Just a question as to why there are virtually no threads on tappet adjustment.


I am asking this as I have a tappet sort of noise from the back of the engine for 1 min after start up that sounds like a failing hydraulic tappet, but we don't have hydraulic tappets.


Made me think if they are not hydraulic, why don't they need adjusting?

 

We don't have rocker arms and mechanical tappets either. The cam lobes rides on a disk sitting on the end of the valve stem. They are adjusted by replacing the disks. They also don't wear much so you don't hear of much need for adjustment.

As to the ticking sound that goes away with some oil pressure you might try a heavier weight oil or even a can of RESTORE for a quick check. Not much at the back of the engine to 'click'.

 

Thanks for that, I've not eliminated manifold or egr gasket leaks/cracks yet so could be that. The sound comes back on start up after only sitting for a few mins. Not sure if that points to a manifold leak or not.

 

A can of RESTORE will confirm or eliminate oil pressure as an issue in a minute with no harmful affects.

Exhaust gaskets do not fix themselves on warm up in my experience.

 

A tappet requiring adjustment would not do that.

 

I don't think that it is an oil pressure problem as it sounds worse under heavy throttle and best at idle and oil pressure always shows at the mid position regardless of rpm or engine temp.


Anyway do you mean this stuff AMETECH Restore?

 

Restore is a common oil additive here in the colonies but not sure about the UK. Surly you have a similar snake oil thickener. I don't buy into all the 're-plates your cylinders and bearings' claims but it does thicken the oil enough to raise the oil pressure. You could achieve the same by moving to a higher weight oil.

Commonly used to raise oil viscosity to quickly eliminate oil pressure as the source of a problem and certainly won't hurt anything.

Engine Restorer

 

Without knowing anything about what year or model you own the tappet or rattling noise you're hearing at start-up could very well be the cam chain tensioners telling you they're getting ready to break and that would be a catastrophic failure of the upper motor.

That noise at start-up is a sign of just that kind of failure so check the threads here and stop driving it until your sure of the problem because as an overhead cam motor there are only shim adjustments and they're hardly ever necessary in these motors and are definitely NOT a DIY job.

 

Hi, the car type is in my sig, 2002 4.2, so has the new tensioners, also the noise is from the back of the engine so I don't think it's them.


It's always a pita when you get a new problem no one else has had. I'll stick in some RESTORE but gut feeling also tells me it's not an oil pressure problem.


I was hoping that there may be some tappet adjustment needing done as that would be easier then accessing the gaskets for the manifold or egr unit. If a manifold stud breaks it would inevitably lead to an engine out situation.

 

Hi,
I would have initially thought this would be a hydraulic tappet noise, but given their are not any, could this be a lubrication problem.

Is the oil pressure ok, we know the gauges in these cars are not to be relied on. Could the oil pick up be partially blocked.(mine was)

What about a flush to clear oilways then fresh oil. Id check the pressure first, remove the sump and pull of the oil pick up and shake it, those tensioner bits can block it sufficient to restrict oil flow. Hope this helps.

Steveeasy

 

I'll buy one of these and test it out. Anyone know the thread size for the oil pressure sender?


449852 Car Wave Box Oil Pressure Meter Test Kit Tester Gauge Garage Tool | eBay

 

R.D.
This may be helpful and Steve "TheJagwrangler" is a regular contributor to the forum as you are probably aware.
Cheers,
David.
Jaguar V8 Oil Pressure Adapter - TheJagWrangler

 

If you have a copy of JTIS go to section 303-01 under General select Valve Clearance Adjustment & Valve Clearance Check. It would not be easy for me to explain what needs to be done to check and adjust the valves.

It does appear that an adjustment can be done so you may want to hold off on the oil additive until you can check it out. You will need a tool to do the job.

 

Sorry to offer up some bad (ummm, .... horrible) information. For 30,000 miles I had a slight tapping that seemed to come from the front of the engine. It was never detectable from inside the car unless the window was down, and I could hear it echo off a passing structure. And then the engine came apart. I'd spun at least one main bearing and totally munched the crank shaft. Unrepairable. In went a replacement engine. Mucho $$$$.

I could not be more thankful to all the members of this forum for all the help and experience I've received, ...... but....

Get the car to a good mechanic and have it checked out for real. Had I done the same, my costs would have been a quarter of what the engine ultimately cost me. These engines are sweet. They don't make noises.

Good luck!

 

Hey RD, fwiw, motorcycle engines used this valve train since the 70's and are very reliable and very quite. In your case, I sure it is not valve clearance since the noise stops upon warm-up... if it was loose valve clearance, the noise would be there all the time. My '03 on occasion will make a sort of "clinging" noise ... from the rear of the engine, sounds to me from the throttle body area... as if the throttle plate is vibrating. In addition, the noise is only while the engine is at fast idle... a few seconds at best. Try listening in this area.

 

Bhpbug...I think you've me confused with someone else. My only post to this thread referenced the possibility of a cam chain tensioner going bad and the resulting damage.

Even in motorcycles, of which I presently have 4, the failure of a tensioner means an expensive repair.

 

I think he has abbreviated RaceDiagnostics to RD!

 

The sound I have is pretty quite at idle and only loader under load, ie when driving so impossible to track down, from inside the car (RHD) it sounds like it is coming from the bulkhead area behind the steering wheel.


I think the next step it to have an indie listen to it. My closest indie is an hour and a half away so wont be soon.


The sound hasn't changed in the last 20 months now.

 

Ah so son #1<G><G>