So I'm pretty new at all this, but reasonably good with hands on work. I was wondering what happens if the timing belt is not replaced and eventually snaps? Is it a simple matter of getting the vehicle towed then having the entire belt kit replaced? Or is major engine damage caused by this? Thanks

Luke.

The latter!

You have too outcomes.. It can do no damage to engine or it will do plenty of damage to engine. there is about a 1-2% chance of no damage. When it does damage it will be pistons and valves getting into a punch up and valves usually come off second best..:(

Its best you do it to save you thousands of dollars later..:)

Alright thanks for the quick response guys, I'll be taking the replace timing belt and not engine option I think, seems better to be in the long run. :)

Luke.

Depends on the engine rpm at the time, if it breaks at startup, its a heads off, replace exhaust valves type of job. At higher rpm the broken belt can do damage to the cam belt case and crank angle sensor. In a worst case scenario, the belt can jam at the crank pulley, locking up the crank suddenly and damaging the crank itself or shattering the oil pump casing. Replace engine time if that happens. Thats why Mitsu recommends 100,000 km or 5 year replacement, even though the belt can be good for longer. Better safe than sorry.

well timing belt snap you will see values smashing pistons as the cam dont know to do and stop and pistons keep and smashing them so it could kill your motor

Speaking from personal experience; you get to see your car on a flattie, and argue a lot with idiot mechanics. And the engine gets the heads done and your wallet gets emptied. Seriously; change the belt when it's due, risk of damage is too high.

Regards, Tony

It's unanimous then! lol Changing the belt at the right time is a GOOD IDEA!! lol

Hi, the timing belt is seriously not that expensive. One mitsu dealers i know in SA do just the belt only if you want for like $300ish, and they reset the tensioner at the correct torque setting. I would only do the timing belt AND kit if it has reached 200k, which would be a lot dearer.

Hi, the timing belt is seriously not that expensive. One mitsu dealers i know in SA do just the belt only if you want for like $300ish, and they reset the tensioner at the correct torque setting. I would only do the timing belt AND kit if it has reached 200k, which would be a lot dearer.

IMO changing the belt but not the other ancilary items is silly. If the belt has to come off, might as well replace the other bits at the same time

IMO changing the belt but not the other ancilary items is silly. If the belt has to come off, might as well replace the other bits at the same time

I'd agree with this.

Local garage told me that it needed doing but they'd leave it til next time when the next service deals with the the tough stuff at the back of the engine.
Told me to allow $750 for the service, which is usually about $250.

It is all a matter of paranoia. The chances of a water pump leaking is only very high if the coolant is not replaced at its recommended schedule, diminishing its lubrication and corossion resistant properties. Also, the "KIT" if not replaced are not show stoppers. they will give signs before giving up, such as hydraulic timing belt tensioner faulty giving belt slapping sound constantly. valves will not be bent or pistons come flying out.

Each to his own in my opinion.. BUT, the timing belt is a must because it travels through a very small pulley at the bottom, which causes massive tension to the belt at that point. As Madmagna said, they may look brand new, but they still have the capacity to snap without warning past their recomended working life.

Meant to say that my motor's got 75k on the clock and is 7 years old.
Bit of a toss up between age and kms travelled.

I'm planning to do it before 100k, but that could take me a few more years, so maybe sooner as smarter.

Give yourself 12 months to read the manual, buy a cheap belt and tools off eBay, and do it yourself. Shouldn't need to replace anything else. When the big one comes at 200,000, and you still own the car, do the whole lot. You will save plenty money!

Talking about cheap parts:

http://info.rockauto.com/getimage/getimage.php?imageurl=http%3A%2F%2Finfo.rockauto.c om%2FDayco%2FKit+WP287K1AFRO.jpg&imagekey=2455186-0&width=450

Full kit from rockauto, $174 US, plus postage. (Dayco belt). Around $250 AU delivered.

Gates belt by itself is $25.79 US, about $50 AU delivered to your door. Local price is about twice that.

(consequences of not changing the timing belt) = (consequences of not having a car when you really need one !) = S.O.L. = Sh*t out of Luck

So buy a couple of spare Magnas! Second genners are dirt cheap! lol

Do a bit of math.
Assume that your average engine RPM is 2,000 over 100,000Kms. This is likely to be around 50 million circuits of the timing belt.
As some of the pulleys are approx half the diameter of the crankshaft pulley they will have done 100 million revolutions.

Apart from the effect of heat, time and cycles on the belt, the pulley bearings, the water pump bearing and seal all have a finite life.
That is why the recommendation to change these parts.
Gerry

Do a bit of math.
Assume that your average engine RPM is 2,000 over 100,000Kms. This is likely to be around 50 million circuits of the timing belt.
As some of the pulleys are approx half the diameter of the crankshaft pulley they will have done 100 million revolutions.

Apart from the effect of heat, time and cycles on the belt, the pulley bearings, the water pump bearing and seal all have a finite life.
That is why the recommendation to change these parts.
Gerry

And what is the manufacturer's tested life expectancy for these bearings? Without knowing that your maths is useless.
Any bearing that has no play, and turns smoothly, doesn't feel dry or gritty is still ok to use.

Just replaced one of the exterior idler pulleys on a 3L V6. It runs at about 3X engine speed, for 240,000 km. Do the maths on that!

Do you know how to replace the belt?

If not, then it's a no brainer, pay someone to do it when the spark plugs at the back need replacing, at 100,000 service.
It'll cost $400 or $500 more than the usual service.

Otherwise, you'll save money on the belt replacement and pay to get a new engine.

Do you know how to replace the belt?

lol Nobody "knows" how to do the belt until they have done it for the first time! lol That includes me, you and all of the mechanics in the world.

To do it for the first time, you do need to overcome some hurdles.
(1) Read and understand the procedure in the manual.
(2) Collect the parts and tools.
(3) Have the time, place and enthusiasm to do it.

The same goes for changing a tyre, changing a globe on the car, etc. Did you "know" how to put on your socks, shoes and brush your teeth before you did it for the first time? Life is all about meeting new challenges! lol

lol Nobody "knows" how to do the belt until they have done it for the first time! lol That includes me, you and all of the mechanics in the world.

To do it for the first time, you do need to overcome some hurdles.
(1) Read and understand the procedure in the manual.
(2) Collect the parts and tools.
(3) Have the time, place and enthusiasm to do it.

The same goes for changing a tyre, changing a globe on the car, etc. Did you "know" how to put on your socks, shoes and brush your teeth before you did it for the first time? Life is all about meeting new challenges! lol

First time I did the timing belt the car wouldn't start. Went to work and got the mecho to come over. I get a call "Paul....your a ****ing idiot" I'm thinking the worst.....he goes "you left the car in D!............Car starts fine" of course that took me a week to do, now I can knock it down in a day's work.

If your working on a 3rd gen type motor, you will need a 1/4" and 1/2" torque wrench as well as the tensioner tool off ebay.
if your doing a 2nd gen You just need a long screwdriver and a 1/2" torque wrench. Damn the SOHC 12v is alot easier to do. Only thing I MISS about that motor.

Crazy thing happened to me in my old volvo. Driving along and all of a sudden the car just died. Turns out the timing belt snapped at about 5000rpm. Craziest thing was the fact that NOTHING died apart from that. Mehcanic tells me any other engine and i would have been needing a new car.... Man i miss that car.

its not just volvos, there are two types of designs interfearance and non interfearance, many cars are interfearance and many are non, lots of toyotas can snap a timing belt without doing damage, yet most mitsubishi do have alot of damage (i think the realy old sohc 4g63 doesnt do damage) its all to do with how the motor is built

its not just volvos, there are two types of designs interfearance and non interfearance, many cars are interfearance and many are non, lots of toyotas can snap a timing belt without doing damage, yet most mitsubishi do have alot of damage (i think the realy old sohc 4g63 doesnt do damage) its all to do with how the motor is built

:stoopid:
SOHC 12v 6G72 motors used in the 3000GT actually have a lower compression piston making them non interference. (compared to our SOHC 12v magna ones which are) Small piece of info :P

Toyota 3S engines are also non-interference.

Yep, its a design compromise. If you design the combustion chamber for high compression and efficient combustion, and get the valves at the best angle, you will get the valves and pistons colliding if the belt breaks. The overlap is minimal, you just end up bending valve heads so they no longer seat properly, but the pistons aren't damaged. If a valve head broke off the damage would be much worse. I'd be more concerned as to the damage a broken belt unwinding itself off the cogs at high speed will do. lol
We could always go back to the 4.5: 1 compression ratio side valve engines of decades ago to avoid this, but you wouldn't like the (lack of) power or the fuel consumption . . . . . . lol

From some website:
QUOTE:
Most older vehicles were non inteference, while almost all new engines are interference.
To give you an example, a 1990 Plymouth K-Car has a non-interference engine. They run forever. On the other hand, a 2007 Chevrolet Cobalt has an interference engine.
Newer engines try to squeeze out all available power so they tighten the gaps between the piston and the valves for more compression.
Basically, if your car was made after 1995, chances are that it has an interference engine. However, you might just want to ask your dealer. They made the car, they should know.
END QUOTE

And just in case the reader doesn't know . . . . .
http://www.rtsauto.com/wp-content/uploads/2010/08/timing_belt.jpg


And you could always do this to some standard pistons . . . .

http://img2.imageshack.us/img2/6799/1500austspecx19piston.jpg

i recon electric solinoids for valves, wont need to worrie about lift, and have no need for cam shafts, rev the motor to whatever the crank and rods and pistons will take

i recon electric solinoids for valves, wont need to worrie about lift, and have no need for cam shafts, rev the motor to whatever the crank and rods and pistons will take

Fiat have done that.

Sounds like a high tech approach to unreliability.

There you go

http://bioage.typepad.com/photos/uncategorized/2009/03/04/multiair.png

QUOTE:
Fiat Group and Fiat Powertrain Technology introduced their new air management technology Multiair at the Geneva Motor Show. Multiair is an electro-hydraulic valve-timing system that provides dynamic and direct control of air and combustion, cylinder by cylinder and stroke by stroke.
END QUOTE
from http://www.greencarcongress.com/2009/03/fiat-introduces.html

Sounds like a high tech approach to unreliability.

There you go

http://bioage.typepad.com/photos/uncategorized/2009/03/04/multiair.png

:stoopid:

what im proposing is slightly differnt, and i dont know if we have the abilitiy to make the parts it would need, the above design still appears to have valves, i mean just like a realy big injector straight into each cylinder injecting the air fuel mix with no valves, would need to be able to stand stupid ammounts of heat and pressure though

what im proposing is slightly differnt, and i dont know if we have the abilitiy to make the parts it would need, the above design still appears to have valves, i mean just like a realy big injector straight into each cylinder injecting the air fuel mix with no valves, would need to be able to stand stupid ammounts of heat and pressure though

You are thinking of a giant sized fuel injector but for air instead. It would still need a giant pintle valve like a fuel injector has, except it would be the size of a normal valve. lol

Already been done. Its called a turbine engine. Continuous air and fuel injection, continuous combustion, smooth as silk.

http://upload.wikimedia.org/wikipedia/commons/thumb/d/d1/Chrysler_027.jpg/250px-Chrysler_027.jpg
Chrysler turbine car.