14 replies to this topic

[Pavel]

Okay I got the car today, and there is a slight problem:

1st, the idle is very high. If you put it into gear and depress the clutch slightly, engine speed drops.. So cruising at like 15-20mph in 4th gives RPM which would normally be acceptable for idle. I don't have a rev counter.

Now the noise problem... Whenever in 3rd or 4th, anything more than the LIGHTEST touch of the throttle, there comes a tapping/knocking sound from the engine bay (not very loud, and more tapping than knocking). I haven't tried to rev it past the noise in those gears. In first or in neutral there is absolutely no noise even when revved a lot. I'm guessing therefore that the noise comes in only under load... So what could it be?

Keep in mind I changed the head gasket last week. After changing it compression figures were 185-180-180-180 so it's good i'm assuming. Gearbox etc. wasn't touched. Neither were any adjustment screws on the carb!

[Dan]

If your head gasket has been going for some time, and the engine has been repeatedly tuned to correct for the problem then replacing the head gasket will require a re-tune back down to standard settings. You should always tune your engine after replacing a head gasket, or at least check the tuning.

The car should be expected to idle at about 15mph in 4th, and pressing the clutch will always drop the revs a bit because you push the crank hard up against the thrusts. You probably just noticed it because you are concerned about the other problems.

Sorry, got distracted. Kimi Raikonnen's car just failed.

Erm, where was I.

The noise problem could be caused by being out of tune, or it could be the tappets (lifters) need adjusting. Can you give any more symptoms?

[Pavel]

Rockers weren't adjusted after head gasket change, so that's my first guess...

As for the idle I think i may have a manifold gasket leak, ill check that out tomorrow

[clubman katie B.F]

tappets??? engine bushes, mountings, is the engine moving around in the bay back and forth???? I had that noise last week, but replaced engine mounts and top engine steady arm thingy bushes, seems to have worked

[Dan]

But lifting the head wouldn't cause the engine mounts to fail, it will cause the valve clearances to change every time. And Pavel says it's a quiet noise. When my engine mounts go it aint quiet.

[philster]

sounds like it could be either the timing is quite a way out or possibly (as dan said) it could be a head gasket problem. I had this on mine, mostly on hills and it was found to be the mechanical advance in the dizzy had seized causing the timing to be out.

Hope you sort it

have fun!

[Bluemini]

Could be the mains or big ends too if its making a noise under load. Excesive rpm drop when pressing the clutch is due to worn thrusts. The tapping could also be the tappets like previously said, or if the engine is worn out, it could be the cam followers are pitted. I had this problem myself, makes the same kinda noise as tappets, but from inside the engine. A new set will cure it.

[Pavel]

Right about the clutch, i made a bit of an oops! I meant when RELEASING the clutch in gear, RPM drops significantly, wich shows that my idle is a bit high! That'll get sorted today though.

As for the knocking, it may well be engine steadies! My top bolt hole in the block for the engine steady is pretty much knackered...


God, I need a new car ;p

[Dan]

I have always found that worn steady bars give more vibration at idle and a seriuos jolt when coming off power. If it's this then the exhaust will hit the floor behind the drivers seat every time you change gear. You will definitely hear this.

I think Philster could well be right about this. Timing problems lead to knock/pinking and this happens at certain rev ranges depending on the advance of your dizzy. So this could be base timing or a problem with the vacuum unit or weights/springs.

But if the steady bar assembly is tired, get it fixed. If any of the holes are ovaled get them seen to. Snapped steady bar bolts are sent by the devil.

[Pavel]

Right I took it out again today for a longer drive


The noise is VERY much there and isn't quiet. I am led to believe its rockers/tappets which should be adjusted after head gasket change but they weren't.

I highly doubt its cam followers/bearings etc. becuz this noise came after head gasket change mainly so those things weren't touched.

It's only under load, when engine is revved or in 1st etc. then the noise isn't there. Pulling away in 2nd/3rd/4th give the noise.

It doesn't seem to be pinking, more like a tapping/knocking noise. If it's tappets/rockers, is it safe to drive it around 100 miles, since I want to see if the mayo will disappear before attempting to adjust the rockers right now....

[Dan]

Well, it could be but thats's a big 'if' to gamble your engine on. I'd just do the tappets and check the tuning/timing if I were you. It only takes half an hour and if you still have the noise then you know it's a real problem. As long as the head's been heated and cooled at least once and been re-torqued then the valve clearance won't change again for ages.

[Pavel]

Right im officially locked out of the storage room where my haynes manual is!! :S

Can somebody give me a rundown on how to check adjust timing/tappets/valve clearance/rockers whatever needs adjusting, since I'm going to the garage tomorrow and want to get this sorted!

[Dan]

Do you have the last couple of Minimags? There was a complete servicing guide recently.

Maybe someone should do an FAQ on how to do a service and tune-up.

[Pavel]

Nope don't have minimags :S

A FAQ would be rather nice!

[Mini]

Hi Pavel,

Given the history of a head gasket replacement it sounds very much like your car is pinking and needs the ignition timing set. Its best to get this seen to as soon as you can as it can cause damage if its severe.

Cheers