Handbook Engine timing belt

Tis handbook handles timing belt replacement.
Here follow somme key remarks regarding :

• check and replacement intervals
• invoiceable worktime
• technical hints
  
  
• INTERVALS

Only one interval is shown , the scheduled replacement under standard conditions of use.
Under heavy usage, you have to shorten by 20 to 30% the mileage limit : frequent (taxi, ambulance) or cold (and power thirsty) starts - whether by driver's choice or because of local constraints (mountain use) - or non paved road frequent driving, are renowned belt killers...
Needless to say, that limit conveniently applies to standard check for standard use.
Some common sense rules:

• any belt removed after more than a quarter of its planned life has to be replaced.
• all belts should be replaced at the same time : timing belt, fuel pump belt, balance shaft belt ... of course, and drive belt(s) as well !
• the tension roller - basically included in the parts kit you have ordered - should be replaced as well (it is a must for any motor design since the 90's): delaying is false savings, as checking the actual state of the old roller will prove extremely difficult.
• Some car manufacturers do not supply scheduled replacement limit : more often than not, they tend to advise to check the belt(s) at 30 000 km; as the time allocated to perform the check is one third of the replacement invoiceable time, it can be inferred that the replacement will appear necessary at 90 000 km.
• Last but not least, if you have any doubt about the expected remaining life of any belt, remember that the customer, being no fool, should understand easily that the actual cost of belt replacement is a small thing compared to the burden of re-building or replacing the (upper) engine / parts.
  
  
• INVOICEABLE TIME

We provide you with one figure, which relates to complete replacement (belts and rollers).
When we provide several time allowances, they relate to optional equipment (A/C compressor, belt or gas lines) whose removal/setting will require extra time.
nota : if, as a general rule, it is sensible to advise for glow plugs removal - to ease the motor rotation - this operation specific time allowance is not incuded in our figure : expect from 0.5 hour in most of the cases to a full hour in rare occurrences.
A few more common sense rules : "All inclusive" prices , because of their easy understanding by the customer, tend to become 'the' pricing policy. From our own inquiries, it seems that five layers, in ascending work hassle, are the market's backbone:

• 8 valve petrol engine until 1990
• diesel engines, except common rail or pump-injectors
• current multivalves petrol engines
• common rail and P-I diesel engines
• V6/8 engines and vehicles with lousy belt access
  
  
• TECHNICAL HINTS

Water pump:
you'll never find here any data (time or workmethod) regarding the water pump when it is part of the timing belt loop. If it has become almost standard practice among the official networks to (rightly) include it in their quotations, the car manufacturers do not enforce it in writing ...
We have made an iron rule (for your benefit as the warranty of your data quality) to strictly report manufacturer advise.
For this matter, we strongly advise you to include water pump replacement in your quotation, as an option. Surveying your local competitors policy, you will know how to promote this option with each would-be customer. Should it be refused, do not forget to report this denial on the invoice, which then will clearly define the responsibility.

Tightening torque, bolt replacement:

• Any self-locking bolt, nut or screw, must be replaced, as well as any fastener requiring an angular tightening torque.
• Most gaskets, o-rings, etc. should be replaced as well.