What is the max lift a stock valve cover can hold before the rockers hit.
The reason why I am asking with 1.6 rockers I will be at .603 lift.
Any good advice would be helpful.

 

I'm running a 0.606 lift with my 1.6 Pro Mags and the stock covers .

 

uhh, rockers don't raise. they "rock" on a stud, hence the name. if you are thinking that cam lift raises the rocker arm, then wow! you really need to read up. if you are referring to the back of the rocker arm where the pushrod sits, that will not raise as high as the rocker arm nut. basically, the rocker arm nut is the highest point of the rocker arms.

 

thank you for that bit of edumacation. my simple mind is now overwelmed with fantastic info.
rockers rock or why would they call them that. if they would just raise then they would be called raisers
as as for simple geometry, the back end of a rocker raises to rock a rocker so so it can move a valve to open. i was just curious if .600 lift was safe for stock valve covers and it was answered in the first post thanks
avg lift is usually .450-.580 from what i have seen on this site.
i have never done a chevy motor with .600 lift that is why i am asking such an "odd" question. I would rather ask then just do it, then find out later that the parts i installed were wrong. measure twice cut once is what i believe in.
in theory the rocker rocking point can go past the nut if it were the right diameter or like a stamped rocker inside the rocker itself.

 

WAIT just a second here. You said "Rockers don't raise".. But yes they do. Every time the valve opens and closes, that's the lifter raising. However, You're not entirely incorrect either. On the newer LS engines that use torque set rockers, then no. They won't be higher. However, on older SBC motors that used "Full Floating Rockers" then it is VERY possibly to have a rocker come up and hit a valve cover. And you can close the valve cover up with no problem, but run the motor for a little bit and your start getting a strange ticking noise. Check the cover and you'll have marks. This will never happen with the stock stamped steel non-rollers in older SBC, but if you swap to full roller lifters you most certainly can. That's why TONS of companies make extra tall valve covers.

From personal experience, using a set of solid roller lifters, with a set of aluminum full roller rockers, and 7/16 screw in studs, I had it happen. I was trying to get away with using the factory valve cover to try to keep the motor looking more like a sleeper but with the super high lift I had on my cam profile, in conjunction with my rocker arm being flat in shape as opposed to an arch like the stamped ones were, when they came all the way up after the motor was up the temperature I would get some very slight ticking on my valve covers.

And since a lot of stock valve covers are higher in the center and start the slope down towards the outsides which works fine on stock rockers and cam profiles, my rocker became the highest thing in my head every time it was on a lift.


Now the question is highest from what. Highest from the valve cover gasket location? Highest from ground level? Highest from the cylinder bore location, or highest from the lowest part of the inside of the head? No matter which place you choose to measure from one part could be higher than the other.


To those of you worried about this my recommendation is to do what I say here. Assemble your valve train and leave the valve covers off. Start the motor with a spare set of old valve covers you don't care about without them bolted down. That'll help catch the excess oil. Let engine get to normal temp.. . If this is your only set, hurry up and clean them. Put some blue marking dye like machine shops use on the inside of your valve covers. Then install them again and actually tighten them down. With the motor still up to temperature spend the motor over a few times with the key you don't want it really running but if it does start shut it right back off. Best bet is the hand bump the motor over till it gets a good three or four full rotations in.

Now pull the valve cover and check for any marks not caused by you, in the blue marking paint.

If you see where something has made contact you have an issue if you don't see any contact you should be good to go. Step 2 is to clean the blue off reapply reassemble and this time run the engine for a nice little Drive till it's fully up to Temp with some RPM. When you get back pull the covers again and check to see if anything is hitting. If there are no marks, you're in the green.

If you do see any type of marks then buy taller valve covers...


On most modern engines that use the torqued rocker trunion, I'm running a 0.600 Int & Exh lift, and have no issues with stock covers.



Thank you

 

You are replying to a 16 year old thread

with that said any "roller rocker" other than the Crane narrow body 3/8" will require the baffle braces in VC, intake side, to be cut off. Simple mod

 

Yeah, I know I replied to an old thread. But that's must me.. I was actually looking for LS Gen 3 info at the time, but decided to comment anyway for anyone who is still looking to build an older engine as they are still great options. I'm not sure what "Baffle mod" you're referring to? When I had the alum "full roller" rockers hit, they hit the ends of the covers where the metal is rounded over, not anywhere near a baffle. If the Stock SBC valve cover was a square design, and not round, then the front most, and rear most rockers wouldn't have hit at all. I've never had the baffle in a SBC valve cover cause me any issues.

I am still trying to find the max lift a stock LS valve cover and rocker with trunnion upgrade can handle.

 

Most people running 1.6X Pro Magnums find they need to cut back (or crimp the projecting edge) on half of the center-bolt gussets. Had to do that with my Pro Magnums. And yes, as you approach the 0.600 inch gross lift number, you mat hear ticking as the rockers tap the covers. Nothing a light tap of a hammer won’t fix. I believe people have also had to remove/modify the baffle on the passenger side cover, at the rear under the grommet for the PVC line from the
from the throttle body

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