Vernier pulleys fitting question.

[k80rum]

I'm pretty sure this is a dumb question... particularly since I've scoured the archives and DVA's page and can't find it mentioned explicitly.

 

I've not fitted a set of verniers before and trying to picture the approach to take - If I get the exhaust cam at 90deg BTDC, lock the flywheel with a flywheel-locker and the cams with my little metal cam-locking widget, I can go ahead and release the tensioner and remove the belt.

 

Then assuming I've marked the new verniers up as cam and inlet and transferred the timing/locating marks across.. Is the following right?

 

Presumably I leave the cam-locking tool in place and undo the mounting bolts of one of the pulleys. Do I then remove the cam-locking tool, or simply lever the pulley off?

 

I imagine that when I do this the cam in question will rotate a bit as it's no longer held stationary by anything, that the rotation isn't very much and that you rely on watching the direction of rotation and using the transferred timing marks on the vernier pulley to bolt it on and rotate it back into position. Taking this approach to both pulleys I guess, keeps everything pretty much in line before finally using a set of dial gauges to fine-tune everything.

 

Is that right or utter drivel

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

[Casbar]

DVA Has an explanation on his DVA Power website - it explains pretty much everything

[k80rum]

Thanks Casbar Dave's site was actually my first port of call and it mentions:

 

"the horizontal marks on each original pulley can be transferred by laying the original pulley over the new vernier and aligning the appropriate dowel slot on the old pulley with the dowel slot on the new one, the picture below shows the alignment markings transferred onto the verniers from the original sprockets with the verniers aligned how they should be for fitment to the engine when the engine is at 90 degrees BTDC (before top dead centre). "

 

Which gives me a fairly good idea of what to do, but i was after an explanation (or reassurance... ) of what happens in practice when the old pulley is removed as I'm not sure whether everything stays still or not. If I need to keep an eye on the camshaft as it whips through a few degrees, I wanted to be aware of it and understand that I'll need to rotate the new pulley back a little after it's fitted.

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 7 Dec 2007 11:47:49

[oilyhands]

It doesnt matter if the cams move, because you will re-align them when you line up the marks on the verniers.. when the crank is at 90BTDC, the valves cannot contact the pistons so you are quite safe to turn the cams.

 

It's best to retard the inelt vernier by 10 degrees or so and advance the exhaust by the same to make them ultra safe.

 

Oily

[k80rum]

Cool. Thanks Dave

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

[John Howe]

Your not that far away... if you care to run it over to the farm and I'll do it while you wait

 

JH

Deliveries by Saffron, the yellow 230bhp Sausage delivery machine

[k80rum]

John, you're a gent. I'll mail you offline to arrange a date if that's okay? I'd much prefer to watch and learn/help the first time..

 

 

.. plus of course I'd never turn down the chance to visit a farm - there's far too much great machinery to look at. 😬

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

[John Howe]

... and I thought your were going to say, "and eat some of your famous sossiges"

 

JH

Deliveries by Saffron, the yellow 230bhp Sausage delivery machine

[k80rum]

and of course, eat some of your famous sossiges

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54