Trolling at low speed caused an engine lifter noise

[HT32BSX115]

Re: Trolling at low speed caused an engine lifter noise

4 and 2 cycle gasoline engines really don't like idling for long periods of time. They aren't built for that. They're built to run wild and free and thumb their noses at watercops.

Except maybe trolling motors?

I am going to agree with that. No manufacturer recommends operating any engine at idle for long periods of time. (doesn't mean you can't though)

But, "normal" temps are not maintained and wear is increased until normal operating temp (oil & coolant) is reached. Minimum cyl wear and oil consumption etc, occurs at "normal" cylinder pressures which ARE NOT maintained at very low power settings.

Your problem wasn't "caused" by idling though.

Lifters are mere hydraulic pumps to pump up and take the play out of the clearances between the cam and push rods.

Maybe this is just semantics........They're not "Pumps".....but they ARE hydraulic cylinders that are "pumped" up Or more accurately, FILLED by engine oil pressure. If you have adequate oil pressure (which isn't much for a lifter) they'll fill with oil and stay filled up. (They really don't "pump" up.....normal engine oil pressure is insufficient for that)

If you have a noisy lifter you'll see it when you remove the valve cover and check the rockers for a "loose" one.

That lifter might have a leaky check ball that is allowing it to release some "adjustment" oil. The leaky port might be due to sludge or other debris in the oil that has accumulated in lifter body and/or worn the cyl would normally seal preventing oil loss.....

Here's a great video on how they work.... hydraulic tappets / hydraulic valves (or hydraulic lifters) - YouTube

You can try different oils, thinner oils, snake oils, etc etc, but don't expect much difference.......

If you could take a lifter apart, I suppose you could "clean" it (if the problem was sludge/debris etc)......They're pretty cheap though........The usual way to "fix" a loosey lifter is to replace it.

For trolling, I would get a "kicker" It's less wear and tear on the main engine, less fuel used, and an emergency way "Home"!




Regards,


Rick

 

[pjumper]

Re: Trolling at low speed caused an engine lifter noise

My 5.7 merc. will troll all day without any issues. I do run it up to 3500rpm each day I troll. if yours knock you need to find out why.

 

[gm280]

Re: Trolling at low speed caused an engine lifter noise

Except maybe trolling motors?

I am going to agree with that. No manufacturer recommends operating any engine at idle for long periods of time. (doesn't mean you can't though)

But, "normal" temps are not maintained and wear is increased until normal operating temp (oil & coolant) is reached. Minimum cyl wear and oil consumption etc, occurs at "normal" cylinder pressures which ARE NOT maintained at very low power settings.

Your problem wasn't "caused" by idling though.

Maybe this is just semantics........They're not "Pumps".....but they ARE hydraulic cylinders that are "pumped" up Or more accurately, FILLED by engine oil pressure. If you have adequate oil pressure (which isn't much for a lifter) they'll fill with oil and stay filled up. (They really don't "pump" up.....normal engine oil pressure is insufficient for that)

If you have a noisy lifter you'll see it when you remove the valve cover and check the rockers for a "loose" one.

That lifter might have a leaky check ball that is allowing it to release some "adjustment" oil. The leaky port might be due to sludge or other debris in the oil that has accumulated in lifter body and/or worn the cyl would normally seal preventing oil loss.....

Here's a great video on how they work.... hydraulic tappets / hydraulic valves (or hydraulic lifters) - YouTube

You can try different oils, thinner oils, snake oils, etc etc, but don't expect much difference.......

If you could take a lifter apart, I suppose you could "clean" it (if the problem was sludge/debris etc)......They're pretty cheap though........The usual way to "fix" a loosey lifter is to replace it.

For trolling, I would get a "kicker" It's less wear and tear on the main engine, less fuel used, and an emergency way "Home"!




Regards,


Rick

I know very well how hydraulic lifters work. And they can be disassembled and thoroughly cleaned and work perfectly again. Problem is usually be the time they start making noise, because they are dirty and leak down, the face of the lifter(s) have already started to dish out. So that is the reason most just replace them. If the lifter face is still perfectly straight, then of course clean them and reinstall. But there is also cam wear as well. So be the time noises start, it is time for new cam, cam bearings, lifters and maybe pushrods, rocker arms and usually a complete valve job too... And if you are doing all that, you may as well re-ring (possible rebore and all new pistons too) and all new lower end bearings as well. So a complete engine rebuild is usually the final result...as least with me! I've done too many now to count!

 

[bigmikek]

Re: Trolling at low speed caused an engine lifter noise

To conclude ... This engine was new 110 hours ago. I don't think there is a problem except I can't troll at idle for an extended time in forward without asking for a lifter to tell me something isn't getting enough oil. I am not going to worry about lifter wear unless I hear it again. I am going to get a trolling plate so that I can up my rpm's and probably throw that drift anchor ( or two ) in the water and keep an ear open.
I just wondered if anyone else had this happen to them. I can easily take 4 bolts off my outdrive and remove the trolling plate when I am not using it. When I troll, I troll and troll. When I run up river for catty's or to go swimming I won't need it on. A 9 HP kicker or Min Kota electric is just out of the question for a few weekends a year.
I may borrow an electric one tho and see how it runs clamped to my ladder deck on a weekday locally. Thanks everyone.

 

[CharlieB]

Re: Trolling at low speed caused an engine lifter noise

When you say this engine was 'new 110 hours ago' Do you mean this is a brand new crate motor, or a freshly rebuilt?

In either case, hot idle oil pressure can be your problem and needs to be tested. Do NOT assume that your gauge is accurate. Get a real gauge, tap into the oil pressure port and watch the pressure. Record cold idle, running, and hot idle. It is entirely possible the pump is not putting out enough volume to maintain pressure once the motor gets to temperature.

40 psi running can be acceptable IF your idle pressure is also within spec. But I much rather see 60 running and at least 10 idling hot.

Bearing clearances are largelyl to blame. A builder assembling a motor with clearances near the large side of spec often needs to compensate for those clearances by using a high volume oil pump to allow to the increased oil flow.

If those lifters are older and reused they may need replacement also.

Check oil pressures first. The oil you are using is one of the best for a current production motors with tighter clearances.

You may simply need to switch to a 20 - 50 dinosaur oil.

 

[bigmikek]

Actually folks, I am confident this mystery has been solved and I am sorry to say I was wrong about the lifter noise completely.
What sounded like a lifter noise was actually a water pump in the front of the engine.
The cause is that the impeller in the outdrive failed and it caused water flow restriction in the engine.
The engine water pump did a good enough job of circulating water at higher RPMs but at lower RPMs the engine was starved for water and the reason was my impeller was broken in the outdrive.

Now I don't think this is very healthy for the engine and I probably escaped a major meltdown by being aware of this low RPM indication and didn't abuse it too badly.
I think I may have gotten away with some abuse. The water pump on the engine was replaced a couple days ago. It made a tapping sound as the grease on the bearing was coming out the front and it was stiffer turning than the new one is. I ordered my parts for the impeller change and am pretty confident that all my troubles should be over with overheating. I will be changing my impeller more often. Here is a link to my post yesterday about water pumps.

http://forums.iboats.com/forum/engi...e-impeller-failure-can-this-cause-overheating

 

[bigmikek]

I also want to apologize for making all of those here think about oil situations. I did mention that the engine temp was normal. It must have been higher than normal and I didn't realize it. Or the waterpump was still making the noise and we just assumed it was a lifter noise. I feel a bit bad about this but in the end I am following up with this to hopefully help somebody else down the line. No matter what, I do always appreciate the help and thank you all.

 

[friendly_jacek]

Thanks for the update. I fast idle a lot at about 1000 RPM with about 40 PSI oil pressure on 15W40 and never ever hear any knocking, even though the engine is on a noisy side.