How would you know from listening to an engine that the timing belt was out?

E92

As the thread suggests, what I'm wondering is does the engine make a different sound if say the timing belt was loose?

As in a whining sound perhaps? Or does a whining sound that gets louder and louder(slightly) but then disappear when a bit of pressure is put on the accelerator pedal simply mean that the engines' timing belt has gone a bit slack?

This is proof that I know very little about what goes on under the bonnet:D.

And is a tappety engine bad, cause I know that Mitsubishi engines are great for going tappety, I mean apart from the noise of it obviously which is less than plesant, does it actually affect the engine's health, cause you hear lots of cars that are tappety these days?

Thanks in advance.

ford jedi

the main thing to worry about is when all the funny noises stop!!!!

if you have any doubt about a timing belt just get it done it will end in tears!!!

jayok

ford jedi wrote: »

the main thing to worry about is when all the funny noises stop!!!!

if you have any doubt about a timing belt just get it done it will end in tears!!!

But you'll spot this as there's probably be a bang just before the funny noises stop.

Do know re the timing belt though

Inspection is the key. If the teeth look worn, it needs to be replaced. Some cars wear out their timing belts before replacement intervals.

pixbyjohn

First of all determine if your engine has a timing belt or is it a chain. The whine could be your fan belt either. Timing belts are usually changed at a predetermined mileage and usually it does not change how the engine is. A broken timing belt can cause very expensive damage, bent valves, broken pistons and broken rockers worst scenario.
Prevention is better than cure.

ford jedi

after the bang which i forgot about and when the funny noises stop there is a strange quitness almost eary as you criuse along the motorway goin from 100mph slowly to zero in stealth mode .and as you crank your engine and it sounds like it could be a gammy starter motor as its turning over real fast well its not!! shes dead but not forgotton:eek:

pixbyjohn

Regarding tappet noise. This is caused by too much clearance between the valve stem and the camshaft. Excessive clearance actually alters the valve timing by a small amount. some engines have hydraulic tappets which depends on oil pressure to maintain correct clearance. The old ford fiestas were notorious for noisy tappets. In overhead camshaft engines the cams can wear and thereby cause noisy "tappets".
Hope this helps

jayok

... but you can take pride in the fact that the last 500meters that your car travels is pretty much zero emissions

ford jedi

very good jayok:D

jayok

pixbyjohn wrote: »

The old ford fiestas were notorious for noisy tappets. In overhead camshaft engines the cams can wear and thereby cause noisy "tappets".
Hope this helps

Ahhhh - so that's what the noise on my Fiesta was! I learn something new each day.

Ok, sorry E92, I'm done dragging this off topic.

peasant

You don't hear a loose timing belt.

A timing belt is in principle the same thing as a gear wheel, only that the "gears" are on a long piece of rubber instead of on solid metal.

As the name "timing belt" implies, it coordinates the timing between the bottom end of your engine (the crankshaft and the pistons going up and down) and the top end (the cam and the valves going up and down).

The timing is either right and everything works, or it is off and metal hits metal ...end of engine.

The belt may become loose over time, but this will be so marginal that you won't hear or even see it (if you could look at it in motion...which you can't) ...a little bit looser and it may jump one or two teeth and disaster strikes.

The belt needn't break or come off for the engine to eat itself ...jumping one or two teeth can be enough.

Theoretically the engine may still work if it's only jumped one tooth, but even then (unless it's a free running engine of the type where piston and valves can never meet) it is most likely that the pistons catch one of the valves and hammer it into the piston or valve seat ...resulting in breakage and bits of metal grinding themselfs into the engine. The engine may still run, but it will never be right again.

You would hear THAT ...but it wouldn't sound "tappety", just plain sick.

Oilrig

jayok wrote: »

... but you can take pride in the fact that the last 500meters that your car travels is pretty much zero emissions

The one time I had a car that suffered piston/valve contact it was far from environmentally friendly as it coasted to a halt...

Back to the OP's Q, a whiney T belt in my experience is usually over tensioned and will fail prematurely.

Omcd

If your engine is going clankety clank rather than tappety tap after the timing belt has been replaced, but otherwise running OK, (this has been going on for about 50k miles) what could the problem be ?

JHMEG

A loose belt will make noise. A belt that has skipped a tooth with make noise. A dodgy waterpump (which is driven by the belt) will make a noise. Lots of things will make noise.

Bring it to a mechanic. No-one on here will be even able to tell you what it is, never mind fix it.

meathstevie

The amount of moving parts under a bonnet make it impossible to have a guess at what causes a certain noise. Get it checked out. It probably isn't serious timing belt trouble ( yet ) because you'd know all about it.

Atomic Pineapple

E92 wrote: »

As in a whining sound perhaps? Or does a whining sound that gets louder and louder(slightly) but then disappear when a bit of pressure is put on the accelerator pedal simply mean that the engines' timing belt has gone a bit slack?

this sounds like a loose fan belt, does it only happen when you start the car up first?

as for the tappety engine i dunno, what kind of car is it?

E92

Cheers for all your replies. Curiosity had gotten the better of me, that's why I asked:).(I just heard a few cars of various makes making some of these noises in recent days, and was wondering what might be the cause).

And how bad is a loose fan belt(I apologise in advance for my complete lack of knowledge here:D)?

peasant

E92 wrote: »

And how bad is a loose fan belt(I apologise in advance for my complete lack of knowledge here:D)?

Depends on what's connected to the fanbelt: servo pumps, alternator, waterpump.

A loose fanbelt may damage the bearings in those components, a failed fanbelt will make your steering very heavy, the electrics go dead, cause a swift engine death due to massive overheating due to lack of coolant circulation.

Earth Worm Jim

Main culprits for this screeching sounds - fan belt (handy enough) water pump (no so handy) and best to do timing belt as well