Cam timing

[Reese92tsi]

I rebuilt my motor about 4 months ago but I feel that the valve timing isn't exactly right. It looks like my camshaft sprocket marks are 2-3 millimeters off when cylinder 1 is at TDC and on 4G63's I know that the valve timing has to be extremely perfect. I've tried my absolute best to get the marks perfectly zeroed out but the excessive milling of the head is probably preventing the marks from lining up perfectly. It seems that the intake cam is slightly advanced and the exhaust cam is slightly retarted. Would this cause me to loose power or would it cause me to build a little lower or a little higher in the powerband?

 

[gsx951]

Milling the head/deck changes the geometry. Do you know how to "degree" the cams?

 

[1fast97gsx]

get a set of adjustable cam gears and that'll fix your problem.

 

[Reese92tsi]

I don't know how to degree the cams. If I bought some adjustable cam gears would I just zero them out or would I try out different intake and exhaust cam settings and see what combinations will give me a smooth idle, and restore lost idle vacuum? My car doesn't have a smooth idle (sounds like it has cams), and I lost a little lower end torque after the rebuild.

 

[1fast97gsx]

The reason for buying adjustable cam gears is so you can properly degree the cams... ( NOT zero'd out ... that defeats the purpose in getting them ) You just put them on and in your case take the car to a shop that knows what they are doing and they will degree the cams for you.

 

[Reese92tsi]

Could you explain to me the correct way of degreeing the cams. I would rather do it myself then to take it to a shop.

 

[DevilSperm]

did you make the exhaust cam 1 tooth clockwise when you installed the timing belt? they rotate back about a tooth after the tension is up

 

[Reese92tsi]

Whenever the marks are zeroed out at the cams I then proceed to wrap the belt around the idler pulley, oil pump sprocket, then the crank sprocket. When I wrap the belt around the crank sprocket (still making sure the marks at the cams are zeroed out) the teeth will not positively engage the crank sprocket and the crank sprocket will move a couple millimeters away from the TDC mark (this causes the marks to be off before the main tension is applied). I've tried EVERYTHING humanly possible to get the cams zeroed out but it's just not possible. Thanks guys for your help.

 

[DWAIST]

to my knowledge the head would have to milled quite a bit to affect cam timing! i was having the same problem when i installed a bigger 272 hks cam from my old 264 cam! i must have tried to set the timing like ten times and could never get it right on the money!!! turns out the alignment plate on the crank that seperates the two sprockets was worn out! even the dowl pin on the crank was fubared!!! i mean the plate was so screwed there was no way in the world my timing was ever gonna be right! i replaced the dowl pin and the plate and everything was back to normal! give it a look sometime and if it's not it atleast you could rule out that option!!!!

good luck!

 

[DevilSperm]

Whenever the marks are zeroed out at the cams I then proceed to wrap the belt around the idler pulley, oil pump sprocket, then the crank sprocket. When I wrap the belt around the crank sprocket (still making sure the marks at the cams are zeroed out) the teeth will not positively engage the crank sprocket and the crank sprocket will move a couple millimeters away from the TDC mark (this causes the marks to be off before the main tension is applied). I've tried EVERYTHING humanly possible to get the cams zeroed out but it's just not possible. Thanks guys for your help.

when you clamp the belt onto the cam gears, you need to have the exhaust cam 1 tooth clockwise...then wrap the belt around and set the tension...once that is done your cam gears will be perfect