Z3m - Valve Clearance

[Mtomlin]

Can anyone explain to me when a car needs the Valve Clearances done, why they need doing and roughly how often. how can you tell, is it related to performance - eg if the Car is producing great power on Dyno does this suggest no need to check Valve clearances.

Just hearing different stories.

Thanks

Matt

[AngryApples]

+1 on this (in my case for the E46 M3)

I'd like to know what this entails, in non engineer type speak

Edited by AngryApples on Wednesday 15th April 22:17

[belleair302]

I would suggest every two years. Simptons include hesitation under hard acceleration, poor economy and possible heavy oil consumption. Most good specialists have the tools to check the correct valve clearances....to be done when the engine is cold, ie after an 8-9 hour rest.

It is not a difficult job, but is time consuming and needs to be done well. When properly done he engine feels smoother, economy improves, the engine is stronger and 'sings'.

Not convinced many main dealers will understand the science of what is involved....requires more than a diagnostic computer.

Want a more technical explaination of what is involved?

[Disco_Biscuit]

S50 engines which is every 30k inspection 2 service.

Edited by Disco_Biscuit on Wednesday 15th April 22:37

[zmrjason]

Matt,
My car just prior to having its shim service at Bexleys was running real good and sounding great!! It needed something like 12 shims doing (a lot)......you probably wont notice an appreciable difference unless its very neglected BUT the engine probably will! Guessing thats why they made it relatively fixed time frame etc service just to ensure they are as "M" intended :-)

Hope all is good mate, sorry not replied to your email!!!! been i bit mental and I've been a bit slack!

Cheers
Jason;-)

[Banus333]

AngryApples said:

+1 on this (in my case for the E46 M3)

I'd like to know what this entails, in non engineer type speak

Edited by AngryApples on Wednesday 15th April 22:17

Not directed at you AngryApples - but for simplistic information:

Each camshaft lobe is directly above an inlet/exhaust valve. The lobe is "egg-shaped". As the camshaft rotates it opens & closes the valves to allow a petrol/air mix in for combustion & the resultant exhaust gases out of the cyliner head (In my days of aeronautical piston engines it was known as "Suck, Squeeze, Bang & Blow"!).

The forged lobes on a camshaft obviously wear down with time or the lack of oil changes by ignorant owners. That means that the valves don't open as much as they should so not as much fuel/air is input (lack of power) & not as much combustion gas is exhausted.

On the old 1970's Ford Escort Mexico/RS2000's I used to remove the cylinder heads of my cars, re-grind the valves, de-coke the head & re-set the valve clearances every 6 months or so. Times have changed - but it is still a DIY job on older ///M cars. It ain't difficult. Buy a set of metric feeler guages for a fiver & a set of various shims for <£30.

I would not advocate this unless you know exactly what you are doing & have access to the correct torque values.

But the BMW dealer network insist on a wholly uneccessary & exhorbitant charge on their "Service 2" to "check" the valve clearances. I can assure you all that on this highly efficient & perfectly manufactured S54 engine you won't need valve adjustments until around 50-80,000 miles - unless you don't change your oil every 6000 miles & thrash the car to pieces. You will also suffer VANOS problems without regular oil changes......

I await the flames!

Edited by Banus333 on Friday 17th April 10:04

[M5Dave]

Disco_Biscuit said:

S50 engines which is every 30k inspection 2 service.

Edited by Disco_Biscuit on Wednesday 15th April 22:37

Are you sure?

E36 M3 Evo had to have them done at every inspection 1 and inspection 2 service, which worked out about every 14-15,000 miles.

To be fair they probably don't actually need doing till around 30,000 miles, but sticking purely to the service schedule, I'm pretty sure it's every inspection service.

[Disco_Biscuit]

This may be of some help http://www.zroadster.net/forum/viewtopic.php?t=124...