Valve guide wear

Puddin · 07-31-2020, 01:26 PM

Apparently the Lt4 and Lt5 are having valve guide wear similar to the LS7. This info is from the Katech news letter.

"In an effort to stay continually innovate and stay ahead of the pack, we started tracking every LT4/LT5 cylinder head that came into the shop. What we discovered was a valve guide problem similar to the GM LS7 Engine. While it is unknown how many of these engines experience early wear, we saw enough based on our Race Shop inspections and CNC/cylinder head services that we wanted to come up with a solution. And we did."

“We inspect every engine that comes into our Race Shop, and so we began recording detailed clearances of valve guide wear of every set of LT4 or LT5 heads that we saw, and over the past year the numbers prompted us to develop and offer a solution.”

The problem and solution is similar to that identified by Katech several years ago with the GM LS7 engine.

“At this point, we’re not sure how far reaching this issue is or if it is of the magnitude of the LS7s valve guide wear,” said Suits. “But we’re in front of it and our solution will allow our customers to avoid putting other engine components at risk in the event a valve or guide failed.”

Owners of vehicles with LT4/LT5 engines can mail in their cylinder heads to receive the Valve/Guide Package, or can drop off the entire vehicle to get the update and take advantage of one of Katech's Engine Stage Packages offered in conjunction with the update at a discounted rate.

Snowwolfe · 07-31-2020, 01:37 PM

Interesting. I copy and pasted this over at the Z06 forum. Lets see what those owners say about it as well.

ZX-10R · 07-31-2020, 01:42 PM

Long standing issue with GM - pretty disappointing

Rayvan · 07-31-2020, 05:23 PM

Quote:

Originally Posted by ZX-10R

Long standing issue with GM - pretty disappointing

OTOH,
My kid has an '05 GTO with over 200,000 miles on it. Valve guides are fine. When we upgraded his G8GT with new valves/cam etc, We took the heads in to have them checked out & new LS3 valves installed in it., the shop said that the valve-guides were factory fresh at 105,000 miles.

ht600 · 07-31-2020, 08:48 PM

I had a Z06 and watched the issue develop over time and it took about 4 to 5 years after the LS7 came out for the forums to really pick up on it.

(Sorry I know it's anecdotal)

flooZL1 · 07-31-2020, 11:52 PM

Quote:

Originally Posted by ht600

I had a Z06 and watched the issue develop over time and it took about 4 to 5 years after the LS7 came out for the forums to really pick up on it.

(Sorry I know it's anecdotal)

How do you watch the issue develop over time? What do you look for to track its progression?

Puddin · 08-01-2020, 02:09 AM

Quote:

Originally Posted by flooZL1

How do you watch the issue develop over time? What do you look for to track its progression?

I think most people found out by eventually dropping a valve so people just started sending their heads in for repair or went aftermarket.

ht600 · 08-01-2020, 07:07 AM

Quote:

Originally Posted by Puddin

I think most people found out by eventually dropping a valve so people just started sending their heads in for repair or went aftermarket.

Exactly!

(Nailed it)

I never dropped a valve but...

I had the valves changed to Ferrea S.S. exhaust and all new valve train plus bigger cam.

LT4Greg · 08-01-2020, 09:35 AM

Oh no! Something else to be concerned about including the oil pump failure with my LT4! Seems strange that no other aftermarket company that mods and builds ZL1s have mentioned the valve guide problem but I do trust Katech reporting their findings on the issue.

UFDUB · 08-01-2020, 09:53 AM

I suspect (if this is in fact true) that this has a lot to do with mileage, ie the reason we aren’t seeing a lot is that not many cars are driven enough for the problem to rise to the level of catastrophic. I bet very few cars here have reached 50k miles, let alone 100k, which would more likely show patterns of failure vs true reliability. Z06 owners didn’t see issues for years because the cars aren’t driven enough for the issue to become catastrophic until they have developed enough miles.

Just my theory. Ymmv

ZX-10R · 08-01-2020, 11:23 AM

Quote:

Originally Posted by flooZL1

How do you watch the issue develop over time? What do you look for to track its progression?

Blows more oil smoke at start-up, that's usually the primary symptom

KingLT1 · 08-01-2020, 11:38 AM

Seems to be a problem with GM engines that have 1.8 ratio rockers. It seems that most if not all GM engines that have/had 1.7 rocker arm ratio or less have not had valve guide issues. Not saying this is the problem just something that I have noticed. I also remember Brett @ Pray Performance saying he ran into some VG issues on LT heads.

Trochoidal · 02-06-2022, 12:00 PM

Quote:

Originally Posted by KingLT1

Seems to be a problem with GM engines that have 1.8 ratio rockers. It seems that most if not all GM engines that have/had 1.7 rocker arm ratio or less have not had valve guide issues. Not saying this is the problem just something that I have noticed. I also remember Brett @ Pray Performance saying he ran into some VG issues on LT heads.

Kicking the dust off of this thread.

I remember watching the video on this issue Katech found on LT4/LT5. Are you saying Brett saw this issue on the LT1’s with factory ratio rockers?

m6-lt1 · 02-06-2022, 06:12 PM

This thread is from 2020 and I still haven’t seen a single post/enough posts about valves dropping on a bone stock car to warrant any actual concern. Most posts I’ve seen about motors blowing aside from the early zl1 oil pump issues were from people who road course their cars. I’m sorry but I’m chalking this up to an aftermarket company trying to make a buck.

07-31-2020, 01:26 PM	#1
Puddin Drives: 2016 Camaro 2SS Join Date: Apr 2018 Location: Central Texas Posts: 1,011	Valve guide wear Apparently the Lt4 and Lt5 are having valve guide wear similar to the LS7. This info is from the Katech news letter. "In an effort to stay continually innovate and stay ahead of the pack, we started tracking every LT4/LT5 cylinder head that came into the shop. What we discovered was a valve guide problem similar to the GM LS7 Engine. While it is unknown how many of these engines experience early wear, we saw enough based on our Race Shop inspections and CNC/cylinder head services that we wanted to come up with a solution. And we did." “We inspect every engine that comes into our Race Shop, and so we began recording detailed clearances of valve guide wear of every set of LT4 or LT5 heads that we saw, and over the past year the numbers prompted us to develop and offer a solution.” The problem and solution is similar to that identified by Katech several years ago with the GM LS7 engine. “At this point, we’re not sure how far reaching this issue is or if it is of the magnitude of the LS7s valve guide wear,” said Suits. “But we’re in front of it and our solution will allow our customers to avoid putting other engine components at risk in the event a valve or guide failed.” Owners of vehicles with LT4/LT5 engines can mail in their cylinder heads to receive the Valve/Guide Package, or can drop off the entire vehicle to get the update and take advantage of one of Katech's Engine Stage Packages offered in conjunction with the update at a discounted rate.

07-31-2020, 01:37 PM	#2
Snowwolfe Drives: CTV5 V Blackwing on order Join Date: Feb 2020 Location: East TN Posts: 431	Interesting. I copy and pasted this over at the Z06 forum. Lets see what those owners say about it as well. __________________ 2022 CT5 V Blackwing with A10 2021 GMC Denali pickup with 6.2 and A10 2017 Ford Expedition

08-01-2020, 09:35 AM	#9
LT4Greg Drives: 2017 Camaro ZL1 Coupe Join Date: May 2016 Location: Georgia Posts: 5,813	Oh no! Something else to be concerned about including the oil pump failure with my LT4! Seems strange that no other aftermarket company that mods and builds ZL1s have mentioned the valve guide problem but I do trust Katech reporting their findings on the issue. __________________ ZL1 Coupe, PDR, Exposed carbon fiber hood insert, My Link with Nav, M6 6 speed and Silver Ice Metallic. Mods done: ceramic window tint, GM Accessories Camaro floor mats and Roto-Fab CAI.

08-01-2020, 11:38 AM	#12
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,800	Seems to be a problem with GM engines that have 1.8 ratio rockers. It seems that most if not all GM engines that have/had 1.7 rocker arm ratio or less have not had valve guide issues. Not saying this is the problem just something that I have noticed. I also remember Brett @ Pray Performance saying he ran into some VG issues on LT heads. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

07-31-2020, 01:42 PM	#3
ZX-10R Drives: 2019 ZL1 Riverside Join Date: Apr 2020 Location: Charlotte, NC Posts: 1,138	Long standing issue with GM - pretty disappointing

07-31-2020, 08:48 PM	#5
ht600 Drives: 2019 Camaro ZL1 Join Date: Mar 2018 Location: Everett, WA Posts: 50	I had a Z06 and watched the issue develop over time and it took about 4 to 5 years after the LS7 came out for the forums to really pick up on it. (Sorry I know it's anecdotal)

08-01-2020, 09:53 AM	#10
UFDUB Drives: Chevrolet Camaro ZL1 1LE Join Date: Jun 2019 Location: Florida Posts: 127	I suspect (if this is in fact true) that this has a lot to do with mileage, ie the reason we aren’t seeing a lot is that not many cars are driven enough for the problem to rise to the level of catastrophic. I bet very few cars here have reached 50k miles, let alone 100k, which would more likely show patterns of failure vs true reliability. Z06 owners didn’t see issues for years because the cars aren’t driven enough for the issue to become catastrophic until they have developed enough miles. Just my theory. Ymmv

02-06-2022, 06:12 PM	#14
m6-lt1 Drives: 2023 Chevrolet Camaro 2SS 1LE Join Date: Jan 2020 Location: Pennsylvania Posts: 1,037	This thread is from 2020 and I still haven’t seen a single post/enough posts about valves dropping on a bone stock car to warrant any actual concern. Most posts I’ve seen about motors blowing aside from the early zl1 oil pump issues were from people who road course their cars. I’m sorry but I’m chalking this up to an aftermarket company trying to make a buck.

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