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| Re: Burned valve [message #274179 is a reply to message #274177] |
Sun, 22 March 2015 10:42   |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Soft spot in the seat or valve? Bit of side play in the guide? crystal in the metal, seat or valve edge? Blind dam' bad luck? Any reason that cylinder ran lean?
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Burned valve [message #274184 is a reply to message #274177] |
Sun, 22 March 2015 11:13 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Probibly the best choice. I had a head that cracked because of a pressed in exhaust seat after 30,000 miles.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] Burned valve [message #274188 is a reply to message #274186] |
Sun, 22 March 2015 11:55 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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On Mar 22, 2015, at 12:30 PM, Matt Colie wrote:
>
> I hope Jim Miller hops in here. When he was into an Olds engine, he saw a mis-alignment of a water port on the front of the block. It wasn't a place one would normally see. I think it was left bank,
HI Matt,
It was the left bank. The mis-alignment was between the hole in the timing chain cover plate and the water pump; a portion of the water pump casting occluded about 30% of the hole in the plate.
There was no mis-alignment on the right bank, only the left.
This was discovered as I was re-assembling the engine after dealing with a cracked head on the left side....the crack was in the web between the valves on the cylinder closest to the water pump. To this day I wonder if decreased coolant flow due to the alignment problem was contributory to the cracked head.
--Jim "saving the lives of Onans...one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Burned valve [message #274191 is a reply to message #274188] |
Sun, 22 March 2015 12:47 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Here's a picture illustrating the alignment problem. This is a MOCK UP that I put together out of parts in the junk pile to show what I found on my engine (which I neglected to take any pictures of, hence the need for the mock up).
The portion of the water pump casting that is painted white is the part I had to remove with a burr before re-assembling my engine.
http://www.jcmco.com/gallery/album28/aaa
--Jim "saving the lives of Onans...one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: Burned valve [message #274192 is a reply to message #274177] |
Sun, 22 March 2015 12:54 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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That was the head that also had a blown head gasket that led to the rebuild 6K miles back. I recently had the water pump off but did not know to look for the misalignment. Did you open up the steel timing plate cover also? If so, how did you protect from getting metal slivers in the water passages?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Burned valve [message #274194 is a reply to message #274192] |
Sun, 22 March 2015 13:20 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Senior Member |
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On Mar 22, 2015, at 1:54 PM, Kerry Pinkerton wrote:
>
> That was the head that also had a blown head gasket that led to the rebuild 6K miles back. I recently had the water pump off but did not know to look
> for the misalignment. Did you open up the steel timing plate cover also? If so, how did you protect from getting metal slivers in the water
> passages?
It was only necessary to remove material from the water pump casting...while being careful to not remove too much. It would be easy to weaken the casting at that location. I cleaned up everything in the parts washer, followed by solvent wash, followed by compressed air blast.
Did you have your replacement heads magnafluxed or DPI'd? In the process of fixing the cracked head on my engine I had bought two sets of heads, one from craigslist, one from ebay. Two out of the four had cracks in the #1 cylinder...
--Jim "saving the lives of Onans...one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: Burned valve [message #274197 is a reply to message #274177] |
Sun, 22 March 2015 13:50 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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kerry pinkerton wrote on Sun, 22 March 2015 08:06Well crap. The fun just keeps on coming. I've been noticing a 'cough' for the past couple thousand miles...getting progressively worse. Not a backfire...just a cough. Not often, every hundred miles or so.
I don't reallu understand why this ONE cylinder on a 5000 mile engine did this but #7 will always run a bit hotter I think. The shop guy said that he'd prefer to use one of the bare heads rather than put a seat that one because they have had problems with seats due to different expansion rates and crappy fuel.
How did the intake gasket for #7 look? Any appearance of a mis-match there? If it was sucking air from the valley #7 could go lean. Any signs of extra heat? I see a crescent on the intake that made me look.
Sure sorry you are having so much trouble with a new engine. Discouraging.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Burned valve [message #274198 is a reply to message #274177] |
Sun, 22 March 2015 15:33 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Your experience sent me back while I had the hatch open anyway to check the carb mount bolts. Front two lere loose, they're tighter now. Back were snug. Screws are snug now. No air leaks, but srain on the side of the float bowl gasket on down. Maybe missed a bullet.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] Burned valve [message #274207 is a reply to message #274191] |
Sun, 22 March 2015 19:38 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Jim,
Thanks,
I'm glad you came to rescue me.
I thought I still had those pictures. I might, but no telling which backup they are on now.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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Pulling the #7 spark plug wire at the distributor didn't produce any change in RPM or vacuum which indicated it was pretty dead. So Thursday evening I pulled the head and found the exhaust valve recessed a good 3/32nd into the head. 
