| [GMCnet] Blueprinting an Internal Combustion Engine [message #281262] |
Thu, 02 July 2015 09:29  |
BobDunahugh
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
Karma: 11
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I've heard this term bounced around a few times over the years here. And it's a subject that is not well understood overall . It's the process of making EVERY factory dimension perfect. It's expensive, and time consuming. I'll give you some examples. Because I don't want to make this e-mail into a paperback novel. When our engine came from GM. There is what's called the deck height. That's the distance from the center line of the crankshaft to the height of the block were the heads are bolted too. With mass produced engines. This height will always be on the positive side. Too short. The piston could end up running into the cylinder heads. This positive dimension will be in the range of .005 to .020. Depending on engine design, and material used in the block. Blueprinting that dimension will put it to perfect factory specs. That is when the four corners. And all surfaces between will be the same. On our V8's, that also means that both deck heights will be perfect to e
ach other. As to the crankshaft itself. The rod journals aren't always turned to their proper timing to all the other rod journals for proper top dead center timing. This means that the rod journals must be ground to their proper positions on the crankshaft. All four rod journals in our case.The heads. One examples here. CC'ing the heads. This means that all combustion chambers are made to have the same volume in CC's.These three examples are just the tip of the iceberg. So if you hear someone say that their engine was blueprinted. Ask for some details. You will probable not get much of a response back. Because for what it cost. And them seeing the bill. They would know the details.Engine work is time consuming, thus expensive. John, and Teresa are getting off cheap. Their just paying for the parts. I will balance it.
Bob Dunahugh Member GMCMI
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| Re: [GMCnet] Blueprinting an Internal Combustion Engine [message #281267 is a reply to message #281262] |
Thu, 02 July 2015 10:05  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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We blueprinted a couple of 1275CC Spridget engines for an H/P car at Mac's. Took us a week of evenings. Why bother, someone says? Well, it might get you 50 extra rpm or a couple of extra hp. In class racing, either of those means you win instead of you're in the pack.
Bob, will it pay off on a motorhome engine? (Aside from the pride of knowing it's absoultely correct).
--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] Blueprinting an Internal Combustion Engine [message #281317 is a reply to message #281267] |
Thu, 02 July 2015 15:23 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Johnny Bridges wrote on Thu, 02 July 2015 10:05We blueprinted a couple of 1275CC Spridget engines for an H/P car at Mac's. Took us a week of evenings. Why bother, someone says? Well, it might get you 50 extra rpm or a couple of extra hp. In class racing, either of those means you win instead of you're in the pack.
Bob, will it pay off on a motorhome engine? (Aside from the pride of knowing it's absoultely correct).
--johnny
I did all that to the engine in the vette along with splayed 4 bolt mains.
What an absolute waste.
I had big plans on being a drag racer until I found out what I was up against.
I'll never do that again.
Definitely not in a motorhome. That rebuild was minimal machining, done right, but only if necessary.
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Blueprinting an Internal Combustion Engine [message #281325 is a reply to message #281262] |
Thu, 02 July 2015 17:56 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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We had the equipment at Mac's to do it with, and he didn't mind us using it after hours. So, all it took was time. Fun and got Bob (Norwood) a couple of trophies he likely wouldn't of got otherwise.
--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] Blueprinting an Internal Combustion Engine [message #281326 is a reply to message #281262] |
Thu, 02 July 2015 18:04 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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I did the complete blueprint thing ONCE 31 years ago...it was over 2000 even back then. That engine held up to a blower and nitrous though, and is still together today.
Ive learned to concentrate on the things that really make a difference in performance and longevity. Proper bearing clearances, straight deck surfaces, main journal alignment and most of all cylinder finish and clearances. And balancing, always.But even that gets expensive.
Much of the more esoteric blueprinting doesn't really do that much for you, especially on a cost basis
76 Glenbrook
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| Re: [GMCnet] Blueprinting an Internal Combustion Engine [message #281470 is a reply to message #281326] |
Sat, 04 July 2015 20:56 |
bhayes
Messages: 263
Registered: March 2010
Karma: 1
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This thread got me thinking. Do any modern CAD drawings of various GMC components exist? As parts get more difficult to find, it would be advantageous to have accurate CAD drawings to 3D print components that are out of production. At some point in the (possibly) not-so-distant future, 3D-printing the components to build something as complex as our drivetrain will be possible. And just think of the possibilities of being able to modify these components.
Just a thought I'm sure many others in the GMC community have pondered. 
Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
[Updated on: Sat, 04 July 2015 21:18] Report message to a moderator |
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| Re: [GMCnet] Blueprinting an Internal Combustion Engine [message #281488 is a reply to message #281470] |
Sun, 05 July 2015 07:18 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Bryan,
There will be no CAD prints of OE parts from our coaches as GM did not really go to CAD until the early 80's. Theoretically, Cinnabar has all the drawings that exist as they did buy the rights from GM.
To the best of my knowledge, there are no completely 3D processes that can produce the equivalent materials to cast iron or forged steel. I have had 3D parts made in sintered steel (aluminum has been done but it takes real special stuff and I was told that the attempt a magnesium was a great show and the repairs were very expensive), but they were no stronger or tougher than a low pressure powered steel part. The good part was that they could be made without any tooling.
The really neat part is that home desktop grade computers are now more than the power of the mega-buck cad systems of the 80s.
Stand back and watch.
Matt
bhayes wrote on Sat, 04 July 2015 21:56This thread got me thinking. Do any modern CAD drawings of various GMC components exist? As parts get more difficult to find, it would be advantageous to have accurate CAD drawings to 3D print components that are out of production. At some point in the (possibly) not-so-distant future, 3D-printing the components to build something as complex as our drivetrain will be possible. And just think of the possibilities of being able to modify these components.
Just a thought I'm sure many others in the GMC community have pondered.
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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| Re: [GMCnet] Blueprinting an Internal Combustion Engine [message #281504 is a reply to message #281262] |
Sun, 05 July 2015 13:16 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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For interest sake and for a great document to have. I would love to see a set of blue prints (engineering drawings and specs) and casting mold and core drawings and specifications for the 455 engine and parts. It would also be a wonderful addition to Gene's document site.
However. Im sure that there might be aftermarket companies that would love to hsve them too.
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: [GMCnet] Blueprinting an Internal Combustion Engine [message #281513 is a reply to message #281262] |
Sun, 05 July 2015 16:59 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Well, I learnt to balance machinery on a summer job building cotton gins. I built paddle fans that blow the lint through the gin flues. 6 BIG paddles on a hub. Balanced them in lots of 6 on a shadowgraph, and then assembled the rotor and spun it in a lathe with a pickup and strobe like an old style wheel balancer. Weld on a blade till it spun in the green. Just like an engine, you did >not< want to be beside one of those if/when it came apart.
--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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