The harmonic balancer pulley (also known as the crankshaft pulley) sits on the end of the crankshaft on the right side of the car. It's the big piece number 7 in this diagram:
It's basically a big piece of rubber attached to a metal housing, and smooths out the operation of the crankshaft.
And yes, it can break. What happens is that the big rubber piece on the inside can come apart from its metal outer housing. What happens next can be unpredictable, but is usually catastrophic. In my case, as well as in Wei-Shen's, it started digging into the timing belt cover and then caused the timing to jump, which then bends the valves. Which means an engine rebuild, and big bucks to fix. I'm aware of a third case in which it went flying into the firewall. All three cars have seen extensive track use.
If it hasn't come apart, the harmonic balancer pulley lists for $267 and takes about an hour of labor to replace. Replacing it might be a good preventive measure for any car that has been tracked extensively.
If it does come apart, you too may be looking at an engine rebuild like mine*. If so, I suggest you have it done by a place that has experience rebuilding NSX engines. Right now Ted at Woodfield Acura is working on mine; he's done it before, as have the folks up at Acura of Brookfield.
In the future, I'm probably going to have the harmonic balancer pulley replaced every time I have the timing belt replaced, as preventive maintenance.
* EDIT: Here's an update on mine. We originally hoped that we could get away with rebuilding the top end (valves, etc). However, when Ted opened up the bottom end of the engine, he found that the pistons were damaged. To rebuild the engine would involve new pistons (those suckers are expensive!), re-ringing the entire engine, bearings, etc - big bucks. So I am instead buying a used engine and having it installed, which should cost less than a full rebuild, given all the work that would be needed. :frown: I am also going to have a new crankshaft pulley installed on the used engine.
It's basically a big piece of rubber attached to a metal housing, and smooths out the operation of the crankshaft.
And yes, it can break. What happens is that the big rubber piece on the inside can come apart from its metal outer housing. What happens next can be unpredictable, but is usually catastrophic. In my case, as well as in Wei-Shen's, it started digging into the timing belt cover and then caused the timing to jump, which then bends the valves. Which means an engine rebuild, and big bucks to fix. I'm aware of a third case in which it went flying into the firewall. All three cars have seen extensive track use.
If it hasn't come apart, the harmonic balancer pulley lists for $267 and takes about an hour of labor to replace. Replacing it might be a good preventive measure for any car that has been tracked extensively.
If it does come apart, you too may be looking at an engine rebuild like mine*. If so, I suggest you have it done by a place that has experience rebuilding NSX engines. Right now Ted at Woodfield Acura is working on mine; he's done it before, as have the folks up at Acura of Brookfield.
In the future, I'm probably going to have the harmonic balancer pulley replaced every time I have the timing belt replaced, as preventive maintenance.
* EDIT: Here's an update on mine. We originally hoped that we could get away with rebuilding the top end (valves, etc). However, when Ted opened up the bottom end of the engine, he found that the pistons were damaged. To rebuild the engine would involve new pistons (those suckers are expensive!), re-ringing the entire engine, bearings, etc - big bucks. So I am instead buying a used engine and having it installed, which should cost less than a full rebuild, given all the work that would be needed. :frown: I am also going to have a new crankshaft pulley installed on the used engine.
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