917 180 degree V 12

[steamer]

This might do the trick......

http://www.model-engine-plans.com/engineplans/combustion/howell2jet.htm?22,20

Dave

bought the plan set for the V Twin.....NICE...   These carbs would do it I think.    We progress!


Dave

[Vixen]

Do you intend to fit the carbs with remote float chambers or will you try to run them direct from a single fuel tank?

Mike

[steamer]

I'll need all the help I can get, so a elevated day tank with a float leveling valve big enough to handle the engine.....I think.

Dave

[gerritv]

Hey Gerrit....I'll probably use cam calc when the time comes...

Though and index plate showing where the events are would be useful to avoid indexing errors..

Dave

My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.

Gerrit

[steamer]

Hey Gerrit....I'll probably use cam calc when the time comes...

Though and index plate showing where the events are would be useful to avoid indexing errors..

Dave

My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.

Gerrit

Understood Gerrit!...Milling lobes using the camcalc program is very similar to the article that you referenced.    It does help a lot in planning the cuts and the index head, as it spits out the moves to get where you need to go.  However, having a reference chart on the cam blank with the timing events helps keep you from being too "human".....I'll need all the help I can get!!!!    Thanks for you interest!!.

[steamer]

dry Sump System

http://www.aviaid.com/pdfs/dsp_install.pdf

Dave

[stevehuckss396]

My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.
Gerrit

What makes a 917 cam more complex than a cam in any other engine?  Just wondering.

[steamer]

The only weird thing about this cam is the timing gear in the middle, and the ends of the bottom cams drive oil scavenging pumps....but in and of itself....I don't think it's that bad.


Dave

[gerritv]

My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.
Gerrit

What makes a 917 cam more complex than a cam in any other engine?  Just wondering.

I see a lot of lobes on 4 cams. I would think some jigs would be beneficial to keep things sorted. A cam with 2 lobes is challenge enough for me :-)

[steamer]

My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.
Gerrit

What makes a 917 cam more complex than a cam in any other engine?  Just wondering.

I see a lot of lobes on 4 cams. I would think some jigs would be beneficial to keep things sorted. A cam with 2 lobes is challenge enough for me :-)

Agreed.     for the record though, it's a 2 valve per cylinder engine....which at least reduces the number of lobes....but to your point Gerrit, staying organized is key!
This "conversation" thread is about the preliminary work.   The engineering of the components and a plan for their execution.    So all valid points!

Steve and I have been having a conversation off line about ignition...or should I say...he's been "learnin" me!   The 917 had dual ignition, with what I suspect were dual magneto distributors.  That would give it lot's of spark power, and be very reliable.       No I'm not going to do a magneto distributor, but I'll post my intentions for dual distributor ignition system.     It's hard to justify taking one of them out, it was such a prominent feature of the engine.   

Challenges:
making a pair of reliable Distributors and plugs  ( Maybe go commercial there)
associated Electronics
right angle helical bevel gear drive for the distributors ( making the gears)
timing the valve train
timing the ignition system
triggering the ignition system.

The above list^^^ and many other challenges are why I've been doodling in this thread.     There's a lot of smart people here.....

This is all the preparatory work that goes into any engineering project.  The bigger the project, the more engineering and planning is required.

 

Dave


ps....there's always the old saying though......"Everyone has a plan until the first punch!"   

[steamer]

A little doodling.....with my computer.....

It scales pretty close!....

1" bore x 0.812 stroke
40 tooth 32 DP crank and power take off gears.

Crank is about 10" long.....

[Mosey]

Six double throat miniature Webers? No?
Mosey

[steamer]

4 Howell carbs, with 8 dummies.......( 1 carb /3 cylinders)......at least that is the plan at the moment.....

Dave

[Vixen]

Sounds like a good plan to me.   

Mike     

[steamer]

Mike, very preliminary, but nothing that is too difficult.    scaling the drawing has worked pretty well so far.

but it's WAY TOO EARLY...to declare a victory.....


Dave