Cam Belt - What is it?

What's the cam belt in my car?

What's the importance of getting it "done" every x number of kms?

What happens if I don't get it done?

It's booked in for next week but I would like to know what it's all about.

Thanks.

The cam belt is a (usually notched) belt that drives the camshaft from the engine's main crankshaft. The camshaft has lumps on it that push against the valves that open and close the inlet and exhaust ports at the top of the cylinders. This opening and closing is done in precise time with the piston's travels up and down.

If the cambelt slips or breaks the pistons will collide with open valves (as they will be out of synch with one another) and your engine will be destroyed almost instantaneously. Therefore getting cambelts serviced, checked and replaced regularly tends to be pretty important

just as organix said and the belt should be changed every 100,000 k`s. If you don`t change the belt it is possible it will break and wreck your engine big time . tkf

It is also usually expensive[}] at least 3 prime lambs worth.

toast - I will go with Organix's reply in that every time I bought my daughters a new (used) car, regardless of what the speedo said, I would have all the belts changed. Totally insurance against disaster.

I am not a mechanic so no idea but perhaps someone with more mechanical experience could expand on what approximate mileage the check would be required over the life of the vehicle?

TK beat me! Next time you buy a vehicle, buy one with a chain thingie rather than a cam belt - it is meant to last the life of the vehicle. My Nissan had the chain thingie and one less thing to worry about. LOL

Bearing froze on our Polo, causing cam belt to go and result was one knackered engine

DiDi;379925 wrote: toast - I will go with Organix's reply in that every time I bought my daughters a new (used) car, regardless of what the speedo said, I would have all the belts changed. Totally insurance against disaster.

I am not a mechanic so no idea but perhaps someone with more mechanical experience could expand on what approximate mileage the check would be required over the life of the vehicle?

As TKF said, about 100,000km +/- for most vehicles. It will be stated in the service book if the vehicle has one (in English []).

The motor does not get smashed in most cases as most valves wont come in contact we have done a few that have broken and no damage even our Pajero diesel did no damage when it happened to me but a )*&^^%^*&(*()) pain in the neck as had big trailer with stock on. It had only done 23000 but had a fault

Would pantyhose do for a broken cambelt? Anyone else remember the days that you always had a pair on pantyhose in the boot "in case" the fanbelt broke?

I learnt my lesson years ago about carrying spare belts, particularly on the yacht.

Xmas '99 we headed away on the 23rd Dec and sailed over to Coromandel, anchored in a deserted Te Kouma harbour and settled down for a peaceful night. At around 9pm I noticed that the cabin lights were getting dim so started the diesel to charge the house battery. Thats strange, no charging. Pull the engine box off, oh look the alternator belt has shredded. No problem I'll grab the spare belt, Ah crap I used the spare earlier in the year and forgot to replace it. What to do, wait till the morning and hope I can get one in Coromandel town or head back to Half Moon Bay where I know I can get one.

5 hours later at 2am we were at the entrance to the Tamaki River, keel stuck in the mud on an outgoing tide. There was nothing to do but drop the anchor and go sleep till the tide turned and we were floating. We woke at 6am floating and started the diesel, or should I say tried to start the diesel. The starting battery was dead flat. I had used it to power the instruments and nav lights but it still should have held a charge. No problem, I will hand crank it. Dug the crank handle out of the bilges, where it had sat unused since I had built the boat 11 years previous, decompressed both cylinders and started cranking. When I got it spinning the wife would flicked one decompression lever. Do you think I could get it over the compression stroke, no. After 15 minutes I gave up.

Hey, we are a yacht so we hauled sails, upped anchor and short tacked our way up the river to the marina. Lucky it was an incoming tide as it was about the only thing that kept us moving, there was very little breeze.

Next problem, how are we going to get that boat into the marina and onto the berth. There was no breeze and in the wrong direction to sail in the marina. This is where the dinghy 2 horse outboard played it's part. I tied the dinghy in tight stern to stern, mounted the 2 horse on the dinghy transom and used that to push us into the marina and onto the berth. Not sure how well it would have worked in a breeze though. We were back on the marina by 7.30am. By 9am we had been home, had a shower, got 2 new alternator belts and a new starting battery, new belt and battery fitted and were on our way back out the marina and headed back to Te Kouma.

Needless to say I now always have spare belts for the alternator and waterpump, in fact I think at last count I have 4 spares of each.

DiDi no such luck . Or a girl friend with you and that is all I'm going to say on that one . They take a whole workshop to fix and do the timing

Shropshire Blue;379928 wrote: Bearing froze on our Polo, causing cam belt to go and result was one knackered engine

Snap.
We had the same happen on a Toyota 2C diesel engine.The "sealed" bearing was not designed for dusty dirty environments and... bang![] cam shaft bent, pistons bashed, valves buggered etc. New engine time. Ka-ching.[}]

sod;379957 wrote: The motor does not get smashed in most cases as most valves wont come in contact we have done a few that have broken and no damage even our Pajero diesel did no damage when it happened to me but a )*&^^%^*&(*()) pain in the neck as had big trailer with stock on. It had only done 23000 but had a fault

Depends on the motor, many are "Interference fit" motors where the valve comes down into the space where the piston occupies at top dead centre, the rely on the valve coming down after the piston starts on it's way down the chamber and closin g before it gets to the top. Other motors are "clearance fit" or "Non-Interference fit" motors where even when the piston is right up as high as it will go the valve can still protrude down as far as it can and yet not hit the piston deck.

The higher the compression ratio of the motor the greater the chance of there being collisions between the piston and valve during a cam belt breakage.

hey Kiwi, when do you go?