[RomanLini]

Fantastic motor! Especially the blower! Wow!

How did you calculate the rotor profile to ensure full seal (full engagement) at every angle of the two rotors? That's a tough thing to do.

And will you drive both rotors with gears, or will you just drive one rotor and leave the other driven only by the rotor engagement?

[cforcht]

its Steve's design but its pretty much a carbon copy of the detroit diesel roots blower that came on most detroit inline diesel engines. his design uses straight rotors instead of helical. far easier to produce than helical. which would require a mill with a full 4th rotary axis. the rotors are coupled together with a pair of gears under the front cover. if they are not in place the rotors will jam. in practice the rotors never actually touch each other. if they do touch galling usually occurs and then it gets ugly inside the blower. or if it ingests something other than air it will chew things up as well.

[stevehuckss396]

its Steve's design but its pretty much a carbon copy of the detroit diesel roots blower that came on most detroit inline diesel engines. his design uses straight rotors instead of helical. far easier to produce than helical. which would require a mill with a full 4th rotary axis. the rotors are coupled together with a pair of gears under the front cover. if they are not in place the rotors will jam. in practice the rotors never actually touch each other. if they do touch galling usually occurs and then it gets ugly inside the blower. or if it ingests something other than air it will chew things up as well.

It was supposed to be a copy of this one. It is also the reason the heads have a big block chevy valve cover on them. I miss my Chevy so I'm trying to get it back in the garage in model form. It's a BDS blower. I even engraved BDS in my front cover.

[cforcht]

now if that doesnt make your heart race you need to go lookin for a burial site and start diggin.

[Ken_Shea]

Yeah, it gave me a few twinges from the past but I nothing that bad.

[stevehuckss396]

now if that doesnt make your heart race you need to go lookin for a burial site and start diggin.

Scared the crap out of me a few times. 1225Hp and 1000FtLbs torque. Sometimes you would forget what you were driving. Was on the freeway doing 60ish in 3rd gear. Fellow come up next to me and he hits second gear and away he goes. I just left it in 3rd and let er eat. Used all 3 lanes before the tires stopped burning and I got it going straight. By the time I went by him I was up around 160-170ish. Scared him so bad he was using more than one lane.

Good times!!

[stevehuckss396]

I was working on my ignition and it hit me that you have an opertunity to make something better. When I designed the distributor I had to make it "out of scale" so it would work. You won't have to scale it up 1.5 times for it to work and you can make it look a lot more correct as far as size goes.

Something to consider.

[cforcht]

LOL I just made the distributors last night. for now I will stick with the plan in progress. maybe later I will re-make them to scale. but thanks for the info. I did watch you vid. looks good and great to know it actually works. but I was pretty confident your design would work. I tinker with the electronic ignitions for RC on a regular basis since many of my planes are large scale running gasoline engine.

[cforcht]

Besides Steve. I dont think the scale of the distributor is that far off if you compare it to an HEI instead of the old points style or even the aftermarket MSD unilite types. but I do agree the smaller distributors did look better even on the real engines. the HEI was one big ugly distributor.

[dynosor]

the crank is yet to be decided. I am leaning toward a modular style crank.

Hi Craig

I am concerned that the joints in a composite crank will come loose after a short while of running due to the torsional vibration, unless you silver solder them. That said, I think machining a crank from solid would be easy for you, considering my brother and I roughed one out on his CNC mill not very long ago.

He ran the rotary table using the Y-axis data, hence the back and forth motion, using only two programs: One for cutting the main journals and one for the crank pins. All X-axis positioning was driven manually to the desired offset coordinates for the next journal. Positioning of the blank onto the appropriate pair of centers was also done manually. The rotary axis had been positioned directly under the spindle before machining started.

To prepare the blank it was faced in a lathe, then the seven rotational centers at each end were center drilled to accurate depth and appropriate X/Y coordinates in a horizontal mill beforehand. Perpendicular flats on the shaft ends were used to index the centers from end to end.

I just posted the crankshaft machining video on youtube in HD.

http://youtu.be/NV1ZOzAaXbo

[cforcht]

got the blower snouts made.

[cforcht]

also got the rocker arms made. the little parts are where all the time is. doing the big parts first makes it seem like I am flying along when its the little parts that really take all the time.

[cforcht]

heres the distributor housings. note the nice ding in the end of one. where mister butter fingers here dropped in on the floor. needless to say I had flash backs of the Marine corps with the language that was being unleashed.

[cforcht]

Dyno,
I hear ya. Its not that I dont think I can make a one pc crank. I just had my heart set on using ball bearings on all the journals instead of split bearings on three of them. dont ask me why, I know car engines use split bearings and get thousands of miles on them hundreds of thousands actually. maybe I will rethink that. Im at that juncture of I know what I "should" do but its not what I "want" to do.

[cforcht]

Im considering hard anodizing the rocker arms. not for aesthetics sake. but from a wear standpoint on the trunnion area. hard anodizing has a surface hardness of around 60RC. comparable to HSS.

any thoughts?

[dynosor]

Im considering hard anodizing the rocker arms... but from a wear standpoint on the trunnion area. hard anodizing has a surface hardness of around 60RC.

It probably couldn't hurt, but hardness of one part does not have to cause wear in a softer mating part. It is only so if the hard part is rough or sharp so that the contact pressure is high. Think about your car's crankshaft on those soft babbit bearings.

[dynosor]

Dyno,
I just had my heart set on using ball bearings on all the journals .

Ball bearings have way lower friction than plain bearings - that is why RC model engines use them.

If you go this route you can get a head start by buying appropriate diameter gauge pins for your journals - very precise, hard and smooth.


McMaster charge $3.25 for 0.375" diameter plug gauges: McMaster-Carr

They are Rc 62 - 64 with asurface smoothness is 8 microinches or better.

[dynosor]

Ball bearings have way lower friction...

You could also consider if your V8 could accommodate larger ball bearing races as are used in this V12 model:

[ame="http://www.youtube.com/watch?v=UMu_WR2Oj7g&feature=player_embedded"]‪Artus V12 Motor die Entstehung‬‏ - YouTube[/ame]

Bearings can be seen at 1:07

[RomanLini]

Thank you both for the blower info. That's awesome work.

I like the bigger Chevy too!

Im considering hard anodizing the rocker arms. not for aesthetics sake. but from a wear standpoint on the trunnion area. hard anodizing has a surface hardness of around 60RC. comparable to HSS.

any thoughts?

I have a feeling hard anodising may be abrasive, from memory the surface is rough and porous on a microscopic level.

I'm no expert on it though so it's probably best to talk to your anodising guy about it's suitability for a bearing surface.

[cforcht]

I know soft anodizing is porous thats why it will take dye to make it a given color. hard anodizing does not take dye very well.

ahh screw it I will just leave it as is. Im probably over analyzing things again. thats why I can't shoot pool while Im sober.
if they wear out I will worry about it then. its not like I cant make the parts again.