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How muck more lift do you get by switching to 1.6 rockers. I already have a mild cam(have no specs its was already in the engine) headers, wieand intake, 600 edelbrock and msd street fire dist, turbo 400 and 373 posi. I just need alittle more power to get me by til I swap the big block in. not looking to spend a lot of money but my daughter got engaged and I have to pay for a wedding by september it kind slowed up the big block build til next year. thanks, Wes
Example removed, but assuming you don't get any interference, I doubt that you'll really feel any difference, but that's just my seat of the pants opinion.
EXAMPLE: Put 0.505" valve lift into the calc, divide it by 1.5 to get cam lift of 0.3366", multiply cam lift by 1.6 to get new valve lift. In the case of a 0.505" lift at the valve with 1.5 rockers, the new lift at the valve with 1.6 rockers would be 0.539".
I'm not much of a fan of 1.6 rockers. They will add tremendously to the effort placed on the cam lobes and lifters and will probably add only 8-12 hp in my experience, not enough to feel in the seat of your pants. Not worth the effort, seeing as the cam and lifters need all the help they can get. You also have to worry about piston to valve clearance, wiping out the cam by stacking the spring coils solid, breaking rockers, bending pushrods or wiping out the cam if the rocker slot is not wide enough to work properly on the stud. Just not a good idea unless you're fielding a max effort competition motor where everything is measured and coordinated with each other.
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Is this in your C-10 pickup? If so, what do you want to do with it? What's your performance goal?
Ditto what Tech said – the 1.6 rockers have some bad memories for me from a long time ago when I drank the Kool-Aid and slapped a set of really neat gold anodized aluminum 1.6:1 rockers on a rebuild I was doing for a friend. I ended up with a catastrophic failure because I didn’t properly check for coil bind and wound up on the bad side of things with 16 bent push rods and one broken spring that allowed a valve to stay open and destroy a piston – expensive to fix to say the least.
Something that I learned from an old Chevy machinist as a result of my mishap is that the “perfect” ratio on all but a highly modified small block is 1.52:1. He told me that most of the factory stamped rockers vary between 1.45 and 1.50:1 so there’s some opportunity to improve on the rockers without breaking the bank by installing a quality roller tip in a 1.52:1 ratio.
If you feel like you need to replace rockers, Comp Cams (and others) make such a rocker for less than $200 for a set and they’re a true bolt-in, adjust per factory specs and go. They will not give you a seat-of-the-pants boost, but the roller tips will take some heat and stress off your valve train.
Good luck and let us know what you come up with,
Glenn
i would not wast the money as for lift. i have used bigger rocker s when the lobe were as big as what can be put on the cam core and we want more lobe lift 500 and we want 900+ lift . things that can hit ... some have listed and things not added to the list. push rod guid slot in heads or push rods hitting block and head . needing more valve spring . pressed in rocker studs ? pushrod flex .then pushrod hitting rocker body need to check rocker cup and push rod tip if angle starts getting bad i used 210 rocker tips if the rocker cup looks like pushrod side of tip may rim off the push rod cup . like other said you need to know your ok with piston to valve . stud to rocker body slot . valve guid to valve spring retainer . .valve retainer to valve seal . then coil bind that is were the spring stacks up :) as for power do not thing you will see any on the street. there is better made steel stamped rocker arms like stockers but are closer to 1.5 and they sell 1.6 in steel stamp if you still feel the need . i think the biggest wast of money are roller tip rocker arms .but it your money.. going up from 1.5 to 1.6 it easy to work out the math if you know the lobe lift. lets say its 450 its not :) we just use this number. times the rocker arm so 1.5 x450=675 then 1.6x450 =720 then 1.7x 450=765 . some of the stuff i play with is much bigger like 500 lobe X1.7=850 500 lobe x900 lift (: there is many that think there new roller rockers are 1.5 the great thing about rocker arms not many are the same and there no rule that all companys follow as this is not SAE part so on after market rockers . there many come up with different ratio as push rod cup and were it is on the rocker then were stud is in the body size of roller tip size of body i have spent many hours the a dail indicator mounted off the valve retainer reading full sweep on the rocker arms can be a real eye opener
I don't have a concern with my switch to 1.6 rockers. However, it wasn't just a rocker switch. It was an upgrade of my Chevy Fast Burn 385 motor to a ZZ430 clone, which included a matched GM cam, roller rockers and springs. The engine already had roller lifters. It was a set designed for engines similar to mine, and the combination of cam and lifters increased the HP from about 385 to around 430. I would never just switch the rocker ratio without examining the entire engine system.
many of the engines i build that is about the first thing i do. is see what they have for a cam core and were i am going for lift and with what rocker ratios. then work out valve springs and spring setup height and coil bind i had a stroker pontiac were i went to a smaller rocker arm as the heads/ valves just would not take the spring setup i needed to run with 1.6 arms would had to really cut the spring pockets that was not going to happen then a custom set longer valve for the taller spring setup was needed
As I mentioned my daughter got engaged over Christmas and her fiancé is in the military. The wedding date is September and I had planned on building a big block for a spring transplant. I was planning on about a 6k build but the 10k wedding now comes first. I was just trying to get a little more power from the small block with out spending much money. I think at this point I am going to just put in a 2400 stall and call it good. thanks, Wes
A loose convertor and some stiff gears in the rear will make you think you swapped in a bigger motor.Quote:
Originally Posted by 70chevybb
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There is also a 1.3 rocker for SBC. Really should take the stress off the valve train.