Does this valvetrain geometry look ok?

fstarocka

Member
Feb 1, 2013
72
Seattle
Hi all - busy finalizing the 383 in the garage -


Cam is comp XR288, 1.6 roller rockers, ARP screw in studs, +0.100 long valves, procomp alu heads.


I put the geometry tool on at zero lift and it looked fine..


Popped in the comp 5/16 pushrod (7.250 length - 5/16) -


The crane roller tip rocker just looks a little angled - the wear pattern is slightly over the center but not a lot - I put the bare head on as I wanted to check PVC as well, so the 0.014 shim should only slightly raise the head which would probably center the pattern a little more -


Im probably ok with the pattern but the rocker seems angled - this ok?



At zero lash:


70b33edd-8f49-4809-801b-8b9344d9a3da-jpg.613915




Wear pattern almost perfectly centered:

d1b23d7a-684c-4706-8491-b4dd50add274-jpg.613916







Does this angle look ok?


96c92ae3-039c-4e19-b42c-c39c2808b371-jpg.613917
 

ChevyReb

Veteran Member
Lifetime Gold Member
Feb 4, 2003
4,495
SC
Is the cam a small base circle? And you have no head gasket on it yet? When I did mine I think I had the heads installed and torqued to spec. I do recall using the low tension spring like you have. I don't think I've seen the blue plastic false rocker.
 

fstarocka

Member
Feb 1, 2013
72
Seattle
not small base and i did not have the shim gasket on - it would only make a tiny difference but i will re check of course- kinda shopping for rockers.. another 200 off the wallet!
 

sandlapper

Veteran Member
Oct 9, 2020
1,344
SE CSA
with different rockers, suggest you repeat your measurements.

Real valve springs Usually pull valve a little tighter to seat while raising tip a smidge. But it sounds like you're getting very close regardless.
thumbs-up-linear-icon-line-260nw-1252760281.jpg
 

Rosster

Veteran Member
Gold Member
Mar 1, 2020
890
Any reason why your not looking at alignment at 1/2 of lift? That’s where lifter should be in the exact center on the stem and rocker body parallel with retainer.
 

fstarocka

Member
Feb 1, 2013
72
Seattle
Im redoing that check - i used the geometry checker tool and mine was perfect, and i roleed it over and the wear pattern looks ok but ill confirm once new rockers arrive.

Comp pushrod tool arrived so bound (red loctite!) i have to turn it in the bench vice!
 

1320feet

Veteran Member
Oct 23, 2019
511
Calgary, Alberta.
Also check the rockers slot to stud clearance at both ends. Usually one uses longer valves to allow for taller springs. Usually with taller springs one uses larger retainers. That's a small retainer in your photo. If you are using larger retainers, also check clearance between rocker and retainer. If you don't need the longer valves, I wouldn't use them. Your rocker arm is up high on the stud. A shorter valve will place the rocker lower on the stud where it's stiffer.
 




Top