The Le Rhone 9C

[derekwarner]

 ...'make a ‘custom’ spacer that will fit over the cylinder threads' ...

I am a little lost here,  are these [nominal 1/32"] custom height spacers to compensate for some radial alignment of the cylinder head XX 
 diameter x 32 TPI - thread & relationship to a port?

Derek

[Craig DeShong]

Derek

Yes.  I can’t control how the cylinder will align when it snugs up against the engine case but the cylinder needs to be aligned so the spark plugs, when threaded into their receivers are aligned parallel to the front of the engine case.  More importantly, since the cylinder heads attach to the cylinders with four cylinder head bolts, this will allow proper head alignment with respect to the intake pipes and valve pushrod.

in order to facilitate this relationship I need to make spacers that, when the cylinder is properly aligned with respect to the engine case, take up the space between the edge of the cylinder that faces a flat on the engine case and that flat.  Since I couldn’t control the start location of the threads on the cylinders, this spacing will be different for each cylinder.  The custom made spacer for each cylinder will be sized in thickness so that just as the cylinder tightens up against the spacer, and the spacer against the cylinder flat, the cylinder will be aligned properly.

I see the as a repetitive process where I’ll start with a spacer too thick, and then keep working the thickness down, trial fitting the cylinder to the engine case, until the cylinder aligns properly.  Then do likewise with the next cylinder until all nine are aligned properly.

[sid pileski]

I understand the described process.
How/what did they do on the full size engine?

Sid

[bent]

Not sure how big the thread is, but you can buy laminated shim stock in rings up to 1.5" i.d. from McMaster Carr, might make the process of adjusting the shim height a bit easier?  If you can't find the right size, you can purchase sheet stock and cut ring shims from it, or have custom cut shims made (McM offers that).

[Elam Works]

How/what did they do on the full size engine?

There was a threaded locking ring; basically a jam nut. The cylinder was screwed in to a depth set with a distance gauge, then turned to the nearest position that would align the cylinder with the manifolds/pushrod/etc. Then the locking ring (already in position) was run down the cylinder base and jammed against the crankcase spigot. The process is shown in the assembly animation video posted earlier in the thread.

-Doug

[Jasonb]

Don't know how much material you have to play with but the other alternative is to take metal off the cylinder shoulder. You should be able to work out how many degrees further the cylinder needs to turn so the holes line up and then it's just a case of x/360 x 0.03125". If you play about swapping cylinders to find the best fit you probably won't need more than half a turn eg 15 thou off any one.

[Craig DeShong]

Thanks for stopping by.  Also- thanks for the comments / questions.

Sid: Doug answered your question.  No need for me to elaborate.

Ben and Jason:  Thanks for your suggestions.  I will always, respectfully listen to the advice of others.  In the past, several of you have kept me from heading down a path that would have ended in a traffic wreck.  In this case though, I believe I’ll follow my original plan.  I can easily make spacers from some steel stock.  The magnetic vice on my surfacing machine will hold them securely in place while their thickness is being reduced.  The surfacing machine will accurately remove as little material as ½ of a thousandth of an inch at a time.  I should be able to easily ‘fine tune’ the thickness of each individual spacer to the cylinder on which it will be used.  Still, thank you for your suggestions, I do appreciate them and you folks often come up with a better solution than the one I’m contemplating.


Work continued today on the remaining four cylinder jugs.  In the photo below I’m drilling the top four holes that will allow the cap screws, coming up from below, to attach the cylinder head to the cylinder.



Below I’m cutting the relief inside the cylinder to allow the air/fuel mixture to reach the spark plug.



Below, the Volstro rotary milling head is cutting the top of the cylinder back, leaving the spark plug boss.  On the full size I would assume this boss is formed when the cylinder is cast.



The next step was to cut the cylinder fins that abut the spark plug boss and don’t continue completely around the cylinder.  The remaining fins I’ll cut on the lathe.



Drilling and tapping the hole/threads for the spark plug.



Here I’ve reversed the fixture in the vice and am drilling the holes in which the cap screws that attach the cylinder head will pass.  These holes have a larger diameter than the previous holes and allow the cap screws to drop into the hole and stop at the shoulder formed between these holes and the ones I drilled in the first photo of this post.



The cap screws reside deep within the cylinder.  Here I’m using an extended drill to complete drilling out the passage to the correct depth.



A family photo of the four remaining cylinders.


This work is progressing faster than I expected.  Rather than finish the cylinders by the end of November, I’m thinking I may actually complete them by the end of October.

[cnr6400]

 

[bent]

Well, yeah, with a surfacing machine why bother with shim stock?  Nice work on the cylinders.

[Craig DeShong]

Thanks for stopping by, and thanks for the comments/suggestions.

I’m rolling right along with these cylinders; maybe there is something to be said with time savings in bringing them all along at the same time.

Today was concerned with drilling/boring/reaming the cylinders to their finished diameter.

Below I’m drilling the center out to ¾ inch (my largest drill).  I started with a ½ inch, then graduated to this ¾ inch drill.
]


Next was the task of boring the cylinder out to a tad (ten thousandths) under the final diameter of 1 inch.



I have a 1 inch ream from a previous project, so I used the ream to finalize the bore diameter and achieve a smooth finish.  I might do a little light honing, but the surface of these cylinders looks pretty good.



The family shot of the four remaining cylinders.



Tomorrow afternoon I’ll start the single remaining task of cutting the remainder of the cylinder fins.  If I have a good day I might finish these cylinders tomorrow!!!

[crueby]

Moving right along on the cylinders - great stuff!

 

[Kim]

Excellent progress, Craig!   

As long as you're having fun, you're doing it right

Kim

[Craig DeShong]

Thanks for stopping by and… thanks Chris and Kim for the encouragement.

This afternoon I finished up the remaining items on the four remaining cylinder jugs and with this, the cylinders have been completed.

First was cutting the remaining fins, progressing down the cylinder side.  In the photo below I’m well on the way to finishing this cylinder’s fins.



The last step was to cut down the remaining diameter below the lowest fin.  This was done by standard turning.



Below: the engine case with the nine completed cylinders mounted to the case and in position.  I have to make the spacers that hold the cylinders in position from rotating yet but I’m in no hurry with them; they can wait till later.

[petertha]

Looking great!
Not wanting to jump too far ahead but what is your plan on the overall ignition system? Are you miniaturizing something along the lines of the FS engine, or have another plan in that regard? You mentioned spark plugs - what size/type?

[MJM460]

Hi Craig, to have all cylinders at that stage and mounted up is a major milestone.

Well done.  It certainly looks like the production method on similar parts was time efficient.  It must feel good to have made so much progress.

MJM460