Speedfoos Valve Lap

Just me and a buddy lapping my valves with a vacuum line and a drill.

Category:

Autos & Vehicles

Tags:

• Speedfoos
• D17
• Turbo

[DepakoteMeister]

It's a poor method.

Lapping involves turning the valve to and fro to perfectly match it to the valve seat. This method can create ridges detrimental to flow.

And of course modern valve and seat cutting is so accurate that lapping is no longer required post cut.

[speedfoos]

@DepakoteMeister

So you're saying when you tear down the head on a street car and have it resurfaced you shouldn't lap the valves back in so any oxidation and carbon on the valve seats and valves can be removed? We're not grinding new seats here, nor are we race prepping a cylinder head. Yes, ideally everything should be done via valve machine at a machine shop, but I've had good results with this method for years.

[seapeddler]

Do you remove the vacuum line when finished?

Or does the line supply vacuum to the valve?

Can you lap a valve with hospital-grade Seafoam?

[speedfoos]

I like to leave the vacuum line attached for easy re-lapping while the head is bolted to the car. Work smarter, not harder. I would have used medical grade Seafoam, but its not legal for purchase in my county. Stupid blue laws.

[seapeddler]

@speedfoos Humorous.

[speedfoos]

@seapeddler Indeed.

[speedfoos]

You're thinking about it too hard. The vac line (or any line with a small ID) slips over the end of the valve stem and you slip the other end over a drill bit. The valve springs and retainers are not installed when you do this.

[ctr99ek]

So the vac line is on the valve stem? not sure how you did this

[speedfoos]

Good. Keep doing it that way.

[ForSunday]

Hmm i think doing it by hand is more precise and reliable.