changing cam belt on a 16V - advice wanted

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juraj
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changing cam belt on a 16V - advice wanted

Post by juraj »

Hi all - recently I posted the below in the peugeot forum but got no replies, ... , so I have posted it here now in the hope of some ... i know its a peugeot but it shares its engine with the BX 16 v so its not very off topic I hope.

I just got a 405 16v and the cam belt has been on for about 85000km, so i have plans to replace it.

I have done a few 8v BX 1.9 petrol belts - no real difficulty so far. But on reading the Haynes manual for the BX ( i assume the BX and Peugeot 405 16v engines are the same) it talks about the extra complication of the tensioners not only tensioning the belt but also ensuring correct valve timing, hence an electronic tension measuring tool called a "Seemtronic 87' is required.

Or is it?

I have a read a few posts here regarding the 16v cam belt change and many people say the old 90deg twist on the longest belt run is an adequate tensioning technique.

What are your thoughts?

bye all

j
Kman
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Post by Kman »

I replaced the timing belt on a MI16 years ago (with the engine out of the car however), and can only remember it as a straight forward job. There was no need for any special tools, timing is ensured by locking pins through the two cam pulleys and the crank pulley, and belt tension was determined by the old 90 deg twist.

Unlike later 2.0 16V engines(where the pulleys can be loosened and rotated slightly while the cam shafts remain locked), the cam pulleys are bolted directly to shaft, so it is not possible to distribute the tension exerted by one tensioner to the entire belt, hence the two tensioners (?). The additional challenge with a 16 V engine will thus be to equalize the tension on both sides of the cam pulleys. I guess a rough check would be to tension the belt, turn the engine over a few times, and verify that the timing holes are in the exact same position in relation to each other, i.e. the locking pins fit in their holes just as they did before releasing them.

Regards

Kristian
addo
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Post by addo »

Aren't you in Sydney?

There are some catches in the Mi16. First up, the alignment pins are shouldered - either buy some correct ones or improvise carefully. Without a good pinset you will have far more difficulty.

Secondly - access is very poor. You absolutely need to follow the BOL comments on removing two of the three motor mounts as you'll be jacking the whole lot up and down a few times, pivoted on the nearside mount only.

Thirdly, the rearmost tensioner is a bugger to loosen. You'll need an Allen key ground to make the short end even shorter.

Fourth - when refitting tensioners, make sure the displacing force of belt tension, makes the tensioner want to rotate clockwise. Does this make sense?

Fifth - if replacing the water pump, chase the mounting threads with a chasing tool - not a regular tap. Blow them clean with air or carby cleaner spray.

Sixth - expect to find other stuff in need of replacement. Water hoses, motor mounts, also consider a thermostat if it's unknown age. At least test its function. Don't replace oil seals if they're not leaking significantly, and similarly leave the rocker cover sealed up.

Seventh - make a match mark between the inner and outer sections of your damper, and note if the marks change in alignment after the car has run again for a while. Replace if it does move regularly.

That's about it; clean all as you go and reassembly will be much more pleasant.
juraj
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Post by juraj »

hey thanks for the quick and very informative replies,

and addo yes i am - do we know each other?

bye
addo
Sara Watson's Stalker
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x 93

Post by addo »

I don't recall meeting any Mi16 drivers other than PT, so you probably haven't met me.

There is a guy in Tasmania (on Aussiefrogs) who can supply the shouldered pins in light alloy, the idea being if you forget they're in and crank the motor, they might just shear and save the valves.

Oh, and a strip of perspex mirror plus mini-Maglite helps for eyeballing stuff, too.
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