pauls99z28

iTrader: (32)

Ive read several post about lifters and to avoid valve loft.. Im coming close to doing my H/C/I and want to make sure i cover all my areas so i wouldnt be wasting Hard earned money on avoidable damages. I have BTR SLR lifters that i switched over the LS7 lifters and am now wondering if i should spend the extra $300+ to go Morels 5206's. Im probably just getting a little paranoid but damn alot of money is on the line here.

*So, what is valve lofting?? what do i need to do to avoid it?? *

Thanks for the Help.

96capricemgr

iTrader: (1)

lofting is the lifter being thrown off the nose of the cam lobe. It is done on purpose in some cases specifically lift restricted classes.
You avoid it by letting a truly good vendor help spec your valvetrain. I am not saying popular or this weeks favorite I am saying find someone good and trust them.

pauls99z28

iTrader: (32)

Thanks 96capricemgr!

JakeFusion

iTrader: (7)

Agreed. Or talk to several. You'll get a pretty good sense of what's needed.

With that said - here is how you should approach the valvetrain, from both the lifter side of the rocker, and the valve side.

Lifter side. You need a cam with controllable endurance type lobes (mild off the seat, controlled ramp, etc) as that's the single biggest issue with valve loft. Good lifters need to be able to handle the pressure of the springs and the ramp rates of the cam. I'd even say get those with link bars to avoid any issues with the trays. Weight on this side of the rocker arm isn't hurting you. So go with the link bars and the biggest, stoutest pushrods you can fit. Pushrod flex can launch a lifter off a lobe as well.

On the valve side. You need just enough valve spring pressure to control the system. You don't want excessive amounts as that can wear down lifters and rocker arms over time. A way to match that is to go with less agressive cam lobes and much lighter valves. On this side of the rocker arm, weight is critical. So opt for hollow-stem valves or smaller valves in the heads to save weight. Also Beehive springs are worth it if you can control the valve with them. The newer beehives are pretty good with upto 160lbs seat pressure and upwards of 400-420# open. They weigh little and have good harmonics. The lighter the valve and the less aggressive the lobe, the easier it is to run that.

Lastly is the rocker itself. Go for the strongest and lightest rocker (it has to do what both sides of the valvetrain have to be) The stock GM rockers are just that - they are strong and light over the valve.

pauls99z28

iTrader: (32)

Thanks for the post JakeFusion!
I have a better understanding now.
I should've asked that question before i bought my parts.
Well here is my valvetrain parts that i already have so hopefully it works out..

-Tickperformance SNS torquemax3 LS2 version(Martin recommends the BTR springkit for these cams)
-AI 226 Heads with AI installed BTR Double Spring kit .660"lift
-BTR SLR lifters But might switch to Morel 5290 or 5206's for peace of mind..lol.
-Pushrods not yet purchased till i measure length. (any recommendations on brand and max thickness for stock bore pushrod holes would help)
-Stock rockers w/upgraded comp trunions.

I will be starting a new thread on my build once i get all the parts in.
Again thanks for anymore feedback!

pauls99z28

iTrader: (32)

I would like to add that nothing is set in stone yet till i start tear down. I can always return/resale buy new parts. SO if anyone thinks i should change anything out from my valvetrain partslist feel free to chime in..
Thanks

JakeFusion

iTrader: (7)

BTR springs are fine. I have custom TFS/PAC Dual Springs on my heads with Ti retainers. BTR use a very lightweight Ti retainer too. Again, weight being the enemy on the valve side.

The BTR lifters are probably fine - just no one has run them.

The Tick cam has good lobes, so it shouldn't beat the **** out of the valvetrain.

Ai will sell you the same pushrods I have - Manton 11/32" - they will fit the stock LS6 heads. They are not as stout as 3/8" but they are better than the 5/16" most go with.

pauls99z28

iTrader: (32)

Thanks Again JakeFusion!
I just finished reading up on the 11/32 pushrods and thats definitely the route im gonna take.. There is always something to learn