If you’ve been around cars a while and had a few projects, chances are you’ve gotten a mystery motor. A mis-matched, grab-bag motor can be a scary unknown when it comes to defining your build, but it can also be a steal if the parts inside are worth the risk.

Identifying the pistons in your engine can be a difficult task if you don’t know how to read the signs. Piston statistics are vital when determining several engine conditions. Deck height, compression ratio, valve clearance, and extension camshaft size. Piston construction is also an important point to understand when selecting these aluminum reciprocating parts. Forged, cast, cintered, hyper-eutectic? What sort of engine application you have will determine what properties you want in a piston.

If you are lucky enough to open your engine, and find the forged aluminum beauties produced by JE Pistons you are in luck. JE uses a coding system that makes its products traceable. In this video, Sean Crawford of JE Pistons walks us through the tell-tale signs to identifying the JE Pistons you have found in your mystery motor. A six-digit part number can be used to cross reference the piston through the JE website. If a part number (PN) is absent form your piston it may have been a custom order. Below the part number another six-digit number denotes the job number or order number. With this number, a quick phone call to JE will net you the history of your custom piston.

So next time you encounter a JE Piston, fear not that you have an unknown variable. A visit to JE’s website or a phone call is as far as you need to identify your piston.