E30 Zone

Right then, I’m stumped. The M20 was sounding more and more like a bag of spanners so I thought I'd give it the once over. I did the simple things first like checking the oil levels, made sure the oil feed pipe wasn’t blocked, checked to see if any on the injectors were noisier than the others and even fitted the customary big wedge of blue tac to the top of steering column. Nothing out of the ordinary there.

I then decided to check the valve clearances which turned out to be little or nothing, couldn’t even get the thinnest feeler gauge under some of them. So like a good little boy I adjusted them all to correct tolerances and now it sounds even worse. I’ve hunted around on the forum for any tips but I’m stumped as to why now that the valve clearances are adjusted to the right tolerances (heck, it sounds like my old mark 1 fiesta!). Any suggestions as it’s embarrassing how bad the engine is sounding! Appreciate any help

Can you explain exactly how you measured and set the clearances? Especially what did you do between adjusting each one?

Engine was stone cold and adjustments were made to 0.25mm

Rotate crankshaft to bring the first rocker (closest to the dizzy cap) of cylinder 1 to be on the peak of it's camshaft lobe.

Loosened locking nut, rotated the eccentric till feel a slight drag on the feeler gauge.

Carefully tighten locking nut and recheck clearance

Rotate camshaft to bring the next rocker along from (dizzy cap end) to be on the peak of it's camshaft lobe.

Repeat adjustment...

Rotate camshaft to bring the next rocker along from (dizzy cap end) to be on the peak of it's camshaft lobe...

...repeat above steps till reached the last rocker next to firewall and all done.

Thinking about it, would be worth re-adjusting following the firing order?

From what you've written it sounds like you've adjusted the clearances with the cam in the wrong place?? The clearances should be set with the lumpy bit of the cam pointing directly away from the rocker.

Ooops, sorry it's been a month since I'd done them and I'd forgotten how I'd done it...my bad! Yeah thinking back, I adjusted the valve clearances when the rockers where on the back of the lobe. I borrowed my mate to keep an eye on my work as it was the first time I'd attempted adjusting them. As an ex-mechanic he's a handy mate to borrow everynow and again! He's was also stumped as what was going on with the tappets sounding louder.

e301988325i wrote:From what you've written it sounds like you've adjusted the clearances with the cam in the wrong place?? The clearances should be set with the lumpy bit of the cam pointing directly away from the rocker.

I.E. Always should add up to seven. If the valves on two are fully open, then adjust five, if #four valves are fully open, adjust three and so on.
Doesn't matter what order you do them in, as long as you do them all. I slacken off all of the nuts first, tightening them as I go. When all the nuts are tight, I know I haven't missed one.

Just a thought but are you sure that your feelers are metric and not imperial as 25 thou is .63mm and it's an easy mistake to do as I have been there done that and got the t shirt .

Good point on the metric vs imperial, you had me running to the tool box to check! Unfortunately I'd used the right size which means it not a simple case of re-adjust using the right size!

I'm gonna wield some spanners at it over the bank holiday weekend and just check everything again (not that I'm paranoid or anything!). I'll have another look as well and see if anything is on the funk like odd shaped eccentrics. Cheers for the help gents

id be interested to know what you come up with, as mine can sound like a train and iv never been able to pin point it. i know some is from the injectors but lord knows where the rest is from.

Are you sure your exhaust system is well sealed? Escaping gas from one or more manifold joins could be mistaken for valve noise.