Valve Lapping 101

Okay, you lot've already cut or footing your valve seats to the correct angles; you've basis the valve face in your valve refacer. Are you ready for final associates of the cylinder head? Maybe, maybe not. The side by side pace in many cases is to lap the valve to the valve seat for a final, perfect fit.

Valve Lapping with a hand held lapping stick

Lapping has been around for as long as engine edifice has been around. It's a very simple, straightforward process.

All lapping tools work in the same manner. This means the tool is attached to the valve head, lapping compound is applied to the valve seat or the valve face and the tool is rotated left and correct to lap the valve to the seat. It's kind of similar trying to commencement a campfire by spinning a stick fast enough to create plenty heat to ignite your kindling. Of grade, with valve lapping you're not going to even try to start a fire, but the motion is the similar.

First, select the type of lapping tool yous prefer. Goodson offers a diverseness of types and sizes including:

  • Traditional Valve Lapping Sticks (VLS-xv, VLS-thirty)
  • An Extra-Large Mitt Valve Lapping Stick (VLS-75)
  • Vacuum Style Lapping Sticks (VLV-fifty)
  • Powered Valve Lapping Tool (VLP-100)
  • Air Powered Valve Lapping Tool (AVLP-300)

Allow's take a await at each of them.

Traditional Valve Lapping Stick

The traditional and extra-big lapping sticks are operated entirely by hand. They include a suction cup on one or both ends that you'll utilise to attach it to the valve caput. Sometimes a little spit will help to keep the suction loving cup attached. Of form, information technology's always best to make certain all oils have been removed from the valve surface to ensure the suction cup mates to the valve. Suction cups are available in a variety of sizes to fit a range of valve heads.

Vacuum pump valve lapping stick

Some other blazon of valve lapping tool incorporates a pump to create vacuum to ensure the tool stays attached to the valve head. Don't play with these unless you want to give yourself 1 heck of a hickie. They generate a lot of vacuum!

Powered Valve Lapping Tool

If y'all're looking for a powered lapping tool, you're in luck. Goodson offers ii of them. First is the Powered Lapping Tool that you drive with a power drill. The tool is designed to change the rotary action into an effective oscillating move.

Air Powered High Performance Valve Lapping Tool

Last, but non least is the meridian shelf unit of measurement that most NHRA Acme Fuel teams (and other race teams) use. The Air Powered Valve Lapping Tool. This heavy duty unit operates on xc PSI of shop air and makes quick work of valve lapping.

The only affair left to talk about is Lapping Chemical compound – a silicon-carbide, grease-based paste.

Valve Lapping Compound, several sizes and grits available

Selecting the correct lapping compound is generally a matter of personal taste. Goodson offers several grits; from 120 to 1200 so you lot have lots to choose from. If you're only getting started, yous may want to experiment with unlike grits until you discover what works best for you lot.

There are pros and cons to valve lapping and over time, y'all'll find out which applications need to be lapped and which ones don't. Practice makes perfect, but keep one matter in mind:

Lapping is a finishing step and should NOT be used to correct a bad seat, or worse yet, a valve that is improperly ground.

Equally e'er, if you have any questions nearly Valve Lapping or whatsoever other engine building topic, contact the Goodson Tech Services Department at 1-800-533-8010.