Thread: Why?

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I have wondered for a long time.
On solid lifters, the lash is set to X thousandths on the back side of the cam lobe. That is easy to visualize.
On hydrolic lifters, there are a myriad of wives tales on setting, several different techniques for setting, either torque, or back side lash.
Perhaps it is my misunderstanding on how a lifter works, especialy hydrolic.
My presumption is, the oil in the lifter acts also as a non compression medium that affects lash. If the spring in the lifter is the only real resistance, aside from the physical solidity of both the base, and spring compression, then several other factors come into play.
With the rockers I have chosen to install, the directions call for setting the rocker on the backside of the lobe, and tightening untill the pushrod stops turning. What is stopped turning, and how much torque is the test?
It may sound overcomplicated, but, it is hard to describe mechanical actions without pictorial perspectives.
After eliminating twist, then turn 1/4 to 1/2 turn and it is set.
Hokay.
Does this eliminate the pressure the oil in the lifter creates? Is the lack of twist, an easy twist, or a twist under pressure?
I understand the lifter is a pump that charges the pushrod to lubricate the rocker assembly, and ultimately lubricate the cam lobes through drip off.
I understand, tightening to eliminate clack on hydrolic lifters. A slight clack is good for mechanical rockers. It gives the valve time on the seat to moderate temperature.
With hydrolic lifters I am in the dark.
Why is the rocker set this way?

http://www.cranecams.com/?show=faq&id=3

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

Hah! Ask and Ye shall recieve.
Very comprehensive tutorial. Thanks, I appreciate it.
It sounds like adjusting the rockers is simpler than mechanical rockers. You do not need a feeler guage!
Thanks Tech1

Screwing them down 'till you can't turn the pushrod is not the proper procedure. The first time I did adjustments on hydraulics I did it that way. It too me quite a while to figure out why the engine would crank and crank yet still never fire.

Originally posted by pelligrini
Screwing them down 'till you can't turn the pushrod is not the proper procedure. The first time I did adjustments on hydraulics I did it that way. It too me quite a while to figure out why the engine would crank and crank yet still never fire.

I think what they are trying to say is feel some drag or resistance.Yes this will work.I have built quite a few engines over the past 15 years and I have never had any problems with this.

So, it really is just making it an effort to turn the pushrod, rather than putting positive drag on it. That also would make sense, other wise it would be inducing pre-load on an item that would be preloaded.

Much better to set juice lifters with the engine running.

Originally posted by docone31
So, it really is just making it an effort to turn the pushrod, rather than putting positive drag on it. That also would make sense, other wise it would be inducing pre-load on an item that would be preloaded.

Exactly. When I set the rockers in this manner no more mess in the shop.

Originally posted by R Pope
Much better to set juice lifters with the engine running.

Why?

With juice lifters, I have always had good results backing off the rocker stud, with the engine running, to the clack, then tightening so the clack just goes away. The rockers always worked well that way.
With these rockers, they are 1.52 Magnum Rockers. The rocker can be damaged by excessive lash during adjustment. Since I have never adjusted rockers the "new" way I was severly confused by the approach.
Tech1 really sent a good tutorial that helped explain the actual mechanics of juice rockers. I have found out, there are some subtle differences between the type I learned on, and the new ones.
Once the Magnums are broken in, and have a few miles on them, then if it is neccessary I can splash set them. I do have a set of spray deflectors. I have gotten used to working on a cooler engine however. I find it is easier to do complicated things on a cool engine than when every hose, metal part, and especially the manifold burns when bumped into.
Less noise, less fan wind, fewer people who just seem to come out of nowhere and that is the time to talk about something that has nothing to do with the engine.

"fewer people who just seem to come out of nowhere and that is the time to talk about something that has nothing to do with the engine."

So this happens at your place too, I thought it was just my neighborhood.

Originally posted by techinspector1
"fewer people who just seem to come out of nowhere and that is the time to talk about something that has nothing to do with the engine."

So this happens at your place too, I thought it was just my neighborhood.

Just crack open the headers and you don't have to put up with them.

Huh?.....Huh?....Can't hear you.....Huh?.....Yeah, see you later

They always want to come by and help,they make it by ,but, I think i get less done! and in that way they certainly always help

Yeah, I especially like the ones that put their fingers in the moving mass! They really do. You are adjusting valves, and they stick their fingers in it.
Then there are the people who just have to distract you in a critical operation and ask if they can borrow the tool you have in your hand right now!
Then there is the good ole boy with a beer in his hand who slept in the car last night. He always tells ya, you shoulda greased the muffler bearings. That is what it is.
You try to ignore him and he tells you the only purpose for a torque wrench is to torque the framistan. It is always the framistan. Who mikes anything? Don't need one anyway.
These are my neighbors! When I work on my van, I have to take it out of the garage and bring it to the back of the house!
I never ask them a question. I need to get it done.