Alright, let's play a little game. Take a listen to the following video and lets if can identify all the noises.

https://www.dropbox.com/scl/fi/6j02c...iva9dzgb8&dl=0

 

Opps - try this link

https://www.dropbox.com/scl/fi/6j02c...iva9dzgb8&dl=0

 

Disclaimer: I didn’t listen.

only comment: my 2002 XKR has a decent amount of piston slap noise when it’s stone cold. As soon as the engine warms up to 140-160 F + then it’s as quiet as a church mouse. And still quiet on up to when it’s fully warmed up

are your noises temperature dependent ?

many engines have piston slap noise, not just the X-100’s. For me, it’s not a
problem. If a person is in a hurry to drive off with the engine cold, then I can see how it might be irritating .As long you can keep your foot off the accelerator until it goes away then I’ve found it usually doesn’t get worse as the miles accumulate.


Z

 

The first thing to do is to decide whether the noise/s are less or more when the engine is hot or cold or maybe doesn't make any difference.

With the engine at the temperature at which the noise is worst, use a socket set to relieve the tension on the accessory belt tensioner whilst the engine is running but only run it for a minute if it's already hot. If you're not confident using the socket set on the tensioner with the engine running then remove the belt entirely. It's not difficult on the X100.

Once you have removed any possibility of the noise originating from anything which is driven by the belt, you are left with internal reciprocating engine noises such as cam chains, valve clearances, injectors, bearings, pistons etc. You can then focus on using a listening device/stick on the engine itself. Remove the oil filler cap and see if that increases the noise.

It sounds to me as if it is related to the cams so listening with the filler cap removed might prove instructive. Then removing the cam cover on the noisiest side and checking the cam chain and clearances might be worthwhile. I'm assuming that the original plastic upper cam chain tensioners were replaced with the metal version many years ago.

Richard

 

Thanks Z for the reply. The video was taken at cold right before a test drive. Thanks for the tips! Enjoy the ride!

 

Thanks Richard! Very good info. I am looking to purchase this ride. I wanted to confirm that the noises/ticks are some what minor and I can deal with them at home. Fingers crossed that this beautiful Vanden Plas comes home with me.

 

If the engine is using **** water 5w30 then remove the noise with 10w40 or even better 15w40...worked for my piston slap.
Remember in the old days we had 20w50

 

Hello Pal,

I’m curious, when you were using 5w-30 did your piston slap go away when the engine warmed up completely ? Or
was it always present regardless of engine temperature ?

On my car, 2002 XKR , the piston slap always goes away once the engine has reached normal operating temperature.
(I’m using Mobil 1 0w-40)

from what I know about oil, a 0w-40 is just as thick at operating temperature as any variation of XXw-40. Only when the motor is cold does the first number come into play.

Z

 

Don't know much about piston slap, but this is what my engine sounded like at 45k miles (had barely moved in 2 years) and a belts and pulleys service resolved it. Warming the engine up would make the noise go away. I'd follow the advice above about the accessory belt. a mechanics stethoscope or another listening tool could probably identify which pullet is squeaking.

 

In the winter I never got piston slap with 5w30 but in the summer i did so I changed to 10w40 to cure it MOT man said it ran like a sewing machine Am now using 15w40

 

I'm struggling to understand how a thicker oil could stop piston slap, but there you go. It can certainly reduce bearing noise, at least for a limited period, but that is because the oil is under pressure in the bearings. It's not under pressure on the cylinder walls.

Richard

 

Its squirted on the back of the piston and gets on the walls

 

I understand that .... but it is not under pressure so how does it close the gap in any meaningful way?

Richard

 

it closes it simply by being thicker. It gives a thicker “cushion” when the piston tries to “slap” the cylinder
wall. So you don’t hear it, or at least hear it less.

That’s all.

 

The difference in oil thickness in this unpressurised situation would be so slight compared to the sideways force being exerted by the piston against the cylinder wall that, as an engineer, my instincts tell me that any reduction in noise would definitely fall into the "hear it less" category. In fact, so much less, that it would be barely perceptible to the human ear. 😉

I've done a web search and, whilst I certainly don't believe much that I read on the internet, I can find dozens of references to "thicker oil not noticeably silencing piston slap" and zero references to the opposite.

Anyway, let's leave it as the beauty of all forums is that we can all have diametrically opposite views but it is of no consequence either way. 👍

Richard

 

You are certainly entitled to believe what you wish.

However, perhaps it will be most instructive to experience piston slap yourself and then find out as countless
others have done that a thicker oil makes it go away.

we aren’t taking about massive clearance reductions here. As there isn’t much piston to cylinder clearance involved. Engines that are totally in spec with regard to piston clearance sometimes have issues with piston slap. It’s not always a worn out piston issue. Although that certainly makes it more pronounced..

Starting out on the tech side of engines in the late 1960’s / early 1970’s I worked at a Triumph motorcycle dealership.in OKC. That was my first introduction to excessive piston noise. It went away when the engine heated up, as long as a thicker oil was used. Much like today’s X-100’s.

How the thick oil works is certainly a lively topic for discussion. That it works is something best experienced individually.

 

It appears to be me and the rest of the interweb. 😉

Richard

 

that reminds me of the old quotation , “who are you going to believe, me or your lying eyes…”

in this case I’ll believe my lying ears.

you can lead a horse to water, but you
can’t make him drink.

all the best

Z