So I recently did a timing belt change on a B16A2. One thing I thought odd was when I removed the crank pulley, it looked like there was evidence of a spline on the end of the crankshaft and inside the crank pulley, but it was nearly worn smooth. The key was in good condition, no indications that it was being strained or hit hard by the rotation. But I find it hard to imagine that the key is the only thing holding the crank pulley onto the crankshaft. Now I'm noticing, as the engine is idling, that the crank pulley noticeably vibrates/wobbles/shimmies. No other pulley under the hood is doing this. The crank bolt was tightened to spec @ 130 ft-lbs.

Should I be concerned about what-appears-to-be a worn spline? What would cause the crank pulley to vibrate like this?

 

There's no spline on any crank shaft/pulley that I've seen, but I sure haven't seen them all. And that key is the only thing keeping the pulley aligned. As for the "vibrating" goes, are you sure that it's wobbling, or does it just look like it's wobbling? It's possible to have an imperfect pulley. One particular explorer that I saw this on, seemed to have a good 1/2" of wobble. The pulley must not have been sitting true when the grooves were machined, which created the optical illusion of pulley wobble. If you held a stationary object next to the edge of the pulley, there was actually very little runout. But if you put that same object next to that belt, because of the grooves being off, the belt moved to & fro drastically. So the pulley wasn't actually wobbling as it seemed to be. Just something to think about.

 

Thanks, 94gsr. It definitely wobbles, but not sure if this is a new development or not. All other pulleys have no "to/fro" movement at all when compared to the crank pulley.

Civic owners - is there a spline on the end of the crankshaft, or is there only the key that keeps the pulley in place? Should I attempt re-torquing the crank bolt just to make sure? Maybe I'm just overly concerned about nothing.

 

just as 94gsr stated, there is no splines on the end of the crank shaft

the reason for groves being cut into the inside of the pulley is so corrosion and whatnot has a place to go instead of permamently bonding the pulley to the crankshaft.

as long as the belt groves are running true i would not worry about it, JMHO

and dont be so quick to discredit what someone has told you

 

The crank pulley on my '95 GSR has something like that. The end of the crankshaft does NOT have a spline, only a keyway. But inside the hole in the pulley there's grooves broached into the bore. I figure that's to keep it from seizing to the crankshaft.

If you're worried about it try this. Take off the pulley, take out the woodruff key, put the pulley back on without the key. It should slide nice on the crankshaft, & spin, without being loose. If there's clearance (if it rattles), you'll have to mic the shaft & the bore of the pulley to find out which one is wrong.

If that's all OK, check the pulley. There's a rubber layer between the hub & the pulleys. Make sure that's not loose or rotting. Put the key back in & put it together. Maybe that rubber part is crooked but not loose? Anything like that means you need a new pulley. But what you want is for the belt grooves to run true, not the outside of the pulley.

 

Thanks for the advice, guys! It totally makes sense what the purpose of the crankshaft pulley grooves are for now. The belt grooves do seem to be running true, so maybe there's nothing to worry about. I will check the "rubber layer" just to make sure.

 

my honda accord alt. belt be slipping off and try to eat into my timing cover wht could be the problem it seems as it is wobbling.