Home » Public Forums » GMCnet » [GMCnet] Part II The Untimely Demise Of A Well Maintained 455
| [GMCnet] Part II The Untimely Demise Of A Well Maintained 455 [message #280958] |
Sun, 28 June 2015 20:29  |
BobDunahugh
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
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>
>
> Continued from Part 1
>
> So what did happen to this well maintained (by it's owner) 455. It appears to have slowly started in the bearings selected, but mainly acerbated by contamination of the oil. Some of the source of the foreign material, may have been introduced while other work was done, or may have been introduced by the engine oil cooler.
>
> You may think that the oil filter should have removed the contaminants. This is the situation. Oil comes out of the oil pump and goes directly to the oil cooler. If there is any trash in the oil, it then comes back to the oil filter to clean out the trash from the cooled oil. After leaving the oil filter, it goes directly to the bearings and lifters. So this oil should be clean for use, right? Not quite so. There is a oil filter bypass valve in the oil filter support housing. When the engine oil is cold, and thicker, the oil filter can't flow enough oil to lube the engine correctly. The oil filter bypass valves allows unfiltered oil to go to the engine bearings. In reality, the bypass valve is always bypassing unfiltered oil. And yes, GM planned it that way. I tested that oil filter bypass valve today. It opened at 6 oz of pressure.
>
> The oil in the system is mostly clean all the time. The filter's job is to remove extremely tiny contaminants, mostly carbon from the combustion of gasoline in the combustion chambers. As a note, newer engines are made to not allow as much combustion contaminants to enter the crankcase. That's why synthetic blended oils are recommended and are are so good for so many miles in newer engines.
>
> With the old design of the engines that we have, it's best to change your oil at shorter intervals. In this manner, you end up draining the contaminant of carbon that are too fine for the filer to hold. This carbon is very abrasive in our old technology engines. That's one of the reasons why engine oils get black. So it's best to use mineral based oils in our 403's, and 455's. For this reason, you will never see me put synthetic oils in any of my older tech engines. Plus, you should never leave any type of used oil in an engine for more than a year.
>
> So if you drive less then 4,000 miles a year, what good is synthetic oil?
>
> This engine had a High Volume oil pump which had nothing to do with this engine failure at this time. But the extra load of the HV pump was causing extra deterioration of the stock oil pump driveshaft. But the HV oil pump just may have been what got Glen, and BJ the last few miles home.
>
> There is no doubt in my mind, and the minds of others, that GM did a great job in their design of the 403, and 455. There are lots of well maintained GMC's out there that have traveled a lot of miles over the years. The other day, Fred Hudspeth had a post that talked about the OEM engines that came in our GMC’s back in the day and his thoughts on why those OEM 403's, and 455's held up so well. He had a very good point. We use our engines in the way GM intended them to be used. Fred's point, and I totally agree, was to remanufacture them to the exact specifications that GM did when new. Don't go by the wide range of what might be shown as allowable clearances. Have it really built purestock as NEW. I'm not one of those old guys that think things must be kept purestock no matter what. That's not me.
>
> If you want to put any engine in a service that the manufactures had no intention of it being used changes from stock are a must. As an example, I have several Yenko Stingers. (Corvairs) I take a Corvair engine that has a whopping 164 cubic inches, and a base HP of a huge 95 ponies. It is then modified so that when it's checked on a dyno, it can crank out 242 HP. The RPM redline is in the 8,000 range. No turbocharging, no nitrous, just pure engine. In this situation, mods are required. A friend once said that an engine like that is a hand grenade, with the pin half pulled. He has a point there.
>
> My point here is that with our stock engines, OEM parts, and to new OEM specs will get that performance that GM designed into these engines to start with. (So here I go sounding like Wes at Cinnabar ) GM really knew what they were doing, and time has proved that. My OEM 403 has 154,000 miles on it. On the last long I trip got 10.122 MPG with a carb, pulling Linda's 5,000lb lift van. Our 403 GMC pulls loads that can reach 21,000 lbs GVW. I ran some tests on my 403 last year, and don't plan on doing any more tests till it gets to 180,000 miles. ( Go read Fred's e-mail to see his point. )
>
> As to the High Volume engine oil pumps in freshly remanufactured engines, I fully understand why a HV oil pump is a good idea for some of the engine builders. The coach owner comes in to pick up their coach with its rebuilt engine. It had a stock oil pump installed. The engine reaches normal operating temps. Oil pressure on the road is at 35 to 40 PSI. They stop at a stop light and the gauge drops to 25 PSI. The owners thought is, that's not right, the pressure should stay at 35 PSI. But remember, on the road the pump is at 1,300 to 1,700 RPM. At idle it's at 300 RPM with no load on the engine. So to make the owner happy, the builder puts in a HV oil pump. The HV oil pump idea sounds like a great improvement, as more of anything is always better. Put in a HV pump so the gauge stays a 35 all the time. There is NO deception here to the customer in any way. It just puts the coach owner in an improved comfort zone, and the engine builder looks good. To demonstrate how little oil pressure these engines needed back then, most cars had a light that came on if the oil pressure was to low. The light came on at 7 PSI. That is ALL THE MOTOR NEEDS AT HOT IDLE! Folks who run a DigiPanel will hear their alarm screaming at them when the pressure drops below 20 and some of them have gone to a HV oil pump for that reason (Kerry Pinkerton for one).
>
> Please remember that I'm NOT putting anyone down, or saying that I know more then anyone else. Just engage some common sense, and do what puts you in your comfort zone.
>
> Just my 2 cents worth. Dialog Welcomed.
>
> Bob Dunahugh Member GMCMI
> 78 Royale
> 4 Original Yenko Stingers
> 3 Corvair Convert
> 1 64 Chevelle Convert
> 1 96 LT1 Impala SS
> All Restored
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| Re: [GMCnet] The Untimely Demise Of A Well Maintained 455 [message #281152 is a reply to message #280958] |
Tue, 30 June 2015 23:32  |
BobDunahugh
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
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I posted this topic so that we as a whole might get some other ideas about the failures of engines that have had major work completed on them. One thing could be added, as to a rebuild, and a remanufactured engine. It is generally felt that a remanufactured engine gets bored, crankshaft turned, line bore checked, hardened valve seats installed if not so equipped, and a cleaning that makes all the parts that will be reused. Look like they have never been used. Then checked for cracks, and any other defects. Then put back to GM specs. with new bearings, pistons, rings, oil pump, cam, lifters, timing chain with sprockets, valves, valve springs, and valve keepers. Anything short of this is a rebuild. If just rings, and bearing are installed with no machine work done. I don't know what you'd call that. Other than, not much.Bob Dunahugh
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| Re: [GMCnet] The Untimely Demise Of A Well Maintained 455 [message #281157 is a reply to message #281152] |
Wed, 01 July 2015 02:44 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Bob,
What you've called a remanufactured engine sounds like the basics of a blue printed engine. That's what Dick Paterson builds which
is why his engines cost more than most. I tore down one of his engines and got the list of specs it was built to so that's why I'm
commenting on what he does. Also the engine in Double Trouble was built by Ken Frey and it has around 80,000 miles on it since being
rebuilt so I'd say he knows what he's doing as well.
The remarks above are NOT to be construed that the other people or companies don't do a good job, I don't think it's right for me to
comment as I have NO DIRECT EXPERIENCE with them!
The final sentences of your email below remind me of the 1955 / 272 cu in Ford I rebuilt when I was in the USAF at Westover AFB in
Chicopee Falls, Massachusetts. I didn't have much money so I rebuilt it in the car at the base hobby shop. I reamed the ridge, miked
the cylinders and crank and installed over size rings and undersize bearings. It also got a 3/4 race cam and a four barrel carb.
When it was done and ready to fire up I hit the starter and the engine wouldn't turn over! The starter solenoid clicked and the
starter tried to turn but it wouldn't turn the engine. To get the thing to start we hooked it to my buddies truck and got up to 25
mph and I popped the clutch. The rear tires screeched for a second and then the engine turned over and fired up. I had a tach so I
kept it running at 2000 rpm (break in the cam) and he towed me back to the auto hobby shop parking lot where I let it run long
enough to break in the cam. I then pulled it back into its slot in the shop and shut it down. I let it cool down then we changed the
oil and filter. When that was done I hit the starter again and off she went! Thing ran pretty good as I blew up three manual
transmissions and a couple of rear ends hot rodding it. The car met its final demise when I was driving down a dirt road near
Westover one night and hit a BIG pot hole. The lower control arms tore out of their frame mounting points because the front
crossmember had rusted so badly there was hardly any good metal left. The front end took a nose dive into the dirt with both wheels
splayed out. I hitched a ride back to base and came back the next day only to find that someone had stolen the carb so I took the
plates off and kissed it goodbye.
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Bob Dunahugh
I posted this topic so that we as a whole might get some other ideas about the failures of engines that have had major work
completed on them. One thing could be added, as to a rebuild, and a remanufactured engine. It is generally felt that a
remanufactured engine gets bored, crankshaft turned, line bore checked, hardened valve seats installed if not so equipped, and a
cleaning that makes all the parts that will be reused. Look like they have never been used. Then checked for cracks, and any other
defects. Then put back to GM specs. with new bearings, pistons, rings, oil pump, cam, lifters, timing chain with sprockets, valves,
valve springs, and valve keepers. Anything short of this is a rebuild. If just rings, and bearing are installed with no machine work
done. I don't know what you'd call that. Other than, not much.Bob Dunahugh
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Part II The Untimely Demise Of A Well Maintained 455 [message #281174 is a reply to message #280958] |
Wed, 01 July 2015 08:49 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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I was always taught - 'freshened' new rings and bearings, grind the valves. "Top" take the heads down to the machinist and have them reworked. 'Overhaul' take it apart, clean it up, replace everything that isn't spec and assemble it to spec. 'Remanufacture' Take a bunch of them apart, clean each of the pieces, discard anything that doesn't mike standard, assemble a set of matching parts, then build engines to new factory spec. Note that a 'remanufacture' was assembled out of a box of matching parts, not necessarily from the same engine. If you bought a 'reman' from Avco or Teledyne, it was the latter. If you bought a rebuild from Mac's, the non spec parts were either brand new factory or PMA, and they had all lived together before the thing was disassembled. They're familiar with each other. There used to be "top" and "rebuild" gasket kits available for most popular engines at a savings from individual pieces.
--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
[Updated on: Wed, 01 July 2015 08:58] Report message to a moderator |
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| Re: [GMCnet] The Untimely Demise Of A Well Maintained 455 [message #281179 is a reply to message #281152] |
Wed, 01 July 2015 10:31 |
Joe Weir
Messages: 769
Registered: February 2013
Location: Columbia, SC
Karma: 7
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BobDunahugh wrote on Tue, 30 June 2015 23:32
...If just rings, and bearing are installed with no machine work done. I don't know what you'd call that. ...
LOL. The "bumblebee aerodynamics" rebuild. It works, despite all evidence that it shouldn't. I don't have that kind of luck, but I've heard stories...like Rob's.
76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator, brakes, Sully airbags, fuel lines, seats, adult beverage center... those Coachmen guys were really thinking about us second hand owners by including that beverage center...
Columbia, SC.
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| Re: [GMCnet] The Untimely Demise Of A Well Maintained 455 [message #281189 is a reply to message #281179] |
Wed, 01 July 2015 11:40 |
James Hupy
Messages: 6806
Registered: May 2010
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That we know as an "Okie" rebuild. What Pofolks do when that is all they
can afford. Not your best job, but it might get to to the the land of milk
and honey.
Jim Hupy
On Jul 1, 2015 8:31 AM, "Joe Weir" wrote:
> BobDunahugh wrote on Tue, 30 June 2015 23:32
>> ...If just rings, and bearing are installed with no machine work done. I
> don't know what you'd call that. ...
>
>
> LOL. The "bumblebee aerodynamics" rebuild. It works, despite all
> evidence that it shouldn't. I don't have that kind of luck, but I've heard
> stories...like Rob's.
>
> --
> 76 Birchaven - New engine, trans, aluminum radiator, brakes, airbags, fuel
> lines, seats, upholstery, adult beverage center... those Coachmen guys were
> really thinking about us second hand owners by including that beverage
> center...
> Columbia, SC.
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| Re: [GMCnet] The Untimely Demise Of A Well Maintained 455 [message #281208 is a reply to message #281189] |
Wed, 01 July 2015 15:31 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Jim,
Thanks! Looks like this "Pofolk" Airman Second Class did an "Okie" rebuild despite being from Nooo Joooisy!
And it did last long enough to save up for another car - a 1957 Buick Roadmaster convertible with wire wheels that had about 12,000
miles on in when I bought it in 1966. It was owned by a guy in my barracks that was a Weather Observer. It belonged to his
grandparents but had serious electrical problems. When you hit the brakes the headlights would come on, turn signals would cause the
brake lights to flash, the running lights turned everything on! I lifted the carpet on the drivers side and noticed the wire bundle
to the rear had a big lump in it. When I grabbed the lump sparks flew! Turned out hey had left it out in the rain at some time and
the cloth insulated wires got soaked and corroded together. Spliced in new wires one at a time and Bob's your Uncle! I left it in my
parents driveway when I got sent to Viet Nam. When I came home in September of 1968 he had sold it for $500 "because it was in his
way in the driveway." A year or so later I found the same model car in Hemming's that was being sold for $14,000 and showed it to
him noting, thanks Dad!
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: James Hupy
That we know as an "Okie" rebuild. What Pofolks do when that is all they
can afford. Not your best job, but it might get to to the the land of milk
and honey.
Jim Hupy
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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