I was replacing the timing chain/gear set in my son's 1992 S10 Blazer 4x4, ordering the Cloyes set from an online source with the gaskets. In comparing the two sets laying flat on the table, they appeared to be correct. Anyone would not normally notice any abnormal differences and install the new set. But through my experience with the occasional mis-labled or mis-boxed part, I always compare the gears over each other to confirm the chain link count, tooth count & diameters.

However in this case, when I slid both of the bottom drive gears (loosely) back onto the crankshaft, that's when things did not match up. It has apparently been mis-machined and the teeth did not align with the old gear as seen in the photo. The replacement gear was off a couple degrees or so.




I called the online source and sent them the photos. They were very grateful in letting them know of this defect and said they would try to check their existing stock for others and promtly refunded my money.

I purchased another set from my local parts store and compared the two on the crank and they matched exactly. Both sets had the S-511 stamped on the bottom gear, but the one gear must've been machined on a Monday morning. So always double-check your parts!!

 

Wow! I would suspect many would have just put it on unaware until they tried to start their engine. It pays to check everything every time.