Interesting Situation with noisy M40 engine

[dialup_2001]

Firstly thanks in advance for any help. I have bought a 145K mile 318 Touring. It has a fairly tappity engine, upon driving it home from the dealers, it seemed to cut out a bit, I liked the car and so decided, bugger it, I won't return it, just fix it.

It is not the noisiest M40 I have owned, it won't rev over 3200 rpm.
Regardless of speed, load, foot on the clutch, off the clutch, downhill, uphill, HOWEVER, let it tick over and suddenly boot it (whilst depressing clutch) and you can get it to 4.5k!

The interesting thing is, I am very lucky to have another e30 coupe with the same engine, just swapped over the rotor arm and dizzy cap as they were very bad, no change.

Please help me, what should I try next. Thank you in advance and can you adjust tappets? if not, how can I quieten engine.

[miniblob]

I am by no means an expert, but from what i've heard/read, I thought it was normally a knackered cam that stops these engines from revving!?!?

Had an M40 with the same issue once, but it was a scrapper, so I never looked any further and just assumed cam!!!

Someone will be along with a proper answer soon!!!!

[cypriot_boy_2k7]

Probably the camshaft not letting it rev up, the tappets are hydraulic so no adjustment can be done.

[dialup_2001]

OK, is this easy to visually inspect for stepping in the contact area of the cam lobes?

[Billwill]

The hydrolic tappetts can make a noise...I had to replace all of mine.

Cam wear is quite common if oil changes have not been done....if you remove the tappet cover you will see the oil-feed tube running accross the cam-shaft. Make sure this is not blocked and check to see if the cam-shaft is worn.
A worn camshaft is the usual culprit for the M40 not revving over 4,500 RPM.

If you do not know the history of the engine it is best you replace the timing belt and idler and tensioner pulleys and while you are about it you can remove the cam-shaft and have a good look at it and maybe change the hydrolic tappets at the same time.

The Haynes manual gives you the procedures and there is a Wiki here as well.

A word of warning...before removing the camshaft make sure you block all the small oil-return holes on the downside of the head. These hole are just large enough for the small followers on the top of the valves to fall down into the sump.....ask me how I know this



If the cam-shaft and the head section that the cam runs in are worn and the hydrolic lifters are shot I would return the car back to the dealers if I was you!

[TPS]

These hole are just large enough for the small followers on the top of the valves to fall down into the sump.....ask me how I know this

Oh Dear!

[dialup_2001]

OK, thanks, I think it might be easier and cheaper to just change the engine for something a bit newer without the heavy modification. A friend of mine runs the BMW breakers in Kent so I could choose any engine.

[Morat]

If your mate has an E36 M3 in for breaking then you could be in for some fun