PSC31 Engine rebuild

[lsbrodsky]

Hey all,

Finally got to examine my removed 3GM30. The problem was a catastrophic failure of the rings on #1 piston. Deduction leads me to conclude that this was directly related to the haul out and the hard start when I picked up the boat to go home. There are stories about tilting the boat too much and getting water into the exhaust manifold. Quite likely that was the problem although I could never prove it because I never saw the lifts. Despite many cautions about babying the engine by running it at too low of a speed for too long, there was absolutely no indication in the cylinders that this was a problem. In fact, except for the scored #1 cylinder, everything was beautiful. I think that kills the myth that running at 2000-2500 for cruising speed is detrimental to the engine. This turned out to be a very expensive haulout, although I don't have the bill yet for the rebuild. On the plus side, I will now have a rebuilt 3GM and don't expect anything other than routine maintenance for a long time.
Larry
ASYLUM
PSC31

[Vasco]

Larry,

Was your engine hydrolocked? This can happen when you keep cranking [b]without[b] shutting the raw water intake. Seen that happen to a 3GM30F. Bent the rods and sheared some bolts off the crankshaft.

[lsbrodsky]

Probably not, no damage other than cracked rings. Mechanic thinks that could have occurred with a small amount of water present. I am well aware of the prohibition about cranking too long. This start was a slow and rough start, very much unlike the past history of the engine. Subsequent starts, even days later, were just fine. This engine has always fired right up, except when it was time for injector service and the weather was cold. New injectors solved that problem. But, on the trip home after this rough start I had the first oil leak ever, which led me to high crankcase pressure, which led to the engine being removed. I was smart to get to it quickly. I probably only had 3 hours of run time on it with the oil leak.

Larry
ASYLUM