Lifter Preload

[bLinded_]

Hey guys,

 

I just have a little question regarding running a reground cam profile in my 5K engine I am in the process of building.

 

Now, I am aware that having the cam shaft reground will have an affect on lifter preload and valve clearances, but what I am unsure about is how to correct this as there is no way to adjust the rocker gear as the 5K has hydraulic lifters, and I don't particularly want to convert to solids. Basically, if the cam lobe diameters have been reduced by x, that means that the pushrods will be now that much too short for the rocker arms, am I correct? :'( So, if I get the head shaved by the same value x, will that cancel out the reduction of the lobe centres resulting in lifter preload to be corrected? I don't know if I am on the right track here so that is why I am after help. :'( Just need to know, will shaving the head down by the same amount as the lobe centre reduction maintain normal preload and thus allowing me to put the camshaft in and have the engine running? And, if not, what do I need to do to get it to work? ;) The engine in question is a dished piston 5K running standard hydraulic lifters, and the cam profile is a Tighe 104.

 

I have been looking around on here and the internet, but, due to the fact that this is my first engine build, having a second opinion(correct advise) helps alot. ;)

 

Thanks for you time,

 

-Alex :y:

 

 

Edit: A picture might explain what I am trying to get across easier, so Ill post one up tomorrow if I get time. :jamie:

Edited August 23, 2008 by bLinded_

[coln72]

Ran a reground cam in my 5k with out any isses with lifters. Just fitted it and fired her up.

 

If you want to get carried away you could machine down the rocker posts.

[bLinded_]

Hmm, thanks for that response Coln72. Maybe I should just put it in and see how it goes then? :'( What's the worst that can happen :jamie:

 

Also, when fitting the reground camshaft, is it a necessity to have the lifters refaced? When I dropped off the head at the engine builders, the guy there said that the lifters would need to be refaced, however, I am unsure if it is okay to not have them done, as I know someone that runs a reground camshaft but never had the lifter refaced. I guess I am just trying to figure out exactly what I can and can't do in order to have it all working properly. I don't particular want to be spending extra money on things if it is fine to go without them, and, not knowing what needs doing means that for all I know, the engine builder could be trying to get as much money out of me as he can. ;)

 

If anyone has any one else has info regarding the matter, please fire away. :'(

 

-Alex

[coln72]

you probably should but I never bothered :jamie:

[Felix]

What's the worst that can happen !jamie.gif

 

The worst thing that could happen would be the circlips that hold the lifters together popping. If that was to happen, the events afterwards wouldn't be so good.

 

Read HERE the part on measuring lifter preload to see what you actually end up with. You may be fine like coln72 and have no issues.

Edited August 24, 2008 by Felix

[bLinded_]

Cheers, thanks heaps for that info Felix. :jamie:

 

I am "expecting" the head back this week, so I guess I'll do as per that link you sent, and find out actually what the preload is, then go from there. Is what Coln72 said about grinding down the rocker posts the best solution to increasing preload should I need more? Or would either skimming the head down, or having the lifters ground down be better options. I know I am probably thinking ahead of myself at the moment, as chances are I may not have to worry, but I am trying to straighten out all the different bits of information in my head and make better sense of it. There is alot to learn when doing this type of work. ;)

 

-Alex