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eat a beaver, save a tree
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672 Posts
Discussion Starter #1
i'm trying to find out some info on hydraulic roller cams.
i have used solid cams for the past 15 years with good success, but i thing a hydraulic roller would do the job better.

if my thinking is correct, the solid flat tappet isn't really needed if the engine isn't going to turn over 6,500 rpm. so a hydraulic roller would work fine or even better with the same duration @.050" lift & similar advertised duration "if" the engine isn't going to spin to the moon. the hydraulic roller would have a more aggressive lobe for faster opening & slower closing than a solid flat tappet cam, more lift, & less friction. the only drawback that i see is the weight of the hydraulic roller lifter & cost. a rev kit would be a must on a hydraulic roller engine turning 6,200-6,500 rpm.

how much horsepower & torque difference would be between the two?
the cam i run now is a lunati solid flat tappet 249-259 @.050" .540-.561 lift with a 106 l/s. i shift at 5,500 rpm with this cam. the hydraulic roller i'm thinking of is a comp cams XR300HR DUR 248-254 LIFT 562-580 lift with a 110 l/s.

i think the hydraulic roller would be a better choice than what i'm running now.
 

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Buick Hybrid Guy.
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255 Posts
Several reasons now days to install a roller cam.
Today's oils have been restricted to not run the additives that kept flat tappet cams alive. 99% of the engines produced today run roller cams/followers ect. So... when we see a flat tappet style cam round the lobes off we assume it's the cam maker... when actually it's the oil that can't keep it lubed enough anymore.
The rollers are more expenicve but in the long run between performance gained and the reliability of the valve train over a long period of time you are money ahead!
Make sure to use the recomened dist. gear for that camshaft. Steel gear won't work very long ;)

I'll try to find that article on oil and additives and post the link.. intersting info.

Keep that lobe sep at 110 or above... with the 106-108 you won't like the brakes/idle/gas mileage... and you can't spray it :( what's the fun in that?
Lol..
~Scott
 

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Buick Hybrid Guy.
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255 Posts
That's a nice article on the cams Grumpy... :thumbup:

If it's more of a street car a hyd. roller would be the best bet. No adjusting through the year.

Your running a 406SBC right? I ran that setup in my 89 Camaro years ago with a regular flat tappet Hyd. cam. (Nitrous Grind) from Crane.
I never ran it above 6000rpm and was running 11.60's on the motor and 10.50's on 150hp No2. It was my summer daily driver back when gas was not even pushing 2.00/gal. Now it'd be stupid to drive it daily. :mad:

Basic build with stock 5.7rod/400 crank/block/ Elderbrock RPM heads/RPM intake 750Vac.carb. 350TH trans/28-3200stall w/9" 3:89 gear.
I've moved on to Turbos and injection now but it sure was alot of fun back then. I still miss the sound of a good running small block :sweat:
Good luck with the decisions...
Scott~
 

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eat a beaver, save a tree
Joined
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672 Posts
Discussion Starter #7
johnsongrass1 said:
A rev kit is never needed BTW.
what is your thinking of this? i've seen several people swear by them.

myself i don't know, that's why i'm asking.
 

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Buick Hybrid Guy.
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255 Posts
I built a 385 for a buddy of mine with a solid roller and a rev kit. He spins it hard so it needed it. I never spin my stuff hard as I think it's too hard on parts.
Maby some one here has more of a technical answer but it's needed once you start running up the RPM's over 6500 to help with valve train stability.
~Scott
 

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1,441 Posts
REv kits are not used by most builders any more. just select the proper valve springs and you are good to go.Asmallblock valve train set up with proper springs , geometry correct, etc. can handle 8000 all day long no problem.
 
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