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Adjusting Ex Cam Gear

Mr_G

By Mr_G,
in Engines & Forced Induction

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Mr_G Mentor

Mr_G

Posted
Posted

Hey guys,

Just replaced my adjustable cam gear on my car today with a branded one in suspect a distinct sound might go away, guess I was wrong.

Anyhow, the old cam gear I found out was set at -2deg when really it should have been set at -4deg.

What I found when mounting it, was that I had to set my new one to -2deg to mount because at -4deg, those 4 bolts wouldnt line up.

Now basically I want to set it @ -4deg. Its currently on -2deg. Just wondering how would I go about setting this as im pretty sure the belt has to move whilst the adjustment point is loose, in order to set it @ -4deg...

Correct me if im wrong, but what im going to do is turn the harmonic balancer using a rachet with the cam gear adjustment loose till I line it up. Basically once I line it up @ -4deg, i will lock it in.

Is this basically how I set the gear? is tehre an easier way?

Its on a RB25DET by the way

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Craved Grand Master

Craved

Posted
Posted

i would think that it would be easier to take the cam cover off and move the cam with a spanner to the desired position .. since your only trying to move one thing rather than moving the crank and the inlet cam ..

either a big shifter or a open ended spanner will fit on the hex section on the cam closest to the gear.

BHDave Grand Master

BHDave

Posted
Posted

I'd just turn the engine over slowly with it loose. Bit more effort to turn it but alot less work than pulling off the cam covers.

Once you do lock it in place, turn the engine over by hand a couple of times to check for any contact between pistons and valves. It shouldn't be a problem with stock or low lift drop in cams but it pays to be paranoid sometimes.

Mr_G Mentor

Mr_G

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  • Author
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Thanks for the advice guys, ill pop out to the garage soon and give it a shot :cheers:

By the way, would there be much difference in mid range adjusting from -2deg vs -4deg?

Alot of guys on here found better results setting it @ -4deg. Just wanna know what im looking forward too :D

Mr_G Mentor

Mr_G

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Quick update:

Ive now set it @ -4deg and it seems alot diff as in the car idles alot lumpier and doesnt pull as hard as it used to when it was set to -2deg.

Does this mean I need to go get the car retuned since it was tuned on the map of setting -2deg ?

Feels abit more sluggy in the mid range since changing it to -4deg

blind_elk Grand Master

blind_elk

Posted
Posted
What I found when mounting it, was that I had to set my new one to -2deg to mount because at -4deg, those 4 bolts wouldnt line up.

Of course they won't line up - the relationship between the teeth and the cam bolts has been dislodged by 2 deg!

Simplest is to remove the rocker cover from the exhaust side and manually adjust the cam.

You're absolutely sure it'as only -4 deg, not a whole tooth or something, because normally 4 deg doesn't have much effect on the idle quality.

And all you are doing by adjusting the cam is moving the power band - you don't necessarily get more power, you just get it at a different rev band.

Beer Baron Grand Master

Beer Baron

Posted
Posted

BTW remeber. 2 degrees on the cam wheel is 4 degrees actual crankshaft revolution. so the people you speak to need to clarify which they are talking about. perhaps that is why the old gear was -2 on the wheel which is actually -4.

Mr_G Mentor

Mr_G

Posted
  • Author
Posted

In comparing the modified std ex cam gear I had to my greddy one I just put in, the adjustment amount in comparison was 2deg in difference. But do most of the people on the forums set it @ -4deg as in camshaft degree or ex cam gear deg?

blind_elk Im 100% sure its -4deg, not a whole tooth as it idles fine with -2deg. but -4deg its abit lower on idle, and sounds quite lumpy... Also I marked down exactly (using white out) where the marking on the cam gear goes in accordance to the timing belt, and it went back on exactly.

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