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Noise and Oil Pressure Fluctuation - New Rebuild


Jocko_51_B3B

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Engine is finally complete.

Engine bored and sleeved.

New pistons standard size.

New main and rod bearings.

New valves.

New valve seats.

New valve springs

New cam bearings.

Polished crank journals.

Kept the old valve guides, tappets, keepers, cam, crank, etc.

Added five quarts of 30W break-in oil.

As soon as fuel made it to the carburetor, it started right up and sounded pretty good. Ran it several times for a total of probably 45 minutes to an hour and started to hear a periodic squeak/rubbing/chirping noise along with about a 1-2psi fluctuation in oil pressure. The oil pressure fluctuation was not present during the first few start-ups. Pulled the engine. Completely disassembled the engine. All main bearings, cam bearings, piston walls, tappets, were well lubricated. No spun bearings. No dry spots or damage that I can see. Should I have ignored the noise and oil pressure fluctuation in hopes it would "work it's way out"? I'm scratching my head after a lot of work.

 

 

Edited by Jocko_51_B3B
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Where was the noise coming from... front/rear  low high etc.

I've seen the front seal rub on the timing chain/or slinger if used...using the wrong front seal or crushed down cover...this of course won't cause oil pressure change though..

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Well, it looks like part of the problem is my fault. I incorrectly installed the #2 cam bearing upside down causing it to interfere with the #2 cylinder exhaust tappet. This could very well have caused the the chirping noise. Also, the bearing should have been inserted a little further into the block.  Fortunately I installed the identical #3 cam bearing correctly.

 

My oil pump looks, feels, and pumps oil fine so I don't know why I have a small fluctuation in oil pressure

 

The #2 cyl exhaust tappet interferes slightly with the cam bearing.              The curved notch in the bearing should be next to the tappet for clearance.

20190414_134413_1555285009828_resized.jpg.685e8e31ccd1a75ce291bd6c94654286.jpg                      20190414_134429_1555285007051_resized.jpg.42f9b77bb5c8fefbcaaa2843a6dbb76b.jpg

 

 

Edited by Jocko_51_B3B
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Whoopsie....?️!

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Am I mistaken or is the cam brg lube hole facing the wrong way also.  Is'nt is supposed to be facing the piston side of the block as well as beimg upside down?  I haven't been inside one of these engines before so correct me if I'm wrong.

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The cam bearing lubrication hole is on the correct side. I made sure of that. The bearing needs to be flipped upside down, not turned around. My focus was on the hole and not enough on tappet interference. I didn't realize that tappet interference was a possibility. The good news is that my mistake caused  me to disassemble the engine from which I was able to see that oil was getting everywhere it needed to go. All main, rod, and cam bearings and journals were in good shape and had plenty of oil. 

Edited by Jocko_51_B3B
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