The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 'Ole Green'

schovil69 · 09-06-2022, 02:09 PM

So, the list of TO-DO's is down to installing the engine lift cables and we proceeded with start up. The first time it tried to run there was backfire through the carb such that it appeared every cylinder was backfiring. Reverified everything accessible that is timing related and found no trouble there. While bumping it to find TDC on #1 it took off but was immediately shut down because we were not prepared to run it. I put the plug back in and the next time it started and ran as it should. The rockers were extremely noisy, though. Adjusted the rockers and the engine sounds better on that front.

Rocker adjustment is a bit non-conventional. Usually, I would run the engine then loosen a rocker until noise then tighten it until no more noise. For whatever reason, I am not able to fit the socket onto the rocker nut very well. It's nearly impossible in some instances. As a result, I have been resorting to adjustments with the engine off which goes something like this: Bump engine until a valve is depressed on a cylinder then tighten the other rocker on that cylinder until there is no more up/down movement of the rocker arm.

There's a remaining issue, though, that sounds like rocker arms needing adjustment that doesn't quite match that of rockers needing adjustment. To err on the side of caution, I plan to go back through the rocker adjustments and add an additional half turn after the rocker movement ceases. What's weird about this noise is that when standing beside the driver door with the hood up and the engine running, this sounds appears to be coming from under the pickup, like maybe from the rear of the engine. From the front with the hood up and engine running it appears to be louder on the passenger side of the engine.

Overall, it's difficult to locate the origin. It sounds to me like a metal on metal click and seems to occur regularly, like with every cylinder. Sounds like maybe an exhaust leak but placing my hand around the manifold to pipe connection cannot locate a leak. I don't feel any blast of air that I would expect from an exhaust leak. I'm wondering if it could be the distributor to cam relation but haven't pulled the distributor yet. A check of the oil does not reveal any evidence of metal in the oil which has put removing the distributor lower on my list of items to check.

Any other thoughts on the potential source of sound?

09-06-2022, 02:09 PM	#23
schovil69 Registered User Join Date: Oct 2013 Location: Lincoln, NE Posts: 115	Re: 'Ole Green' - 1970 Chevy C10 Engine Rebuild So, the list of TO-DO's is down to installing the engine lift cables and we proceeded with start up. The first time it tried to run there was backfire through the carb such that it appeared every cylinder was backfiring. Reverified everything accessible that is timing related and found no trouble there. While bumping it to find TDC on #1 it took off but was immediately shut down because we were not prepared to run it. I put the plug back in and the next time it started and ran as it should. The rockers were extremely noisy, though. Adjusted the rockers and the engine sounds better on that front. Rocker adjustment is a bit non-conventional. Usually, I would run the engine then loosen a rocker until noise then tighten it until no more noise. For whatever reason, I am not able to fit the socket onto the rocker nut very well. It's nearly impossible in some instances. As a result, I have been resorting to adjustments with the engine off which goes something like this: Bump engine until a valve is depressed on a cylinder then tighten the other rocker on that cylinder until there is no more up/down movement of the rocker arm. There's a remaining issue, though, that sounds like rocker arms needing adjustment that doesn't quite match that of rockers needing adjustment. To err on the side of caution, I plan to go back through the rocker adjustments and add an additional half turn after the rocker movement ceases. What's weird about this noise is that when standing beside the driver door with the hood up and the engine running, this sounds appears to be coming from under the pickup, like maybe from the rear of the engine. From the front with the hood up and engine running it appears to be louder on the passenger side of the engine. Overall, it's difficult to locate the origin. It sounds to me like a metal on metal click and seems to occur regularly, like with every cylinder. Sounds like maybe an exhaust leak but placing my hand around the manifold to pipe connection cannot locate a leak. I don't feel any blast of air that I would expect from an exhaust leak. I'm wondering if it could be the distributor to cam relation but haven't pulled the distributor yet. A check of the oil does not reveal any evidence of metal in the oil which has put removing the distributor lower on my list of items to check. Any other thoughts on the potential source of sound?