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- Mar 13, 2022
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Hey yall, had my first flywheel issue:
Rebuilt an echo QV 6700. New everything. Even upgraded to the grey echo, newer pawls/flywheel. Cinched down the flywheel nut very tightly.
Started tuning the saw from a rich tune, to right where the rpms peak off a righ tune. That's when the harmonics of those upper RPM's loosened that flywheel and sheared the flywheel key.
Very discouraged, after adding up the cost of all these parts and time into this saw. So much so, that it had me questioning why the fk I even mod saws. Why can't I "leave good enough alone"?
Anyhow, after some rest, I realized that it's a lesson in disguise: you can't just wipe that surface and call it clean. It was my fault. I remembered my welder talking about how he had trouble welding my full wrap handle on another saw, as the aluminum was impregnated with oil.
Another instant, I had rebuilt the high-pressure oil pump (hpop) on my 7.3 powerstroke. This pump is what fires off the injectors, bringing the oil to thousands of lbs of pressure. A year later, one of the hpop fittings had loosened up, blowing oil everywhere. Lost my truck for months, until i figured out the problem.
Same deal: course thread steel fittings, aluminum hpop housing. I guess I forgot an important step: It's recommended to use loctite 680 on the threads. After degreasing everything, the loctite 680 kept the hpop fittings tight.
Anyhow, loctite 680 is used to hold press-fit cylindrical parts in place. Its especially helpful when machining tolerances are loose.
After scuffing up the surfaces of my replacement flywheel, and cleaning the surfaces with degreaser, I'm going to use loctite 680 on both the threads and the tapered crank-end.
I'm betting that's this loctite 680 would be especially helpful for a saw where the surface of the flywheel may have been compromised by a sheared flywheel key, but you might not have a replacement handy.
Rebuilt an echo QV 6700. New everything. Even upgraded to the grey echo, newer pawls/flywheel. Cinched down the flywheel nut very tightly.
Started tuning the saw from a rich tune, to right where the rpms peak off a righ tune. That's when the harmonics of those upper RPM's loosened that flywheel and sheared the flywheel key.
Very discouraged, after adding up the cost of all these parts and time into this saw. So much so, that it had me questioning why the fk I even mod saws. Why can't I "leave good enough alone"?
Anyhow, after some rest, I realized that it's a lesson in disguise: you can't just wipe that surface and call it clean. It was my fault. I remembered my welder talking about how he had trouble welding my full wrap handle on another saw, as the aluminum was impregnated with oil.
Another instant, I had rebuilt the high-pressure oil pump (hpop) on my 7.3 powerstroke. This pump is what fires off the injectors, bringing the oil to thousands of lbs of pressure. A year later, one of the hpop fittings had loosened up, blowing oil everywhere. Lost my truck for months, until i figured out the problem.
Same deal: course thread steel fittings, aluminum hpop housing. I guess I forgot an important step: It's recommended to use loctite 680 on the threads. After degreasing everything, the loctite 680 kept the hpop fittings tight.
Anyhow, loctite 680 is used to hold press-fit cylindrical parts in place. Its especially helpful when machining tolerances are loose.
After scuffing up the surfaces of my replacement flywheel, and cleaning the surfaces with degreaser, I'm going to use loctite 680 on both the threads and the tapered crank-end.
I'm betting that's this loctite 680 would be especially helpful for a saw where the surface of the flywheel may have been compromised by a sheared flywheel key, but you might not have a replacement handy.
