BRM's Flexible Honing, Surface Finishing, and Deburring Blog Blog

BRM's Flexible Honing, Surface Finishing, and Deburring Blog

BRM's Flexible Honing, Surface Finishing, and Deburring Blog is the place for conversation and discussion about how to solve difficult finishing problems. For over 50 years, Brush Research Manufacturing (BRM) has helped customers use brushing technology to clean, rebuild, and resurface components ranging from engine cylinders to brake rotors to flywheels to firearms. BRM's Blog on CR4 provides real-world examples of how flex hones and wire brushes work. It also evaluates related technologies and invites questions from the community.

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Valve Jobs in Classic Car Engines

Posted November 05, 2012 1:03 PM by Brush Research

Leaded gasoline boosted engine compression, reduced knocking, and provided lubrication for valves and seats. An inexpensive octane booster, anti-knock agent, and valve wear preventive, tetraethyl lead (TEL) also fouled spark plugs, gummed up engines, and polluted the air via automobile emissions. Today, most countries, including the United States, have banned TEL from motor fuels. For the owners of classic cars, the end of leaded gasoline means lead substitutes, alternative fuels, or engine overhauls.

Valve Jobs and Unleaded Gas

As Jim Smart of the Auto Enthusiast Weekly explains, "there's everything to be gained" by overhauling your classic car's engine so that you can use regular unleaded gasoline. Engine mechanics need to start with a plan, so Jim recommends "a blueprint valve job that includes new valves, guides, hardened seats, value springs, and Viton seals." The services of a competent machinist are essential, and all valve jobs should begin with value guides that are in parallel. The right tools for a valve job are important, too, and that's why we recommend a small-diameter flexible hone.

Valve Guides and Bronze Inserts

As the slide show that accompanies Jim's article explains, valve guide honing is a key part of the engine overhaul. Although some engine builders replace their valve guides altogether, others keep the factory originals by using bronze inserts. Acting as a valve stem bearing, the bronze insert is driven into the factory value guide. "Bronze inserts," Jim explains, "are an economical high-wear answer to valve job life because they wear well and control oil flow to valve stem". Measure the valve stem to the proper size, and then use a ball hone to improve the surface finish, "like honing a cylinder bore for piston rings".

Flexible Honing for Valve Guides

Built with a stiff metal steam and abrasive nylon filaments, the Flex-Hone from Brush Research Manufacturing (BRM) is a cylinder honing tool that features abrasive globules for a soft cutting action. Unlike honing stones or other rigid hones, BRM's flexible hone produces a uniform pattern of peaks and valleys for optimum oil retention. Users sometimes call our brush tool by other names (including ball hone), but the results speak for themselves. For valve jobs in classic car engines, we recommend using a small-diameter Flex-Hone.

Author's Note: This CR4 blog entry originally appeared in BRM's Flex-Hone Blog.

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#1

Re: Valve Jobs in Classic Car Engines

11/05/2012 5:33 PM

I always used a drill motor and valve grinding compound. Works great!

The one thing I would consider, if doing a complete rebuild on an older car, would be to switch over to synthetic motor oil.

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#2

Re: Valve Jobs in Classic Car Engines

11/13/2012 4:32 AM

hi this is a helpfull piece of information thanks.

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#3

Re: Valve Jobs in Classic Car Engines

11/24/2012 5:43 PM

Since "classic" cars are old, and often have high mileage, their engines usually need rebuilding despite lead no longer in gasoline. So it makes sense to do all of the things recommended in this article if you need to rebuild anyway. Octane has also gone down, so you might consider lowering compression via dished pistons or thick head gaskets. If originality isn't important, you can replace your carburetor with computer-controlled fuel injection and possibly keep your original compression. But it is still good to clean up cylinder sealing and valve train geometry.

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