Valvetrain advice

Hello, I’ve recently built my first engine (Predator 212 generation 3). It’s been a really fun and educational process, and I’m looking to take the engine to the next level with an upgraded valve train (mainly ratio rockers). I’m looking for advice on what supporting mods will need to be made to the valvetrain to safely handle 1.3 ratio rockers. Also what rockers would you recommend: cheap stamped steel, billet steel, roller tip? (I don’t want to spend too much money)


Engine currently consists of:


Predator 212 generation 3 block and crankshaft


Stock head… for now


Dyno CM camshaft (with 22 pound valve springs)


ARC billet connecting rod +.040”


ARC billet flywheel 6625


Predator Hemi flat-top piston .550 compression height (for 0 deck height)


.027" MLS head gasket


22mm Chinese Mikuni carb kit


Homemade large header (no muffler)




From what I understand it’s not a good idea to run the cheap stamped 1.3 ratio rockers with this cam, Also I assume I would need 26 pound valve springs for this cam and rocker ratio combo? I’ve heard it’s not a great idea to run 26 pound springs with stock valves, retainers, keepers, etc, although I know people do it. So is there a relatively inexpensive way to safely run my desired rockers? The reason I’m interested in this rocker ratio is because I’ve heard that the CM cam with this rocker ratio and a similar sized carb is supposed to be a really good combo. Thanks for any advice.
 
I have built a couple and I don't think you can do a quality valve train on the cheap. I used stainless steel valves and automotive style retainers and keepers. Go Power Sports and OMB warehouse both sell kits with springs
for about $65, including everything you need. Chrome Molly push rods are also
a good idea. They won't make you go faster, they are like the rod and flywheel,
they are so your motor does not self destruct. I only used ratio rockers on one of the three I built. I bought the Gage aluminum roller tipped , EXPENSIVE
$190 and I am not sorry, they are quality stuff. The other two builds use champion shaft rockers $ 25 and they hold up well at high RPM but they are just 1to1 ratio. Be careful about coil bind with that much lift, and also with your longer than stock rod you need .030" clearance between piston and head
you might need to add another .010" head gasket to get that. There are many
videos you can watch to show you how to check both.
 
Thanks for the advice on the valve train, I am aware that I am cutting it close with my piston to head clearance, if I do end up modifying it further I’ll probably take your advice and throw another .010 head gasket on.
 

mike97760

Site Supporter
At one time, maybe still, there were a couple of ratio stock-type rockers on the market. One was pretty thick, the other pretty thin. I dont know you would know which you would be getting if you ordered some but the thin ones didnt last one race before they broke, the thicker ones were fine.
 

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