Bowtie316

iTrader: (1)

I have done some searching and have not found much information. What I am looking for, and would like to start a conversation about, is how much lift, with what lobe profile, and what spring can I install and expect to last 100k miles without breakage or maintenance?

For instance, will an ls6 cam, with ls6 springs and hardened pushrods last 100K?

What about a cam with XE lobes, with .575 lift and 918 springs?

What about XE-R or XFI lobes at .600 lift and 918 springs?

What is the most I can get away with?

At what point is a trunion upgrade needed?

outkast6991

iTrader: (34)

Anything other than stock is going to need checked/replaced. A softer lobe with a good spring may go a ways but 100k is asking a lot

redtan

iTrader: (5)

While a cam with mild lobes and good engine maintenance might last close to 100k, the springs will certainly not. Even with mid .500s lift, aftermarket springs will not last more than 30k.

JakeFusion

iTrader: (7)

LS6 cam and springs will last 100k miles because they are from a production engine designed to last 100k miles.

You might get 30-50k miles out of an aftermarket spring with an aftermarket, mild lobe.

Alvin@PCMofNC

Check out comps LXL lobes. I like them better than XER's. In fact with all the horror stories of LSK lobes I still have yet to have a broken valve spring with them. Can't say the same with XER's.

JakeFusion

iTrader: (7)

I would agree the LXL lobes are a bit better than XE-R or LSK. Great for exhaust lobes. I doubt you could get anywhere close to 100k with a set of springs with them, but they'd be good for 20-40k miles.

Bowtie316

iTrader: (1)

Well this is interesting. I would have assumed that if ls6 cam and springs could last that long, I could go a little more lift with aftermarket springs.

While truthfully I will never try to go 100K on a set of springs (I can't leave anything alone that long), I kindof wanted to use that as a target so i would end up with a reliable valvetrain.

So it sounds like if I wanted to use a cam with LXL lobes and .575 lift, I would probably be okay as long as I replaced the springs at about 30K?

JakeFusion

iTrader: (7)

It comes down to lobe aggressiveness. LS6 lobes are very mild. Aftermarket cams come with much more aggressive lobes, which is why they make more power. Those aggressive lobes need to be controlled and the entire valvetrain needs to work as a system. Lift has little to do with how aggressive a lobe is. You can have high lift, lazy lobes. LXL has higher lift than XE-R, but the XE-R is much more violent.

I've posted this many times, but this is what you need to do to have a reliable valvetrain that will make power:

-Endurance lobes on the camshaft like LXL, HUC, or EPS - you can make power with these, but you don't need to destroy your valvetrain with violent lobes to gain an extra 3-5HP
-Lifters that can withstand added spring pressures and more aggressive camshaft ramp rates (LS7 can work, but I prefer the Morels)
-Pushrods need to be stiff and the 5/16" you see I don't feel are adequate - pushrod flex can cause a lifter to "loft" or literally come off the camshaft and crash back down, damaging the cam and lifter - this happens because the pushrod flexes like a poll vault and launches the lifter - 11/32 or 3/8 would be better
-Rockers need to be lightweight over the valve and strong - stock GM are the best in this regard
-Valve springs need to have enough pressure to control the lobe of the cam, but not so much pressure it wears the valve tips, flexes the pushrods, or collapses the lifters - it's a balance
-Lightweight valves make it easier to spec the other components - trying to control a huge, heavy valve makes everything else work harder

The general rule of thumb is go as light as possible over the valve side (rockers, valve springs, and valves) and as stout as you can pushrod side (pushrods, lifters).

My setup adheres to these principles pretty well. EPS/LXL lobes on the cam, hollow-stem LS3 valves, Morel lifters, 11/32nd pushrods, and stock GM rockers with upgraded trunions.

Bowtie316

iTrader: (1)

Great information and thanks for taking the time to post.

Now on spring maintenance, can you just check the seat pressure with it installed and replace any low spring? or do you replace the set if you find one low, or do you just replace them every so often?

DietCoke

iTrader: (18)

Use a PAC 1518 for longevity, not the far weaker comp spring.

02fbody35th

If your worried about reliability and maintainence. I would go with the gm hot cam. It's lift is .525 which is what a ls6 cam is. And it's lobes are real easy on the valve train. Also it makes great power and an awesome sound. I put down 370/370 with a hot cam and long tubes. It's a great cam!

JakeFusion

iTrader: (7)

I'd pull an intake and exhaust pair off two cylinders and have them tested. If they test within spec, you're good to go. I'd do that around every 10k miles or 1 year. Whichever comes first.

I'd replace every 3 years or 30k miles regardless of how they spec out. Just for peace of mind.

I'd also use a BR oil like Joe Gibbs when swapping everything in to give the lifters and cam a good coating of ZDDP. I'd also run Valvoline VR1 10W30 to protect the components from catastrophic failure. Newer oils are designed for emissions, not protecting a high-end valvetrain from imploding. Two things to look for in oil: sheer/cushion and total wear. High levels of ZDDP help with wear, but oil also acts as a shock absorber, and in a valvetrain, this is very important. Valvoline VR1 and Amsoil Z-Rod are two of the absolute best oils on the market for sheer/cushion protection. VR1 over 100k PSI of cushion, Z-Rod around 95k. Mobil 1 that GM recommends? About 65k...

Bowtie316

iTrader: (1)

Definately!

The cam I was going to use has more lift but less duration. It’s a lunatic voodoo 217/223 .549/.549 lsa113, but I started to wonder if I could get away with the EPS truck torque 2 or something similar.


Great information on valvespring maintenance. That is plenty doable if it keeps the motor alive.

I had heard great things about VR1 but I already bought some Rotella T-6. Any idea where that falls on the cushion chart?

JakeFusion

iTrader: (7)

~69k IIRC

It's not a bad break in oil to be honest. The VR1 is $5/qt so it's not terrible. It's not $16 for a jug like Rotella, though. VR1 also must be changed every 3k miles or 6 mos. It has lowered levels of detergents in it. The VR1 NSL has 0 so you can't run it at all on the street.

96capricemgr

iTrader: (1)

while OEM springs and cams last as in don't break at 100K there is usually power to be had in fresh spring long before that due to high rpm float.

Bowtie316

iTrader: (1)

I didn't plan for this thread to end up on oil as it seems many have, but oil has been on my mind.

After researching a little bit on shear properties of oil, I think I may have an explaination as to why my 98 z28 would start to loose oil pressure (10lbs less than normal) at around 5000 miles on a oil change (conventional Valvoline 5w30). I thought it was due to the filter plugging up because I am used to a larger filter. But from reading it appears that the viscosity modifiers had likely broken down and thinned the oil out.

I'm going to use the rotella in my 5.3 mild cam daily driver and keep researching for the correct oil for my 6.0. Thanks for the input.

PREDATOR-Z

Lingenfelter uses good lobes on the GT2-3, check them out.

JakeFusion

iTrader: (7)

Yeah, I didn't mean to take it down that road, but for longevity, oil has to be considered a key component.

GT2-3 uses what look like relatively mild lobes. I know LPE uses it as a supercharger camshaft, so it can't beat on the springs too bad. And it would be a decent little bump over an LS1 camshaft. Looks to be pretty close to an LS6 cam with more lift.

Bowtie316

iTrader: (1)

I have looked at that one before, but it has a 118.5 intake center line, not sure on the LSA, and that kept me from considering it a viable option.

PREDATOR-Z

Contact LPE, talk to them, perhaps they can order custom with that lobe family.