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correct way to torque timing sprockets.

Posted: 19 Feb 2021, 12:42
by lolomovil
Hello, I've readjusted the vernier type camshaft of my fulvia s1 and I am wondering what is the correct way to retighten the timing sprockets. When I try to tighten it, the chain flexes as bit and I don't know if this will be harmful to the engine.

Best regards.

Re: correct way to torque timing sprockets.

Posted: 19 Feb 2021, 14:36
by bmarler
not sure what you mean by flexing? in order to reach a proper torque value it's best to immobilize the sprocket so it can't move at all. (put a rod through the sprocket hole if there are any.) if there isn't a convenient way to do that i will jam a shop rag in the teeth to stop rotation. i either fold the rag or roll it and insert into the chain/teeth. you need to use care so that when you back up the chain to retrieve the rag you don't jump teeth. the rag method still lets the sprocket move a little when tightening but i think a reasonable torque value is still obtained.

Re: correct way to torque timing sprockets.

Posted: 19 Feb 2021, 15:06
by lolomovil
Thank you very much for the reply. By flexing I mean that as the pulley moves the chain slackens. I was tempted to use a bar in one of the sprockets hole as you say but before that, i prefer ask in forum. The rag method seems good to me too. I have also thought of making a small tool like the used to lock the camshafts in modern engines.

Re: correct way to torque timing sprockets.

Posted: 19 Feb 2021, 18:25
by Huib
A bar through one of the holes in the wheel is what I use. Steel bar with fuel hose around it.

It would be nice to have a tool like for modern engines. I doubt however if that is possible. One would have to take off one of the bearing caps to mount it. That is not possible with the rocker shaft going through the caps.

Re: correct way to torque timing sprockets.

Posted: 23 Feb 2021, 00:21
by lolomovil
Thanks all for the answers.I've another question regarding the sprockets fixing bolt. As can be seen in the illustration, the sprocket fixing system consists of a bolt (22), a locktab (9) and a washer where the locktab (15) is housed. The latter has a slot to allow space for pin (6), but this space wider than pin. Does this have any reason? In my opinion this slot allows to change the final position of the locktab so that it is aligned with the bolt, but I am not entirely sure. In my case, after applied the correct torque (6.2 Nm) the locktab is not aligned with bolt face, that is why I propose the above reasoning.

Best regards.

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[url=https://postimg.cc/VJL78jNL][img]https://i.postimg.cc/VJL78jNL/20210222-094955.jpg[/img][/url]

Re: correct way to torque timing sprockets.

Posted: 23 Feb 2021, 17:02
by Huib
Don't worry about the alignment. Just bend it with an angle.

Re: correct way to torque timing sprockets.

Posted: 25 Feb 2021, 00:07
by lolomovil
Thanks Huib. I'll do it that way.

Regards.