4afe tapping

[beefer]

Hello fellow 7th gen owners. As is customary, my first post is seeking help with a problem. Shocking and unheard of I know. Anyways, down to business.

The patient is a 1994 corolla 5 speed sporting the 4afe motor. 165,xxx on the odometer. Just coming into its prime for a classic like this. I bought this car for a paltry $1. Yeah, practically stole it. Only catch is that it didn't run when I got it. Replacing the ignition coil got it fired up. The previous owner had told me that it had a rod knocking. I wanted to hear it before I tore it down and started replacing parts that didn't necessarily need it. Got it fired up and it was quiet as a mouse at idle. Even all warmed up it idled like a champ. Give it some revs and theres a little bit of smoke coming out the exhaust but the car has been sitting for the better part of five months. Gave it some more gas and it starts tapping. Very high pitched and sounds like its coming from the head as opposed to a bottom end issue. Driving around the block it runs smoothly and has the expected amount of get up and go. After a bit of research I decided to check the valve clearances. All checked out as within specifications. I also checked if the two gears on the intake cam were lined up. No problems there either.

Now I'm not sure where to go. I'm starting to second guess my declaration of this being a problem in the top end but it really does sound like it. I've also been told that the 4afe is known for wrist pin issues. Being a Honda fanatic primarily I've never run into that issue nor do I know how to diagnose it if it is the case.

In a nutshell, what do I need to look at next?

Thanks,
Ben

[speedy25]

You hit all the obvious problems. Next I would remove the accessory belts and see if the noise is still there. After that its major disassembly. If the noise is stable and not too loud you may just want to get your $1 worth and drive it.

oops! forgot one more thing. Your "ticking" may be an exhaust leak. Many have mistaken that noise for a mechanical problem.

-SP

[beefer]

Well turns out it wasn't an exhaust leak or anything else somewhat innocuous. Dropped the oil pan this afternoon (that stiffener between the trans and motor is really annoying btw) and cylinder 4 is knocking. About 2-3 mm of play on the crank end. Next time I get a couple hours and the proper socket for the rod bolts I'll drop it out and see what kind of condition everything is in. Hopefully I'll be able to put some new bearings in it and run it for another 50k miles or so. But we'll see how things look.

I hate it when I'm wrong.