I have found the source of my knock: (see thread in Engine for more info:

Finding Source of Knock (http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=9;t=011989)

I pulled the plug on cylinder one and the knocking goes away. I'm going to pull the motor out this weekend and pull the pan. What exactly should I be looking for? Should I take the head off that side? Should I pull the piston and the rod? I have assembled a few motors, but never had any problems in the bottom end of the motor. What am I looking for besides bearing failure?

History/Facts: Motor is a mid 60's small journal 327 w/76cc heads (don't know why the heads are so big??). Bought the motor for $150 a couple of years ago. Supposed new rebuild that cought fire and burned a truck down. Started up fine, runs ok - just knocks.

You're probably looking at a new crank kit and re sizing of number one rod
graemlins/sad.gif

What I wonder is why #1 seems to be the rod bearing that goes bad after a rebuild

Rod knock, I concur with Dean.

Dean, Maybe it's because #1 is the furthest away from the oil pump? I don't know, it might be because #1 rod bearing is the last to get oil. Or it's just one heck of a coincidence! graemlins/clonk.gif

Thanks. I figured it was somewhere on #1, but how do I tell what the problem is? I was planning on new rod and main bearings but I was hoping to avoid any machine work. What exactly am I looking for. Sorry to beat this one to death, but I'm out of money and I need my daily driver back :D .

Jeff,
I could be several things other than a rod bearing. I would pull the pan first and take a look at the rod bearing. If it appears to be the culprit, you are going to have to try to measure the crank before deciding what to do next. I would pull the rod caps off number 1 and 2 and compare the two. If you can feel any difference in the crank, it probably going to have to come out to be reground. The rod might also need reconditioning or replacing. If the bearing and the crank look good....it could be a piston pin, or even a collapsed skirt on the piston. Only way to find out is to pull the piston out to see.
Hope this helps,

Thanks. I'm going to go out tonight, do a compression test on that side (1,3,5,7) and then pull the motor and the oil pan. I'll report back tomorrow morning.

Could I have problems with the piston side and have good compression?

My #8 was knocking and I thought for sure it was something serious but it ended up being a leaky head gasket and water was in the cylinder.

I pulled the rod engine and the pan and I have the following pictures of rod bearing 1 and 2. Rod journal is measuring 088 to 090. There are no gashes or scratches, but you can feel slight (very slight) changes in the surface. I actually thought #1 looked better than #2, but #1 was quiet when I pulled the spark.

Rod Bearing 1

http://www.littlecars.com/bearing1.jpg

Rod Bearing 2
http://www.littlecars.com/bearing2.jpg

Forgot to mention. compression was 150 on #1,#2 and #3. I didn't go any farther because I wanted to get the motor out :D

More updates. Took my story and my parts on the road and talked to two machine shops here in Wichita. Names have been changed to protect the innocent. :D

Shop 1 - Rod caps don't look so good. I would build the bottom end. .002 on the crank is too much.

Shop 2 - Said back of the bearings are black due to pre-ignition or detonation. Wants to see piston/rod number 1 and he will measure. He's concerned that the little end swings free in the pin. Told me to get .001 shims and shim bearing until it locks on the crank. If it takes more than 3 shims, that is the problem and we have to turn the crank. If not, it needs new bearings.

I actually agree with both. I'm thinking about doing the bottom end, but I need something cheap now, so I'll pull #1 and take shop 2 the rod.

Comments?

it's time to forget about the rod bearings, if the crank was gone and some of the bearing in your pan, that would be the knock,your still looking... piston pin? any metal in pan? is there scoring in cylinder bore, piston all the way up looking from bottom.

Pulled the crank and all the pistons today. Two broken rings. #1 top ring broken and problems with #6. Got the block, crank and rods in the burban ready to head to the shop on Monday.