A "Wallaby" of my own

[steamer]

Thanks George! Good to hear that ...the pinions are only 20 tooth and .25" long...so I may worrying for nothing

Dave

 

[ref1ection]

Good looking start to the engine. I haven't had a chance to follow much on here recently but just read this from the start. Great tutorial on the use of faceplates.

Ray

 

[steamer]

Thanks for the interest Ray! It's not the only way to do it or even perhaps the best way.....but the prefered way in my shop with the tools at hand. One of the goals of this thread is to explore that.

Thanks again!

Dave

 

[vcutajar]

Dave

Did you buy or make the gears of the pump?

Vince

 

[steamer]

Hi Vince,

I bought them. they're 10 tooth 32 DP 20PA pinions. They don't make very low tooth count cutters commercially, and considering these gears were about $5 each....I just bought them

I got them from Stock Drive Products.

Dave

 

[vcutajar]

At that price it's not worth doing them. Locally I do not have that luxury. So my next project is to learn how to do gears.

Vince

 

[ProdEng]

Vince, most people will ship overseas, it's always worth asking. I bought my mill from a supplier in USA and he put it in the post! The cost with shipping was $1200 while the Australian dealer wanted $2900!!!!! Ask me why I rarely buy anything in Australia?

Jan

 

[vcutajar]

Jan

I am trying to convince my conscience that I need gear cutters. ;D ;D

Vince

 

[steamer]

Too much going on at home and at work!,,,,,Im off for the holiday tomorrow, so I'll try to finish up on the pump....I'll download the camera eventually..... :

Dave

 

[steamer]

Well, actually got out in the shop this morning and guess who followed me in! My Son!

We took the bearing pilot down on the oil pump after I lapped in the oil pump gears...just a smig...with some rubbing compound. He got to drill an ream a hole in a fixture, put on some feed on the cross slide, engage the power feed, and stop it before the bed dial indicator got to zero....all on the 12" Logan!.....with me ever so close to the action mind you.....

Had a really nice time and I taught him a thing or two....sweeeeeeet! woohoo1 th_wav

I took pictures but still need to get a reader. :

Dave

 

[Don1966]

Glad to here that Dave, that is great. Bet he was excited and anxious. I will be looking for some photos.

Don

 

[ShedBoy]

I am trying to convince my conscience that I need gear cutters. ;D ;D

Vince
I got a full set of good involute cutters from this place a a good price. They will also sell singles.
http://www.ctctools.biz/servlet/StoreFront

Shipping is always reasonable and fast

Dave I just wish my son would show some more interest but he is 16 has wheels and a girlfriend so I am way down the list. Great work so far, are you dreading or looking forward to hogging into them block castings?

Brock

 

[steamer]

.....Great work so far, are you dreading or looking forward to hogging into them block castings?"

Thanks Brock for the interstest and support!

OH looking forward to it!...work has just been nuts!

I'm trying to get the gear driven accessories all sorted so that I can bore the cam gear cover and block/sump casting all in one go. The oil pump has at least 3 concentric datums superimposed on a two non concentric locational datums spread out over 3 seperate castings...the only way I can figure with my little bird brain is to do the boring all in one go after finding the gear center with a toolmakers button.....which is why I'm doing the pump now.

Dave

 

[stevehuckss396]

3 concentric datums superimposed on a two non concentric locational datums spread out over 3 seperate castings

Hahaha!! WHAT???????

 

[metalmad]

I think he said he installed the wipers before the windscreen, cos a little bird told him too ;D ;D
Pete

 

[steamer]

Steve...you laugh, but Pete knows what I'm talking about

The oil pump gear has a hub that extends to the rear of the engine. The od of this hub forms a bearing with the oil sump casting.
The ID of this same hub forms a bearing with the OD of the pump housing.

The ID of the pump housing is the bearing of the driven pump shaft, driven by a square drive from the end of the gear hub above. These 3 concentric diameters need to be just that. Concentric.

The position of these 3 concentric diameters determines the mesh with the crank shaft gear mounted on the upper engine block (casting #2) ....but it doesn't stop there!

The pump sticks out from and is located on the other end by the timing case. The location is dictated by a pilot diameter that is NOT concentric with the previous three!...but eccentric. So the front end of the pump is located differently. (on casting #3)

I'll have to bore the sump in position using a toolmakers button to locate the gear in proper mesh
Bush this hole with a bearing to suite the gear hub
Install the partially machined timing cover, face it and bore in the same location for the rear pilot bearing of the pump
With a couple of screws, temporarily locate the pump in position using the pilot bearing and sweep in the flange which is eccentric.
Remove the pump
Bore the timing cover in position to the eccentric 7/8" PILOT.
All should line up now.
I didn't design this thing, I'm just building it!

If I designed things that way at work, they'd a fired my A$$ LONG AGO!.....but what do I know! :

Image from the Hemingway Site......cropped to show this section of the GA....oil pump on lower right

Existing image on Hemingway Site.....references duly noted.

Like I said.....fussy little part.......
You'll notice the bushing on the crankshaft to form an oil seal...that positions the timing cover.


Dave

 

[swilliams]

Still following along here Dave. Question about the oil pump. Does it just pump oil through the crankshaft, or does oil go to the gudgeon pins and even up through the push rods? Good to hear your son is getting into it.

Cheers
Steve

 

[steamer]

Hi Steve,

Thanks for the interest and support! The pump feeds the mains, the rod big ends, and the timing gear idler shaft, but not the wrist pins.

Dave

 

[steamer]

I used a very inexpensive and effective home made reamer for the pump parts. I was going to write it up, but I already did! :big:.......guess I type too much

http://www.homemodelenginemachinist.com/index.php?topic=9854.0

The reamer and D-bit I used on the pump where made from .125" HSS reamer blank....but the method is the same.

Dave

 

[swilliams]

Thanks for the answer Dave, having never built an enclosed crank type engine it's good to get across some of the detail.

Steve