APC™ - Frequently Asked Questions



How thin/thick can you apply APC?
As little as .00035” per side (.0007” diameter) to .010” per side (.020” diameter) or more

What is the price for APC skirt coating?
Prices vary according to the number of pistons. There are also additional charges for extra thickness, oversize pistons and large diesel pistons. The cost schedule is listed on the ORDER FORM

What is the turn-around time?
Standard processing time is 7 to 10 days. We also offer expedited services ranging from same day processing to guaranteed 5 day for an additional fee. These fees are listed on the ORDER FORM

Does it matter whether the pistons are new or used?
No, we can successfully coat either type.

What if my piston skirts already have a coating on them?
Coating preparation includes removing any existing skirt coating to insure the best adhesion.

How much weight does the coating add to the piston?
The weight that APC adds to components is negligible so there is no need to re-balance any part of the rotating assembly.

If I want to coat my pistons will I have to change my clearances?
No, continue to use your preferred set-up. APC is designed to be self-clearancing and can be accurately applied to a thickness tolerance of .0005” +/-.

Which abradable coating is right for my application?
APC is offered in several different formulations. The engine information that you provide on the top of the ORDER FORM will help the coating lab determine the correct formulation to use.

How do you know how much coating to put on my pistons?
Every Order Form includes a Thickness Calculation Worksheet. When ordering, you can either specify a Target Coating Thickness based on your worksheet calculation or just indicate a specific thickness to be added to the diameter. That and the engine information that you provide on your ORDER FORM will help the coating lab determine the correct amount.

My cylinder bores are different sizes. Can you size each piston to a specific bore dimension to fit each cylinder?
Yes, we can size each piston for a specific bore. Please include a note indicating the bore size for each cylinder of your engine (Example: Piston #1 = X.XXX", #2 = X.XXX", etc.) Be sure to check the box labeled "Individual sizing" (located just under "Additional Charges") on your ORDER FORM. Write "SEE NOTE" in the blank space next to "Finish Bore Size".

How about if my cylinder bores are all the same size but the pistons are different sizes due to wear, skirt collapse, etc?
Provide the Finish Bore Size in the space provided and be sure to check the box labeled "Individual sizing" (located just under "Additional Charges") on your ORDER FORM. We will then measure each piston to determine the amount of coating that needs to be added to achieve the correct size.

Can you coat the ring land area?
Yes, but it adds considerable cost to the job. Coated ring lands can help minimize rock-over and keep the piston straight in the bore in stroked engine applications.

After my engine is assembled with APC skirt coated pistons, what is the recommended break-in procedure?
The break-in procedure depends on the power level, engine type and how tight the piston coating is to the cylinder wall when it was built. If more than 75% of the clearance recommended by the piston manufacturer is taken up by the coating, then it is important to do heat cycles and create conditions that sequentially heat/expand the PISTONS in short bursts to higher and higher temperatures with time to cool at idle between intervals. The temperature of the pistons is related to the power so there needs to be a load on the engine when increasing PISTON temperature at each interval. This means that you can’t break in the coating on a run stand or just with heat cycles and no load present. If you have a filled block or a high power engine for drag racing the pistons will expand faster so you have to be more careful on the break-in, or build in some extra clearance knowing that the pistons will grow quickly.

Water cooled versus air cooled, piston alloy/architecture, and other factors can all contribute to the break-in schedule. As a rule of thumb, if you don’t know how an application will behave with abradable powder coated pistons then start off with more clearance and stay light on the power during the break-in. You can always go tighter on the next build.

Do you offer a crown coating?
Yes. ThermBar™ thermal barrier coating is a reflective type coating composed of ceramic and metallic materials.

How thick is it?
ThermBar as applied is .002” or less.

How long will the skirt and crown coatings last? Many dry film lubricants are designed to be "sacrificial" and eventually wear out. APC is designed to clearance itself until the optimal fit is achieved. The porosity of the coating helps maintain the oil film that the piston is riding on. Theoretically, the coating could last indefinitely under these conditions. Barring any catastrophic failures, ceramic thermal barrier coatings are virtually permanent.

What components can benefit from coating?  

APC –pistons, oil pumps, superchargers/blower rotors, turbo housings, gears

ThermBar –pistons, valve faces and stems, exhaust ports and combustion chambers