Customer Support


Installation Instructions

PRIOR TO BALANCING:
Please verify that your entire shipment of RaceTec / AutoTec Pistons and related components have been packaged and shipped correctly . If for any reason this package or related components have been damaged or lost in transit, please contact the freight carrier or distributor where the pistons were originally purchased. The end user or engine builder MUST completely measure and inspect all parts supplied with this piston kit prior to balancing or final assembly for proper fit, clearance or concealed damage. Any pistons or related components, which have been altered or damaged in any way, are not returnable.

Custom pistons are returnable only for manufacturing defects.

Piston to Cylinder Wall Clearance: This set of RaceTec / AutoTec Pistons is manufactured from Aerospace quality aluminum alloy. Aluminum, when subject to temperature fluctuations, will expand accordingly. All RaceTec measurements are taken at a temperature of 72° Fahrenheit. Please keep temperature variations in mind when performing any final machining operations and setting final assembly clearances.

1. The "Gauge Point" or skirt measurement point on these pistons is located .200" up from the bottom of the skirt.
2. The actual running clearance for the pistons has been built into the design of the skirt shape. Please see the table below
for the normal range of clearances.
3. Performance applications using power enhance rs such as superchargers, turbo chargers, and n itrous oxide along with
cold water cooling may require additional piston skirt to cylinder wall clearance. Coatings such as Nikasil may require less
piston skirt to cylinder wall clearance.

RaceTec 2618
    Bore Range                 Min. Clearance
   3.000" - 4.000"             .0030" - .0038"
   4.001" - 4.250"             .0038" - .0045"
   4.251 " - 4.500"            .0045" - .0050"

AutoTec 4032
    Bore Range                 Min. Clearance
   3.000" - 4.000"             .0020" - .0028"
   4.001" - 4.250"             .0028" - .0035"
   4.251 " - 4.500"            .0035" - .0040"

PISTON DOME TO CYLINDER HEAD AND SPARK PLUG CLEARANCE :
All RaceTec / AutoTec high compression piston designs take into consideration the wide variety of aftermarket cylinder heads available today. We strongly recommend the minimum static clearances between the piston and cylinder head are no less than the following guidelines; engines with steel connecting rods = .040", and aluminum connecting rods =.060". These static clearances should be checked at Top Dead Center (T.D.C.) with the head gasket in place, the piston assembled to the connecting rod and crankshaft, and using modeling clay to determine the clearance. Make sure to rock the piston back and forth at T.D.C. to ensure a proper measurement.

VALVE TO PISTON CLEARANCE (V. TO P.): The actual clearance between the valve and piston is influenced by many factors; c am lift, rocker arm ratio, duration, lobe separation, valve margins on cylinder heads, f lat or angle milling of the cylinder head deck surface. RaceTec recommends a minimum clearance of .100' between the valve and piston. This clearance can be verified by using modeling clay. Please make sure to follow your cam manufacture r's recommendation for setting and checking clearances as well.
When checking these tolerances , make absolutely sure that the cam has been set or degreed exactly as it will be run in the engine.

CRANKS HAFT COUNTERWEIGHT TO PISTON CLEARANCE: This is the clearance between the bottom of the piston and crankshaft counterweight. Please make sure there is a minimum of at least .060" .

PISTON TO CONNECTING ROD CLEARANCE: Our piston forging designs are intended to work with the majority of aftermarket connecting rods available on the market today. We recommend at least .040" clearance in all directions when all components are assembled together.

WIRE LOCKS: (Standard on most RaceTec Piston assemblies) Wire locks are installed by taking one end of the wire at the gap and installing it into the receiver wire lock groove of the piston. Make sure to spiral the lock into the receiver groove of the piston.

DO NOT, under any circumstance, kink or squeeze the ends of the wire together to install. This may cause immediate failure of the wire to retain its original shape into the receiver groove. Using a 3/8 or 7/16 flat bottom brass drift punch will greatly help in pushing the wire locks into the groove properly. IMPORTANT NOTICE: Once both of the wire locks and the wrist pin have been installed into the piston, we strongly recommend using a brass drift punch to drive the wrist pin back and forth several times. This will help to seat the wire locks into their receiver grooves.

WARNING: Never re-use wire locks; they are a one-time installation part.

SPIRAL LOCKS : Spiral Locks should be gently pulled apart to approximately .250-.375 so that one edge of the lock can be inserted into the spiral lock receiver groove of the piston. Once this is done, gently spin the spiral lock so it coils itself into the receiver groove. This procedure should always be done by hand and never forced into the receiver groove with a hand tool. Most pistons using spiral locks will use two (2) locks per receiver groove for a total of four ( 4) locks per piston.

WARNING: Never re-reuse spiral locks; they are a one-time installation part.

Rail Supports : Rail supports, when needed, s hould be installed in the oil ring groove first , with the dimple facing down, and located in the wrist pin cu tout on either side of the piston. Once installed , it should be fully seated in the bottom of the oil ring groove before oil ring installation. The oil ring should then be installed in the normal fashion above the rail support.

NOTICE: Due to the inherent nature of performance products and applications, all parts and products sold by RaceTec Pistons, Inc. are sold without any expressed warranty of
merchantability. RaceTec Pistons, Inc. shall not, under any situation, be liable for any incidental or significant damages, including but not limited to, damages for loss of property
or equipment, lost profits or revenue, cost of purchase which may arise and/or result from the sale by first or second party sales, installation or use of these parts.
RaceTec Pistons, Inc. product is recommended for racing and/or off -highway use only. It is the responsibility of the end user to check local state and federal laws and emission
regulations prior to use.

RaceTec Pistons, Inc. reserves the right to make product improvements, change design, materials, and specifications, or make pro duct changes without incurring liability or
obligation with respect to similar products previously manufactured.

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