Valve problem - ZR-1 Net Registry Forums

BAlex1990zR1 · 12-26-2017

My valve guide (not seal) has came loose and slide down valve stem . Anyone every seen this or fixed

oricale · 12-26-2017

This seems to be due to the locating ring slipping...however suprising that it would slide down(would suggest other issues with the guide):

The only correct repair is to pull head, cam cover cam, lifters and springs above the guides and inspect all guides for movement and then if all is good get the guide out and replace...however since they are 90' heads have a head job done and install seals since the 90's didnt come with them.

Im curious if the guide "floated" for a bit after it fell riding on the valve.?..wonder if there is any damage to the guide boss

Dempsey

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Hib Halverson · 12-31-2017

If you have a head with a "loose guide", as "oricale" suggests above, the only solution is to remove the head replace the guide and, if necessary, repair the head.

With an LT5, if the heads are coming off, it's best to pull the engine.

Also, if you have one loose quide, you want to check all 15 others. As "oricale" suggests, you might as well service the heads and, while your at it, install seals on the exhaust valves. '90s didn't have them and you can reduce oil use if you add exhaust stem seals.

Jagdpanzer · 12-31-2017

First I’ve heard of this happening but not surprised given the LT 5 guide design. The guide relies on a retainer clip ring to prevent the guide from being installed to far during factory assembly or from dropping down the bore during operation. Initial installation is with a interference fit which, if within proper tolerance, should retain the guide for the life of the engine. However, if the guide fit was on the loose side then I could imagine the valve operation working the guide loose and eventually pushing the guide past the retainer ring like you have experienced. No question the head will have to come off for repair. Most likely the guide bore in the head will have to be machined out and a oversized OD guide installed. Usual work for a competent motor machine shop.

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Jagdpanzer · 12-31-2017

Like the others have said good time to do a valve job and install exhaust stem seals.

Jagdpanzer · 12-31-2017

Here is what the valve guide looks like with and without the retainer ring

And in the head

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BAlex1990zR1 · 01-01-2018

With no timing marks
What the best way to remove the head?

12-26-2017	#1
BAlex1990zR1 Join Date: Dec 2017 Location: Bradyville Posts: 4	Valve problem My valve guide (not seal) has came loose and slide down valve stem . Anyone every seen this or fixed

12-26-2017	#2
oricale Join Date: Oct 2011 Location: STAFFORD VA, Posts: 576	Re: Valve problem This seems to be due to the locating ring slipping...however suprising that it would slide down(would suggest other issues with the guide): The only correct repair is to pull head, cam cover cam, lifters and springs above the guides and inspect all guides for movement and then if all is good get the guide out and replace...however since they are 90' heads have a head job done and install seals since the 90's didnt come with them. Im curious if the guide "floated" for a bit after it fell riding on the valve.?..wonder if there is any damage to the guide boss Dempsey Sent from my SM-G955U using Tapatalk __________________ [B][I][COLOR=red]1990 ZR1[/COLOR][COLOR=black] [U]#00077 [COLOR=red]RED[/COLOR]/[COLOR=red]RED[/COLOR] (10Y022 PEP CAR) [/U][/COLOR][/I][/B][B][I][COLOR=red]1991 ZR1[/COLOR][COLOR=black] [U]#00517 ("Irene")[COLOR=red]WHITE[/COLOR]/[COLOR=red]RED-SOLD:cry:[/COLOR] [B][/B] [/U][/COLOR][/I][/B][B][I][COLOR=red]1992 ZR1[/COLOR][COLOR=black] [U]#00445("The Revenant")[COLOR=red][COLOR="Black"]BLACK [/COLOR][/COLOR]/[COLOR=red]RED(2016 T.O.D!) [/COLOR] [/U][/COLOR][/I][/B] [B][I][COLOR=red]2009 [COLOR=red]Z06!![COLOR=black]BLK/BLK rare Linen interior[/COLOR] 707HP!![/COLOR] [/COLOR][/I][/B] [B][I][COLOR=red]2006[/COLOR] BLK/BLK Z51 (Just SICK FAST!)SOLD)[/I][/B] [B][I]1996 BLK/BLK LT4 Grnsprt(sold...Twice!)[/I][/B] [B][I]1991 RED/REDL98(Fell off the shipping truck:([/I][/B] [B][I]1980 BLK/RED L82(Sold)[/I][/B] [B][I][B][I]1990[/I][/B] RED/BLK(sold.....In Japan)[/I][/B] [I][COLOR=black][B][I]2006[/I][/B][/COLOR][/I] [COLOR=red]Mustang GT[/COLOR] ([B][I]mach 1[/I][/B])[B](sold)[/B] [COLOR=black][B][I]1969[/I][/B][/COLOR] [COLOR=red]Mach[/COLOR] [B][I]1(sold in Japan)[/I][/B] [COLOR=black][B][I]1969[/I][/B][/COLOR] [COLOR=red]Mach[/COLOR] [B][I]1#2(sold)[/I][/B] [B][I]WAZOO Member...[/I][/B] [url]www.evolution-motorsport.com[/url] facebook/evolutionmotorsportengineering Your Local [url]www.Amsoil.com[/url] dealer/user.. Victory Loves Preparation Last edited by oricale; 12-26-2017 at 10:59 PM.

12-31-2017	#3
Hib Halverson Join Date: Jun 2005 Location: CenCoast California Posts: 899	Re: Valve problem If you have a head with a "loose guide", as "oricale" suggests above, the only solution is to remove the head replace the guide and, if necessary, repair the head. With an LT5, if the heads are coming off, it's best to pull the engine. Also, if you have one loose quide, you want to check all 15 others. As "oricale" suggests, you might as well service the heads and, while your at it, install seals on the exhaust valves. '90s didn't have them and you can reduce oil use if you add exhaust stem seals. __________________ Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878

12-31-2017	#4
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,661	Valve problem First I’ve heard of this happening but not surprised given the LT 5 guide design. The guide relies on a retainer clip ring to prevent the guide from being installed to far during factory assembly or from dropping down the bore during operation. Initial installation is with a interference fit which, if within proper tolerance, should retain the guide for the life of the engine. However, if the guide fit was on the loose side then I could imagine the valve operation working the guide loose and eventually pushing the guide past the retainer ring like you have experienced. No question the head will have to come off for repair. Most likely the guide bore in the head will have to be machined out and a oversized OD guide installed. Usual work for a competent motor machine shop. Sent from my iPhone using ZR-1 Net Registry __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake Last edited by Jagdpanzer; 12-31-2017 at 09:04 PM.

12-31-2017	#5
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,661	Valve problem Like the others have said good time to do a valve job and install exhaust stem seals. __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake Last edited by Jagdpanzer; 12-31-2017 at 08:50 PM.

12-31-2017	#6
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,661	Valve problem Here is what the valve guide looks like with and without the retainer ring And in the head Sent from my iPhone using ZR-1 Net Registry __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake Last edited by Jagdpanzer; 12-31-2017 at 08:02 PM.

01-01-2018	#7
BAlex1990zR1 Join Date: Dec 2017 Location: Bradyville Posts: 4	Re: Valve problem With no timing marks What the best way to remove the head?

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