How does Timing Belt affect the Engine?

Question

I have a 97 Volvo 850 gasoline car. My next service for a oil change with replacement of the timing belt (according to their book recommendation) at Volvo dealership is going to cost me dearly... at a price tag of CAN$500/600 range! I was told that it's very important to have the timing belt replaced before it breaks but the belt is working alright so far. They said if it breaks, it's going to damage the engine and it will be very very costly... Any opinion and suggestion out there? I appreciate if someone can give me a second opinion. Thanks!

Answer 1

On the vast majority of engines, if the timing belt snaps, say goodbye too your valves, piston, or engine in general.
Some cars (very few) have a "FREE RUN" engine. These are so low performance that when the belt breaks, the engine will just stop, because of the valves no longer functioning.
HOWEVER, most engines' valves operate close enough to the pistons, with the TIMING of both the only thing keeping them from running into each other.
When the belt breaks, the cam stops turning, so the valves stay in whatever position the happen to be in at the time.
Because of the crankshaft still trying to turn (think inertia, centrifugal force, etc.) the pistons are still going to move a bit, until the energy in the crankshaft is used up, OR THEY HIT SOMETHING, LIKE AN OPENED VALVE!
You WILL either:
a)bend a valve
b)crack a piston head
c)crack a piston (with the broken off pieces scarring up the cylinder wall, remember, the piston will continue to travel a little bit)
d)crack a cylinder wall, possibly through the water jacket
e)all of the above
-or-
f)none of the above, because ya might get lucky, as even a blind squirrel finds a nut now and then!

Answer 2

Fredrick, the person that gave you the information that you described is absoutely right. It is critical that the timing belt be changed at the proper intervals. If it breaks, the pistons and valves will strike each other resulting in bent valves, cracked piston heads which will result in the need of a engine overhaul or a new engine. The timing belt keeps the crankshaft and camshaft in sync so that the engine can run. Please follow the recomendation of your owners manual. You dont have to go to a volvo dealer to do the work, you may can find a reputable mechanic to do the same job for a lesser labor rate.

Answer 3

I live by the golden rule- If it's not broke, don't fix it!!! worse case senerio-- you could bend a valve if it goes while driving the car. But you may just end up throwing off TDC (top dead center) on cylinder 1 piston..easy fix for experienced mechanic...my suggestion to you-- get the oil changed and leave the timing belt alone, unless you are experiencing trouble with starting the car, or keeping it running. Eccentially, the timing belt is what turns the camshaft, and if it breaks, the camshaft stops turning, resulting in the engine stalling, and throwing off TDC. Hope this answer helps you. Don't let some High priced shop tell you you HAVE TO change the timing belt. Timing belts are designed to last the life of the car usually...not always, but usually if the car is not used for abusive driving manuvers, and is well mantained overall (i.e. all normal maintenance is done on a regular schedule). Another suggestion is you could have the timing checked using either a timing light or like on most newer cars, you may need to take it to the shop and have them hook it up to a machine. That will tell you if the timing is off. Good Luck to you.

Answer 4

First , find out if this motor is what is known as an "interference motor", meaning that the intake and exhaust valves will hit the pistons. If it is by all means replace the timing belt. As stated in other replies, the timing belt keeps the valve train TIMED to the pistons. The $500/$600 cost will be cheap compaired to the cost of a repairing the engine.

Answer 5

Your engine has what is called an interference design. This simply means that the pistons and valves occupy the same space at different times. If the timing belt breaks or slips, they try to occupy the same place at the same time, with the result that your engine is instantly trashed. Change the belts.

Answer 6

The timing belt keeps the valves in sinc with the pistons.
On some vehicles if it was to break while running some or all of your valves could/would be bent/broken resulting in an upper engine major failure. If this was to occur repairs would cost more than 1000 USD.

I am unsure about your particular engine but this failure was chronic on the mid eighties Ford Escorts.

Answer 7

Never question maintenance suggestions. They are there to save you money in the long run. Upper engine damage could result if the belt breaks. Bent valves, damaged pistons, etc.
Master tech 40 yrs.

Answer 8

The Timing belt keeps valves/pistons in sequence for its combustion performance, if the timing belt breaks....the valves will bend, the motor can seize and if this happens when you're driving on the highway, the valve/s can break and end on top of the piston/s and you'll have what we call here in Australia "DETONATION", which means your piston can crack and in some cases end up out of the side of your block and snapping your crankshaft, and it will cost you a fortune to have repairs to your car...so replace it asap and you'll be ok....

Drive Safely.....

Answer 9

If your timing belt goes you might as well buy a new car. I'm not sure technically what the damage is but it happened to me once and we just got rid of the car because it wasn't worth it.

Answer 10

if you think thats expensive, you shouldnt have bought a european car. cracks me up, all these people gotta be big shots with thier european cars, and then they complain the most when they have to pay to fix them.