Huron, Ohio) A load coupler is connected to the crank and a load housing will be bolted to the rear of the block. Make sure that you've already installed the bellhousing dowels. The dyno shop needs to use its in-house headers that are fitted with air-fuel ratio sensors and/or temperature sensors. Some shops will have headers fitted with individual temperature sensors at each cylinder, in order to gather cylinder-to-cylinder comparison data, which can then be referred to for fine-tuning, fuel mixture adjustment, valve lash adjustment, etc.

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