car question

okay, I am definitely naive when it comes to these things, and there are probobly better-more important-questions to ask on this board, but I really want to know and understand this. What the heck is a timing belt? I was told that mine needed replacing, but then this other guy I know said that there was no way to tell if it really needed replacing or not. How does one know when his/her car’s timing belt needs replacing? What does a timing belt do? What happens if it is not replaced? Please-help remedy my ignorance of this matter! :slight_smile:

tipi :slight_smile:

A timing belt basically keeps your car idling when you take your foot off the gas. If you did not have it you would have to start your car everytime you hit a red light. Timing belts do need to be replaced on average every 8000 miles (some may say 6000 but you can get wear in it for a while). To tell if you need it, look at how your car idles when it is warm and in nuetral. On average a good timing belt will make your engine idle at 1 and 1/2 to 2 rpm. If you engine shudders when you stop at a stop light, then you probabaly need a new one and if your engine idles below one or at one then you may have a problem (since it differs with each car). In reference to your problem, you may not need to replace so much as get someone to tighten it. Ask a mechanic to tighten it and see if that makes a difference in your idle speed.

While trying not to be technical, think of a timing belt as a long flexible gear which holds various moving engine parts in their proper relationship with the ignition system and themselves.

This coordination assures that the engine will run-------and run properly.

Depending upon the engine you have ,and it’s design, a broken timing belt could mean an engine that wont run-----or one that is exrtensively damaged and expensive to repair.

The recommended change point is based on an average. Extending the time is a crapshoot in which you do not own the dice.

IT’s one of the few things in which the manufacturer’s recommendation really has some significance.

The option is to change it or gamble.

See you in Vegas???

The timing belt drives the camshafts of the engine to open and close the valves so that
the fuel/air mixture gets into the cylinder head’s combustion chambers. If you drive until the belt breaks, you could be facing anything from a cylinder head overhaul to a major engine rebuild. Costly stuff.

Are you sure you didn’t mean 60-80,000 vs. 6-8000?

What kind of car do YOU have? 6000 or 8000 miles for a timing belt? I just had my car (1990 Honda Accord) in for a timing belt replacement, and it cost about $500 and the recomended replacement interval is 90,000 miles… God help me if I had to spend that much money every 6-8K!

Lest we think that it’s just because I have such a swell car, I seem to remember the 1984 Ford Escort that I had ten years ago needed a timing belt at 60,000 miles. And I can tell you, that’s about the life of a Ford Escort.

      • Some car engines use external rubber/nylon belts while others use internal chains. Many people tend to call both “timing belts”. The chains last a lot longer, but you can’t easily inspect their condition and they cost much more to have replaced when they break. - MC

DOH! do not listen to me. My info on the timing belts replacement comes from my brother on that and I forgot to take in that he races his car professionally. Every car is different

      • Tip, do not buy a car from Heath’s brother. (-No offense, Heath) - MC

ummmmm…kindof along the same lines…what are “lifters” my friend recently had his replaced, and when he said this, I had NO idea what the heck he was talking about. :slight_smile:

tipi :slight_smile:

haha Tipi, I thought you mean you need a new one but you meant your car needs one. hee hee. tsk. Some of them can go a really long time. You didnt say what car you have. You check your car manual cause it says in it.
Don’t take someone’s word for it. Ask around.

Sometimes a mechanic says you need one. You bring the car in. You leave. He puts the car on the other side of the lot. You come back and you pay for it. & he never did anything, tsk.

Some cars don’t even have one.

You can’t see it but you’ll most likely find it right in back of the fan.

Lifters are a key component in the valve-train. The valve-train’s function is to open and close the intake and exhaust valves. Lifters can become damaged from insufficient lubrication or just years of normal wear and tear. A rapid ticking while the engine is running is one good indication of worn lifters.
I tried explaining this to my wife once and her eyes just sort of glazed over. She found this site for simple explanations of basic engine functions:

(hmmm…should I really try this, oh, well) Without illustrations this might not be comprehensible, 'coz I’m not a leading light in the manipulation of the English language.

That said, “lifters”:
First we need cams:
A cam can be thought of as a circular thing w/a bump on it. If it is rotated and something is resting on its semi-circular surface, every time the bump comes around the thing resting on it is lifted up and comes back down when the bump has passed.

So, you’re typical auto engine has a shaft with two of these cams per cylinder - the camshaft (which is (small world isn’t it) turned by the timing chain). On these cams rest objects that are called lifters - they’re the things that get lifted as the bump comes around. When the lifters get lifted, so do the pushrods that rest on top of them and through a rocking horse motion they push up one end of the thing they’re in contact with (rocker arms; hinged at their center, when the pushrod pushes up on one side, down goes the other) and this results in the valvestem (thing in contact w/the other side of the rocker arm) getting pushed down. In your typical overhead valve engine this results in a valve opening. If your friend’s car doesn’t have any chrome thingie on the fender that say something like “DOHC” we’re probably still on the same page. If your lifters are not functioning well, your valve timing will be off and the car will run like a sick dog. That being said, if your friend’s car is less than ten years old and it is the same one w/the timing chain problem, if it’s not running at the barely crank scared to take it out on the street level, your friend may be experiencing a major hose down from the Oracle at the Garage.

No kidding MC…3 sets of tires, one valve job, and numerous up keeps and such He is still racing

Funny thing: On 5/27, my car died on me. I couldn’t for the life of me figure out the problem: it wasn’t the battery, it wasn’t overheated, and it wasn’t out of gas. I had it towed to a repair shop, signed the work order, and went on my already-planned trip out of town. Yesterday, I came back to collect it, and found out that the timing belt had snapped, after being weakened by the radiator leak. (I had noticed, and mentioned to the mechanic(s), that I had been having to put in radiator fluid unusually often, considering that it wasn’t summer. They showed me the belt that they’d replaced. Shudder…

Remember, I’m pulling for you; we’re all in this together.
—Red Green