hydraulic tappets & engine flush????

Latest info from Volvo site suggests that:- the petrol engines used in the 440 series don't have hydraulic tappets (according to my Haynes manual). They use inverted bucket tappets with a shim (might be called a biscuit?) to set the valve clearance. Clearance is adjusted by using shims of different thickness. One advantage of this system is it does not tend to go out of adjustment. I think it unlikely the noise is associated with the valvegear. To get at them it would be a manifold and gasket removal job, and it was then a very very fiddly job replacing them.

any further thoughts appreciated folks.

On 26/11/03 8:47 AM, in article bq0imc$1sq8f3$ snipped-for-privacy@ID-13002.news.uni-berlin.de, "Mad Sad Dad" decided to come out from under the bed and slurred:

So, the noise goes away after a short period? I wouldn't be worrying about it. Sounds pretty normal to me.

Cheers Hammo

Noisy tappets never hurt any engine.

If the noise goes away when hot, I'd cease worrying.

I've not found any way of curing permanently noisy tappets apart from replacement.

just had MOT,

was the

oil change and

hasn't.... He

it would solve

moved around

of the sump.

Sound advice IMO. I've never been an advocate of flushing oils for the very reason mentioned.

in broken bits

Although from your later post the engine has buckets and shims. That doesn't guarantee that the noise doesn't come from the valve gear. Wear on the camshaft, buckets or shims could still have made the valve clearance a little excessive. Enough to make them a little noisy. If you can live with it the chances of it developing into something more serious, or breaking something, is highly unlikely. A car can do many thousands of miles with noisy tappets, without causing any real harm to the engine. Only if it gets worse, and starts to affect performance should you think of getting it fixed. At that point it might be better to consider getting rid of the car, as unless you do it yourself, it'll almost certainly cost more than the car is worth to fix it. Mike.

Mad Sad Dad let forth with a mighty belch and uttered :

Hold on a mo.

Bucket+shim not need adjustment?. true they do stay in adjustment for longer, but not need adjustment?, I'd dispute that. If the valves recess into the head, the gaps close up. The engine tends to get a little quieter initially, then it loses compression and burns the valves. For them to get noisy and tappety, the clearance must have increased. This points to wear in either the cam face or the bucket if they are inverted, or the shim if shim over bucket.

That it quietens upon the engine warming suggests that expansion in some component is taking up clearance -or- its taking some time for an oil cushion to form.

Sufficient wear in the cam face/shim/bucket to be audible would not be likely to go away completely so quickly. Could do, I guess, but not likely.

Next up, oil feed to the cam, ie, is the guy certain that the oil feed is adequate. If the cam is oil starved, it'd make a bit of a rattle, but not usually for so long unless it was in serious trouble.

One thing that is not in dispute is that flushing a highish mileage engine is likely to dislodge crud and cause more problems than it solves.

Does the HBOL for this car specify a check interval for the valve train?

Yes. If you flush the engine you will probably end up with just gunk blocking the inlet holes to the hydraulic tappets. Then they really will be buggered.

No

Well that's absolutely normal. What has happened is that whilst the car has been standing, a small amount of oil has seeped fromt he tappets, hence they become a little slack and rattle. When the engine has warmed a little, oil is able to flow into the tappets and they take up the slack. As for valve cleaner, that will have no effect upon the tappets.

Behaviour like this is totally normal for an engine of that age. AS long as you don't thrash the heck out of it before it's fully warm and quiet, it's no problem.

Robert

A local mechanic said yesterday in an email to me:- The old VFRs changed from screw adjustment to bucket & shim and what they say is all true to an extent, however, new good oil should make it noticeably quieter, even if it was so far out that it didn't disappear. If it doesn't, it could be a broken shim (unlikely) or side lash in the rocker arm due to wear (very possible). its another of those " is it worth throwing another 200 quid at" jobs.

Before I go and chat to him ...

What does VFR mean?

Is "side lash in the rocker arm" painful or worth repairing??

I can't help you with your car problem, but...

I think he's referring to Honda motorcycles with VFR, which I believe stands for Vee Four Racing. I know the first versions of those bikes had camshafts that were referred to as, "Made of chocolate" they were so soft and wore out so quickly.