Installation Instructions for Speed of Air® Hyperformance PistonsTM
Please read all information before installation

Each piston will have the piston skirt dimensions, piston diameter and part number located in either of two areas depending on the design of the piston. (refer to figures 1 and 2 below).

Calculating the Finished Bore Size for Piston Skirt:

When using pistons that are coated with either UltraWear M42TM, the skirt coating is not added for calculation to determine the bore diameter. Do not measure over the coating and add clearance!

UltraWear M42TM

1. Locate the machined, un-coated skirt diameter dimension on each side of the skirt as shown below. It will be on either the piston pin pad or the wrist pin area on above the wrist pin.

2. Refer to the manufacturer’s recommended specification for cylinder-to-piston skirt clearance. Using the stamped as-machined, un-coated skirt dimension add the amount of clearance required. Example: Skirt dimension of 4.0265” + the Required clearance of 0.0035” = 4.030” finished bore size.

Fitting Piston to Cylinder:
UltraWear M42TM

1. Prepare piston with wrist pin but without rings and locks.

2. Holding the wrist pin, insert the piston upside down into a dry cylinder.

  • a. If any resistance or fitment issues: STOP and call Technical Support. Do not force the piston into the cylinder as it will damage the piston.

3. Clean the piston and cylinder for final assembly. Re-oil both cylinder and coated skirt. Complete assembly.

Break-In Procedure

The following procedures are designed to produce progressive heat cycles to allow proper seating of the piston rings.

Engine Dyno Break-In:

1. Warm up the engine normally with little-to-no load applied. Shut off the engine and allow to cool to ambient temperature.

2. Restart and begin warm up procedure by applying a light load progressively to about 50% load with a minute of idle time between loaded run time. This allows the piston to cool and collect more oil on the skirts. Run times should be about 10 minutes. Shut engine off again and allow to cool. Note: This procedure will also allow sufficient break-in of flat tappet cam shafts.

3. Restart and proceed with your normal break-in procedure to full load.

In-Vehicle Break-In:

1. Start engine and check ignition timing. Allow engine to warm up to at least 160 degrees. Vary the RPM slightly with no load on the engine. Note: This procedure will also allow sufficient break-in of flat tappet cam shafts. Shut engine off and allow to cool to ambient temperature.

2. Restart engine and warm back up to operating temperature with a slight load applied and varying RPM.

3. Now apply some load for 15 minutes to bring up the piston temperature progressively, starting with light to medium loads. Driving the vehicle is the best way to apply loads. Allow a minute of idle time between loads to allow the pistons to cool and collect more oil on the skirts. Progress to heavier loads.

Note: Many factors determine the number of progressive heat cycles. If the engine seems tight when advancing to the next power level, shut the engine down and allow it to cool allowing more oil to collect on the high spots. Restart engine and give more time at previous power levels.

Questions on Installation or Break-in?

Please contact Speed of Air Engine Technologies, LLC Technical Department toll free at (833)-7624649 ext. 2 or email

Notice to Customers in California:

Speed of AirTM Engine Technologies LLC sells competition use-only performance parts. Competition use-only parts are clearly labeled as competition use only in the product listing page and may only be used according to the guidelines posted below.

Competition use-only parts may not be sold or used on a vehicle that is used on or off highways other than those vehicles used exclusively for competition. Competition use-only parts are aftermarket parts that replace or otherwise interfere with the operation of an emission control device such as a catalytic converter or oxygen sensor and may be sold and used on an automobile that is used only for closed course competition.

THESE PARTS ARE LEGAL FOR USE ONLY IN COMPETITION RACING VEHICLES AS DEFINED UNDER THE CALIFORNIA LAW AND ARE NOT LEGAL FOR USE IN ANY OTHER MOTOR VEHICLE California law defines a “racing vehicle as a competition vehicle not used on public highways”. (Calif Health & Safety Code 39048). These parts may only be used on competition vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event. Competition only motors vehicles may not be driven to a racing event on a public highway and must be transported on a trailer or other carrier. USE OF THESE PARTS IN ANY OTHER VEHICLE MAY SUBJECT YOU TO FINES AND PENALTIES FOR VIOLATION OF FEDERAL AND/OR STATE LAW. It is your responsibility to comply with all applicable federal and state laws relating to use of these parts in compliance with all applicable federal and state laws.




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