Timing Belt and Engine Valves


#1

I posted just a part of this question without going io any detail. (This is my first time). A couple of days ago, when I started my car, it made a banging noise and then cut off. All of the dash lights came on, and the car would not restart, although it sounded like it was going. I took it to a mechanic that I never used before because I’m new to my area. He said that the timing belt has gone into the engine and the valves may be bent. The only way to know if the valves are bent is to replace the belt for 500.00. If the valves are bent, then it wil be 3000.00 for a new engine. It’s a 1997 Volvo. What are the chances that my valves are bent, and does this seem like the correct diagnosis?


#2

how many miles? Timing belts are supposed to be replaced at something like 60k miles (check your owners manual). On many cars, if the timing belt breaks, it causes valve and cylinder head damage, which could mean a new engine.

Looked up 97 Volvos, and depending upon engine type, 50k-70k is recommended for belt replacement. My internet source says all volvo engines are interference engines, ie, if the belt breaks, your engine is gone.


#3

SOME VEHICLE VALVES (MIGHT BEND) WNEN THE TIMING BELT BREAKS.SOME ARE MADE THAT WHEN THE BELT BREAKS, THERE IS NO DAMAGE.IN MY PAST CAR, IF THE BELT BROKE THE ENGINE WOULD JUST SPIN FASTER THAN NORMAL.IF IT WAS BROKE ALL THE WAY INTO ,THERE IS NO WAY THE CAR WOULD EVEN TRY TO START.WHAT IT SOUNS LIKE IS MAYBE THE BELT BEGAN TO COME APART WITH STRIPS OF IT HITTING AS IT TURNED.BUT NOT ALL THE WAY WHICH COULD HAVE KEPT IT IN TIME WITH NO VALVE DAMAGE. I HAD AN 88 CAMERY BELT BREAK NO THERE WAS NO DAMAGE TO THE VALVES. I ALSO HAD ONE BREAK ON A FORD RANGER WITH NO DAMAGE.CALL AUTOZONE AND ASK THEM IF THE CAR IS AN INTERFERENCE TYPE IF THE BELT BREAKS.ASK THEM OF A GOOD REPAIR SHOP AND TAKE IT THEM.I THINK YOUR CAR IS OK AND THE BELT HASNT BROKEN INTO YET, ONLY STRIPS OF IT HITTING THINGS AS IT TURNS.DONT DRIVE IT IF IT STARTS AND DONT TRY TO START IT.THAT COULD BE WHERE YOU CAUSE TROUBLE IF YOU TRY TO DRIVE IT TO ANOTHER SHOP.PULL IT OR GET A WRECKER…GOOD LUCK!


#4

It’s quite possible for the valve(s) to bend if a belt breaks on an interference type engine. The intake valves are usually the ones to bend because the intake valve heads are larger in diameter. The exhaust valves will usually clear, but if this repair is performed a complete valve job should be performed.

Here is where I have an issue with your mechanic. You do NOT have to replace a belt for xxx amount of dollars to determine if the valves are bent.
There are several methods and all of them are very easy to do.
Compression test.
Removal of the valve cover and inspection to note if there is excessive valve lash (fit basically) on the intake valves.
Removal of the spark plugs, bring any or all cylinders up to TDC of the compression stroke, apply some compressed air to the cyinder(s) and note if air is blowing back out the intake tract.

I don’t know if there is any misinterpretation here, but bent valves do not mean a complete new engine is needed. Simply repair the cylinder head and file off any sharp nicks that may exist in the piston tops.

Hope some of that helps and don’t know what to say in regards to the bit about replacing the belt to determine valve condition except that it’s pretty misguided.


#5

You’ve got the wrong mechanic. At the bottom of this page, click on Actual Car Info. Then, scroll down that page to Mechanic Files. Input your zip code and the miles you are willing to go to a shop/mechanic. Up will come a listing of (mostly) satisfied costomers comments. Read and choose. I DO hope you find a well-rounded (though, NOT necessary rotund) mechanic.


#6

No reason to replace the timing belt to figure out whether there’s major engine damage. The guy sounds like he’s not sure how to determine extent of engine damage without replacing timing belt. Definately follow hellokit’s advice and look up another mechanic.


#7

Most Volvos do have interference engines. See http://www.gates.com/downloads/download_common.cfm?file=428-1466_web1.pdf&folder=brochure

That doesn’t absolutely mean the valves are bent, but in all probability they are. Look for good used engine at www.car-part.com . Get the car to a reputable mechanic who knows what he’s doing.