Strange noise from engine

[bomar76]

Re: Strange noise from engine

Originally posted by nitedmn:<br /> Yesterday I pulled off the starbord valve cover and rolled the motor over by hand. All 8 lifters appeared to be moving fine. I didn't check the other side.<br /><br />I'll cut the filter open and see what I find. Thanks for the suggestion.

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[mmainelli]

Re: Strange noise from engine

pity you threw out the old oil. Take a small jar to the boat yard and have it chemically tested for metals. If something is internally banging, chances are it's also throwing off metal traces. From what you describe, it's not valve chatter. Maybe you threw a timing chain link that smacking inside the chain cover. Or maybe a bad timing chain gear tooth (that would help to toss a chain link). Or a worn piston wrist pin, or a connecting rod. Check the oil first for metal.

 

[nitedmn]

Re: Strange noise from engine

Originally posted by mmainelli:<br /> Maybe you threw a timing chain link that smacking inside the chain cover. Or maybe a bad timing chain gear tooth (that would help to toss a chain link).

Hmm... This is definaly something I'll check. The sound does appear to be coming from the front of the motor (haven't confirmed it though). This is why I originaly suspected the water pump.<br /><br />This weekend and I'll be checking the filter for metal pieces and possibly uncovering my timing chain.

 

[nitedmn]

Re: Strange noise from engine

After spending way to much time searching for all the pieces to my gear puller I took the timing cover off. The chain and all the teeth look brand new (they should since the motor is almost brand new). **sigh**<br /><br />Some rain started to move in so I had to cover the boat. I'll be pulling the oil fiter and cutting it open next.

 

[Boatist]

Re: Strange noise from engine

When he talking about a stuck lifter he does not mean the lifter is not moving. What he means is the internal part of the lifter is stuck. Hydrolic lifters are filled with oil and have a plunger pushed up by a spring. When the engine is sitting for any length of time then the lifters that have valves open will likely have all the oil forced out by the big valve spring. Normally this lifter would fill back up with oil pretty quick but only thing that pushed the plunger up in the little spring in the lifter. If the engine has had water in it could be rusted and stuck.<br /><br />Only way I know to see if it is a stuck lifter is with the valve cover off and engine running first listen and see if can isolate the noise and time it to a moving valve. <br /><br />You can take a rag and put on top of the lifter side of the Rocker arm and push how down hard with the engine running. If it is a stuck lifter the sound will change when you push on the bad one.

 

[nitedmn]

Re: Strange noise from engine

Boatist...<br /><br />Thanks. I'll check this too. Last time I started the motor I noticed I could faintly hear the noise when the motor was cranking (I had unpluged the ignition coil earlier and forgot to plug it back in so the motor didn't start). If I take both valve covers off and have someone crank the motor for me it should be fairly easy to time the noise with one of the valves.