[Ari]

Hello All,

My RR is a 1995 LWB with 112000mi, it has developed a tic-tic noise while the engine is cold. Once the engine is at normal operating temp the noise becomes a knocking. The knocking is active at idle speed but goes away at 2000rpm and above. There is no apparent loss of performance, I've tried to identify the source of the noise using a stethoscope and is seems louder at the oil pan but it can just be resonance. I don't really know where is it coming from... Any ideas?

Thanks!

 

[rufant]

Sounds like a big end unfortunately. That is the shell bearing between the conrod and the crankshaft, at the 'big' end of the conrod.

I give a description of how to test one for one on it's way out here

viewtopic.php?f=4&t=32868&p=254355&hilit=+wooden#p254355

Another thing you can do it drain the engine oil into a clean light coloured pan and let it settle. Then drain off the oil into another container till you get down to the last bit, if this has bearing swarf in it (very small metal shavings) then it's likely you have a problem.

Engine rebuild or replacement is the only permanany fix i'm afraid.

Lets us know what you find.

 

[stuart460]

does sound half engine speed could also be a slipped linner

 

[Ari]

Thanks for the replies. Tonight I removed the belt, that made the noise very clear without all the other stuff running. Even without the belt I could not identify the origin of the knocking. I've also disconnected the spark plugs one by one but the noise was not effected. Tomorrow I'll check oil pressure, remove the spark plugs and check the pistons for excessive play as suggested by rufant. Maybe during the weekend I'll remove the sump and check the oil. Would I be able to inspect the liner from below?

 

[rufant]

Maybe during the weekend I'll remove the sump and check the oil. Would I be able to inspect the liner from below?

I don't know, i've never had the sump off. Maybe someone else can advise?

 

[stuart460]

yes you can see the liner's i would be inclined to start with the valve train work rocker sticking follower before you look at a poss liner or bearing

 

[hilleng]

the ticking noise when you startup is more than likely a hydraulic tappet.the nocking noise could either be a piston or main or bigend bearing.check the oil pressure with a guage and see if u have about 60-75 psi when cold.if it is a bearing liner then a rebuild is in order as it is not worthwhile just to repair that one fault without doing the engine.the bearing surface on the crankshaft may be damaged to where it will require regrinding .sorry!!

 

[Ari]

I removed the oil sump and tried to force the big ends up/down, could not find any radial play on the big end bearings. There is some minor play in the longitudinal sense but I believe that is normal to avoid friction between the connecting rods that are mounted together. Is that correct? I also checked oil pressure and it is fine. Maybe now I should look at CAM and valve train?

Thanks All!

 

[Danny]

You won't find a worn big end like that. The piston is a tight fit into the cylinder and won't just flop up and down as you try to wiggle it.

 

[flagrover]

I had a similar noise and it turned out to be a rocker arm and push rod. Thought I had a frozen lifter, but it was just a worn out Rocker. Take the rocker assembly off and inspect it well. Instead of being domed like the rest this one was pyramid shaped and the push rod matched (round pyramid, not sure what to call it...lol) Took 30 min to fix. Not sure this is your issue but it sounds close.

 

[rufant]

Much shiny stuff in the oil when you drained it?

 

[Ari]

The oil was clean, no shavings.

 

[rufant]

As you have come this far you might as well take each big end cap off and inspect them. A worn bearing should be pretty easy to spot. If you want to know what to look for just say.