Engine making "clackity clack" noises

[nic26]

As a very 1.measure I would switch off the engine and turn it by hand - step by step. This way you can hear mechanical sounds (not really all, like not in bearings) but you can also feel things. If nothing unusual comes up proceed with the ideas given above where the valves are 1 of my 1. points.

Oh and another not bleeding knuckles point: go to a friend and listen to his Diesel. Do you hear the same noises?

Nic26

[reed1v]

Originally Posted by nic26

As a very 1.measure I would switch off the engine and turn it by hand - step by step. This way you can hear mechanical sounds (not really all, like not in bearings) but you can also feel things. If nothing unusual comes up proceed with the ideas given above where the valves are 1 of my 1. points.

Oh and another not bleeding knuckles point: go to a friend and listen to his Diesel. Do you hear the same noises?

Nic26

Or just listen to small diesel engines on Youtube.

[reed1v]

Originally Posted by Celestialsailor

In another life I was a motorcycle mechanic at two dealerships. After 1000 miles of running a new bike, almost all valve clearances would be less or tight.
Not the first time Reed has spouted off about an imaginary fact.

Not that I doubt your veracity, but new engines are a different reality than one well broken in. Any mechanic would know that.

[reed1v]

Originally Posted by Guy

Really? Where does the valve go if the valve face and the seat wear? Perhaps you should re-think your reality.

Where they go? Ever heard of excess oil consumption? Blue smoke out of exhaust? As they wear, they get loose, tolerances go off, and you get more clatter than usual. With carbon buildup they can also get sticky.

[jkangas]

V


Sent from my iPhone using Cruisers Sailing Forum

[a64pilot]

You guys did notice OP said he changed oil and the noise went away?

[HappyMdRSailor]

Originally Posted by farm sail

not an absolute, it can go either way sometime valve clearance will increase other times it can decrease. some design are more likely to go one way or the other. but not always

Agreed... And similar designs but different mfg's can go both ways too
(insert creative bi joke here)

Originally Posted by a64pilot

You guys did notice OP said he changed oil and the noise went away?

They were making so much noise about valve clearances they didn't notice the quiet...

[reed1v]

Originally Posted by a64pilot

You guys did notice OP said he changed oil and the noise went away?

Which is why folks mentioned low oil as the cause of the noise. Also could be the old oil was so dirty that it was causing blockages. Wonder how his oil filters looked?

[a64pilot]

Only way I can think of low or dirty oil causing an engine to make noise is if it has hydraulic tappets, but that is a rhythmic metallic tap tap tap. We have all heard it sometimes on cars whose hydraulic lifter have leaked down until they pump back up right after starting. Mazda Miata's are famous for it

[darylat8750]

Originally Posted by HappyMdRSailor

Agreed... And similar designs but different mfg's can go both ways too
(insert creative bi joke here)



They were making so much noise about valve clearances they didn't notice the quiet...

Ah... Yup....

[model 10]

Somebody name just 1 piston engine in this whole wide world with poppet valves that gets more valve clearance when the valve faces and seats wear.

[a64pilot]

Originally Posted by Guy

Somebody name just 1 piston engine in this whole wide world with poppet valves that gets more valve clearance when the valve faces and seats wear.

I can only come up with a couple of theories that might explain a "loosening" valve train.

1. Carbon build up between the valve face and it's seat.
2. camshaft, rockers, valve rotators or tappets wearing excessively. Lycoming aircraft engines are bad about losing cams, but when they start wearing and wear goes though the hardening, you lose a cam quick, and often a crankshaft too from excessive metal in the oil.

I've never experienced valves getting loose myself, I have adjusted valves on engines that were loose, but feel real sure they were that way because someone didn't know what they were doing when they adjusted them, like maybe adjusting to cold specs on a hot engine.

On edit, It was common on GM engines back in the day if you installed high performance springs and a cam that the studs in the head would loosen increasing valve clearance, fix was to "pin" the studs by drilling through them and inserting a roll pin.

I have never seen the carbon build up either, maybe possible I guess?

[reed1v]

carbon buildup usually means the engine was run below specified temperatures, common in sailboats where the engine is used to enter and leave slips or moorings. Folks assume a cold running engine is a happy engine. Not true. Have worked on albins, bmws, and yanmars(the best) where folks had removed thermostats in the mistaken belief that would solve their overheating problems. Usually results in carbon buildup and engine failure over time.

[darylat8750]

Originally Posted by Guy

Somebody name just 1 piston engine in this whole wide world with poppet valves that gets more valve clearance when the valve faces and seats wear.

The issue is that other parts of the valve train besides the valves and valve seats wear also.

1. My '66 Triumph opened up so bad that I had to adjust valves after every race. Always needed to be closed a little. It was the cam followers that wore so bad that they needed to be replaced every season. (It wasn't the surface on the cam that wore, but the interface between the lifter and the push rods.)

2. '70 Corvette with after market cam and solid lifters intake valves would usually get looser (but not always) and the exhaust valves usually got tighter.

These examples had very aggressive cam profiles but I had several '80s street bikes that could "go either way".

[model 10]

Anybody remember the Duntov 30 30 cam?

Carbon build up on a very worn valve stem can cause the valve to stick part way closed. With solid lifters, you would then have no gap and no noise. Side play in the valve guide will cause smoke for sure but it's not the kind of thing that makes a noise. From the few older Perkins type engines I've looked at, I don't think they suffer from the same kind of problems that a piece of junk English motorcycle or lightweight airplane engine suffer from. I might fly over an ocean in a Lycoming or Continental powered airplane but no one would ever put one in a boat.