CC305, LPE219, and Crane227 are all proven cams that are daily driveable.

 

I'll take a shot at this; it's somewhat complicated to explain, but I'll do the best I can.

These are two terms that are often thrown around; LASH and PRELOAD. Explaining what they mean and how they're applied is what I'll try to do.

The terms "lash" and "preload" are often confused with each other and those terms are often used interchangeably, as if they mean the same thing, but, technically speaking, they're different things. Sort of like the difference between a flex-plate and a flywheel. You know, a flexplate is for an automatic transmission and a flywheel for a manual trans.

The term "lash" is a term used to indicate a clearance between the valve stem tip and the outboard end of the rocker arm. It means an 'opening' or 'gap".

Technically, "lash" applies to solid/mechanical camshafts, not hydraulic cams. Because of the way they're designed, mechanical cams require a clearance/opening/gap/lash to operate correctly. The recommended amount of clearance (lash) is specified on the cam card that comes with the cam and the installer uses feeler guages to find and set the recommended clearance (lash).

Hydraulic cams are just the opposite. They do not require any clearance between the outboard end of the rocker arm and the valve stem tip. Hydraulic lifters have movable, internal parts and when adjusting hydraulic lifters all clearance (lash) is removed. The point where all clearance has been removed is referred to as "Zero lash". See what I mean about "confusing"?

Once Zero lash is found, an additional amount of depression (preload) is applied. Finding Zero lash is where the term "heel" and/or "base circle" comes in. Those two terms are also used interchangeably but in this case, they mean the same thing.

Finding Zero lash is the point where so many guys get confused (even more) and make a mistake. In order for the preload to be correctly set, the lifter has to be on the "heel"/"base circle" of the camshaft lobe. It's finding the "heel"/"base circle" that causes the problem.

Preload is the amount the installer depresses the lifter's movable plunger and can vary depending on personal preference in many cases. The preload is adjusted by using the adjusting nut which is screwed onto the rocker arm stud. Some like 1/4 additional turn, others like 1/2 additional turn, etc. GM usually recommends one-full turn from Zero lash.

All this business can be even more confusing once you begin to make the actual adjustments, but when that time comes, we'll walk you through it.

What's amazing about all of this is once you learn how to do it, it becomes a piece of cake. Sort of like learning to ride a bike; difficult at first, then becomes second nature. Remember how many times you crashed but don't anymore? LOL

Jake

 

what cam did you diside on goin with? did you endup gettin the 195AFRs yet? i have a 224/230 .540lift 112 cam and hogged SR waiting to be installed in my 355 if i ever get around to droping the money on some AFRs.

 

I haven't gotten around to buying the cam, but I'm planning on doing it soon. I'm probably going to go with the CC XFI excellent midrange/good top end cam

 

Great info on here! I learned a whole lot!

I have a question on torque converters: What is the stall number, what is it stock, and how does an aftermarket help?

94lt1vette94 this is a good thread