Hey all,

Over the past year, I noticed that my cam gears are wearing down. They have lost at least .020" per side. If the diameter is now smaller, doesn't that mean I am increasing the cam speed per turn and loosing valve open time? I'm sure there are technical words for this. Anyway, I advanced my timing a few months back and it helped, but it seems to be getting worst as far as low end and top end. Not major, but noticeable.

What could cause this wear? Should I do anything else but change the gears? Any advise welcome. Thanks,

Sigfrid

 

what kind of cam gears? what kind of timing belt? tension on belt?

 

The gears are from Vishnu, the belt is the stock one and I got them installed with the cams so I am not sure what tension. I was under the inpression that the tension was spring loaded and non adjustable. Thanks,

 

Belts will wear out metal over time. (When I'm talking about wear, I mean very very minute amounts.) It should not be anything to worry about though. Check the tension on the belt, as an overtightened belt will obviously wear down metal a little quicker, as well as the belt itself.

 

Are you saying the gears are wearing down?

If so the speed will remain the same since you have same # of teeth. What will be different is the slack on the belt which will automatically be adjusted by the hydraulic auto tensioner. Everything should be the same as before until the auto tensioner runs out of travel from taking up slack and the belt slides off ruining the head or even pistons, or the gears slip and do the same.

 

That's what I was thinking too. I figured the auto tensioner would pick it up and that was it. I then thought about it some more and am now worried. Changing the diameter of the cam gear does not change where it starts or where it stops, but it will change it's speed in realtion to the crank. The smaller gear should open the valves later and close them earlier, effectively changing the slope of the cam and lowering overlap. The wear on my cam gears is not minor. It is well over >020" per side if not double that.

 

wow i have the same cam gears hope this isnt happening to my car.
what mileage do you have on your camgears?

 

You know, I've noticed a little bit of wear with my Fidanza cam gears over the last 1-2 years. My cam gears look exactly like post #11 in this thread: https://www.evolutionm.net/forums/sh...+cam+gear+wear. I don't think the wear has gotten any worse, but it's just on the edges of some of the gears as if they rotated wrong for just a little while. I rechecked the tightness of the adjustable bolts and the car still runs fine.

 

That picture looks nothing like mine. Mine is well eaten up. I will shoot some pictures and try to attache them.

 

Not very clear picture. I hope you can see there is a substantial wear area.

 

have you called vishnu andd asked them about this?

 

Vishnu will probably charge you extra for that custom result. Seriously, replace them with higher quality parts before it costs you a lot more.

 

Any suggestions as to what brand is depandable and good quality? As you mentioned, it's not worth it to wait/take a chance on hopping over a few teeth and having the valves kiss a piston.

Sigfrid

 

One of the best manufacturers for cam gears out there is Unorthodox Racing (UR).

Geo at Titan can get them for you, and get you a very good price as well.