Practically Classics Forum

ive noticed on a lot of ads recently that engines are being fitted with timing chains, so they don't need changing.. i worked for a chap who had one go on his trafic, it was an expensive day for him..

rich. wrote:ive noticed on a lot of ads recently that engines are being fitted with timing chains, so they don't need changing.. i worked for a chap who had one go on his trafic, it was an expensive day for him..

What, don't need changing like the BMW & Audi ones that break, and the Nissan ones that stretch and the resulting difference in the crank and cam sensors put the engine into limp mode? If they used a decent chain they'd probably be OK, but you wouldn't want one of the new ones on a pushbike.....

and the Nissan ones that stretch and the resulting difference in the crank and cam sensors put the engine into limp mode

My Navara was always doing this - the dealer always said it never it did for them when on road test at one point they had the motor for 3 weeks purely on road test and never found the problem eventually the timing chain let go and the engine was dead at 65,000 miles !

Mercedes Benz have always used timing chains. The single row chains will break, double row chains are less likely to but the guides are made from plastic and can break over time. If they do, the chain will jump time and result in valves colliding.

Single row chains were good for about 40k miles, double row are good for about 100k miles.

Ford 300 straight six motor had the solution with timing gears.

alabbasi wrote:....Ford 300 straight six motor had the solution with timing gears.

A safe head is the only absolute solution, but even then, with the fibre toothed camshaft gears on the Ford Koln and Dagenham V4 & V6 and the IL4 and IL6 found in Volvos up to - in the case of the 4 - the early 240s which still came with the old pushrod engines, a little knocking sound that appears endy but happens on load will begin so gently that the temptation will be to ignore it, then the distributor will cease to be driven, the valves will stop where they are and black smoke will close both lanes of the southbound A1M for two whole hours while the driver of the stricken [Volvo 142S] explains, red faced, to the fire crew why exactly his car had created this environmental disaster and that no, thanks fellas, the car is not on fire and the RAC are coming with a pair of gears, a sump gasket and the correct tool to pull the fihre gear onto the camshaft without punching the core plug out the end of the block.

Right enough though, if you were fitting a steel camshaft gear to a B20, it would probably be the least likely engine of all time to fail its camshaft drive. But the steel conversions were hellish noisy and not as cheap as factory mixed pairs and the oil pump would still have its fibre gear..

Whereas the belt on a typical modernish engine can be changed in ten minutes if you leave half of the old one in place to guide the new belt in and most petrols are safe, nearly all Japanese ones are, they leave the chains for the interference engines.. But strangely not for the hardest to reach Diesels.

Din;t need changing?

Tell that to all the owners of A-Series engines with rattling timing chains .. because they have stretched ..

OK less likely to break than a belt but then again belts tend not to snap but the tensioners seize and take the teeth off .. just like this in fact ..