SMURFN' Z28

iTrader: (2)

While the camaro is down for the winter i decided to fix a few things. Installing viton valve seals is high on the list. As long as I am doing this, I planed on using some 1.6 ratio rockers. I opted out of getting a cam because i dont want to use things that can't transfer over to a 350 and the cam in the 85' TPI was not too increadibly bad. Seeing as the car is an 85' that means i use non self-aligning rockers correct? I think my stock pushrods and springs should be fine (only 50k on the car) I was just torn on weather I should get full roller harland sharp 1.6rr or comp magnum 1.6 roller tips and save some money. this car is NOT daily driven if that has anything to do with it.

1991 RS 305

https://www.thirdgen.org/techbb2/sho...hreadid=267459

SMURFN' Z28

iTrader: (2)

ya, i saw your thread. i am not questioning that 1.6 rockers will help. I am wondering if it is worth it to poney up the extra cash for a full roller rocker.

IrocZS383

I believe that the harland sharp rockers are aluminium, in the long run these will fatigue and wear out. The biggest gain from going to a roller rocker is the fulcrum not the roller tip, most of the time the roller tip will slide on top of the valve just as a non roller tip rocker will. If it was me I would go with the comp cams pro magnums, they are rebuildable and have a lifetime guarantee I believe. They essentially last forever, lol.

SMURFN' Z28

iTrader: (2)

will those fit under my stock valve covers with no problem?

IrocZS383

that part i am not sure of, i am going to try and use them under my stock valve covers when i get them, but that won't be for another month, you could try doing a search on here, there are several members who are using them. another plus to them is that they are as lightweight to the valve as an aluminium rocker.

SMURFN' Z28

iTrader: (2)

the ultimate question has to do with the dollar to horse power ratio. Is it worth it power wise to spend over 100$ more than the roller tip comp magnums (i don't think these will break either) or would they be no good on a possible built 355 sometime in the future.

TPI-Formula350-

the Roller Rockers will fit under a stock valve cover. You will have to remove afew pieces of sheet metal bracing from inside the valve cover. There just spot welded on and u can bang them out in just afew mins...

406TPI

iTrader: (1)

Roller tips are a waste of money, either go full rollers or save your money for something else. Your 85 does not have self-align rockers FYI. If you go with full rollers, you should also get hardend pushrods and use guide plates too

Dr.NickRiviera

I'll jump in and ask a question too. If I go 1.6 rockers and an LT-1 cam, will the valve springs from an L98(rebuilt so new springs) work, or would i need something like Z28 springs?

SMURFN' Z28

iTrader: (2)

1. Why are they a waste of money? they are proven to be a good perfomance booster.

2. Don't my heads come from the factory with hardened pushrods and sufficiant guides? I may be mistaken but thats what I thought.

I am not trying to be stuborn here and i have not made my mind up yet on what I want to get, I am just looking for some REAL reasons why it is worth it for me to spend over 100 dollars more on rockers. I guess the only thing that would "proove it" to me would be time slips or dyno runs showing me a significant gain on full rollers over roller tips under 6000 rpms. The only other thing that would convince me would be if roller tips would wear out my valve train. (I find that hard to swallow tho based on the fact that Stock stampted rocker motors can last a very long time.)

Guest

Any 2 parts that only slide and dont rotate will wear, eventually producing a flat surface if in fact the round roller part doesnt actually turn. I haven't looked, but I've never heard of it happening. I also have 14k miles on mine, and they undoubtedly rotate during use just fine.

FYI some other examples of 'useless' parts using the same logic that there's no rotation going on are any sort of needle bearing... like ones used in full roller rocker arms, roller lifters, etc.

hot68

Pretty much covers it

406TPI

iTrader: (1)

#1...No...if there was a performance difference, it would be very negligible.....the main source of friction in a rocker is the fulcrum which also generates heat...sometimes lots of heat on ball-fulcrum units. Now, if you are talking about going from 1.5 to 1.6 rockers, yes there is a performance advantage, just do the math.

#2...No again, sorry You don't have to use hardend pushrods and guidelplates, but I would on those heads. The choice is yours.

It's really not a tough choice man, if you don't want to spend the extra cash, don't. I was just saying don't waste your money on roller tip only rockers....just use stamped non rollers and save your money for something else.

SMURFN' Z28

iTrader: (2)

I just find it funny how I see so many people can claim their opinion as fact. There are a heck of a lot of posts on here with people claiming to get decent gains from comp magnum 1.6 rocker, but there is also an abundance of people that say that they are worthless. needless to say these people never seem to have ever used them. I just dont see how increasing the rocker ratio and at the same time gaining consistancy by using precision enginered rockers from comp that are far far superior to the stamped crap from the factory can be "worthless" Is this the same kind of "worthless" as modifying a TPI or using iron heads ? Basically, by saying that the comp magnum roller tips are no good, you are claiming that all the power to be gained from rockers lies in the reduction of friction and not the increas in lift. I understand the concept but doesnt anybody have REAL PROOF?!!

That being said, one thing i do know is i will invest in some 30$ hardened push rods from summit seeing as i dont have harded push rods.

I am sorry for being like this, but i am a scientist and i like to SEE real proof. So if you want me to shut up, lets see some.

Guest

Only go with a hardened pushrod if you are using guideplates made for them, otherwise just stick with normal pushrods. The hardened ones will not be nice to the heads on the car.

IrocZS383

the comp magnum rockers with the roller tip are not a complete waste of money because as was stated earlier it is a more precision piece than the factory and you are increasing the ratio, but the real source of friction is the fulcrum not the tip, the roller tip will rotate but it doesn't produce that big of a gain.

CC89Formula

yes they would work if the LT1 cam is stock however, they are basically the same cam so there really isnt much of an advantage to going with an LT1 cam

SMURFN' Z28

iTrader: (2)

I think everyone knows that... what I am asking is:

How much power is to be gained by reducing friction with Roller rockers?

It would seem to me that the power gained from the reduction of friction through roller rockers in a street motor would be neglagible compared to the power gained from a solid increase in lift. I look at it this way... how much more power does a roller cammed LB9 with a T-5 (similar cam to mine) make than my non-roller non-peanut cammed LB9? Not all that much.

hot68

Its your money...a ratio change can net some performance gain and they are are not a bad piece but the roller tip does nothing performance wise. (except maybe in the trade rags) As stated before save you money for something better if your after performance. JMO

D's89IROCZ

If all you are worried about is a strength problem. The Magnum roller tips are 85 percent stronger than a stock stamped unit . That was enought for me to buy them . I found this test done to them in a book called "Building Chevy smallblocks on a budget"by David Visard. He was impressed with them. There is a good article on rockers , ratio's , materials , etc . Just look at the two designs ....on is needle bearings ...the other is a pivot ball. Useing logic one says one is better ....only you can say if it's worth it . The regular magnums have nothnig wrong with them ...and take a fair mount of abuse ...... the others will take more ....how much do you need ?


Hope it helps a little . But there are some books you can get that have some real testing in it ( if thats what you need to see for convincing )

406TPI

iTrader: (1)

Why don't you just spend your money and do some dyno testing, seems that's the only thing that will convince you that what I and others said is true. I don't understand why you have to come on here and bust people's chops for trying to help you out when you asked for it in the first place. You have a long hard learing curve ahead of you if you approach every aspect in this manner. BTW, I have used them(rockers) all in the past too.

"I look at it this way... how much more power does a roller cammed LB9 with a T-5 (similar cam to mine) make than my non-roller non-peanut cammed LB9? Not all that much."

Two completely different animals. If you understood the function of a roller cam you would understand it's benifits more clearly. It's not ALL about peak lift and duration numbers.

doc

WOWWWW, this post has gotten alot of attention.

Sorry, I am too tired (sp) to read all of this, but I would go with the full rockers which are the Pro Magnum 1.6 rockers from Comp Cams, their on-line cataog pg 311.

I have had both the Magnum (roller tip only) and now the Pro Magnums. The Pro-Magnums are much better.

SMURFN' Z28

iTrader: (2)

ug... we are arguing for no reason! I never denied that the pro mags were better. I KNOW THEY ARE! All i was saying is spending over 100 dollars more to yeild maybe 5 more hp than the regular mags on my 305 TPI is not flippin worth it!!! good day sirs

robsgta

Welllll I have seen several stock tpi 350's including my car gain around 22 to 26 dyno horse power from using fully roller roller rockers. I have seen a 91 305 tpi z28 convertible gain 18 horse power from using them @ 4800 rpm. I am using cranes gold self aligning they also make them non self aligning they also did cost 300 dollars that do fit under our valve covers the same ones work on lt1's center bolt valve covers.
I did read an article a few years back where an engine builder dismantled a bran new GM motor and checked the cam and vale train for accuracy and the stock rocker arms were poorly maid with tolerances + or minus .020.
If spending money is an issue just upgrading to newer after market pieces would be good and Manufacturer specs would be met. (unlike gm's)
All small block chevys respond well to higher lift I would go with 1.6's if were you and hardened rods & guide plates if you have guide plates then just get the rods . If they are not hardened they will gall really bad against your guide plates .

Money is power

contactpatch

How much power is -->Really<-- lost at the fulcrum?
{of non-roller fulcrums}
.
Keep in mind that total friction horsepower is
on the order of 50 HP at high rpm, for the whole engine.

1991 RS 305

SMURFINZ28 quote...."All i was saying is spending over 100 dollars more to yeild maybe 5 more hp than the regular mags on my 305 TPI is not flippin worth it!!! good day sirs"....................


.......OK!.......Only you can determine that for yourself! David Vizards has tested this exact sort of thing in books. He loves the Comp Roller Tips in street-daily driven type applications, especially since these engines rarely see anything above 5K. Theyre a great bang / buck. If you feel your stock LB9 TPI kicks out enough RPM to justify full rollers, then go for it! Mine is stock-ish, with all the same tweaks everyone else does to TPI's, and I don't feel they're worth it. The additional $100+ plus possible valve cover clearence issues were'nt worth the small gain to me. ......yet, some guys on this thread think they are, and love them. Personal prefrence! Just like some guys hate / love Flowmaster, etc. Either roller tip / full roller, in a increased, accurate ratio, will yield a improvement.