LT5 valve guide failures - ZR-1 Net Registry Forums

grahambehan · 11-05-2019

Found on a recent teardown

Graham

billschroeder5842 · 11-05-2019

Yikes- that is scary!

XfireZ51 · 11-05-2019

Graham,

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

grahambehan · 11-06-2019

Quote:

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 · 11-06-2019

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

grahambehan · 11-06-2019

Quote:

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 · 11-06-2019

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 · 11-06-2019

Quote:

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 · 11-12-2019

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!

11-05-2019	#2
billschroeder5842 Join Date: Nov 2016 Location: Southlake, TX Posts: 584	Re: LT5 valve guide failures Yikes- that is scary! __________________ Bill Schroeder Texas Proud! 1991 Corvette ZR1 #1388 2015 Challenger Scat Pack Shaker

11-05-2019	#3
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,669	Re: LT5 valve guide failures Graham, Any sense on the cause of failure? Are these OEM? __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

11-06-2019	#5
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,669	Re: LT5 valve guide failures Thx Graham. Any outward signs, ie oil burning, spark plug coloring, indicative of a problem here? __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

11-06-2019	#7
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,646	Re: LT5 valve guide failures 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 __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake

11-12-2019	#9
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: LT5 valve guide failures 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! __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)