[SOCAL.M6.ZLE]

Hey Team,


Can someone help me here?
Any reason why I cant use this simple valve spring tool for the LT4?


Why is it that the LS motors have this simple DIY tool, but the LT motors require a $150 tool?

[radz28]

Gen Vs have canted valves, unlike all SBCs before it.

[SOCAL.M6.ZLE]

Makes sense... So maybe i just just need to put a different hole in this plate? or... am i not understanding the issue.

[SOCAL.M6.ZLE]

anyone want to sell or lend theirs out?

[radz28]

The difference means the axis' of the valve angles are not in-line, like LS engines. You can draw a straight line through the tops of the valves (which means the bottoms, at the combustion chamber are all in-line, too) from front to back. All of the factory valve angles are at the same - 15* tilted toward the intake manifold (LS7s were the only ones tilted to 12* for better flow, but you'll find AFR and TFS had 12* angles, if I recall). All Gen III and Gen IV heads, including anything from GMPP, were in-line (C5R included). In fact, (I'm pretty positive) only Edelbrock and MAST (MOZEZ) made canted-valve heads for LS-engines (maybe ALL PRO, but I think they used Edelbrock canted heads with their own CNC-job). Those are aftermarket RACE heads, though, requiring their own specific intake manifolds.

LT-engines, however, are canted - something around 2* "out" on the intake and some 2* opposite on the exhaust. They're also angled 12* (like the LS7) toward the intake. What this would look like in the combustion chamber, is: the valve faces would now angle TOWARD the center of the combustion chamber. Anyways - as a result of this (the cant'ing), the pockets, stands, and valve guides are all "twisted", instead of in-line, so any LS valve spring tool will likely not work.

If you look-up big-block Chevy heads (porcupine heads, from the old days), you'll notice a more exaggerated angle.