14ft Aermotor E602 with E702 guts?

[tom b]

Hello, forum. I just ran across something I cannot easily explain and thought the higher intelligent minds could clue me in. A friend recently acquired this mill and wanted some help assembling the beast. At first glance externally it was a 14 ft E702 with thread in arms, all angle iron tail bone, cupped shim swivel on mast pipe etc. When I removed the helmet, it was again all E702 with keyed pinions, adjustable stroke pitmans, keyed spout washer, replaceable slide in bearings, etc.
Then I saw something that started me thinking (rare occasion my wife Terri would say)! It had the two pipe plugs sticking out of the side of the case just below the top rim which I only had seen on Late 602's to help drive out the pinion pins. I decided to finally check the model number on front of case and it said "E602". I had a few choice words and tried to figure out what this hermaphrodite is. My only conclusion, which is probably wrong, is this being a very late 602, maybe, just maybe the factory had a few of these bad boys left from a previous pour and decided to convert them by machining to the 702 specs. Please, all you Aermotor experts enlighten me as other than my hair brain answer I cannot believe some machinist would re invent the wheel and do all the work needed to convert a 602 to take 702 guts.
Help!
Tom

[Kevin]

Tom, I have found similar mills with a mix of 602 and 702 parts. Same with early open gear models.
Aermotor made special hubs (Part #723) so you could use your 602 wheel arms on the 702.
I believe they used upped what they had on hand when they changed models.

Aermotor_702_with_V-spokes_ad.jpg

[Bryon]

Need photos.

[PaulV]

Need photos.

Tom, if you can, post pics so that we can see what you're working with.

[tom b]

Thanks guys for comments. I will go over and take some pics next week and post.

[Ron Stauffer]

The 723 hub was not used on E & F 702 motors for changeover as the E & F 602 had thread in spokes. The only E & F V spokes were in open gear mills.

Even tho threaded spokes were used on E602 it was a different hub and spoke from the 702. The E602 spoke was a smooth shaft without spoke brace and had no tightening nut against the hub. The E503 hub threaded holes for spokes had a bottom and were threaded to the surface of the hub. The spoke threads on the 602 and 702 were the same. The E702 hub had threaded holes that were open thru and there was about an 1/8 open hole at top before threads started. The E702 spoke has a tightening nut and threads that stop about an 1/8 before the nut to match the threaded hub.

I saw a changeover E once and the hub had no number on it. This would have been a lot easier changeover hub to do as it only required machining the hub to accept the larger 702 shaft. As I say this, the snouts on 602 and 702 cases are different at least on the 12' and under V spokes so maybe not so easy.

Hub shafts on the E702 is 1 15/16" and for E 602 1 13/16".

The only changeover for main gears in Aermotor catalogs is the 753 which allows putting 602 gears in a 702 case. It would be very hard to put 702 main gears in the wide babbited saddle of the 602 case

If your case is marked E602 and everything inside is 702 and matches the hub & shaft of a 702 described above, somebody was having fun or bored at the casting foundry that day by changing the 7 for a 6...

Ron Stauffer
Montrose CO

[tom b]

Thanks Ron for your education on E602 vs E702. You are correct as the spokes have no tightening nut and are smooth with only bolt on clamps to act as spoke brace. I decided to brave the rain.....yes rain we had today in Sunny California and go take some pictures. Here they are for your examination and comments. Don't be shy let me know if you can nail down this head turner. Thanks, Tom

[Ron Stauffer]

Tom
Hub, case, spokes and brace clamps - all standard 602. Spokes go in the other way but are easy to time

Updated 702 style yoke and pump rod

Main gears - latest 602 two stroke style & standard 551 bearing bar. Two stroke 602 main gears pitman bosses are maybe 45 degrees apart - 702 main gear pitman bosses are 180.

No pics of small gears so cant pass judgment. Hub shafts for 602 are same OD from end to end. Hub shaft for 702 has smaller OD at the small gears, a step in shaft size.

Ron

[tom b]

Ron, that explains what he has. I had no idea the larger mills were ahead of the curve with designs that were incorporated later in the 702 models. You are a wealth of information on these big guys. I was aware of the 723 hub for later 702's but that was it.
Do you visually time the arms according to the angle of the threaded end; and lastly, it looks like the PO used a pipe wrench to thread in hub spokes. Nice if you could double nut the spoke ends and thread but being as long as these spokes are, I would be afraid of shearing off spoke ends. Thanks again for everyone's reply and to Kevin for the crated motor pic.
Regards, Tom

[Kevin]

Ron, as Tom said, “You are a wealth of information” thanks for the info!