Machine Builders Network+ Forums Machine Builders Network General Discussion Anatomy of an engine failure

It may be understandable that I have become somewhat evangelical about molybdenum disulphide usage in all my engines.

Another remarkable thing about the torn down engine was at the time they were selling for about $90. When I realized that the Harbor Tool engine was basicslly identical to those being used on the 1500W generators I bought one to replace the engine on the cheapo generator. Not actually a bargain in terms of labor. The exchange requires a complete dissasembly of both engines and total reassembly of new engine using only the tapered shaft crankshaft off the old engine. Total time for swap out about 9 hours. (At least for me.) Reason heads have to come off is that the govenor drive gear hits the skirt of the piston, preventing crankshaft removal without pulling head to move piston out of way. Otherwise swap out could be accomplished in far less time. (I guess part of that 9 hours was due to farting around trying to remove crank without pulling head...)

Anyway, when all was apart I took the time to mic the connecting rod journal on both new and old engines. Verified that the old crank was within a thou of the new one. Not suprising given connecting rod being made of aluminum and crank of cast or forged iron. So virtually all wear occurs on conecting rod bearing.

The swap out does sacrifice the low oil shut off switch as the HF engine doesn't come with one. Not a big loss. In exchange the HF engine comes with a full metal cam. (Unlike the original gen engines which were nylon and typically failed at about 1050 hours (+/- 50).) Guess I've swapped out about three of the engines so far. Have another waiting for me right now... if I ever become mobile enough again to perform the swap.

Doc