OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs valve stem grind

Can I ask what method people here adopt for grinding valve stems for returning clearances to correct spec when tolerances are tight?

Hi Aldo. My method is to clamp a short piece of steel about half to an inch square to the bench grinder's tool rest. I set up the steel block with a square so that it is exactly at right angles to the side of the wheel. Then I hold the valve stem firmly into the corner between the tool rest and the base of the steel block, so it is guaranteed to be square to the wheel both horizontally and vertically. Hold the valve head to apply light stem-end contact with the side of the grinding wheel and rotate the valve.

Tecumseh's service procedures specify the same method but with a short V block clamped to the tool rest, instead of the square block.

Do not expect good results from anglegrinder-based solutions. The wheel of an angle grinder does not run especially straight: the bearings have slack and are too close together. The usual wheels are also much too coarse.

Thanks Grumpy.

I got heavy handed on the exhaust valve and went over by .006". What would be the best method to rectify this? I have no tool to cut the seat so my options are leave it, lap the existing valve, replace the valve and start again?

It's a bit late now but the way to avoid that outcome is to keep dropping the valve back into the guide, holding it down with a fingertip, and measuring the tappet clearance. You just keep doing that after a second or less of light-pressure stem grinding each time.

I don't recommend cutting (or, heaven forbid, lapping) the seat deeper by anything like that amount anyway. The best answer in my opinion is to buy a new, or better, find a second hand, valve.

Thanks Grumpy, I have located a replacement valve. I needed to reassemble the engine for floor space and it started and ran nicely. I will install the new valve and try a better system to ensure an even grind on the valve stem.

The excess clearance seems to make the starter harder to pull. I'm guessing the decomp feature is minimised as you mention in the other post.

It does start on the first pull every pull though now unlike before it was a bit iffy on a hot start.

I don't know of that side valve engine having a decompressor Aldo. However you reported that the tappet clearance was negligible, so there is a good chance the exhaust valve was not seating properly. Now that you have clearance it should have more compression, which will both make the starter cord harder to pull, and improve the way it runs.