Valvetrain Geometry Facts Or A Bunch Of Bull Crap?

[fiveohlover]

I have been trying to figure out how to check for push rod length. I have read all about it on here and other sights and don't know who to believe about how to do this or that. I called up summit racing tech today and i asked them about how to check for push rod length and they have never even heard of using a solid roller to check valve train geometry. Also i asked them about the wear mark on the valve tip. I have heard through research that you want the thinnest wear patter possible. Summit told me that that doesn't matter if the wear pattern is wide. So i don't know who to believe or what to do exactly.

Can anybody help me out and explain in good detail exactly how to check for push rod length and how to verify valve train geometry.

Combo
afr 185
stud mount roller rockers
skorpion racing 1.6 rockers
comp xe 274hr cam

using a converted solid lifter and a comp cams pushrod length checker with 0.050 increments

 

[rbohm]

first you want to use a lifter that is of the type and size that you are going to use for real.for instance if you are going to use factory hydraulic roller lifters, then dont start with a flat tappet cam and lifter as you will never get the right geometry.

you can modify a hydraulic lifter by removing the spring and replacing it with a solid sleeve to keep the push rod cup in place.

i assume that you already know how to actually do the operation for checking valve train geometry so i wont bore you with those details. as stated teh width of the pattern isnt important, the location of the pattern is however. you want it as close to the center of the valve stem as possible.

 

[89oem]

here's a link to ed curtis' info on valve train adjustment , lash etc..

you may know all this but its a good overview while you're in there... looks like rbohm has you covered on measuring etc...

http://www.flowtechinduction.com/tech-info/

 

[fiveohlover]

Hey thanks for the link. Some things that are not clear to me is when using a solid lifter for adjusting is do you have to add the preload that you normaly would have with a hyrdrolic to your pushrod length?

 

[89oem]

there are folks here far more qualified than me... that being said i would suggest you buy the under $20 tool to measure for self comfort etc...

here is another good link from summit that may help....


View: https://www.youtube.com/watch?v=OmzbHgVY3cI

 

[fiveohlover]

They d0nt use the method of using a solid roller. If i use a converted lifter do i need to add the preload amout that i would normally set to my overall pushrod length?

 

[jAEded]

I just made sure the lifters were pumped up when I checked the pre-load.

With a 5/16 - 18 cap screw, one full turn from zero lash would give a preload of 0.056". In a perfect world.

 

[fiveohlover]

i will being using a half turn, do i need to add 0.028 to my push rod length?