Problem:
I’ve seen complaints from Suzuki Sidekick / Geo Tracker owners about their 1.6L engine bogging down.
Cause:
The problem is usually from a loose bolt that holds the timing sprocket on the crankshaft. The loose timing sprocket puts force on the sprocket key (woodruff key) that aligns the lower timing sprocket on the crankshaft. The force then damages the key, and sometimes wallows out the key groove in the crankshaft.
Result:
With the sprocket loose, and the sprocket key unable to hold the sprocket in position, it can allow the timing sprocket to move on the crank, and retard the timing.
Fixing The Problem:
You have to determine how severe the damage is, and what you want to do to fix it.
Before you stress out, remember that the sprocket key is intended to align the timing sprocket for proper timing. It wasn’t intended to hold the sprocket it place. The important thing here is that the timing sprocket is in its proper position when it’s bolted back on to the crank.
If the key has damaged the sprocket, it will probably be much easier to replace the sprocket. You’ll also need a new sprocket key. You can usually find a replacement sprocket key and timing sprocket on ebay. You’re not going to find a woodruff key to use as a sprocket key in a hardware store.
The closest thing you’ll likely find for a sprocket key (if you can’t find an original replacement) is a woodruff key from a small block Chevy engine. The Chevy key is just slightly larger than the stock key, and can be filed to fit.
Replacing the crankshaft would obviously require an engine tear down to remove the crankshaft. An option is to fix it with some Loctite 660:
Once you’ve taken care of the damaged sprocket key (and crank if needed), reinstall the timing sprocket and inspect the timing.
Make sure you use Loctite when you re-install the timing sprocket on to the crankshaft, and torque the bolt to 94 lb-ft. Remember, this problem was caused by the sprocket bolt coming loose.