valvetrain geometry
#11
RE: valvetrain geometry
+1 to what everyone is saying, but i'm thinking that once your lifter isnt collapsing and your pushrod seems longer you'll be right where you wanna be with your current length.
taking bets, whos down?
taking bets, whos down?
#12
RE: valvetrain geometry
well, in the vid its at stock (6.250") length. the pattern is alil inside the center line of the valve. i'm thinkin with a solid lifter it will move it right in the center of the valve. gotta get me a junk lifter and find out.
will...
will...
#13
RE: valvetrain geometry
sounds about right. When I made a solid lifter i didn't have to grind the thing down, just turned the plunger thing over and removed the spring, then i put it back how it was. Not 100% sure if it was right after that or not though but it should have been.
#14
RE: valvetrain geometry
when i revamp my VT im going to use a "solid" hyd roller, but the last time i checked pushrod length i didnt do that, but luckly i still got a good wear pattern, from the engine running that is. but it kinda makes me wonder if it is 100% right.
#15
RE: valvetrain geometry
You do not have to use a solid roller lifter to check valvetrain geometry. As long as the valve and the stud are parallel (most heads are) then you can use a regular old hydraulic lifter to check it. All you do is leave the lock nut off. Instead of the valve moving down when the cam rotates, the rocker arm just moves up the stud. This works because the valve and the stud are at the same angle, so rocker arm movement is exactly the same as if the rocker was tightened with the lock nut and the valve was moving down. I just put a thin coat of grease on the valve stem tip, and rotate the engine over to see where the wear pattern is going to be. Once you rotate it, just slide the rocker back off, and there you go, you can see exactly where the tip of the rocker is going to be on the valve stem tip.
#17
RE: valvetrain geometry
sorry tyler, but thats about as inaccurate as setting your timing by ear. Or just slapping gears into a rear end.
If you aren't going to do the job right, keep it to yourself. Don't teach people the wrong methods when it comes down to something as important as valvetrain geometry!
If you aren't going to do the job right, keep it to yourself. Don't teach people the wrong methods when it comes down to something as important as valvetrain geometry!
#18
RE: valvetrain geometry
ORIGINAL: tyler72
You do not have to use a solid roller lifter to check valvetrain geometry. As long as the valve and the stud are parallel (most heads are) then you can use a regular old hydraulic lifter to check it. All you do is leave the lock nut off. Instead of the valve moving down when the cam rotates, the rocker arm just moves up the stud. This works because the valve and the stud are at the same angle, so rocker arm movement is exactly the same as if the rocker was tightened with the lock nut and the valve was moving down. I just put a thin coat of grease on the valve stem tip, and rotate the engine over to see where the wear pattern is going to be. Once you rotate it, just slide the rocker back off, and there you go, you can see exactly where the tip of the rocker is going to be on the valve stem tip.
You do not have to use a solid roller lifter to check valvetrain geometry. As long as the valve and the stud are parallel (most heads are) then you can use a regular old hydraulic lifter to check it. All you do is leave the lock nut off. Instead of the valve moving down when the cam rotates, the rocker arm just moves up the stud. This works because the valve and the stud are at the same angle, so rocker arm movement is exactly the same as if the rocker was tightened with the lock nut and the valve was moving down. I just put a thin coat of grease on the valve stem tip, and rotate the engine over to see where the wear pattern is going to be. Once you rotate it, just slide the rocker back off, and there you go, you can see exactly where the tip of the rocker is going to be on the valve stem tip.
http://www.compcams.com/Technical/FA...inGeometry.asp
#20
RE: valvetrain geometry
Here is some more helpfull information provided by Nate at s.b.f. tech
Adjusting Valvetrain
This is the system I use when adjusting stud mount roller rockers on my small block Fords with an Hydraulic Roller Camshaft. This will also work for almost any engine using adjustable roller rockers* and a hydraulic style cam and lifter combination (roller or not). My particular Roller Rocker Arms on my 351w with World Products Windsor Heads are Trick Flow 51400520 - 1.6 ratio for a 7/16" stud.
1. Remove the valve covers, and pick a cylinder you are going to set the preload on. I think the easiest and fastest way is to just follow the firing order. For the 5.0 HO and 351w the firing order is 1-3-7-2-6-5-4-8. Start with the No. 1 cylinder (passenger side front).
2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop. You are now ready to adjust that cylinder's intake rocker arm.
3. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so.
4. Now pull up and down (or rotate) the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the movement of the pushrod, you are at "Zero Lash". Turn the adjusting nut down one quarter to one half turn from that point. Lock the adjuster into position. The intake is now adjusted properly.
5. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.
6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.
*If you are using a bolt down pedestal type rocker, or using a mechanical camshaft, consult a Chiltons/Haynes or other manual for guidance, as this procedure works only on valvetrains using adjustable stud mount rocker arms and hydraulic lifters.
Nathan Moonen
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