Vauxhall cambelts-Network Q - Dave N
Saw a sign in a VX main dealer workshop yesterday, saying that mechanics, sorry, technicians, must ensure that all cars over 30K miles that are to be sold through Network Q scheme, must have cambelt and all tensioners and idler pulleys replaced, unless they have absolute proof that they have already been done.
Vauxhall cambelts-Network Q - DavidHM
Given that the person doing it is probably earning less than a tenner an hour, and the part cost is under £20, the marginal cost of a cambelt change on a Network Q car is probably £40 on average.

Given that ECOTEC engines (i.e., most Vauxhall multivalves) have a recommended interval of 40k, and the likely cost of a warranty claim, even at wholesale prices, is likely to be £600ish - plus the extra that a car with a new belt can command - it seems absolutely logical, and not at all frightening, that Vauxhall are cautious about this.
Vauxhall cambelts-Network Q - kal
Its disgraceful that so called hi tech modern 16v engines are designed with such basic design faults. Why do these manufacturers not use chains as some of the Japanese cars do? Fords used to have a problem with broken belts on old CVH engines which lasted only 30,000 miles. But thats 15 years ago, for GM to produce a new range (back in 1995) of hi tech 16 v engines with such a basic design fault is nothing short of disgraceful. Ford had solved the cam belt problem with its 16 v engines in the early 1990's.

Vauxhall cambelts-Network Q - geoff C
Why all the fuss? Belts were introduced because they are quieter than chains and, being outside the engine are simple and cheap to change when needed. They don't stretch as much as chains do when they wear and maintain the cam timing accurately.

What is so bad about precautionary change at 40,000? (Only once every 4 years for the average private motorist). Chains also wear and alter the cam timing. Tensioners are needed to take up the slack - remember rattling timing chains. Chains do break sometimes and they are much more difficult to renew than belts. The chaincase is also a prime site for sludge to collect.

However, it is a mystery to me why belts break. I've changed a few (Cavaliers and a Polo) at the recommended mileage and without exception they all still looked like new.

Does anyone know why belts fail? I suspect excessive tension is one cause. The engine expands more than the belt, which means that if the tension is set when the engine is cold it could be too high when hot.
Vauxhall cambelts-Network Q - Dynamic Dave
Does anyone know why belts fail?


Main cause is a either a worn tensioner bearing, or a seized waterpump. More often than not a worn belt will fail on cold start up as that's when the engine is at it's tightest.
Vauxhall cambelts-Network Q - steveb
My dads belt failed on his old Escort CVH engine about 15 years ago, on a cold start-up on the drive. The RAC man reckoned he was dead lucky, no valve damage etc because of the slow engine speed, only cost c£50 at the time to replace the belt.

Steve
Vauxhall cambelts-Network Q - kithmo
Its disgraceful that so called hi tech modern 16v engines are
designed with such basic design faults. Why do these manufacturers
not use chains as some of the Japanese cars do?
Fords used to have a problem with broken belts on old
CVH engines which lasted only 30,000 miles. But thats 15
years ago, for GM to produce a new range (back in
1995) of hi tech 16 v engines with such a
basic design fault is nothing short of disgraceful. Ford had
solved the cam belt problem with its 16 v engines in
the early 1990's.

There's nothing hi-tech about the new Ecotec engines from Vauxhall. All the technology used was in use in the eighties by Rover and Ford. MGA's had twin cam 16v engines back in the sixties, Mk3 Ford Escorts had hydraulic tappets and the Rover 216 (Honda Accord shape) had emission controlled fuel injection.
Vauxhall cambelts-Network Q - superannuated rocker
MGAs most certainly did not have 16 valve engines back in the 60s. There was a twin cam version of the MGA in the late 50s which had 8 valves but this was very much a special and was not altogether successful. The first production 4 valve per cylinder (16 valve) car was the Dolomite Sprint in 1973 closely followed a few weeks later by the Escort BDA. Although the Ecotecs were launched in the 90's the basic engine design was introduced in 1988 as the 150 bhp Astra GTE engine.
 

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