WOLFWALKER Posted March 28, 2011 Share Posted March 28, 2011 I have a '74 mack R model with a ENDTB675 engine, the raditor after a small accident hit the crank shaft counter weight and bent it about a 1/4" and it apears to be crooked and wobbles though it is still good and tight when the engine is running, the pulleys behind the counter weight look fine and still running true. My question is can I have it rebent straight or could I replace it with another counterweight off a used ENDTB675 engine without any problems or will I have to have the whole shaft and weight re-balanced? Anyone know where I could buy one real cheap? Contact me at - wolfwalker223@aol.com Quote Link to comment https://www.bigmacktrucks.com/topic/18498-bent-crank-weight/ Share on other sites More sharing options...
smorse54 Posted March 28, 2011 Share Posted March 28, 2011 Hi,you don't want to try to straighten the harmonic balancer and you sure shouldn't run the engine with a bad one.These have a ring inside that is free to turn to balance the pulses and vibrations. A bent one will cause damage to the engine.Another one doesn't have to be balanced to the motor, but these will were out over time and the ring won't turn inside.You can tell if you put on a bad one, the fan belts will throw off. Good luck,Steve 1 Quote Link to comment https://www.bigmacktrucks.com/topic/18498-bent-crank-weight/#findComment-75086 Share on other sites More sharing options...
Rob Posted March 28, 2011 Share Posted March 28, 2011 Don't run the engine with a bent harmonic balancer! You will destroy the block, and crankshaft if not done already!! Pull the bent balancer from the crankshaft, set a dial indicator up on the front of the engine and check for bending of the snout through 360 degrees of engine rotation by hand. Hardly any deflection of the needle on the indicator denotes a scrap crankshaft.Rob 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/18498-bent-crank-weight/#findComment-75087 Share on other sites More sharing options...
Bollweevil Posted March 28, 2011 Share Posted March 28, 2011 Don't run the engine with a bent harmonic balancer! You will destroy the block, and crankshaft if not done already!! Pull the bent balancer from the crankshaft, set a dial indicator up on the front of the engine and check for bending of the snout through 360 degrees of engine rotation by hand. Hardly any deflection of the needle on the indicator denotes a scrap crankshaft.Rob A new balancer is not cheap. Even though they are prone to run a long time, they are still considered to be a maintenance item. They should be inspected regularly and replaced if suspect. They are a lot cheaper however than an engine. If you just have to find a used one, pick it up and shake it, if it rattles it is no good, inspect it for leaks, dents, or bulging. Clean the paint off on both sides in an area 90 degrees apart, thats 4 places. Measure it with a micrometer at these places you should have no more than .010 difference. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/18498-bent-crank-weight/#findComment-75091 Share on other sites More sharing options...
theakerstwo Posted March 29, 2011 Share Posted March 29, 2011 And for what ever it means to you i would not use a used one that i dont know about if they give it to me. a new one from mack is 327 dollars and worth the money to me. There is some after market balancers out there.Like done been said you can mic it by the mack instruction if you want to.But do not run the engine with that on the engine. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/18498-bent-crank-weight/#findComment-75092 Share on other sites More sharing options...
rhasler Posted March 29, 2011 Share Posted March 29, 2011 The importance of the vibration damper cannot be over-emphasized. ReMack engines even have a warning label stuck to the timing cover advising of this fact. Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment https://www.bigmacktrucks.com/topic/18498-bent-crank-weight/#findComment-75102 Share on other sites More sharing options...
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