Hello all,

I just did a rebuild on a 1991 civic 1.5 and have a strange tapping noise coming from ‘approximately’ where the wrist pins or rings would be at TDC. This tapping does NOT resonate thru the head or cover, nor the oil pan, and definitely not a rod knock. After over an hour covering every inch accessible with my stethoscope, the sound is obviously loudest coming out of either side of the upper block @ cylinder #3, although #2 is a close possibility. I would think a wrist pin, yet, although these pins were sticky due do a good engine overheat, they easily worked free with a shot of penetrating oil, and definitely had no play. The cylinders honed evenly and easily, the block deck is straight, the newly ringed pistons slid in with no problems, and the head was thoroughly checked at the shop. It runs excellent.
Sooo, any ides anyone? Much Appreciated, and Be Well!

 

So, I just tore the engine down again to I.D this noise, yet I find myself stumped. Again, wrist pins seem fine, no signs of a piston slapping the cylinder walls. The only thing slightly unusual was that the new thrust washers width was a tad shyer than I expected for new ones, yet thicker than the old ones. Still, I get no crank play. Besides, the tapping is definately up high. also, pistons are not contacting the head or valves. Hmmmm ???

 

Found It ! Omg, unbelievable. 100+ honda rebuilds and I've never found this before. The #2 cylinder 'only' was warped/ovalled about .008. Could only rotate the piston in the sleeve about 45 degrees in either direction from install position before it stuck at the skirts. Same piston spun 360 degrees in #s 1,3&4. Pistons from 1, 3&4 could NOT spin without sticking in Cylinder #2. So confirmed, bad cylinder 2. Bizzare or what?! Another block was the only practical repair, as sleeving it is well over twice the price of a good used block. Luckily, I had a spare one laying around, installed it, did the re-re-rebuild, (lol), and she purrs like a kitten! Something I will absolutely check for now on !

 

Wow, nice fix!