Jeebus, I'm completely baffled here. Hope someone's smarter than I am.

96 GSR, B18C1, about 90K miles. I just did the 90K timing belt change. Also did the water pump, the tensioner, the main seal and both cam seals. Put it all back together and started up. Nasty rattle in the top end. Yikes!

Went back and checked *everything* twice for correct torque, you name it. A-OK.

I did do the valve adjustment, properly. I did do the tensioning procedure, rotating three teeth CCW on the exhaust cam gear before torquing down the tensioner pulley. Still rattles.

Dealership guy said that an undertensioned belt can make the distributor rattle. Someone's comment on the site said the noise might be the bearing in the dizzy about to let go. I traced the noise along the head with a screwdriver to the ear. Yeah, the rattle is strong in the distributor casing.

Retensioned the belt aggressively, rotating five or six teeth CCW this time. No difference.

Bought a 30K mile Type-R distributor off of ebay. Installed it after verifying that the part number stamped on it was compatible with the engine. Instant start, rattle still present. Arrrrgh!

There is only one thing I can think of. The new timing belt was bought off of ebay -- Honda-labeled, in a sealed bag, with the correct inventory code on the bag label and the same part number printed on the new belt as the old belt. But the new belt was noticeably *longer* than the old one, like 3cm or so.

That struck me as weird. Shouldn't the old belt be a bit longer because of service stretch in the fibers? But I figured that the factory must know what they're doing, and the part numbers did all match.

Believe me, I am NOT in a big hurry to put the original belt back on to get a cross-check. But at this point, it might make sense to try, unless someone has a better idea.