NEED HELP Valve spring retainers popped off

chaphar540

Original poster
Member
Aug 31, 2019
6
Houston
I just rebuilt the engine in my 2003 Ascender, 4.2l I-6, and had a valve job done at a machine shop. Put everything back together, cranked it up. It ran for a while, and then fell dead. Finally figured out that I lost compression in #5 cylinder because the valve spring retainer had popped off. Replaced keepers on valve stem and started it up again. Everything was fine at first. Next morning hard to start. Now the same thing has happened at #6 cylinder. Does anyone know why a valve spring retainer along with the keepers would come off of a valve stem?
 

mrrsm

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Oct 22, 2015
7,639
Tampa Bay Area
Just a Few Questions:

(1) Did you use the proper tool (GM KENT-MOORE EN-47945 VALVE SPRING COMPRESSOR) for this unique application after ensuring the individual Pistons involved had been rotated around by hand to Top Dead Center to avoid “Dropping a Valve”?

http://rover.ebay.com/rover/1/711-5...0001&campid=5338077216&icep_item=401609122104

KENTMOOREVSCOMPRESSOR1.jpgKENTMOOREVSCOMPRESSOR2.jpg


(2) Did you re-use the Old, Original Keepers...or replace them with any Off-Brand NON-OEM Quality Keepers to match the Valve Stems in the GM 4.2L Aluminum Engine Head?


(3) If not... what OEM Quality Parts and more precisely... What R&R Procedures did you follow to re-install the ‘freed-up’ Keepers?

QUALCASTVSKEEPER.png


(4) Did you completely remove the Tiny Valve Springs and very carefully examine them for any spiral fractures and/or breaks in the Spring Wire Coils? If the the Spring Steel has failed and cannot return enough spring pressure to maintain the pressure between the upper and lower contact surfaces between the Valve Spring Washer and the Engine Head Valve Guide Seal... it would become very likely to allow the Valve Keepers the opportunity to loosen and easily escape with a serious risk that the Valve(s) can drop inwards and make contact with the Piston Head(s).

If this unfortunate event were to happen out of the normal (4) Stroke Cycle and sequence... THAT is Very Bad Thing to have occur inside of an "Interference Engine" like this GM Atlas 4.2l (24) Valve LL8 Motor.
 
Last edited:

chaphar540

Original poster
Member
Aug 31, 2019
6
Houston
I didn't replace any of the retainers or keepers myself except for the one that popped off. When I took it in for a valve job and picked it up, I didn't ask what all was done to the head. I was told that none of the valves had to be replaced, and I would assume that they used new springs, keepers, and retainers, but I do not know for sure. I was thinking that maybe the keepers are the wrong ones for the application.
 

chaphar540

Original poster
Member
Aug 31, 2019
6
Houston
Incorrectly installed? Wrong ones? Did they replace the keepers, retainers, springs or are they the original?
I don't know if they replaced the items mentioned and didn't ask what all they did, but was told that none of the stems had to be replaced. I was thinking that maybe the keepers are the wrong ones for the application, however, if they are the wrong ones, then they replaced them, but with the wrong size.
 

chaphar540

Original poster
Member
Aug 31, 2019
6
Houston
Just a Few Questions:

(1) Did you use the proper tool (GM KENT-MOORE EN-47945 VALVE SPRING COMPRESSOR) for this unique application after ensuring the individual Pistons involved had been rotated around by hand to Top Dead Center to avoid “Dropping a Valve”?

http://rover.ebay.com/rover/1/711-5...0001&campid=5338077216&icep_item=401609122104

View attachment 90706View attachment 90707


(2) Did you re-use the Old, Original Keepers...or replace them with any Off-Brand NON-OEM Quality Keepers to match the Valve Stems in the GM 4.2L Aluminum Engine Head?


(3) If not... what OEM Quality Parts and more precisely... What R&R Procedures did you follow to re-install the ‘freed-up’ Keepers?

View attachment 90708


(4) Did you completely remove the Tiny Valve Springs and very carefully examine them for any spiral fractures and/or breaks in the Spring Wire Coils? If the the Spring Steel has failed and cannot return enough spring pressure to maintain the pressure between the upper and lower contact surfaces between the Valve Spring Washer and the Engine Head Valve Guide Seal... it would become very likely to allow the Valve Keepers the opportunity to loosen and easily escape with a serious risk that the Valve(s) can drop inwards and make contact with the Piston Head(s).

If this unfortunate event were to happen out of the normal (4) Stroke Cycle and sequence... THAT is Very Bad Thing to have occur inside of an "Interference Engine" like this GM Atlas 4.2l (24) Valve LL8 Motor.
Took the head to a machine shop for a valve job. The only keeper I replaced was the one that initially popped off.
 

mrrsm

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Supporting Donor
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Oct 22, 2015
7,639
Tampa Bay Area
At this point... running the Engine at ALL should be out of the question until you can poke a 7-9mm Digital Camera Probe inside and look around within the affected Cylinders via the open-vacant Spark Plug Wells for any disturbed metal on the Piston Heads; and by that I mean the signs of any scratches in the carboned up surfaces or dents or holes in the Piston Tops...ANYTHING.

If you mean to salvage this engine... you are right back at Square One and ALL of us really do wish it were otherwise. From this point forwards... you should proceed cautiously and consider whether or nor it will be less expensive to just find a Low Mileage (Year In Kind) Swap-In Motor, rather than pick up the shovel again and dig the hole you're in any deeper. :>(
 
Last edited:

chaphar540

Original poster
Member
Aug 31, 2019
6
Houston
At this point... running the Engine at ALL should be out of the question until you can poke a 7-9mm Digital Camera Probe inside and look inside of the affected Cylinders via the vacant Spark Plug Wells for any disturbed metal on the Piston Heads; and by that I mean the signs of any scratches in the carboned up surfaces or dents or holes in the Piston Tops...ANYTHING.

If you mean to salvage this engine... you are right back at Square One and ALL of us really do wish it were otherwise. From this point forwards... you should proceed cautiously and consider whether or nor it will be less expensive to just find a Low Mileage (Year In Kind) Swap-In Motor, rather than pick up the shovel again and dig the hole you're in any deeper. :>(
Thank you. I am going to remove the head again, and depending on what I see, I am thinking about either replacing the head with another or replacing all the keepers myself as long as theirs no damage internally.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,639
Tampa Bay Area
Without us all having "The Back-Cloth" of the Story regarding what original disassembly-reassembly Parts, Pieces and Procedures you worked with... Feel free to consult with the Members if you think it would be helpful... Here are a few important suggestions that I'll toss your way this afternoon:

(1) To obtain the BEST Possible Instructions... Visit the Link listed below and Download the Complete GM OEM Digital Factory Service Manual for FREE... (Courtesy @Mooseman):

https://gmtnation.com/forums/threads/need-service-manuals-get-them-here.361/

(2) Please... Do NOT Be Tempted to Re-Use the M11 X 2.00 TTY Head Bolts or ANY other Torque To Yield Fasteners... including the Harmonic Balancer-Crankshaft Bolt. Period.

There are a handful of very excellent and very experienced Members with this repair who will never steer you wrong ...so...

Welcome to GMT Nation....
 

chaphar540

Original poster
Member
Aug 31, 2019
6
Houston
Without us all having "The Back-Cloth" of the Story regarding what original disassembly-reassembly Parts, Pieces and Procedures you worked with... Feel free to consult with the Members if you think it would be helpful... Here are a few important suggestions that I'll toss your way this afternoon:

(1) To obtain the BEST Possible Instructions... Visit the Link listed below and Download the Complete GM OEM Digital Factory Service Manual for FREE... (Courtesy @Mooseman):

https://gmtnation.com/forums/threads/need-service-manuals-get-them-here.361/

(2) Please... Do NOT Be Tempted to Re-Use the M11 X 2.00 TTY Head Bolts or ANY other Torque To Yield Fasteners... including the Harmonic Balancer-Crankshaft Bolt. Period.

There are a handful of very excellent and very experienced Members with this repair who will never steer you wrong ...so...

Welcome to GMT Nation....
Thank you
 

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