I'd like to use my original valve covers (stock low profile) on my 406 engine - to make it look as stock as possible and retain the stock linkage and hoses. How much rwhp will I lose by using stamped as opposed to roller rockers? I figure if the stock Z/28 rockers can easily rev to 7000 rpm they should be fine on a 406 that'll peak around 6000. Whatta ya think??? I've also seen stamped rockers with roller tips...are they any better than stamped?

If you used full roller rockers, CompCams Spintron indicates about a 30 horse reduction in lost horsepower over stamped steel with balls.

On my 406 build I used their 1304-16 ProMagnum chromemoly roller rocker arms 1.52"x7/16th stud under my seven rib Z-28/Corvette valve covers, with 4600-16 HiTech Rocker Arm Adjusting Nut w/ polylock 0.3" shorter than standard length.

http://s45.photobucket.com/albums/f63/3454545/?action=view&current=DSC02821.jpg

http://s45.photobucket.com/albums/f63/3454545/?action=view&current=DSC02849.jpg

Larger Dave

If you used full roller rockers, CompCams Spintron indicates about a 30 horse reduction in lost horsepower over stamped steel with balls.

On my 406 build I used their 1304-16 ProMagnum chromemoly roller rocker arms 1.52"x7/16th stud under my seven rib Z-28/Corvette valve covers, with 4600-16 HiTech Rocker Arm Adjusting Nut w/ polylock 0.3" shorter than standard length.

http://s45.photobucket.com/albums/f63/3454545/?action=view&current=DSC02821.jpg

http://s45.photobucket.com/albums/f63/3454545/?action=view&current=DSC02849.jpg

Larger Dave

thats interesting- did you use an extra thick gasket...thanks for the info

30HP? I'm still running stock rockers on my motor... I been thinking of switching them out soon for some rollers... we'll see if it gives any noticable gains.

Yes thick blue Moroso gasket short polylocks. Also frictional horses are a function of RPM the higher they twist the Spintron the more horses it takes to turn it over per unit of time. That 30 horse figure peaked at 7200 RPM; your mileage may vary.

For those who do not know what a Spintron is; it is a reverse Dynamometer. Instead of a engine driving an eddy brake or water brake. They use an electric motor to spin the engine with ignition off and measure how much power is consumed by friction.


Larger Dave

I could swear I've read that power gains with roller rockers are minimal, like 2 to 5?

30 HP is around 10 percent of most "normal" engines, thats WAY to high an estimate you barely get that with a set of good headers over stock manifolds. If you got 2 HP by changing to rollers I'd be surprised.

I agree. I believe most of the power gained from rollers is due to the true ratios. Stock rocker dont give a full 1.5 ratio.

Randy

if we're only talking 3-4 rwhp and it's mostly lost above 5000+ rpm than i'm gonna just use stamped 1.6's with the roller tips and use my stock valve covers......i hate the look of the the tall valve covers

I'd be surprised if you got that much horsepower. Most dyno testing shows less thatn 5 horsepower.

if we're only talking 3-4 rwhp and it's mostly lost above 5000+ rpm than i'm gonna just use stamped 1.6's with the roller tips and use my stock valve covers......i hate the look of the the tall valve covers
I run cheap summit brand stamped roller tip 1.6 rockers, and have been perfectly happy with them. Never tried plain stamped covers, but they clear my repro finned covers (with oil drippers) just fine.

Someone on here a while back run my engine setup on Desktop Dyno. They told me if I changed to roller rockers it showed I would get a 10-15 HP increase.

That's funny because destop dyno doesn't have an input on the type or rockers used. You may have gotten 10 to 15 HP going from 1.5 rockers to 1.6 rockers.

You could use valve covre spacers.

You could use valve covre spacers.

yeah, I know but IMHO I think they look like crap

Out West I am running the Magnum on my AFR heads with the stock Z covers. They seem to clear the oil baffels . No Noise.

I'd like to use my original valve covers (stock low profile) on my 406 engine - to make it look as stock as possible and retain the stock linkage and hoses. How much rwhp will I lose by using stamped as opposed to roller rockers? I figure if the stock Z/28 rockers can easily rev to 7000 rpm they should be fine on a 406 that'll peak around 6000. Whatta ya think??? I've also seen stamped rockers with roller tips...are they any better than stamped?
Comp roller tips are a true 1.52:1 vs. stock stamped. No lateral loading on valve guides. Maybe a good alternative to full rollers. They fit just fine w/stock covers.

I want to say, Elgin and Pioneer both make stamped, roller tipped rockers??

Good value to me. I don't know if both make 1.5 and 1.6 or not tho???

And I like the CC Magnum roller tipped cast rockers b/c they are more accurate than the stock stamped ones.

pdq67

Went back and looked at the CompCams Spintron test and they used 3/8th pushrods and their heavy duty springs so it wasn't just based upon frictional losses of the roller rockers. Instead they found that improvements in the valve geometry, and improved control of deflection both at the push rod and the rocker; it resulted in 30 horse power worth of more air being pumped through the engine during the Spintron test which actually peaked at 9600 RPM with a LS-1 engine.

Similarly Crane Cam's News Letter #124 Mar06 notes claims a 15 RWH gain, which got hem banned from racing (only in NASCAR are improvements to performance routinely banned).

http://cranecams.com/?show=newsLetters&no=224

Yes I agree you would only pick up about two to five horse just in frictional savings with roller rockers, but they do more than just cut friction. I run CompCams stuff on my 406 and Crane Gold on my 582, and I work for neither; it's just my vote of confidence in their products.


Larger Dave

Anything more than 5-8 hp gain from reduced friction for a street engine is marketing hype; the main benefit of roller rockers is reduced valve guide wear, over a LONG period of time.
:beers:

Yeah my engine guy told me to stick with stamped.

Comp has an article where they tried 1.5 stamped, roller tipped and full roller. With no other change the full roller made 11 HP more than stamped. I say if your going to pay $150 or more for roller tipped, then why not go ahead and buy the full roller for the same price? Angus Racing Series rockers are USA made, 100% Billet Alcoa Aluminum (strongest kind), handle .800 lift, and cost $160 to your door. I've got them and they're very impressive. I just figure you should make your money work for you.. if your going to spend $150 on something then you might as well squeeze as much HP out of it.

I've never heard of Angus rockers. Where did you find 'em? I'm afraid I'm gonna have to see some proven durability before I put anything in my engine. Good luck - I hope they work out and help lower the price of some of the other stuff on the market.
PDQ, I'm running 1.6 Elgin roller tipped on my son's 383 build. They're nice and thick, look like they should hold up well. They were less than $75, I figured it would be worth a try at that price. We're also using some Crane "Kool Nuts" that are poly locks made for conventional style rockers. They drip oil directly onto the edge of the ball rather than making it drip down the rocker stud.

First of all, I 'm not "plugging" Angus...I could care less if anyone else uses them..I'm just throwin out some info if anyone cares. Angus is a small company that hasn't had all of the huge marketing $. Small companys aren't always a bad thing. If you were to do a search for angus roller rockers on the web you'll see tons of sites where people are using them. Alot of search "hits" has Angus next to the words Comp, Crane, Scorpion, Crower, Lunati.....can't say the same for Proform, ProComp, CAT, or any other off shore, Chinese, weak junk. Here is a blurb from a dealer...

"These are not the CHEAP IMPORTED inferior rocker arms that have flooded the market. Angus Racing rockers are made right here in the U.S.A., CNC machined from Billet Alcoa Aluminum and one of the most dependable rockers on the market. We'll stand these rockers up against any others out there because it is made to withstand any and all punishment from hard core racing as well as a must for the after market cylinder heads. This Rocker Arm features cut out pockets for larger spring diameters, able to withstand lifts up to .800 as well as open valve pressure over 1000#s. The 8620 heat treated steel trunion along with the oversized roller tip features better rocker to spring clearance as well. The rocker is manufactured and assembled with heat treated pin, nose roller, seat pressed under 5000#s of pressure as well as case hardened needle bearings. The set also comes complete with 16, oxided, steel hardened poly locks.
Manufactured for hard core racing with a wider body style, they will give you all you need for whatever your application is!!

comp pro-Magnums clear under stock gm valve covers.
aren't they roller enogh?