I just finished installing my cams and broke the promise I made to myself to wait 1000 miles to rev them above 5K about 100 miles in. My question lies in the high-RPM, boost area. The engine vibrates pretty violently above 5500 or so. I'm wondering if this is normal for agressive cams ( GSC S3's) or if I possibly messed up the balance belt and I'm sitting on a time bomb.
The car idles as well as one could expect (actually better) and drives normally below 5K RPM So do BIG cams vibrate the crap out of the engine at High RPM or am I F'ed? I also have an unsprung clutch disc and poly front motor mount if that matters

 

Sounds like a balance shaft is out of phase....

 

+1 on the balance shaft. Sucks to say it man, but you gotta tear it apart again lol.

 

Per their web site: "The S3 Cams are avalible in a Solid Lifter cam and a Hydraulic Lifter Cam for the Evo 4-8 4G63. These cams are ment for the 1000whp+ to take advantage of a very large turbo. these are NOT suggested for anyone running smaller than the GT42R and should not even be considered!
S3 Specs."

Which cams did you get, the solid lifter or hydraulic? if you got solid did you put in solid lifters? Also there was no mention about upgrading valve springs/retainers on their site, did you use stock valvesprings/retainers?

 

Ouch... More work ahead of you bro.

 

Something isnt right for sure. This isnt normal.

 

I didn't figure that it was right. Am I ok to drive it for the rest of the week or should I be tearing this apart now? Does the oil pump shaft include some kind of balance apparatus or is it all on the tiny little belt that I should be worried about?

And yes, I know it's WAY too much cam for my current application. However, they are an earlier version with less lift (10.8 mm) that I got for crack-head cheap.

 

+1 Same thing happened to me except I remember it starting to vibrate at a little lower rpm like 4k or so.

 

I could be desensitized to the vibes due to the clutch and motor mount. Does the oil pump shaft have anything to do with engine balance? I assume it might because it has timing marks, but if not, I'm gonna try and finagle my finners behind the timing belt and just move the balance shaft. (should be fun...)

 

Yes, the Oil pump has a balance shaft sitting behind it.

The easiest way to set that shaft to time is to spin the sprocket until it the white dot wants to naturally sit in that area. you will see what I am talking about when you start to spin it. Or you can do it per the manual and remove the bolt on the front/bottom of the block and rotate the sprocket until you can get a about a 4 inch screw driver to go in the hole.

 

It’s your balance shaft. The oil pump shaft can be out 180 and still line up as per the timing mark. This is do to the gear reduction of the oil pump. You should fix this sooner than later or keep the rev's as low as possible.

Also as an FYI the sold lifter profile is less aggressive on the opening and closing events than the Hydraulic vrs. This has to be done do to the precise valve movement with the solid lifter verse the slop of the hydraulic lifter. This is the reason why we frown on people running solid lifters on our hydraulic profiles.

 

Don't know how a balance shaft can get off time relative to crank with just a cam change. Your oilpump gear might be off though.

You did not rotate crank backwards after reloading the tensioner did you?

You are going to have to remove the serpentine belt, pulley's and etc to view all the timing marks for the belt. Should be able to stick a screw driver in the fwd shaft with all the other marks lined up.

Might as well replace the belts too if they're not new.

Motor mounts wont make a car vibrate at high RPM, just at idle

 

Yes, this was an R&R on the timing belt and balance belt. I redid it yesterday and both shafts were off. oil pump was off by like five teeth balance shaft off by one. I also misspoke. I have the GSC 280's and NOT the S3's. It turns out I might be an idiot.