taman86

iTrader: (19)

as of right now i am running stock rockers with the trunnion upgrade on PRC .650" double springs with a FMS F13 cam and stock length pushrods and stock lifters, stock heads, 96mm big *** intake. would going to roller rockers be beneficial and pro's and con's of stock or RR. what brand would be recommended for my set up. im considering going with roller rockers but not sure if i would have any gain. also i wanna have a setup that i can throw better parts at and be able to take i.e. nitrous, p&p heads, larger cam. also i want a very stable high rpm valvetrain, so in the future i would be using light weight valves instead of traditional Stainless steel valves which are pretty heavy. also what does adj. rockers mean exactly and when does 1.8 or 1.7 need to be considered? thanx

kris

vettenuts

iTrader: (4)

I found that as I swapped out cams (have had two) I could not get a good narrow wipe pattern from stock rockers despite spending quite a bit of time trying. I also found the same thing with Crane stud mounted fully adjustable rockers, i.e., the wipe pattern was wide. I then went to Yella Terra's and found I could get a centered wipe pattern that was only 0.045" wide. These are what I am now running.

I wouldn't expect any gain from rockers (maybe 5 hp) but rather would consider whether there is a benefit to the geometry and setup. If you decide to go aftermarket, I think the Yella Terra are a better design then Harland Sharp with larger trunnion shafts and bearings.

taman86

iTrader: (19)

you're right there and that was what i was asking. would roller rockers be beneficial to help with my future setup of wanting a stable high rpm valvetrain and therefor would need a good valvetrain geometry. that is interesting though about the sotck rockers and not being able to have a narrow wipe pattern.
are you using the light weight yt's?
also what does "adj" rockers mean exactly?

taman86

iTrader: (19)

oh also, when would using 1.8 ration rockers not be recommended?

Exidous

iTrader: (11)

Going to a 1.8 will increase your lift by a fair amount. IE a .588 becomes .623 with a 1.8 rocker vs a 1.7 rocker. PTV clearance may become an issue dependent on many factors like valve size and head milling/design.

The wide wipe pattern of the stock rockers is probably due to the way it makes contact with the valve. If you were to make the curve of the stock rocker a full circle it could be the size of a quarter or bigger. The roller rockers use bearings the size of a pea and therefore have a MUCH smaller contact patch. It's all about having it as centered as possible.

I am giving the scorpion 1.7 rockers a try next week along with a slightly longer push rod to quiet down the valve train a bit. I'll try to let you know how it goes. The TSP 228r cam that I am using has a smaller base circle than the stock cam and is giving me .05" exh and .06" int preload on stock LS1 lifters with a 7.4" push rod. Has a lot of sewing machine goin on. :-) Going to give 7.425" a try to get it to .075" and .085" respectively.

The stock rockers with trunion upgrade are a great setup btw for the price. The can handle 7k fine from my own experience on the dyno and from what I have read. They cannot be beat for the price.

vettenuts

iTrader: (4)

I wouldn't use 1.8's with the F13 you are running. I am running the lightweight YT's on my car. As for adjustable, the Cranes and some others don't bolt in like stock rockers, they float on the valve stem and pushrod and the amount that the nut on the rocker shaft is tightened determines the lifter preload and the wipe pattern. Other adjustable rockers like Yella Terra or Jesel have the adjustment nut at the pushrod cup but again you can precisely set the lifter preload.

taman86

iTrader: (19)

i see, so pretty much if you have a barrel adjusting nut that mounts the rockers to the studs then it effectively does the same thing instead of the adjusting nut being where the pushrod cup is, is that what im getting there.

i know they are a great upgrade for a decent street/strip car, the problem that im running into is that if they will be good enough to make a stable high rpm valvetrain and have good geometry and if it would be beneficial to upgrade to roller rockers with the weight savings that comes with a good rocker set up along with the proven stability also.

taman86

iTrader: (19)

m not trying to say that i want my car to be a dedicated track machine, i just want to be able to have a very stable valvetrain when i decide to wind the tach up to 6500 or 7k without running into any long term damages cuz quite frankly, if you're running a heavy valve and you run the tach over 6k on a frequent basis, then you're gunna be needing a valve job on your heads alot sooner then if you're running a lighter valve, hence the ls6 or ls7 sodium filled valves.
so my goal is to have a very well put together valvetrain and to make it as light as possible, as strong as possible, and as stable and smooth as possible with a little give and take of course also with a budget friendly price tag. i mean i know as well as anybody else that jesel makes the best rocker setup hands down, but i really dont feel like dropping a grand on a set, to me that seems a bit over kill for a street/track car, if it was an all out race car then that would be a whole different story. kinda got a lil off topic from rockers to valves there but just giving an example.
if anyone thinks my mind set is wrong then plz give me some advise, but from i can see i believe im on the right track.

69LT1Bird

iTrader: (1)

For your goals stock rockers would be fine or have the trunnion upgrade done to them if it makes you feel safer. There are MILLIONS of stock rockers on cars that rev over 6000 RPM's so that shouldn't be an issue.

slt200mph

iTrader: (42)

I've been running stock rockers for over 216,000 miles now with no problems...when I had a more agressive cam in the engine saw 7000 RPMs countless times in its life time..now I have a milder cam that I shift at 6500 RPMs..never have had any problems with valve train stability..it is a daily driver heads/cam all the bolt ons making 452/418 ...with the pinion upgrade your are running the most reliable rockers on the market...check around and you will see that YT and Scorpion have had some reliability issues...if you are going to have a all out race car you might want a aftermarket roller rocker (like T&D or Jessel)..but for a street car do not waste your money...

soundengineer

iTrader: (16)

you have to remember somethiing... its not necessarily about having less weight over the valve... its about having even geometry between the valve and the pushrod..
meaning if your rocker is not a 50/50 balance... it creates more stress somewhere
the ideal situation is to have a rocker that is perfectly balanced over the tip and the tail so that it takes less work to move it back and forth.
this combined with a nice centered wipe pattern = good geometry.
in general... the more money you spend on a set of rockers, the better it's design...
Nascar uses Jessel rockers...but not just the same ones we can get for our street cars...
they use a specially designed version that is perfectly balanced and has a small and accurate wipe pattern...unfortunately one set of 4 cylinders is worth about $3000...

this is part of teh reason they can spin the engine to 9800 rpm race after race with no problems

djfury05

iTrader: (30)

OP if you've done any research at all on this topic before making a thread your either ignorant or just an idiot.. the stock rockers with the trunion upgrade is the best you can get.. end of story.

aftermarket rockers are not any lighter than the stock rockers.. with the yella terra's they are actually thinner and more prone to breaking.. there has been countless threads on whose broke YT's yet people still ask if they are better then stockers... do a search

soundengineer

iTrader: (16)

first off.. take off the horse blinders
secondly, quit being a jackass calling people idiots... there are no stupid questions... just stupid answers like the one you just gave

3rd... just because you like the stock rockers...doesnt mean they are what he needs or wants.
the stock rockers may have a light overall mass... but they arent very balanced...
balance is the key to efficiency...
as a perfect example...
http://coolthingsinrandomplaces.com/?p=78

this thing uses a small small amount of electricity thanks to its near perfect balance...

you get rockers that are balanced, you get a better rocker

YT's have the issues that they are not very well balanced and the reason they break is because they have a lot of mass on one side and less mass on the other...this combined with the material they are made of = a lot of stress = more prone to breakage...
and I've seen stock rockers break too...they are not without flaws.

lubelizard

iTrader: (5)

Looks like you need a beer and some chill time. It's all good, baby.

djfury05

iTrader: (30)

I know I don't know what my deal is today lol I've been pissed at everything.. guess its that time of the month.. I apologize OP

vettenuts

iTrader: (4)

The problems with the Yella Terra was a small production issue that was found and corrected. Yella Terra has been very up front on the issue, how it was found and how it has been corrected. The weight of the Yella Terra has no bearing on the few failures they have had.

The OP should do a thorough search and come to his own conclusions. Then he should try to get an optimized setup with the stock rockers and his cam. If he finds what I did and most don't check, he may start to look elsewhere again.

taman86

iTrader: (19)

to djfury05, man if i had found what i was looking for i wouldnt have made a thread but all of my searches didnt come up with the answers what i was looking for, not specifically for my set up just the pro's and con's of stocks with the tunnion upgrade like i have versus roller rockers you know. and thanks for everyone's advise on this, ive came to my own conclusions.

BIG_MIKE2005

iTrader: (116)

Then please explain why people switch back to stock rockers either with or without the trunion upgrades to stabilize their valvetrain at higher RPM's when they start having issues with these aftermarket rockers? I have seen numerous top engine builders on this site tell people to go back to a stock rocker if their motor is having valvetrain issues with aftermarket rockers.

I'd rather keep my stockers (with trunion upgrade) and reliability then **** away money on aftermarket rockers.

Now if its a race only motor spinning close to 8k RPM's I could see wanting a high end set of rockers, but definetly not the YT's or anything on their same level. At that point you gotta really step it up in the valve train parts. But for 90% of the guys on this sight not even spinning 7k RPM's the stockers are VERY hard to beat performance & realibility wise IMO.

soundengineer

iTrader: (16)

the truth of the matter is.. that most people dont bother with proper setup and double check of their aftermarket rockers... its not just a slap it on and set it crank it down to proper torque values...
you have to check the setup height...shim or shave the pedestal if necessary to get the geometry correct.
most of the reason people say to use the stock rockers comes back to that geometry and install height being correct already. no fuss no mess easy to do.

the big boys dont use "stock" rockers... they use pro rockers with proper install

BIG_MIKE2005

iTrader: (116)

I'd agree with people not double checking things properly causing some of the issues.

But IMO if these aftermarket rockers were designed properly there wouldn't be a need for modifying the pedestals to get the correct geometry & install height.

Guess I'm just one of those guys who doesnt see the sense in spending that extra money on aftermarket rockers for a engine that will never see 7k+ RPM when a stocker with trunion upgrade will do the job just fine & eliminate the potiential geometry issues.

I'm guessing by "big boys" your referring to cars spinning 7k+ RPM easily & high dollar engine assemblies. Which is a far cry different than a street car making like 500hp.