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cam timing question

Started by mrlctorana , Sep 21 2006 08:56 PM

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11 replies to this topic

#1 mrlctorana

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Posted 21 September 2006 - 08:56 PM

Hey guys, just wondering if you advance the cam do you have to change anything else to suit, as in ignition timing??? We are talking about a blue 202.

Cheers

Les

Edited by mrlctorana, 21 September 2006 - 08:57 PM.

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#2 Tiny

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Posted 21 September 2006 - 08:58 PM

Gday les.

you dont HAVE to change anything else.. Just remeber when doing the timing that 6 degrees on teh balancer will actually be 8 degrees if you;ve advanced the cam 2 degrees!!

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#3 mrlctorana

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Posted 21 September 2006 - 09:09 PM

Ahhh Ok, Cheers Tiny.

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#4 _82911_

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Posted 21 September 2006 - 10:06 PM

Close big fella.. but not quite.
You forgot that the cam rotates at half the crank speed.
So 2 deg on the cam = 4 deg on the balancer. :tease:

MR lc what are you advancing the cam for????
If you are looking for more top end.... get a grind with a tighter lobe seperation like a 106 deg or even a 104 if you really want it to cut in higher..
If it is bottom end you are looking for drop your diff gears by a couple of points and got to the tighter cam and rev it harder! :rockon:

Just a sugestion...........

Cheers Greg..

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#5 _LX8VD69_

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Posted 21 September 2006 - 10:09 PM

advancing the cam timing will only give you better response from down low, the down side is it will rev out quicker

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#6 Tiny

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Posted 22 September 2006 - 07:59 AM

God damnit

I KNEW i'd get shot down!!

No seriously.. Thanks greg!! Gotto got this info RIGHT hey!

Cheers mate

Tiny!

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#7 Tiny

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Posted 22 September 2006 - 08:02 AM

Just an added note.. I thought that advancing the cam gives you the same "profile" as the cam always has.. but brought in slightly earlier in the timing sequence... So for example, you may be able to have a slightly larger cam profile, but advanced or retarded slightly to bring the events on eariler or later compared to crank revolutions?

Am i right, and why would this be such a popular thing to do? I know that the cam in the monaro is advanced by about 2 degrees!! ( and NOW i know why it pings so hard when i dial in 10 degrees advance on the ballancer!!)

Cheers

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#8 warrenm

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Posted 22 September 2006 - 08:51 AM

As Tiny said advancing the cam brings the torque in a couple of 100 revs early but runs out early & retard is the opposite.

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#9 mrlctorana

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Posted 22 September 2006 - 10:36 AM

Thanks a Lot guys, Im not advancing the cam, but was just talking about it with a mate while i was putting motor back together, and thought I'd ask but it makes sense now.

Have dropped diff gears to 3.7 and with the supra box I find it a pretty good comprise between strip and street although Im gunna have to steer away from the strip for a while so I can try and keep it on the road a little longer, hehe, but I can't help myself I'll end up back up the strip before the year is out, and as long as Im quicker than the previous 13.5 i'll be happy...

Cheers

Les

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#10 _Sammy_

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Posted 22 September 2006 - 11:26 AM

Just an added note.. I thought that advancing the cam gives you the same "profile" as the cam always has.. but brought in slightly earlier in the timing sequence... So for example, you may be able to have a slightly larger cam profile, but advanced or retarded slightly to bring the events on eariler or later compared to crank revolutions?

Am i right, and why would this be such a popular thing to do? I know that the cam in the monaro is advanced by about 2 degrees!! ( and NOW i know why it pings so hard when i dial in 10 degrees advance on the ballancer!!)

Cheers

i have the same +2 on the cam, and the reason for this for me was because it had a bit of extra torque down low without really effecting top end too much, compared to less/more advance that is.

i guess you can get a grind thats to suit what you need but to get a custom grind is a bit more pricey than an off the shelf billet and the straight cut timing gears (for a 202) come with the option to advance/retard

so that is the main reason i did it...

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#11 TerrA LX

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Posted 26 September 2006 - 04:22 AM

holden done it for years, take the holden V8 for example, fit a standard cam sprocket from a HQ to a HZ and you advance the same cam that resides in all models for a power increase as thats all they changed through out the models, so there is oviously is some gains to be made if you can tailor a cam to suite your needs.
of course you would need dyno time to confirm your findings.