nskyline34

iTrader: (2)

I’m trying to make sure I get ever HP I can out my LS6 and make sure that it will hold up to 7000 rpm well too. I have my OE rockers and a trunion (comp cam) upgrade sitting at home as well as a set of yella terra non adjustable roller rockers. I’m not sure which to run? I’m running PRC .650 double springs, comp cams .080” hardened pushrods and a cam that about 230’s duration and .62X/.61X” lift. I’m wanting to make sure that the valve train is as stable as possible for 7,000 rpm because I’m doing the Mojave mile and it will be at high RPM for a few seconds. I know nothing is bullet proof, just wondering which SHOULD be better? I'm going from stock LS6 retainers (assuming steel) to Ti, so I know this will save approx 15g-ish, so I'm hoping this will offset the weight of the YT rollers?

OE weight – 281 grams per pair
OE nose weight – 11 grams per pair
Yella Terra weight – 168 grams per pair
Yella Terra nose weight – 31 grams per pair (because of steel roller bearing at the nose)

I feel like the lower overall weight of the yella terras are best, but I’m worried about that much more over the nose weight? Thoughts? Or am I being too nit-picky for only 7k rpm?

Again, price is free since I have both. Which would you run and why?

nskyline34

iTrader: (2)

no one?

Burken01

iTrader: (88)

Stock rockers with trunion upgrade has proven itself over and over.

That's my vote

Inflame

iTrader: (2)

I agree. I am going to be taking my LS6 to 7000 RPM this year too for road race use, stock rockers with trunion upgrade.

KCS

iTrader: (20)

Stock rockers w/ the trunion upgrade should be fine.

vettenuts

iTrader: (4)

What kind of guides are in the heads should factor into the decision. Also, you should set the wipe up on the heads with either rocker prior to measuring for pushrods. Finally, I think your pushrods are the bigger issue. The 5/16" pushrods will being flexing at the RPM with those springs and lift. I would upgrade to at least 11/32" OD pushrods. ID doesn't play much in pushrod stiffness.

handyandy496

iTrader: (9)

My car loves 7000 rpm. I have the .105 wall Comp/Trend pr's

nskyline34

iTrader: (2)

For road racing? Like 7,000 rpm all the time for hours? Ok, this makes me feel better. I've seen a couple youtube videos of guys doing it, but wasnt sure if this was normal or what was done to the bottom end.

I'm considering pulling the motor after my April run and throwing in a set of ARP rod bolts, but I know if I do it wont stop there...

nskyline34

iTrader: (2)

So if you guys had a set of free YT roller tips sitting next to your OE with trunion upgrade, you would really put in the OE upgraded ones? I dont understand why? It will cost me zero dollars either way, but more time to upgrade the OE's (press them together)

I will work on grabbing some larger PR's. I agree with you gentlemen. Bought these and now I've changed my mind on the RPM's.

nskyline34

iTrader: (2)

will these work with LS7 lifters? What rockers are you using? also what valve springs?

handyandy496

iTrader: (9)

Aluminum tends to crack and break and the stockers are just as light. Run light valves too. I would check the trunions after every race also.

handyandy496

iTrader: (9)

LS7 lifters are junk. I.m using stock w/trunions and 30-50 preload morels. The wide ones with link bars.
yep I said it. lol

nskyline34

iTrader: (2)

The stock ones are 2x as heavy though? Over the nose they are a little lighter, but when comparing OE with steel retainers vs YT's with Ti retainers they are the same weight over the spring. But the OE's are a little more than 40% heavier? I get what you mean though, the aluminum is very easy to fatigue, especially with a lot of spring load ( I should see a max of about .650 inches X 463lb/inch = 300lbs) and then a lot of RPM and heat. So really good things for me to consider and think about.

I'm half way considering running which ever gives me a better wipe pattern for the event, then this summer upgrading to a set of shaft mounted ones before going back for 200. (might pull the motor and do ARP bolts in the bottom end and then spin 7200-7300 (cam will start to fall off around 7100-7200 or so). BUT that is spending a LOT more money and a LOT of time during the summer with a fun toy torn appart.

I'm only making 3 runs down at the MM:
1. 150mph tech pass - wont even break 6000 rpm
2. 180mph pass in the 1.5 mi
3. Everything it has to try an squeeze in 180 in the 1.5mi

No sense in hurting things. Then once I get home I will pull the valve covers off and inspect things and then over the summer I will definitely play with it and play hard, but not 7,000 rpm hard. haha

"LS7 are junk" I tend to not agree with blanket statements with no facts; but with a good argument and data (FACTS), I'm definitely open to hearing about another view.

For 7,000 rpm I think an LS7 will be plenty fine; then for my 7200-7300 I would agree that the link bar lifters would be better yes, but I havent heard of any major COMMON failures caused by an LS7 lifter in the due to turning 7000-7500 rpm regularly. I HAVE heard of people using an LS7 lifter for that 7k-7.5k rpm range a lot though with zero issues.

(mind you this isnt a 'set it and forget it' deal. This is have a summer of fun, which for me averages 2,000 miles, then pull things apart in the winter and replace things if warn even a little)

handyandy496

iTrader: (9)

Gm won't even put ls7 lifters in a ls7 vette lol. Look into it! There oil slots move out of the oil gallery with high lift cams so you can run em not me. Can u say tap tap yap.lol. The ls7 lifters have to use a .050 longer pushrod. That's less ridgity and a .090 preload. No thanks.
For over 7000rpm endurance racing I would be running solids but that's $$$$.

Darth_V8r

iTrader: (4)

+1 on the thicker pushrods. Your 5/16" pushrods probably have 080 wall thickness. The 11/32 mantons run 125 wall thickness.

If you have stock valve guides, use the stock rockers. If you have aftermarket guides, the YT will be better for preventing scrubbing. If the stamp on the YT is centered don't use them. If it is offset, they are ok.

On the lifters, you can get more power with shorter travel lifters. Best would be LLSR. If you want hydraulic, then Johnson short travel with link bar and axle oiling. Not saying anything about LS7 lifters. But your OP said you wanted every pony you could get.

With the valve train you want heavy on the back side and light on the valve side. Don't worry about the extra lifter and pushrod weight. Do worry about lighter valves - particularly the intake.

nskyline34

iTrader: (2)

THIS is what I was wanting. I agree with the pushrods. I bought them new, but second hand so I can easily get my money back out of them. (not that they were spendy to begin with)

The heads are getting aftermarket guides in them yes. (PRC stage 2.5)

What do you mean about the stamp being centered? Can you elaborate please? What is bad about centered ones? (Just trying to learn in general)

I'm assuming that the shorter travel lifter is better because less of the lobe gets 'soaked up' by the hydraulic lifter, and transfers it to the valve better acting more like a solid lifter right? (and I do NOT want solid lifters - I will gladly give up power and/or RPM for this). And yes, my original post said I want to get what I realistically can, but I'm not spending a kings ransom on this. Moto season is going to be starting up soon so I cannot be broke! lol

I will look into the valves (comparing weights on my scale). I agree/understand about the weight on the back side vs over the valve/front side of the rocker fulcrum. This is why I was having an internal battle because of the over-the-nose weight. BUT there is a lot to be said about the moment of inertia too which the YT's have.

Thanks for your input and please help educate me more on my questions above. I will look into what you just said in the mean time.

nskyline34

iTrader: (2)

I am wondering about the smaller diameter oil passage in the manton pushrods - the comp cams 7955's I have have a 0.1525" hole for oil. The mantons have 0.104" hole. This is a reduction in cross sectional area of about a 50%. Running a stock LS6 oil pump (NOT ported or anything) I feel like I could starve the topend?

What about these pushrods:

http://www.texas-speed.com/p-285-com...-pushrods.aspx
https://www.texas-speed.com/p-637-te...ds-single.aspx

Larger outter diameter, but keep the oiling.

nskyline34

iTrader: (2)

Yea, not spending $1,000 on lifters. lol

Will the LS7 ones work/hold up well for the occasional flogging or should I go to a more entry level link bar lifter? ($400-$500 range) ?

Inflame

iTrader: (2)

When I get the rest of the supporting mods (springs and 11/32 push rods), i'll be going to 7000 RPM 1-2 times lap in 10-12 laps for 5-6 sessions for 2 days.

So about 100-200 7000rpm shifts a weekend.

But, I only have the ARP rod bolts and hardened 5/16 push rods on LS6 valve springs for now... So I'll only be hitting 7000RPM if I really need it to make a pass. Once I get the supporting mods it'll be a regular thing.

nskyline34

iTrader: (2)

Thanks for the reply. I really worry about the tiny oiling hole in the 11/32" PRs. I like the idea of the .105" comp cams ones more since the hole is the same size, but they wont be quite as rigid as the 11/32".

When you did your rod bolts, did you do them one bolt at a time and just replace them with pistons and rods still in the motor, or did you pull it all apart and do them with a rebuild? Doing mine in summer and cannot decide how I want to. (car only has 18k miles on it). I'm thinking about pulling the motor, popping off the pan and just replacing them 1 rod at a time, retorque and go to the next one.