120 Ford-Lehman light ticking noise

[rgano]

This concerns a port FL120 2715E main engine which has been ticking for the last few hundred hours. Stbd engine has no such noise. Engine has about 6000 hours on it. Today, I tried to use my 29-years of twin FL120 stewardship to get a handle on where it was coming from. All I could do was use a big screwdriver to my ear moving around the engine. My best guess was in the vicinity of cylinder 5. Removing the valve cover to listen did not reveal anything new. The injectors have never been pulled for maintenance. We set the valve lash a couple years back. I wonder if it could be a burned exhaust valve. I have heard the whistling of a burned gasoline engine exhaust valve, but am unsure about what a diesel might emit. We made an MP4 file in which the tick can be heard in the background of the idling engine, but I have no means to link to it or include it here. I am thinking the injectors should be pulled and serviced before we get a Lehman mechanic in to listen, Glad to fwd it to anybody interested; just PM an email to me.

 

[SoWhat]

Amazon sells inexpensive automotive stethoscopes that will help pinpoint noises.

Not sure it will help. Lehmans have traditional valve train complete with cam hitting tappets, tappet hitting pushrod, pushrod hitting rocker arm, rocker arm hitting valve, etc. lots of places for a tick.

I would recheck the valve lash. I suppose it is possible for an injector to tick on the intake stroke, but my money is on a sticky tappet or a worn and loose pushrod.

 

[rgano]

We were tending to discount need for another lash adjustment, but we'll do that anyway and hope you're right. Gonna check head bolt torque before the adjusting. Thanks.

 

[rgano]

This afternoon we went down to the boat and retorqued the head and set the valves. We think it is quieter now. Those injectors have still got to get serviced.

 

[Barking Sands]

You could swap suspected injectors to a far end of the engine. Or even your other engine to see if it follows.

Also dont forget about the mechanical lift pump. It is cam driven as well. If particular parts develop excessive play they can grow a faint tick as well. That another easy item to swap between motors to eliminate.

 

[rgano]

You could swap suspected injectors to a far end of the engine. Or even your other engine to see if it follows.

Also dont forget about the mechanical lift pump. It is cam driven as well. If particular parts develop excessive play they can grow a faint tick as well. That another easy item to swap between motors to eliminate.

I checked the lift pump area with my screwdriver "stethoscope" and did not detect any odd noise there.

I used to send my injectors in for rehab every 2,000 hours, and here my brother sits with his at 6,000 never having been lifted. And he lives within easy driving distance of the shop in Mobile I used. There is no missing or other untoward behavior indicating injector trouble, but these two engines could end up sounding a LOT smoother after the injector rehab.

 

[psneeld]

I always thought my Lehman was making a ticking/tapping sound. Various things to get rid of it didn't, just changed my frame of reference from time to time on the noise.

Still going with nothing serious at 4000 hours I am guessing (sold boat but still in touch with owner)

 

[rgano]

I always thought my Lehman was making a ticking/tapping sound. Various things to get rid of it didn't, just changed my frame of reference from time to time on the noise.

Still going with nothing serious at 4000 hours I am guessing (sold boat but still in touch with owner)

I think that is where we are going with this one, especially after he gets those way-overdue injectors looked at.

 

[Mike GB32]

Not questioning whether it can happen but can someone explain to me how an injector can make a tapping sound?

 

[diver dave]

I have had a small exhaust leak cause a ticking sound. It was a gas motor.

 

[Barking Sands]

I used to send my injectors in for rehab every 2,000 hours, and here my brother sits with his at 6,000 never having been lifted. And he lives within easy driving distance of the shop in Mobile I used. There is no missing or other untoward behavior indicating injector trouble, but these two engines could end up sounding a LOT smoother after the injector rehab.

He is clearly part of the "If it ain't broke don't fix it" crowd

 

[alormaria]

You can hear a "light ticking" noise next to a running Lehman?

 

[jleonard]

You can hear a "light ticking" noise next to a running Lehman?

 

[RT Firefly]

Greetings,
Mr. a. MY thoughts exactly!

 

[Comodave]

I assume a “light ticking” noise is relative…

 

[SteveK]

You can hear a "light ticking" noise next to a running Lehman?

Actually, on my mechanical survey both the tech and I could hear the tick of #3 injector at idle, works fine revved, needs to be changed.
So yes, if you have an ear for it, you can.

 

[Mike GB32]

But...but...but...what is it on an injector that ticks?? I understand that the valve touching rocker arm etc. could be noisy...but...
Help me understand

 

[diver dave]

But...but...but...what is it on an injector that ticks?? I understand that the valve touching rocker arm etc. could be noisy...but...
Help me understand

Mech injectors have several moving parts. Needle valve etc

https://youtu.be/P5-yxENaLDU

 

[SteveK]

But...but...but...what is it on an injector that ticks?? I understand that the valve touching rocker arm etc. could be noisy...but...
Help me understand

nothing.
maybe ticking can be tapping, knocking sound. Injector cleaner may clear it up.
Here is one of many videos to demonstrate. Warning, not a Lehman.

 

[BeeJay]

This concerns a port FL120 2715E main engine which has been ticking for the last few hundred hours. Stbd engine has no such noise. Engine has about 6000 hours on it. Today, I tried to use my 29-years of twin FL120 stewardship to get a handle on where it was coming from. All I could do was use a big screwdriver to my ear moving around the engine. My best guess was in the vicinity of cylinder 5. Removing the valve cover to listen did not reveal anything new. The injectors have never been pulled for maintenance. We set the valve lash a couple years back. I wonder if it could be a burned exhaust valve. I have heard the whistling of a burned gasoline engine exhaust valve, but am unsure about what a diesel might emit. We made an MP4 file in which the tick can be heard in the background of the idling engine, but I have no means to link to it or include it here. I am thinking the injectors should be pulled and serviced before we get a Lehman mechanic in to listen, Glad to fwd it to anybody interested; just PM an email to me.

Can’t recommend you do this if you value your fingers. But you can slip a feeler gauge on a running engine to isolate a noisy valve in the train. Borrow your mates feeler gauge or use some shim though.

 

[Mike GB32]

Wow. I really don’t know enough about fuel injection.
Thank-you.

 

[ronobrien]

You could swap suspected injectors to a far end of the engine. Or even your other engine to see if it follows.

Also dont forget about the mechanical lift pump. It is cam driven as well. If particular parts develop excessive play they can grow a faint tick as well. That another easy item to swap between motors to eliminate.

I am not sure about moving the injectors around. Years ago, as a mechanic for Mack Trucks,the injection pumps were calibrated to specific injectors. The set had to be installed in the same order that they were calibrated. It may be different for FL but my hunch is that the process may be the same.

 

[psneeld]

Injectors on a Lehman are random in my experience, a set shipped is not labeled.

 

[ronobrien]

Good to know.Thanks.

 

[rgano]

You can hear a "light ticking" noise next to a running Lehman?

29 years of experience with a pair of them gives one that ability, yes.

Our plan with this pair of family-owned Lehman's is to wait out hurricane season and get the injectors overhauled then. While this almost insignificant tick may not go away, they will doubtless run better after 6000 hours without injector overhaul.