o lash and no preload???

[442 Guatemala]

Hi I buy a new camshaft, rockers and springs from Mondello for my 1966 442 with 400 engine, the instructions says that I have to keep 0 lash and no preload, I really have no idea what means. can anyone tell me what 0 lash and no preload mean, and how to do that when installing my new camshaft and rockers?

thanks

Alex

[don71]

The factory olds valvetrain is non adjustable. It is a 0 lash system. You only need to worry if you are using an adjustable after market rockers.

The hydraulic lifters used in oldsmobiles have about .050 preload built into them. They are designed to take up a little slack. You want your preload somewhere in the middle. You don't want the plunger in the lifter to bottom out or stack up to full travel or bind on the retainer.

As long as the pushrods are the right length you are ok. IF you had the heads milled and a valve job done it could be possible to have push rods too long. But using the newer thicker head gaskets that we have today, it will make up for some that material taken away in milling the head.

When you have everything installed the push rod should spin, but not move up or down. That is 0 preload.

[442 Guatemala]

Originally Posted by don71

The factory olds valvetrain is non adjustable. It is a 0 lash system. You only need to worry if you are using an adjustable after market rockers.

The hydraulic lifters used in oldsmobiles have about .050 preload built into them. They are designed to take up a little slack. You want your preload somewhere in the middle. You don't want the plunger in the lifter to bottom out or stack up to full travel or bind on the retainer.

As long as the pushrods are the right length you are ok. IF you had the heads milled and a valve job done it could be possible to have push rods too long. But using the newer thicker head gaskets that we have today, it will make up for some that material taken away in milling the head.

When you have everything installed the push rod should spin, but not move up or down. That is 0 preload.

Hi don, my new valvetrain system is adjustable, so what i have to do to obtain 0 lash. I also have new valve springs rockers and pushrods acording to the new camshaft. I also have new hydraulic lifter just like original ones so im sure they have the right length, so I have to car about preload?

thanks

[don71]

Take a look at this link, see if it helps...

http://www.cranecams.com/?show=techarticle&id=2