There are two common "Bad" noises on cold start up.
Rythmical Grinding Noise often with metallic clank.
This is caused by insufficient transmission fluid . Its not sealed for life and if you have this noise you are about 2.5 Quarts (2.5 litres) short on your fluid fill. Remember to fill with the engine running. The noise may go away or reduce as the engine warms and the fluid expands.
Click like a tappet knock ( Excess valve clearance noise

Shows starting point for my measurements

Later dipsticks will have full mark at the higher level.
)
Its not a valve clearance problem but its piston slap. It sounds like out of adjustment valve clearance because its in rhythm with the spark plug firing as the tap only occurs on the unloaded part of the piston movement. If you dont have the piston slap yet then to avoid it you need to increase the oil level as Jaguar Directive. If you do have it then increase the oil level ,add Molyibdonem oil treatment or consider increasing the oil viscosity. There is no vehicle component called a tappet. As there are two variants of dipsticks fitted the photo show you how to check ..small knick in the stick at the new level.

 

Inverted buckets (w/ shim) are also commonly called “tappets”. At lest the usage is commonplace in the western USA.

Tappet is a generic term used for any part that is directly in contact with the camshaft lobe.

Z

 

I knew someone would take the bait. Take me a picture of a tappet and I will tell you what its called.
Tappet comes in the same ball park as Bendix......just slang expressions

 

slang to you is precise description to millions of others .



no need for me to waste (more) time on semantics by looking for a photo when I’ve already posted the generic yet all encompassing definition, commonly used.

tappet : any part that is directly in contact with the camshaft lobe.

in our cars that’s the inverted bucket with shim.

why don’t we move on to a more substantive discussion, like “up is the opposite of down”, etc etc

good day !

Z

 

Tappet = either one of the Car Talk brothers, Tom or Ray, take your pick....

 

If a mechanic was given a diagram of a valve train in an exam and asked to name the parts ..Tappet would be a wrong answer .
So if its a conventional push rod system whats the bit in contact with the camshaft called ...A cam follower...QED

 

it must be lonely speaking truth in a world of liars.



Z

 

As to the dip stick, I may have misunderstood but according to Tech Bulletin 100-17 to ensure the additional 1 litre of oil the correct dip stick is part XR8-2806 and that has no notch in it. This applies to early 4 litre V8 emgines.

However, the TB may have been superseded?

 

It’s my understanding of the post that the notch was added by the owner

Z

 

Ah, I see.

 

Maybe it's incorrect nomenclature, but I've always called them tappets, or sometimes cam followers if it's a Sunday.

Then there's the rocker arms on an OHV motor

 

The part of the valve train that contacts the cam lobe is called more than one thing, bucket tappet, tappet, cam follower, lifter and there are probably more names used more colloquially. As long as the persons involved in the discussion understand what the part is, it's okay.

 

So any comments on the use of Molyibdonem ..raising the oil level or using 20/50 to reduce further wear?

 

i don’t know of any credible evidence that ahows a heavy viscosity oil such as a 20w-50 reduces wear vs a quality 5w-30 or 0w-40, etc.

However, there’s quite a body of published evidence demonstrating that the greatest wear protection can be achieved with a quality synthetic oil.

According to the owners manual that came with my ‘02 model, one should use the viscosity that is appropriate for the general climate in which the car will see the most usage.

For me that’s a 0w-40 in the cooler months and a 5w-40 in the summertime.


Z

 

I agree with all that but on a worn engine with piston slap I am wondering if the thicker oil will cling to the bore better when the engine is stopped and reduce the click/wear on start up ? I am sure the Moly will help. Dont always get any click maybe 25% of the time

 

I can’t answer this question with any specificity.

I also have a moderate amount of piston slap. Like most with this occurrence, it does go completely away after the engine warms up. I’ve been hearing it since I first bought the car. At that time the mileage was 116,000. It doesn’t appear to have gotten any worse in the following 60,000 miles.

As measured by my Autool X60 the noise is gone by approximately 150 F / 65 C. I’m comfortable with just letting the engine warm up to that temperature before driving away.

I do have one bit of relevant data that gives me a bit of comfort; according to the last few oil change analysis done by Blackstone Labs there is no measurable amount of iron or aluminum in my used oil.

if there was any wear of substance on the pistons or cylinder wall(s) I believe the oil analysis would show those metals to a measurable degree. For what it’s worth, the Blackstone rep agreed with this conclusion.

I have been using european formula Mobil 1 0w-40 & 5w-40 since my ownership began 4.5 years / 60,000 miles ago. An oil on the thin side. Even so, it appears I’m getting some degree of protection.


I don’t know if a thicker oil would eliminate the start-up noise, but wear does not seem to be an issue based on the limited data I have.

Z

PS: not using moly or any other additive in the oil. I do use Techron Full Fuel System Treatment twice during each oil change period.

 

Very useful and relevant information I will stick with the moly and 10w40 based on what you say.
Great stuff,

 

After seeing the above photos I took photos of my 2002 XKR engine oil dip stick and measured the distance to the fill line using the same starting mark as above photos. Unsurprisingly, my distance to the full mark @ 21.5” / 54.6 cm was totally different.

Note: it takes me about 7.75 liters / 8.2 US quarts of oil to fill to the MAX line during a oil & filter change.

Z

 

I have a 97 XK8 4l non turbo . I know jag raised the oil level 1 quart and offered a revised dip stick..no numbers on mine. Could be a different sump, different dip stick tube or more baffles in the sump to help the pump during cornering. I am sure michaelh can find the advisory .
My stick has no number on it.
The point about thicker oil is that more may stick to the cylinder walls and reduce wear on start up ..hence the moly.Having worked with the guys who were in the problem-solving at the factory some solutions are not obvious. I recall one gearbox with a bearing lube problem and the solution was a deflector cast into the gearbox internals to direct oil spray in the direction of the bearing.

On another topic I managed to get some new front rotors NOS for £45 ($55) The guy said they had very slight rust in the hub area ,sent photo and said would I pay him £25 ($30) ... Perfect .

 

Yes, many engines have an *oil slinger* (Fords term, other manufacturers may call them
some else) used to make sure there is sufficient splash lubrication to critical areas that are not pressure fed. For example, my 1966 Shelby Mustangs have oil slingers to get more oil on the camshaft lobes and distributor gear.


Z

PS nice find on the rotors !