Phillip Robinson

Too much oil

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4 cylinder side valve engine , ford. Unfortunately, for me, I over filled the crankcase by double. I did not check the book, and because I replaced the oil pan, I was confused with the dip stick reading. A lot of smoke, before I realised after idling for 3 minutes, and now a knocking noise. Could be damaged bearing on crankshaft, or conrod bearing or something else.

Just had motor redone, so a basic mistake now forces me to take it apart again.

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I doubt that having over filled the engine with oil that it would have produced the knock. I would venture to guess that something was not done correctly when the engine was rebuilt. Is this a fresh rebuild? Are you certian of oil pressure when the engine was first started after the rebuild? How many hours/miles do you have on the rebuild?

Edited by SBlomquist (see edit history)
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Thanks for the reply. All the articles that I read suggested possible bent rods, bearings scored- as oil became frothy( aerated) oil would not have been pumped. I ran it for 3 minutes, then drained to correct level, still using aerated oil, for another 10 minutes. Then drained and put fresh oil in. Still a knocking noise. Pull engine out or run it to try and locate knock?? Any ideas. Phil

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I still say that if it is a deep knock that something was not done correctly when it was rebuilt. Is it really a knock or maybe a ticking sound. Did the valves get adjusted properly? If so, something you could verify before dismantling the engine is that the valve adjustment was done correctly.

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Deep knock at idle usually indicates a rod bearing failure or new bearing was not the correct size. Was assembly lube used when rebuilding?

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Thanks again for the reply. The history is this- crankshaft was broken in 2 places, 2 conrods were bent and 1 piston was chipped on the bottom. Obviously dramatic.

So, another crankshaft,  4 second hand pistons and conrods, new rings AND had the motor balanced by engineer, including clutch. Another camshaft and bottom pan (which is where I was confused with the oil level), all cleaned, reset valves.

This motor is 80 years old, but that should not matter. I will check knock again, and if still there, then motor out, or, realise that doing the restart might have adverse effects and damage it further. 

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why not drop the sump (oil pan?) and have a look before removing the engine? how confident are you in the secondhand pistons and rod bearings? I would drop the pan and check the big-end bearings first. Also, if it has an oil pump, can you check for output and oil pressure? Is the relief valve correctly set?

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Thanks. Too difficult to remove pan, and about 3 hours to pull the motor out. Aim at the moment is to disconnect generator, start up and see if knock occurs, then    ??? Engine out and check conrods, bearings and any movement. Should know soon, hopefully.

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I am confused as to why you might disconnect the generator before restarting? Is it you just anticipate removing the engine anyway?

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I hear the knock, but not certain if it comes from the generator, only a small possibility, but eliminates the generator being the problem.  After that, there is only the bearings,  conrods or main.

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22 hours ago, Phillip Robinson said:

I hear the knock, but not certain if it comes from the generator, only a small possibility, but eliminates the generator being the problem.  After that, there is only the bearings,  conrods or main.

Or a piece of dirt on top of a piston or some other form of trash that may have been left it there or fell into the spark plug hole.

Does it have a mechanical fuel pump? They can make noise.

You seem to be in a pretty big hurry to pull the engine without any further trouble shooting. (not very difficult to pull the head)?

Don't get me wrong, It very well could have been the aeriated oil lunching a bearing.

Maybe with all that smoke it could have ingested to much oil up into the combustion chamber and hydrauliced what must be inherently weak rods.

Edited by JACK M (see edit history)

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Thanks Jack. Just trying to get ideas. The bearings were second hand, same as the conrods, so a better check here is a good idea. As far as something in spark plug hole, I keep everything clean, so that did not happen_ but , as I say, looking for ideas when it comes out. Pan has no gap big enough to pull out. A suggestion that taking a spark lead off will tell me which bearing is at fault _ I am not sure if motor will still run on 3 cylinders? as I check each one.

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1 hour ago, Phillip Robinson said:

I am not sure if motor will still run on 3 cylinders?

Should run on two and if it is well timed, maybe even one.

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Would running the engine on 3 cylinders have any adverse effect on the main bearings? Because if this idea works, it will tell me the bearing at fault.

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18 hours ago, Phillip Robinson said:

Would running the engine on 3 cylinders have any adverse effect on the main bearings? Because if this idea works, it will tell me the bearing at fault.

No. Shorting a plug is the common way to isolate a problem to a particular cylinder. The engine will slow and run rough of course, but if there is a knock that goes away, you know which cylinder to look at to find it.

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