The Stovebolt Site Forums The Shop Area Engine Shop Knock on #1 cylinder

It's entirely possible- - - - -plus, disabling the ignition on a cylinder with a leaky exhaust could lessen the noise it makes by a considerable amount.
Jerry

HR, can you be more specific on the grit # for the fine-grit emery cloth? On the emery cloth, how do I know when the crank is polished enough? I don't want to do more than necessary and wind up with too much clearance.

Dennis

It's almost impossible to polish enough off a crankshaft by hand to make a noticeable change in the clearance. I usually use something in the range of 320 to 400 grit cloth-backed emery cloth, 1" wide and about 2 feet long, using a shoeshine type motion and rotating the crankshaft so the polishing is done evenly all the way around. This simply knocks down any high spots that might damage a new bearing.

New insert bearings have a very thin top layer of pure tin which allows the bearing to "wear in" to the surface contour of the crankshaft very quickly. Hand-polishing the shaft prevents any roughness that might be present from eroding the wear-in layer.
Jerry

The hunt continues. Is there anything under the timing cover that could cause a knocking sound?

Dennis

Question, is this engine still running? If so get you an automotive stethoscope or a very long screw driver and listen around various places around the motor while it's running.🛠

An often overlooked item is connecting rod side clearance.
I have experienced two engines with a knock that turned out to be that.
On a freshly turned crank it is not much of a problem. But with a crank with a little wear on the journal the rod gets thrown side to side on each revolution of the crank.
As you have done, pulling a plug wire will stop the knock on that rod.

If I have to take the pan off again I will check rod side clearance. What is the fix to that if it is the problem? Yes, the engine runs but I'm not driving it because of this issue. I did get a stethoscope and don't hear anything bad except 2 places. The knocking sound from the bottom of the pan toward the front of the engine. It feels like something is coming in contact with it when you put your fingers there. And very loud with the stethoscope. It fades rapidly in feel and stethoscope as you go up the sides of the pan. The 2nd sound I heard was when I put it to the timing cover. Slight metal to metal sound. Not sure if that is normal. Not the knocking drum sound though.

Dennis

If the pan is still off, check the inside of the pan for the rod coming in contact with it.
I learned that the hard way about 35 years ago when I set the motor on some 2x4s to clean it up before installation.

With a little tinkering you can make a fixture from angle iron and a carpenter's level to get an accurate measurement of how far the #1 connecting rod drops below the oil pan rail, and then use that dimension to see if the pan is deep enough to prevent the rod from hitting it. You've already checked for all the usual causes of a noise- - - -now it's time to put some effort into finding the oddball ones.
Jerry

Thanks HR and Marty for that idea. I'll do that tomorrow.

Dennis

Your noise sounds like the same problem I had a while back. The bottom of the oil pan was pushed in enough along with no cork gasket (just silicon) that the crank shaft was hitting the pan just enough to make a noise. I'll try and post a link to my thread here:

https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1079065/1.html

Good luck!

Success! After all this it turns out the pan was deformed under #1. I looked at it when I first took it apart but didn't notice anything. This time there is a slight wear mark maybe 3/16 long. Before taking the pan all the way off, I put in 3 longer bolts so the pan would hang down further. Started it up and NO knocking. I fixed pan so am now moving forward again. Thanks to all who have chimed in here to help.

Dennis

HOTCHAA,,,I was kinda thinkin that was it!

I'm reading your forum question of a knock on cyl #1 as it applies to my situation. I'm just getting my 52 chevy pick up on the road....original 216. I drove it up the road less than a mile and when I put it in 4th and gained some rpms I started to hear a knock. It went away when I slowed and came back again at higher rpms. Should I investigate the same things you guys advised him to check out? Could the dippers be aimed off? Comments?

Definitely pull the pan and aim the nozzles at the dippers. Above idle speed the rods get lubed by a stream of oil squirted straight across the pan by the same nozzle that fills the trough for idle lubrication. Attach a water hose to the supply tube and see where the water hits the pan on the opposite side. Some guys scribe an "X" on the far side of the pan from the nozzle and aim the squirters to hit dead center. It's a lot simpler than trying to use the factory alignment fixture.
Jerry

Alignment Tool For Oil Dipper Troughs In Pan $25 plus shipping cost two times.

The description for that tool is incorrect- - - - -it's a nozzle aiming tool. There is another fixture designed as a dual purpose tool for checking the depth the rod dipper drops below the oil pan rail, and a gauge on the bottom of the same tool that checks the height of the dipper trough below the pan rail. There are two of those fixtures, one for 216 engines, and a different one for 235's, because of the different stroke lengths of the crankshafts. Just aiming the nozzles isn't sufficient if the trough height isn't adjusted also. Some oldtime wrench jockeys would use a tapered punch to widen the opening of the dippers to give the nozzles a better target to shoot for.
Jerry

thanks guys...after the holliday and the horde of family coming in!