Ageless 9 cylinder radial engine build thread

[starr256]

I decided to purchase the gear cutters needed for the oil pump gears rather than purchase the gears themselves. It was pretty much a wash in terms of cost and I would have three gear cutters when done. Did I mention I am somewhat of a tool junky? Anyway, the gears have been cut and are ready. Next was the stand. It is functional, not pretty. I was going to weld the stand, but realized I had better gain more experience welding before relying on the quality of my weld to handle the anticipated vibrations of an unbalanced engine. The future will be to design and build a test crankshaft that will allow me to test the oil pump efficiency. That operation will require fittings and tubing to the oil pump.
A side note. Center cutting endmills are not flat on the bottom. That's why counterbores a needed. Lesson learned.

 

[starr256]

Mother of Rats! After 6 weeks of effort (not continuous of course, holidays and all), I still have not gotten the oil pump to work. I asked Mr. Hodgson about my lack of pressure and he informed me of number of pertinent items. (1) The completed engine could run up to 2500 RPM. (2) The oil pressure has been found to be as high as 100 PSI. (3) The tolerances on fluid transfer gears and the housing need to be rigorously maintained. I was getting a dribble on the pressure side and no suction on the scavenger side. Carefully measuring and evaluating my machining, I realized I where I blew it. First, I did not initially counter bore the the housing for the oil transfer gears. When I did, I was not spot on with the previous centers, hence the housings were slightly out of round. Second, in a effort to insure rotation of the transfer gears, I shaved their diameters a bit. The combination of the two efforts meant that I had excessive clearance between the gears and the housing. I did insure that the spacing between the transfer gears and the rear main bearing was ~0.001. So, now I will machine a new oil pump housing and a new set of transfer gears. The time spent on creating an environment for testing the oil pump was well worth the effort.

 

[starr256]

Well, I'm back at it after a ridiculously long hiatus to accommodate needed repairs and upgrades to the workshop (stabilize cracked and sinking floor, install wood floor and built two work benches with a bunch of drawers). I have gotten the oil pump working, I think, as I have only tested it with light weight oil. It took remaking the pump gears 5 times and the oil pump body once. Don't feel additional pictures would show anything different. I must admit, design wise, this is a horrendous assembly and maintenance design. Anyway, the bloody thing is somewhat tested and the box marked off. Now for the rest of the back end and start on the front end components. Hopefully, with faster progress and fewer interruptions.

 

[starr256]

Well, after a year of effort, what do I have to show? Aside from 2 five gal buckets of aluminum chips, a 2 pound container of bronze chips, a reworked workshop and lots of life things (COVID, vacations, family visits, etc)? The crankcase, rear main bearing, oil pump, rear seal, impeller air guide and rear cover are done. Attached are the latest parts. My is focus during development is functionality first, finish later.
Note 1: I did find one error in the drawings that was a bit of an issue, mostly due to the order of the parts machined. The air guide is designed to be held in place by being placed between the crankcase and rear cover in a recessed flat. The OD for the air guide is 3.561", and the recesses in the crankcase and rear cover need to mach that. Unfortunately, the drawing for the rear cover has the ID of the recess at 3.375".
Note 2: The interior of the distributor boss on the rear cover needs to be cutaway for the air guide to fit. The drawing shows the cutaway, but no dimensions are given nor any mention in the operations.
Adjustments were made and all is well.
Rear seal - Added note: the shaft oil seal called out in the drawing is no longer made. Need to find one on ebay.

Impeller

Looks ugly, needs that finishing touch I so lack.

I am holding off on the carburetor adapter bolt holes till later.

Oil sump parts
Overall, this project is just what I wanted in turns of complexity and the effort required. I have learned a lot, acquired some more cool tools (the inside micrometer and a tapping head to name a couple), and did not make too many mistakes. So, onward to addressing the timing gearing and the crankshaft.
Peace.......

 

[wngman]

Very slick!
I don't design anything using 4-40 unless it does not require tapping. I fear that even with a Tapmatic you will get a broken tap. Wouldn't hurt to order some nitric acid or find a shop with EDM!
Robert

Have been working on the crankcase for a while. It's not done, waiting on tooling. There were a couple of issues, mostly related to limitations of my equipment and skill.
1. There is an internal cavity for the rods. This cavity was a bear to bore out. Why? The cavity is 0.400" deeper that the edges and the edges are in about 2" into the case. The boring required a long (6"), stout (3/4" diameter) and sharp/hard (A1 drill rod) boring bar I had to make. All of the internal grooving tools I found online were insufficient in depth of cut. The one I made worked, sort of. It chattered ridiculously no matter what I did. Got the job done, but it ain't pretty. Should have asked for help.
2. My 5" rotary table with it's 3" chuck were a challenge. Forget the chuck. Made a plate to hold the case against the table.
3. Bought a Tormak Superfly cutter. Nice, really nice.
4. There are about 140 4-40 holes to be tapped. I am fretting over breaking a tap and have a thread (no pun intended) on holes/tap. One suggestion I latched on to was to acquire a Tapmatic (or other brand) tapping head. Got one on eBay, tested it with 1/4-20 holes in aluminum and was impressed. Unfortunately, I need a different collet for the 4-40 taps. Those are a little harder to find. An interesting note. A friend in the machine tool business told me that they used to sell boat loads of Tapmatics, but the current predominance of CNC machines has made the tapping head superfluous. Not for me though.

View attachment 381818

Have been working on the crankcase for a while. It's not done, waiting on tooling. There were a couple of issues, mostly related to limitations of my equipment and skill.
1. There is an internal cavity for the rods. This cavity was a bear to bore out. Why? The cavity is 0.400" deeper that the edges and the edges are in about 2" into the case. The boring required a long (6"), stout (3/4" diameter) and sharp/hard (A1 drill rod) boring bar I had to make. All of the internal grooving tools I found online were insufficient in depth of cut. The one I made worked, sort of. It chattered ridiculously no matter what I did. Got the job done, but it ain't pretty. Should have asked for help.
2. My 5" rotary table with it's 3" chuck were a challenge. Forget the chuck. Made a plate to hold the case against the table.
3. Bought a Tormak Superfly cutter. Nice, really nice.
4. There are about 140 4-40 holes to be tapped. I am fretting over breaking a tap and have a thread (no pun intended) on holes/tap. One suggestion I latched on to was to acquire a Tapmatic (or other brand) tapping head. Got one on eBay, tested it with 1/4-20 holes in aluminum and was impressed. Unfortunately, I need a different collet for the 4-40 taps. Those are a little harder to find. An interesting note. A friend in the machine tool business told me that they used to sell boat loads of Tapmatics, but the current predominance of CNC machines has made the tapping head superfluous. Not for me though.

View attachment 381818

 

[wngman]

An update that may be of interest.
1. I have tapped 90 4-40 holes to date. All by hand using two taps. The taps are HSS spiral two fluted bottoming taps. Sharp, damn sharp. I was amazed how easy it went. Still have another 50 to go, but I am feeling a bit more comfortable with the process. Why didn't I go with the Tapmatic? The needed collet won't be here for another week or so. Jittery impatience, that's why.
2. Came across another build order issue. I want to finish everything that needs to be done while the crankcase is on the rotary table, as I thing it will be a real bug-a-boo to get it aligned again if I were to remove it. Well, the holes for the value push rod tappets are to bushed (real word here?) with brass busing that are to be reamed after they have been pressed into the crankcase. The holes are 9' off each cylinder's centerline. It will be easy to get the reaming alignment right I leave the crankcase on the rotary table. Hence, I really should make the bushings (18) now, press them in and ream the accordingly. So, we will stop and make the bushings. So many chicken and the egg discussions.

Did you finish the motor?

 

[starr256]

Did you finish the motor?

Oh no. Still a project in process, a very Zen kind of process. Looks to me as if you are much further along.

 

[wngman]

Oh no. Still a project in process, a very Zen kind of process. Looks to me as if you are much further along.

I started in feb. of this year we will have to stay in contact as go along if possible i will be taking a little time away from it for a little while though gotta do a few other things then get back at it

 

[wngman]

I decided to purchase the gear cutters needed for the oil pump gears rather than purchase the gears themselves. It was pretty much a wash in terms of cost and I would have three gear cutters when done. Did I mention I am somewhat of a tool junky? Anyway, the gears have been cut and are ready. Next was the stand. It is functional, not pretty. I was going to weld the stand, but realized I had better gain more experience welding before relying on the quality of my weld to handle the anticipated vibrations of an unbalanced engine. The future will be to design and build a test crankshaft that will allow me to test the oil pump efficiency. That operation will require fittings and tubing to the oil pump.
A side note. Center cutting endmills are not flat on the bottom. That's why counterbores a needed. Lesson learned.

 

[wngman]

I used a boring head that will allow me to face flat the bottom gear cavity flat and hold the .001 gear clearance also a .003 clearance from the rear main bearing my boring head works simular to the waulhoper head