LT5 valve guide failures

[grahambehan]

Found on a recent teardown

Graham

[billschroeder5842]

Yikes- that is scary!

[XfireZ51]

Graham,

Any sense on the cause of failure? Are these OEM?

[grahambehan]

Originally Posted by XfireZ51

Graham,

Any sense on the cause of failure? Are these OEM?

Valve guides are stock. From the uneven tool marks on the end of the guides, they were over stressed whilst being knocked back to perform the port work then knocked back into position. After that it was just a matter of time.

Graham

[XfireZ51]

Thx Graham. Any outward signs, ie oil burning, spark plug coloring, indicative of a problem here?

[grahambehan]

Originally Posted by XfireZ51

Thx Graham. Any outward signs, ie oil burning, spark plug coloring, indicative of a problem here?

No comments from the owner re that, although it has heavy carbon deposits. The actual reason for taking it apart was, no compression on cyl 7 due to the parts of valve guide passing through the cylinder.

Graham

[Jagdpanzer]

Graham,
Do you have any experience with the VG 19292/00 aluminum bronze valve guide SI International makes for the LT5 cylinder head?


Sent from my iPhone using ZR-1 Net Registry

[grahambehan]

Originally Posted by Jagdpanzer

Graham,
Do you have any experience with the VG 19292/00 aluminum bronze valve guide SI International makes for the LT5 cylinder head?


Sent from my iPhone using ZR-1 Net Registry

No sir, not in LT5 applications, but al bronze should be fine.

Graham

[rkreigh]

on the old LSV we saw 3 guides that had noticeable wear after 106k. The other thing was the idler shaft for cam chains.

That was a bit of a surprise. Thanks Phil for all your help on this!