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  #31  
Old 04-13-2006, 05:46 PM
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After hearing Brians 617 purr with a fresh head job, ie new valves, pre chambers. Also he is betting that he breaks 30mpg this summer on the better summer fuel.

I think if you are having running/mileage issues with your 617 you are barking up the wrong tree. At this point in the game a lot of these engines are getting pretty tired.

If the head has never been off I'd think you gain a lot more by pulling it and sending it off to Metric Motors for a valve job.

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  #32  
Old 04-13-2006, 05:47 PM
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Unusual size and shape and only one company makes it as far as I know.

I'm looking at alternatives as it occupies space I want to put my intercooler in. I may end up welding up my own air box.
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  #33  
Old 04-13-2006, 07:48 PM
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Quote:
Originally Posted by imdavid28
Actually when the molecules align, the metal becomes softer..
Not according to the people who do it...

http://www.carbotecheng.com/cryostudy2.html
http://www.metal-wear.com/
http://www.cdpautomachine.com/ecatalog/cryo.html
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  #34  
Old 04-13-2006, 09:52 PM
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Quote:
Originally Posted by ForcedInduction
I've got an itch to pull some extra prechambers from a parts yard and mess with them. Try larger orifice holes and see what happens with the powerband. I just don't want to melt the pistons (I guess waiting until AFTER I get my pyrometer is a good idea )
I too was wondering what this would do. It might be a good idea to know what ratio of the cylinder volume is actually in the prechamber at TDC versus remaining in the main chamber. Anyone have this data??

The more air mass that must pass through into the prechamber, the more pumping losses. However, I'd guess that if there is still a fair amount of air remaining in the main cylinder at TDC, smaller prechamber holes would better facilitate fuel mixing in the main cylinder via higher velocity and turbulence.

What else was done to the C111-III 617 engine besides an aluminum head, intercooler, and lower compression ratio for more boost??

very interesting...
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  #35  
Old 04-13-2006, 11:59 PM
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Quote:
Originally Posted by 1983/300CD

Steel is a special material. It is one of the exceptions to rules just like water is. With that, let me go on.

"Today's cryogenic treatment is a further advancement of this metals-aging "secret" practiced by these old craftsmen."

I visited these sights and none of them seemed to be that of a respectable foundary. I think they are trying to sucker people out of their money.

This will take a while to explain so bear with me.

So hear is the deal. Steel is comprised of mainly carbon and iron (then manganese and other things, bla bla bla, I know.) . Threre is typically two differnt phases in the material. For this we will say alpha and beta (Fe3C actually) are the names of our two phases.

Now, the alpha phase will form a crystal structure. The beta phase, meh, not so much. Its more of that of a glass (liquid, ceramic, dirka dirka...)

Stress is applied to the material. The material begins to elastically deform, until it reaches is yeild strengh. Then this happens. A material plasically deforms by the propogation of dislocations. In other words, lines of molecules break, reform with another line, and pass this "break" on through the lines and lines of molecules. This happens easily in the alpha phase easily because it is in a crystal structure, and molecules slide over one another easier than the messed up arrangement of the "beta" phase.

So these dislocations propogate thought the material till they hit a phase boundary. They stop there. They build up the more that the material is strained. It gets to the point where there is this congestion of dislocations in the material that it resist dislocation movement more and more. This is called stain hardening.

More stress is applied and the steel strains further. The material finally reaches a point where it can no longer pass dislocations through it and the material becomes brittle. Brittle is strong, but not as forgiving. Cracks form through the material form, and the matterial fails. The end.

So the moral of the story. The smaller the grains, the quicker the dislocations become conjested, the stronger the material, the more brittle the material. Visa versa.

An example of large grains being soft is anneled copper gaskets, which they stick in the furnace, grains grow in size, and the material becomes more maleable. Large grains = soft

Sort of. This is where the misunderstanding occurs.

Now I will explain what is going on with the "cryo" system

The process is called quenching. I talked about this before in another post. This is nothing new. You cool the steel so quick that it can't form these two separate phases. Instead, it forms martensite. Martensite has a crystal structure that doesn't like crack propogation. I.E., it is brittle. (and strong) However, brittle matterials are unpredictable, therefore, hardly ever used in engineering. Glass is unbelievably strong....


... if you could cast it free of suface defects and cracks.

Ok I am done for tonight. I hope I was coheirent.
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  #36  
Old 04-14-2006, 02:32 AM
ForcedInduction
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Quote:
Originally Posted by biobenz617
What else was done to the C111-III 617 engine besides an aluminum head, intercooler, and lower compression ratio for more boost??
http://www.allsportauto.com/photoautre/mercedes/c111/III/
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  #37  
Old 04-14-2006, 02:27 PM
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imdavid,
Yes, you were very coherent. Thanks for the info.
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  #38  
Old 04-14-2006, 02:54 PM
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Quote:
Originally Posted by Hatterasguy
After hearing Brians 617 purr with a fresh head job, ie new valves, pre chambers. Also he is betting that he breaks 30mpg this summer on the better summer fuel.

I think if you are having running/mileage issues with your 617 you are barking up the wrong tree. At this point in the game a lot of these engines are getting pretty tired.

If the head has never been off I'd think you gain a lot more by pulling it and sending it off to Metric Motors for a valve job.
I believe he can do that on the highway. I've done it twice on my W123 with 150K miles on it.
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  #39  
Old 04-14-2006, 03:30 PM
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Quote:
Originally Posted by boneheaddoctor
I believe he can do that on the highway. I've done it twice on my W123 with 150K miles on it.
.......we'll see........hopefully the next tank of fuel will be the summer fuel. The difference is so great that you can almost see the difference on how fast the gauge drops.........she's doing a steady 27.5 on the winter fuel........

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