Classic crank cancer (lotsa pics, dialup warning)

[philw349]

The key that holds the pulley to the crank was broken in half

The pulley was a little messed up (hard to tell since my camera was on low res mode doh!)

backview of pulley (note the glaze on the inner part, resulting from freely sliding on the crank)

Here there is a chunk missing from where the key slides in

Here there is some moderate scoring on one side

There is also some more scoring on the other side. (the grime is a factor of a leaking power steering pump I think).



The shop foreman was worried that this problem would come back in the future because of the scoring on the shaft. It's my impression that the problem is caused by a loose crank bolt (not enough ft/lbs on it) from the shotimes article. So I am not as worried as he is.

In any case I told them there was no way I'm doing anything to the crankshaft, I could buy another SHO for much less. The guy was like "really?", I was like "yeah, pretty much.."

But they put it back together, and I must say that it's running the fastest it has since I've owned it, that could be due to driving it in slow motion so much, but it really rips now. Just wanted to share these pics.

Btw, I had a long term "ticking" noise coming from my engine. That went away with this procedure. So that may be added to the possible symptom list of crank cancer. It wasn't a mild ticking noise either, it echoed off of other cars and walls. It's a smooth running machine now.


PS Sorry for the file size of the pictures, they were accidentally taken in in low res, so I didn't want to reduce their quality any further by modifying the compression.

 

[jelloslug]

You seem to be "lucky" (as lucky as a crank cancer victim could be) with your problem. Your crank does not look damaged beyond use.

 

[Rockledge]

Great pics, better than those that are in the shotimes article.

Just curious, and maybe I missed a thread on it(?), but what method did you use to repair the problem?

I had my own "crank cancer" scare a few months ago when my SHO died completely and follow-up diagnosis turned up a whole bunch of trouble codes and no camshaft movement when cranking the engine. There was some intial concern that the timing belt sprocket had mashed the woodruff key to a point where the sprocket was just spinning on the crank, but it turned out to be only a broken timing belt (whew).

I was careful to properly torque the crank bolt when I replaced the belt, but when I see something like this I'm almost tempted to re-torque the crank bolt on a more routine basis. If only it wasn't such a PITA to get at...

 

[philw349]

The repair was to replace the pulley and key with new ones, tighten the crankshaft down properly, and hope for the best. I don't think theres anything else that can really be done. The key and pulley were a special order item which took a few days for the dealership to get ahold of. The key was a few dollars, the pulley was like $150 if I remember correctly, and the labor was like, a lot more than that.

It probably takes years for the problem to surface, I don't believe anyone's worked in the crank area of the car for 3-4 years.

 

[Mike Kopstain]

Phil, The ticking sound is actually a common symptom of a worn woodruff key/ keyway. The sound you heard is the key hitting the keyway.

This problem is most common in cars that were serviced incorrectly. If the crank pulley is not torqued to 126 ft/lbs the above becomes a possible scenario. I had a car come into the shop a year ago that was a brand new crate 3.2 just serviced by a mechanic a couple months prior to us taking delivery. The motor was "finished" but never ran right and needed a bunch of other work done to it.
Nonetheless, I was able to remove the crank pulley bolt with my hand and a 3/8th's wrench. O/T, but among other things, the cam sprocket bolts were all loose and hanging off the sprockets and the car had a sheered exhaust cam.

 

[Axianator]

As with the hub nut after a wheel bearing change, it's probably not a bad idea to check the torque of the crank bolt after a few hundreds miles of performing a front-end 60k service. The crank bolt on my '95 was torqued to spec with a torque wrench in Feb '02 during my front-end 100k service, but subsequently found to be almost hand-loose in December '03 during my rod bearing service job. The bolt was retightened with an air wrench and (AFAIK) has been fine ever since (I need to recheck it, just to be sure). I just hope that the bolt doesn't decide to work it's way loose again and cause me even more headaches. :ruhroh:

 

[Yamaha V6]

That one's better than mine on the crankshaft - you still have some straight wall area on the crank on the gear side, where mine was worn on an angle comparable to the crank gear. I had filled mine w/ JB Weld (Didn't work), loctite the gear (didn't work), weld-filled the area, didn't work, then did all of the above, and then some - welded the gear to the retainer disc, to the dampener also.

That worked up until I parted the car out anyway.

Good luck!

 

[SHOWYA]

Phil,

You should be carefull leaveing the key path chipped like that. Crank cancer will happen again, and it will be worse. The woodruff key will flex and brake the key path some more. I tell you because of experience. I used J-B weld to fill in the gap the first time, and this is what it looked like first time that it happened.

And this is what it looks like second time it happened. As you can see the key broke the key path alot more(about and inch). Welding was performed and used a dremel to grind down excess. Car runs great now ... all the power is back but i fear it will happen again.(It will since Yamaha V6 has gone thru that) I did torqued down the crank bolt progressively to 150lbs.!! (113, 126, 136, 150lbs) Maybe it will hold longer.