TrailTamer
New member
- Joined
- Apr 6, 2011
- Messages
- 246
I just rebuilt a 12v Cummins and everything went well until I test fire it. There was a bad noise within 5 minutes of run time. Borescoped & found valve impressions on top of piston #5. I had to pull the head to see why it no longer turn over 360* by hand.
I’ll pull the piston/rod soon. But, until then, what the hell have happened? How can the piston be loose, move by roughly 1/2” up/down by hand and is over-protruded, even after pushed it back down.
12v Cummins piston looses overextending - YouTube
I’ll pull the piston/rod soon. But, until then, what the hell have happened? How can the piston be loose, move by roughly 1/2” up/down by hand and is over-protruded, even after pushed it back down.
12v Cummins piston looses overextending - YouTube