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Hiya,
Now, I been told once that the stock Chevy stamped 1.5 rocker arms are quite adequate for the average hot rodder. However, I noticed that theres quite a few engine rebuilders here and I could surely get a wealth of info before I take my puny penury to purchase the pukes.
Are they worth it? And what about the fulcrum placement? Would it behoove me to get say, 1.75 to get more lift out of the valves? And are the rollers an enhancement or am I just spinning my wheels?
Depends on cam specs you will be running as to the ratio.... We used to run a bigger ratio on the exhaust valves, trying to scange a bit... No idea if it ever helped or not.... Now about all I run is stock ratio, guess I prefer the good ones from Comp Cams, they're moly.... a bit more expensive but we're racing with them. For the average street usage type engine most guys just run the aluminums. Lots of folks are running the Harland Sharp aluminum rockers and even some of the import rockers and seem to do just fine with them!!!
A consideration, if a rocker breaks, then a lifter can pop out of the lifter bore and there goes your oil pressure...... guess I wouldn't be real confident just settling for the cheapest rocker arms!!!!!
When dealing with the venerable SB Chevy, a good street performance engine can be built with mostly stock parts. Unless you're looking for a high winder, the stock stamped rockers are ok for engines that will peak around 6000 RPM with a hydraulic or mild solid cam.
Beyond that, you can get fancy.
If this is your first shot at a hi-perf build, KISS..keep it simple and safe.
With the SB a little can go a long way.:D
Thanks!
Been running the stock rockers for a while. I may try the exhaust lift but I may just get another cam that'll do the trick.
I really gotta pull the heads an see just what they are. I had em rebuilt but curiouity is now getting the better of me. It might just behoove me to find some decent heads an headers.
Gezzer, your right about keeping is simple an safe, So far the engine's been fine. I guess i'm just wanting to expand it's boundries a bit. See if I can get a few more outa it.
Well, if i'm gonna fit roller rockers i'm definately going for the moly ones. Alluminum scares me. So does the chance of loosing lifters. So far i've tried to make this engine bullet proof, Anyone know what i'm looking at in price?
Ohh, speaking of lifters, what about anti pump up ones? My engine can reach 6000 rpm and probably beyond. However, i'd hate to waste good cash that I could use for parts that will count.
Hey, Geezer! Did you hot rod that caddy? Looks good from here.
Thanks DennyW,
That kinda scares me too them varying ratios. For all I know I coulda got them rockers from anything.
Sooo, should I get 1.5s anyway? just to be sure.
Yeah, I know about all the trouble with big bumpsticks. I never went wild myself but seen lots of guys do it.
I did put in beefier springs but still got the stock everything else.
Yeah,
Only thing that gets me is once in a while I seem to get lifter noise. And I even changed lifters n cam too.
Wonder if it's just lousy lifters or too much spring?
Are you sure they are properly adjusted?Quote:
Originally Posted by Good Wrench
I would appreciate hearing from some of you about the sturdiness of the Speedway roller tipped rockers since I have installed them but not started the engine yet. For this discussion compare tests 55 and 56 of Ryans dyno runs. What this means is that if the cam is small it helps to have more lift on the exhaust but as further tests show with a longer duration cam the cam takes care of the needed scavaging. The Speedway roller tipped rockers are available in both 1.5 and 1.6 ratios. I bought two sets with initial setup using the 1.6 rockers and maybe backing off to 1.5 on the intakes for better mpg. Does anybody have any bad experience with the Speedway roller tipped rockers? Note that the stock rockers "scuff" the valve tip and this raises oil temperature while any roller tip rocker will encounter less friction so the engine should run a little cooler.
http://www.ryanscarpage.50megs.com/combos8.html
Don Shillady
Retired Scientist/teen rodder
If stock rockers scuff the valve stem tip, they do it because the geometry is wrong. You should be able to put a very thin piece of paper between the rocker and valve, turn the motor over and not tear the paper. It will compress the paper, but should not tear it. I learned this by talking with Racer Brown, cam grinder extraordinaire. The rocker tip is designed to "roll" over the valve tip in much the same way as the cam lobe is designed to "roll" across the bottom of a flat tappet while the tappet rotates.
I've run crane gold and race kinetics cheapy aluminum. My latest are mo better than those and are made by Crower. Forged Stainless Steel with over sized bearings ...........
Kitz
That is one beautiful piece of machinery....:DQuote:
Originally Posted by kitz
Hiya,
Yes, lifters were adjusted properly, I usta do a lot of Chevys in college and all ran just fine.
Oil pressure is 60 to 80 at start up and sinks to 45-50 warm.
But 2x I got a lifter noisy after a few grand on the odometer.
Tech1, the roll-but-not-scuff concept is probably the intention of the design and the paper test is neat. I wonder if any tests have been run on any possible oil temperature reduction with the roller rockers or is that just a rumor? I have checked with hand cranking that the pushrods easily clear the holes in the head with the 1.6 ratio rockers but maybe the rollers are needed for 1.6 and higher ratios like the 1.7 shown above and the pushrod holes ovaled for the 1.7 ratio? Again I ask whether anyone here knows of failure of the Speedway roller rockers?
Don Shillady
Retired Scientist/teen rodder
Speedways aren't the highest quality, but you get what you pay for.... I'd say they're about the same as all the others in that same price range....No better, no worse.
They are nice but more than a little "over-kill " for 90 % of the people on here.Quote:
Originally Posted by kitz
Thanks Dave. Kitz, did you have to open up the pushrod holes with the 1.7 ratio rockers?
Don Shillady
Retired Scientist/teen rodder
Oh sure!!!! Next you'll be telling me I don't need rev kits and stud girdles!!!!!!:LOL: :LOL: :LOL:Quote:
Originally Posted by erik erikson
Interesting, I never thought about checking that. BBC standard ratio is 1.7 and I have not seen or read anything that says it is required?Quote:
Originally Posted by Don Shillady
Kitz
anybody know if erson still makes their roller rockers? pops bought these things back in about 94-96 and they still work great, no hints of needles going bad or anything. i love these things. id like to get another set of them.
very funny denny, but seriosly i am very impressed with them. they ahve lasted all these years without a hitch!
Kitz, Sorry, I did not realize you have a BBC. The 1.7 is standard there but would be very large for a SBC and for a SBC the 1.6 ratio is near scraping the sides of the pushrod holes but on mine there is cleanance.
Don Shillady
Retired Scientist/teen rodder
Sooo,
1.5s for me unless I wanna re angle the valves?
Rats.
Well I hope you are running those if you have a mech. roller cam.Quote:
Originally Posted by Dave Severson
Still scratching my head over the benifit of roller rockers. I done all the obvious upgrades now, Headers, exhaust, ect and still want more zip, It seems as rockers do "roll" over the valvestem so rollers may be redundant, I took the car to my local speed shop and the guy says that all I can really do is change the gear ratio in the rear end, (which is still stock) I have a tuned Holly 625 cfm I can use and it does speed things up but it uses a lot of fuel too. I guess i'm trying now to improve the performance without any more fuel usage. I can change the ring and pinion if I have to but it would bring the same result as the Holly.
I guess what i'm asking is if it's worth the expense for a good set of rockers?
Yes its worth the expense----IF your other mods are other than the range of stock specs that chev designed the engine in 1955---IF you are running more lift or duration you will push or pass the limits of the stock rocker system and will be handicapping the performance gains of any cam or head changes. Also to consider---the effects and costs of ratio changes---you can get more valve lift with a higher ratio but on stock heads the pushrod may rub the hole requiring a mod to the heads and the addition of screw in studs and guide plates