Vernier pully - point?

[beavy69]

Whats the difference/advantage to them over adjusting the timing by swiveling the dizzy?

[Adam]

Cam timing, and Ignition timing are two different things.

Dizzy controls when the spark occurs.
Vernier controls cam timing, when the valves open/close.


Afaik, there is no point to a vernier, and everyone leaves them on 0.

[beavy69]

Thanks.

[General Baxter]

they look nice tho lol

[Adam]

they look nice tho lol
As does a GM pulley sprayed red. :p lol

[Stuart]

red = a power pulley and blue = a torque pulley

[Adam]

So is a vernier set to 0 technically the same as a GM pully?

[General Baxter]

red = a power pulley and blue = a torque pulley

lies all lies lol

[Stuart]

its the truth mofo... try it ;)

[SRI crazy]

hey if u aint gna use the pulley to set the timing you would be better off using a standard pulley lol

[beavy69]

So why would you want to advance or retard the cam - turbo? In which case would you set it so the valves open a little later as you don't need so much of a "suck" from the piston due to the air/fuel mix being at higher pressure. And the exhaust gas would then leave at a higher pressure to spin the turbo with more force?

[Stuart]

it all depends on the cam timing requirements from the cam makers. but most genearlly tend to be set at 0degrees.

alstering the cam timing alters the power band in essence. With a turbo you want minimal valve overlap at tdc, but with a single cam tahts fixed regardless of how much you mess about with the pulley.

[Adam]

So could playing with a vernier push power band further down the rev range on my spi motor?
Hmmm, an idea.

[SRlew]

so is it actually worth getting one?

i'll probably buy one still cause they look good lol

[mikey14sr]

I've heard and seen people remove the pin from the end of the cam, put the pulley on loosely, set the cam timing to what they want but so that the standard marks line up, then drill a new hole for the locating pin using the hole in the pulley as a guide. Done this way unless you take the pulley off there's no sign that the timing's been altered, it's an often used trick in certain forms of motorsport.

[Stuart]

i had a kidney slot cut into my std pulley to adjust the timing for the silly cam i have. then lots of threadlock and did the bolt up tight. you cant see the slot toooo well ;) lol

[mikey14sr]

Big washer Stu?

[rc]

carefull playing round with the valve timing, i had a 'tinker' jst to see with mine and ended up melting two valves on the way back from southend
woops :roll:
local engine bulider put it down to to fuel getting trapped in the inlet chamber cuz the valves wern't overlapping at rite time or something and ignitin on the hot valve or sumfin like that. ended up limping it back on a couple of cylinders. was doin bout 120 at the time ;)

[rc]

/\ /\ /\ errr that was 120 kph not mph ok mr plod ;) ;) ;) lol