I'm not a expert but I shaved my head 65tho and I'm running a black mamba cam in a predator and I used stock length chromoly rods and my valve geometry looks good. checked everything at mid lift to make sure the rocker was centered on the lash cap. I would say try it and see what it looks like after you put it back together. you can color the valve stem with a marker then turn the motor over to see were the rocker is contacting the top of the valve stem or lash cap if your using them. I also have stock 1.1-1 rockers as well. and no valve lash will not correct it if your push rods are to short or to long. the geometry has to be strait. again this is just a ball park others will hopefully answer as well.
I think you should be ok but you all ways want to check your valve geometry anyway to make sure you get maximum lift. and OND these are things I've learned from you and other guys here on the forum. Thanks to you I know how to work my way around these motors. just read all you can on this forum and search search search for info that's what I did. helped me gain a lot of info.
https://www.lunatipower.com/Tech/Valvetrain/HowToVerifyValvetrainGeometry.aspx
Knowing what your looking at can help also
Sent from my iPhone using Mores code
Knowing what your looking at can help also
Sent from my iPhone using Mores code
no were in his question did he mention cam I based my answer off milling the head. that's it. he didn't say I put a monster cam in my motor and want to mill it 80 tho. so I'm just willing to bet he has the stock cam. lets see if he will answer that for us?? and since my info was horrible maybe you can explain what he should do.
The geometric relationship between push rod and valve at half lift is that they are square to each other. The rocker tip on the valve face travels in two directions during the lift cycle, first toward and past center then back, and the reverse when closing. If you shave the head the push rod essentially becomes longer and it jacks up the back of the rocker, this moves the starting point for the rocker closer to center and what happens is the rocker ends up sweeping to close to the back edge (the rocker side) of the valve at full lift, side loading the valve (causing excess guide wear). Shorten the push rod and you correct that problem.
right i understand but if he puts it together and colors the tip with a marker and takes it apart and it shows that the ware was centered then would there still be a problem??? wouldn't it be correct geometry if it's riding centered?? if not then i apologize for my advise and i learned the incorrect way on how to check my valve geometry.
There's nothing wrong with hands on advise, understanding the theory of or the workings behind something allow you to vary your techniques as you move through and modify different engine designs. in my case my base experience with small engines is Honda motocross and Harley Davidson shovels.
If like you say, when assembled the rocker tip sweeps back and forth over the center of the valve and passes that acid test you can then consider it to be correct. your advise was good, Crank on dude!
If like you say, when assembled the rocker tip sweeps back and forth over the center of the valve and passes that acid test you can then consider it to be correct. your advise was good, Crank on dude!
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you just broke it down in a different way that I didn't understand and that comes from my lack of experience. I just thought you were saying my info was incorrect or mis leading. I try not to give to much info on here because ill be the first to admit that im no expert. but from the motors I have built it was just the best way for me to find out so I apologize for my ignorance. screw it all lets just ride!!!! lol
push rods and rockers
Yup, the stock 1:1 rocker ratio is pretty forgiving, your only pushing the lift roughly another 0.065'' (1/16'') and 0.025'' is a relatively light cut off the head. your probably moving the contact patch on the valve stem 10-15 thou toward the stud, you can get away with that but if you shaved the head 3 times as much and ran 1.3:1 rockers (0.150' more lift instead of 0.065'') you'd have to shorten the push rod to square that back up as the rocker would be getting pretty close to the edge. With super high lift cams and radical rocker ratios we get into roller tip rocker territory because were running across almost the full face of the valve stem , that's a lot of side loading if you've got big spring pressure and RPM. ( if you want you can ask NOS if that's clap trap!)
Yup, the stock 1:1 rocker ratio is pretty forgiving, your only pushing the lift roughly another 0.065'' (1/16'') and 0.025'' is a relatively light cut off the head. your probably moving the contact patch on the valve stem 10-15 thou toward the stud, you can get away with that but if you shaved the head 3 times as much and ran 1.3:1 rockers (0.150' more lift instead of 0.065'') you'd have to shorten the push rod to square that back up as the rocker would be getting pretty close to the edge. With super high lift cams and radical rocker ratios we get into roller tip rocker territory because were running across almost the full face of the valve stem , that's a lot of side loading if you've got big spring pressure and RPM. ( if you want you can ask NOS if that's clap trap!)
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Been gone, but back with new info. I'm putting a dyno 356 cam in a predator hemi and this is what my valve train geometry looks like. As i rotate engine i can see that at zero lift or center line on cam i have full contact between lash cap and tip of adjuster. When i rotate crank to full lift of cam which is .3555 the tip of adjuster rolls up on the very edge of the adjuster buts stays in center of lash cap , no moving the to edge of cap. i have 1:1 ratio rockers and are using stock push rods that are 5.560" long. Still think after reading everyones input i may need to shorten push rods, comments ?
It's hard to say without seeing what it's doing but I'm trying to fully understand what snakepliscan was saying so I can make sure mine is correct also. But I'm guessing with that size of a cam you would probably need to shortin them up. Check with your cam supplier they might know what length you need. Or you could try gx160 lifters as they are shorter???