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Location:
Perth
Registered:
April 2005
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will advancing cam by 1 tooth work?
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Sun, 24 April 2005 03:06
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Hi All,
I have read about advancing the inlet cams timing. I can not afford or make some vernier cam wheels at the moment. So my question is,
What kind of gain will i get by advancing the cam wheel by 1 tooth?
What degrees does this represent?
and My cams are std in a small port GTI 4ag.
Thanks,
Ty
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Location:
Brisbane
Registered:
May 2002
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 04:55
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Work out how many degrees a shift of one tooth will advance your timing by...then look at how many degrees adjustable cam wheels are generally used to adjust by (+- 3deg seems to ring a bell to me?)....
I think you'll find a whole tooth is way too much.
Cheers
Wilbo
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Location:
Melbourne
Registered:
May 2002
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 04:58
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you will notice there are differnt dowl pin holes on the cam gears... use your imagination
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Location:
Wollongong
Registered:
January 2005
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 04:59
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This sounds like a great idea!
Has anyone actually done this? What could go right/ wrong? What's the general idea for twin cam settings for top end gains? Advance inlet, retard exhaust?
| "corbet01 wrote" |
What degrees does this (one tooth) represent?
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Count how many teeth you have, and divide 360 by that number. That's how many degrees each turn of a tooth will give you.
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Location:
wollongong
Registered:
March 2004
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 05:25
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It will probably just make it sound different, and run bad, and not make any noticable power increase. I accidently put the cam 1 tooth out on my old datto, and it sounded like a tractor and wouldn't idle.
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Location:
Wollongong
Registered:
January 2005
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Location:
Lost in the K hole
Registered:
May 2002
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 08:29
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1 tooth = 12degrees... 
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Location:
Melbourne
Registered:
May 2002
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 08:31
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| ed_ma61 wrote on Sun, 24 April 2005 18:29 |
1 tooth = 12degrees...
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fully sik you need a few more teeth then coz everyone knows its not thorpy stilezzzz unless its >45deg angle
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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 10:18
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I'm pretty sure there's 36 teeth on a 4AGE cam pulley so one tooth there is 10° on the cam or 20° on the crank.
That's a lot!
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Location:
Perth
Registered:
April 2005
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Re: will advancing cam by 1 tooth work?
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Sun, 24 April 2005 10:51
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Thanks for the replys. I haven't actually removed the cam belt cover yet so i will check out the dowel pins. Still learning, always had rotaries and 2 strokes.
Thanks,
Ty
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Club Member
Location:
sydney
Registered:
May 2002
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Location:
Lost in the K hole
Registered:
May 2002
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Re: will advancing cam by 1 tooth work?
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Mon, 25 April 2005 03:22
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10? 12?... whos counting... 
"its a lot"
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Location:
brisvegas
Registered:
August 2004
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Re: will advancing cam by 1 tooth work?
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Wed, 27 April 2005 02:01
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| Bill Sherwood wrote on Sun, 24 April 2005 20:18 |
I'm pretty sure there's 36 teeth on a 4AGE cam pulley so one tooth there is 10° on the cam or 20° on the crank.
That's a lot!
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exactly right..i advanced my inlet cam 1 tooth..sounded a bit deeper..no bottom end..more top end..did my exhaust cam also..not realising i needed to move the dizzy to suit..i started it up, and it sounded lie a 9 sec 13B turbo drag car..
Brap!..Brap!..bur bur..Brap!
so i changed it back quick smart...any half arsed engeeneering workshop place should be able to make yours adjustable for next to nicks.. ($50 or so) also the inlet cam will give you the most noticeable increase..
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Location:
myrrhee
Registered:
March 2004
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Re: will advancing cam by 1 tooth work?
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Wed, 27 April 2005 03:57
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I think the old twin cam alfa's use to move a cam around one tooth and get heaps more top end, but suffer in both low RPM power and drivability.
My idea would be to drill more dowel holes in the cam wheel, each slightly more off set to the tooth above it than the next.
Do this accurately, drill 4 more holes and have timing increments of 2deg.
Good luck with your experimenting and let us know how it goes.
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Location:
Melbourne
Registered:
May 2002
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Re: will advancing cam by 1 tooth work?
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Wed, 27 April 2005 04:10
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I had one of my cams out by one tooth when i first put my engine back together, it ran fine. i didn't notice till some old vw mechanic fixing my dads kombi told me. wound it back a tooth, and found a whole stack of power, mostly down low. i always thought it was my carbs just being shitty for low end.
i don't think you'll find much power over the stock settings. toyota spend a few hours getting the engine to a very drivable state, ie, no big holes in the powerband. start messing with it and you may be going slower. it'll feel more powerful, only because you've made a dip and climbing out of the dip, the car feels fast.
dodgydan
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Location:
Wollongong
Registered:
January 2005
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Re: will advancing cam by 1 tooth work?
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Wed, 27 April 2005 08:29
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Hmmm,
I agree that Toyota spent alot of timing working out cam timing, but not soley for 'better drivability'. Rather, emissions (or the lack of) would be their key goal, with most of the performance focus aimed at acceptable all round drivability.
If adjusting the cam position was no good, there wouldn't be an aftermarket for adjustable cam gears, now would there?
I do agree that fiddling would probably result in less power (or even engine problems), and only a dyno tune would show the gains.
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Location:
Adelaide
Registered:
December 2004
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Re: will advancing cam by 1 tooth work?
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Thu, 28 April 2005 08:22
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Advancing the inlet cam timing will give you gains in the top end but will drop the bottom end. Toyota uses this in the VVT, VVTi and VVTLi systems, but changes it while the engine is running so that you get the best of both worlds.
Adjusting the cam timing on an otherwise stock engine isnt going to give you a hell of a lot of a performance increase and it would be fair to say that the engineers at Toyota have spent a fair amount of time determining the optimum settings for the cams.
If the car is highly modded then you do stand to make quite a difference, but you really should splurge on some adjustable wheels (they look cooler too) and spend some time and money getting it properly tuned on a dyno.
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