Crankshaft balancer flew apart on car at work

[IBCNYA]

So a harmoinc balancer comes apart on a inline four cylinder, whats happens when its no longer doing its job? Im looking fro answers from who ever, where ever, I wanna know... Its my understanding a aluminum crank pulley without a rubber dampener in it will cause excess crankshaft play, leaking seals, bearing wear or even knock. So what if the inner part of a balancer was just slopping around on the end of the crank? Even if you never post, chat communicate with me at all on here I wanna know what you know, cause apparently I dont know.

[steelbluesleepR]

It can start to rattle and eat into the crank, if not fall off completely. it's best to get a replacement, along with a new keyway key. TASauto sells them for less than $50. a lot better than tearing down the motor completely to replace the crank.

[oni_cb7]

I've had many experiences with this (my car twice and my buddy's car once).

If you catch it in time, just replace the whole thing and it will be fine. If you don't catch it in time, then it will wear out the plastic timing area cover, it can wear out the belts, it can destroy the crankshaft bolt (don't let that happen) and it can cause the bolt to walk itself out and destroy the threads in the crank. Don't tell me that this can't happen because I have seen all of it happen on a cb7.

If the bolt breaks then it will need to be drilled and extracted as you will not be able to get to it with a normal wrench with the whole head broken off. Or you might have to just drill out the whole area and tap it so you can use a helicoil. My crankshaft currently has a helicoil in it and has held up for quite some time now.

It could make it so you need a whole new crankshaft or motor. That just depends on how bad you let it get.

[JDMDriver]

If the pulley has walked off:

Disassemble the components
---------------------------

If you're lucky only the key would have broken and need replacing.

If you are not as lucky a replacement pulley may need to be sourced.

Crank Bolt
-----------

If the crank bolt holding the pulley has been sheered off you may be lucky enough to have some thread sticking out. If you have enough thread remaining sticking out then get a nut that can screw on the remaining bolt thread and fill weld the end. That will be your new head and remove with a socket and breaker bar as normal.

If you are unlucky then you will need to extract that another way.

Crank Thread
-------------

If you are lucky you can just put a new crank shaft bolt in there. Sometimes putting in a new bolt slowly tightening then turning in the removal direction and repeating will clean and re groove the damaged threads.

If you are unlucky and the threads are no longer straight and holding then as stated above use a helicoil.

My experience
--------------

I had to replace the crank key, crank pulley and crank bolt. Once assembled the crank pulley has a little wobble in it.

It didn't ruin the plastic timing belt cover or stretch and make my belts snap. It has held on for 3 years and over 30,000 kms so far. I check it if its still tight periodically and it seems to keep its tightness and doesn't need re-tightening.

[foamypirate]

The guys above all gave great advice. I've been through the same situation. I was able to salvage my crank pulley bolt and the crank threads by using the proper tap to recut the messed up threads, but I had to get a new crank pulley. For what it's worth, the Dorman brand crank pulley seemed to be of pretty decent quality.

[Accrdwgnguy]

Happened to my ex's Civic, twice. First time it chipped the keyway, so I put a new key in and put on a used pulley. Second time was 5 months later, I used JB weld to fill the chipped off part and installed a new key, and this time a new Dorman pulley. That lasted until she traded in the car.



Make sure you torque that pulley to spec, or you'll have issues too.