2000SILVERTA

OK, heres the story. I had a MMS 224/224 cam installed by a local speed shop. MMS sent their "shim kit" with the cam. It consisted of 16 spacers for the springs and (this is where the confusion started) 2 flat metal strips for spacing the rockers. The owner of the shop called MMS and they told him to use only one of the spacers for the rockers (I do not have aftermarket heads). Now, after one of their pos springs broke, I installed 918 springs and took off the rocker and spring spacers which I was told I did not need with the 918's. Now my car feels a lot stronger and sounds a little different. Would removing the rocker spacers make any kind of difference???

My car has all bolt ons and is an A4.

Tin Indian

Well, the cam they sold you must have a smaller base circle that the stocker. Thats whey they told you to put the shims under the rocker arms. This does the same thing as useing longer pushrods.

No matter what springs you use, you would still need the shim strips under the rocker arms in order to keep the same lifter preload as you had before installing the new cam.

As far as spring spacers are concerned, I cant think why you would need them under your 918 springs. They have no effect on lifter preload.

Ron,

Tin Indian

In other words, if your new cam has a .025" less base circle (distance from cam centerline to the heal/back side of the lobe) than your stock cam, you would need either .025" longer pushrods [or] ,025" shims under each rocker arm in order to maintain the same lifter preload as what it had with the stock cam.

2000SILVERTA

The cam is ground by comp cams.

I am gonna email MMS and try and talk to them myself. I really didnt think I needed the rocker shims, but we'll see.

Would my cam card have any pertinent info on it? Let me see if I can find it........