Cam shaft, cam gears, cam everything

[eclipse2nr91]

Okay, since the almighty WhoaTed suggested we make more threads that are more detailed for the new subforum, I'm gonna go ahead and let my cam ignorance shine through. :D Okay, first of all, racing cam...can I order one from the 2.0L and it'll replace the stock SOHC for my car or what? I know the cam gears for the 2.0 fit our cars, so I'm not gonna ask about that, although I am confused as all hell now that I went to mvpmotorsports. Here's what it says :

"These provide adjustable cam timing to maximize performance. Indexed in 1º increments, +/- 10º. Unorthodox quality with CNC machined from lightweight 6061-T6 aluminum billet & super-hard anodized timing belt ring & stainless steel hardware. Five-bolt locking pattern ensures they stay in place. Much higher quality than AEM. With the Unorthodox Cam Gears there is no backing out of the cam bolt or slippage on the cam gear locking bolts. AEM uses three bolts and Unorthodox uses five. Price is for one cam gear which works for intake or exhaust."

These are Unorthodox cam gears, and the last part is what I'm not understanding..."which works for intake or exhaust."? I just don't know much about cams in general, so someone please try to clear this up for me before I buy somethin that am totally ignorant about!!


Josh

[miketribal]

ok i give it a shot....

no.. a cam from the dohc will not work... here is why... the 1.8 use a single cam to control the valves -- so that 1 cam opens and closes BOTH the intake and exhaust valves -- there are 8 valves 4 intake and exhaust-- 2 per cylinder.... and the cam shaft is gear at the end for the distributer.

the 2.0 dohc-- it uses 2 cams-- 1 cam ONLY controls the intake valves -- the other cam controls ONLY the exhaust valves-- there are 16 valves ... 8 intake and 8 exhaust ... 4 per cylinder... there is no gear on the cam shaft , it uses a distributerless ignition...

the adjustable cam gears be it obx , aem , unorthodox... etc..
are identicle they are not specific to intake or exhaust... they are the same gear.. all they do is allow you to fine tune your valve timing.. basically you can make the intake valves open a little sooner or a little later... the same goes for the exhaust... now on your 1.8 both intake and exhaust are controlled by the 1 cam... so you put on your adjustable cam gear , now you can adjust when your valves open or close... just remember that if you want your intake vales to open sooner the effect echo on your exhaust.. so if your intake is 1 degree ahead so will your exhaust...

DONT USE THESE FIGURES TO TUNE YOU CAR

im just throwing out numbers...

also if you decide to use a 2.0 cam gear... you will have to take off your upper timming belt cover FOREVER the 2.0 cam gear is almost 1 inch wider.. which is good and bad.. its good cause you can see it and show it off to your friends... its bad cause you need to be very carefull cause if you pour oil in there it will ruin your belts , or if a bolt or something falls in there it can cause some serious problems.

i hope this is helpfull to your cause

[eclipse2nr91]

Thanks tribal, that is a huge help, and I really appreciate it!! So what do you think the cost might be to get the cam gear put in?? Oh, and one last thing I might need explained...opening the valves sooner or later...which does what for the performance? (acceleration and what not) Like if I want better acceleration how should I set the gear, + or - a degree? And what's involved in adjusting the gear??

[Taboo]

Originally posted by eclipse2nr91
opening the valves sooner or later...which does what for the performance?
Advancing the cam timing results in more low end torque, decreased piston-to-intake valve clearance and increased piston-to-exhaust valve clearance. Retarding the cam timing results in more high-end horsepower, increased piston-to-intake valve clearance and decreased piston-to-exhaust valve clearance.

[eclipse2nr91]

Ahh, Taboo, finally an answer...thank you, I've been waitin for someone to help me out with that one for a while:)

[JohnAllanCoe]

eSo with the cam gears, will they actually open the valves more resulting in more power or can you just control when the valves are fully opened?

[Taboo]

Since 1.8L has only one single cam, one can control only when the valves open/close in relation to the crankshaft position. Not the actual duration (how long the valves stay open) or the valve lift - and not even the valve overlap (since both intake and exhaust lobes are on the same cam).
So, if the stock cams opens the intake valve 15' BTDC and closes the intake valve 40' ABDC, the exhaust valve 40' BBDC and closes 15' ATDC - and one advances the cam by 5', then the intake would open at 20' BTDC and close at 35' ABDC, the exhaust at 45' BBDC and close at 10' ATDC. One can simply move (advance or retard) the duration of the intake and exhaust valves only at the same time and without being able to change the actual duration and valve overlap (separation angle).
One would need a custom cam to increase the valve lift, duration or change the separation angle of the intake and exhaust lobes.
:)

[TaLoNBLiNGBLiNG]

Mike, so what you're saying is what we would need on our SOHC is an adjustable cam gear? Seeing how we only use one camshaft for both the intake and exhaust. This would be beneficial to our motors, right? I don't really want to remove the timing belt cover to fit the 2.0 cam gear, so an adjustable cam gear for our SOHC will do just fine?