Is a Pitted Piston Top a Problem?

[revtim]

I have a Tecumseh OHH50 68002F 5.5 HP engine on a wood chipper that just dropped a valve. The little retainer ring had cracked and let it drop into the cylinder. I am getting a new head for it and would like to just go with that if possible however the top of the piston is scarred from the valve banging against it before it came to a stop. There is no hole in it. Can I safely run the engine with the damage to the top of the piston or do I need to replace it as well. Obviously, that would involve more cost and a lot more labor as well. Any input would be greatly appreciated.

 

[reynoldston]

I have a Tecumseh OHH50 68002F 5.5 HP engine on a wood chipper that just dropped a valve. The little retainer ring had cracked and let it drop into the cylinder. I am getting a new head for it and would like to just go with that if possible however the top of the piston is scarred from the valve banging against it before it came to a stop. There is no hole in it. Can I safely run the engine with the damage to the top of the piston or do I need to replace it as well. Obviously, that would involve more cost and a lot more labor as well. Any input would be greatly appreciated.

No problem. I have done it many times. If I was doing the job I would remove the piston just make sure the ring groves aren't damaged. . If you don't want to remove the piston, just try it and see what happens.

 

[Fish]

I would put it back together and run it, if the damage is in the center area.

I had one customer once mowing with his old ohv Tecumseh, he heard a loud whack, and mowed another 50 feet until it shut down. It had sucked in a throttle plate screw, and the
piston hitting it must have made hairline cracks in the rod, as well as embedding the screw into the piston top. The rod then crumbled soon after.

Pulled it apart, cleaned up the engine, everything looked good. Put a new rod in, plucked out the screw, new base gasket, and
new throttle plate screws, and he was back in business.