Wasp .049 parts?

rdw777 Fri Jul 23, 2021 3:46 pm

About forty years ago a co worker found out I built model airplanes and told me they had an old engine that they would give me… He brought it to work the next day but before I arrived he let someone else look at it…. The engine had a prop on it but was stuck…. the Gorilla succeeded in pushing the the rod thru the top of the piston….. When I got home I was able to dig out the pieces but it’s been lying in a parts drawer ever since…

When I started messing around with my old engines recently again I found the Wasp and also a random piston/rod that I thought might work…I have no idea what it came out of…A lot of old parts were just given to me by club members… Diameter is tight but OK (.421) and crank end is sorta OK but a little sloppy, but so is the original rod….Problem is rod length is too long…It fouls the head and will never open exhaust…It may be from a Cub? The one Cub .049 I have is .420 piston dia. and has a wrist pin…Wished I could try this piston on the Wasp rod but they’re both ball joints..

So…. If anyone has a Wasp piston/rod laying around with no home please let me know….I also need a needle valve… Complete engines pop up on the bay but would like to piece this one together if possible…. May be a long shot but thought I would ask…. If I could get her running I would like to try and fab up a Firebaby look alike. I have a Cub .039 that would work good there too….

Robert

Ken Cook Fri Jul 23, 2021 4:11 pm

Robert, I know the feeling all too well and I use the Wasp with regular frequency. I recently picked up a OK Cub .049 X which looks similar to the Wasp with the same mounting. I'm in search of a Wasp backplate myself . Keep a eye on EBAY. It's very common for Wasps to be missing needle valves. You might find some parts engines that won't break the bank. It's a evil cycle because you will find the part you need, fix the needy engine and the donor will need other parts that you will now seek. Ken

Marleysky Fri Jul 23, 2021 4:18 pm

Join the club! You, Oldenginerod, RSV1cox and a few others who can’t stand having an orphaned engine! Hopefully maybe someone has one with a cracked crankcase or parts that’d fit. I think Kim had one screeming on his test stand a while back. Good Luck!

Here’s a link to a earlier thread: https://www.coxengineforum.com/t13632-atwood-wasp-049

Marleysky Fri Jul 23, 2021 4:39 pm

Irony..this just poped up in my newsfeed:

https://www.ebay.com/itm/203524704811?mkevt=1&mkpid=0&emsid=e11010.m1951.l6663&mkcid=7&ch=osgood&euid=f1785805a4af4271812ad2c46d46f4eb&bu=43178429781&ut=RU&osub=-1%7E1&crd=20210723142202&segname=11010&sojTags=ch%3Dch%2Cbu%3Dbu%2Cut%3Dut%2Cosub%3Dosub%2Ccrd%3Dcrd%2Csegname%3Dsegname%2Cchnl%3Dmkcid

from a Canadian orphanage no less....

Here's one you can send a low offer on:

https://www.ebay.com/itm/274847855605?_trkparms=ispr%3D1&hash=item3ffe3573f5:g:x7oAAOSw9Wlg2JHm&amdata=enc%3AAQAGAAACgPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSlHY%252FYTip4QFVjNQrCEJt6vl%252FCu08MmtePCK56M6ZmgRkIfTAL5TLowbbY0uPgHpEYvmHeLJFyKTifaqKqzf34CuwAdC1IBFOW1PPSK84b%252B72HLqDb8miZAWHB6AD0jdd8ehmPjFsFV1CEa8cYboa9Y5AgQYvD4szOwm2uQv5Wf7oKHHZ2JLm8nWjGo99S0JUId6z9cTfIA2vi3qIPsTxZ2qw6D%252FboLsNr7nG67vgbT0doh6TEMsywg7qjdjbWy%252F8lLQj2HspdQpaANzBYo%252BVzV1kPQbyR5%252Bwk7fOZDMEG6LEjqFtwDCaKhJdVAs4FoJFL9sL9d1UMDBwE5%252BCsqMVOLR0Q%252Bny32%252FEYyY%252BzMgZ%252FexlovgoilhKHHcy%252FCtEW1K4DqNl%252FTGun605qmAQVuHy2FtQHBcMrqZ3VG%252BbsZtt7ciRJl4UC5UqzNYjXNv%252FRsVDcEd8zvfIQNqcNApctY%252FkiKNKgdb9BKr277qEqlr%252BXgT4v29gG3Ut%252B49nRO%252BUk%252FzKJdqPczV0eCdUj8lpFQ5O4v6c2DspB15lna%252FUyMQBksEBii6rMgVAB2cQDVoCoNXAm5JPXCh6kG4mpElxT%252FN9Jm1Zc12FxrSZBWRGrW42chmt67r9SkEpOTQAe2oFfpVcMItS2AYc5TTuDi0YZjwvdO0sptdmThZrCZ%252FQ3E%252BLIB%252FIuLzEh7FA%252FgSLok4efoD9Z%252FKmLAhyRnA18cgzq%252FfwBhA%252B0Ktc%252FL%252BdKZSI%252B50PWu28XKlPbclUJcUsjbdz5%252Bu9xzlUaxD5tVmYi4HNmJgxnTugsrf0qx%252FyKGWX7E7Ikrw%253D%7Campid%3APL_CLK%7Cclp%3A2334524

HOLY COW what a link!!!

rdw777 Fri Jul 23, 2021 5:34 pm

Thanks guys, I appreciate the links and may end up buying a parts engine…. Just thought I would let it float for just a bit on CEF just in case…. MECOA lists the needle valve…

Ken, since you mentioned backplates…. I’m trying to make one for my Cub .039….
It has the tank mount but no BP only…. We have a Fab Lab at the college I work for… So I drew it up and printed a proof in ABS…. I don’t think it will play well with the fuel though… The machine shop instructor told me he cold mill it from bar stock from the same files…. So will try and complete it when school starts this fall…

Robert

Oldenginerod Fri Jul 23, 2021 5:59 pm

Not sure, but I have in mind that a WenMac piston/rod assy might fit. Huh...

(Don't know why I think that)

Ken Cook Fri Jul 23, 2021 6:22 pm

Probably because Bill Atwood designed the Wen Mac

rdw777 Fri Jul 23, 2021 7:58 pm

Great info, Thanks! I like to continue to learn things too!….The piston/rod in the photo is about.070 too long overall…. I think…. I’m curious if Wasps or Wen Macs are domed …. I know the Cub .049 is domed as opposed to Cox being flat…. I was surprised when I found at lest the piston bore to be that close….. Could be lapped in if the rod was right…..I’ll get some better measurements for the p/r in case someone may have a Wen Mac part that might fit….. Just rambling…. Fun to contemplate

Robert

Oldenginerod Fri Jul 23, 2021 9:33 pm

rdw777 wrote:Great info, Thanks! I like to continue to learn things too!….The piston/rod in the photo is about.070 too long overall…. I think…. I’m curious if Wasps or Wen Macs are domed …. I know the Cub .049 is domed as opposed to Cox being flat…. I was surprised when I found at lest the piston bore to be that close….. Could be lapped in if the rod was right…..I’ll get some better measurements for the p/r in case someone may have a Wen Mac part that might fit….. Just rambling…. Fun to contemplate

Robert

I've got more than a dozen new WenMac Piston/rods. I believe some are domed and some aren't. Can't recall which, but it may be the difference between glow plug version and glow head version. Pretty sure I have both. I can pull out my Wasp and see if it's domed or flat. I'll measure up a piston and let you know what I find. Glad to give you one if it works, but you'll have to fly it half way 'round the world. Someone closer is bound to have one.

Ken Cook Sat Jul 24, 2021 7:05 am

While I've had extensive amounts of lapping experience, it only works when the piston has already been fit. For example, the Mccoy users have it in their heads that when you smash the top of the piston with a hammer to squash the crown, you can lap it back into the cylinder. Not a good practice as the whole top mushrooms over to one side and or can crack the piston at the baffle intersection. While I've done this, it's extremely short lived. So yes, it can work but for short periods. The problem is that unless the piston and or cylinder is guaranteed round, your essentially lapping off the high spots. Your grinding a oval into a circle basically, which only removes the highs and the lows still may not be contacting the cylinder wall. As crude as a OK is, more than likely it will work due to the high oil content. I just had a contra piston made for one of my Russian diesels. We had to fabricate a outside lap tool to make this that we could adjust in small increments until it fit. This took several hours to do. The same tool would be required if you wanted that piston to properly fit.

rdw777 Sat Jul 24, 2021 12:26 pm

Thank you gentlemen for the thoughtful replies

OERod….Photos show engine at TDC and BDC so you can see about how much too long it is..,. Also a sketch of the…. Also a sketch with measurements…. My best estimate for crank pin because I did not remove it from the case…. Bore fit is fine…. If you could be so kind to measure one of the Wen Mac P/R’s may be helpful…

Ken…. I have found your post on lapping using a brass tube and inserting upside down….This set would have been a good candidate for that cause it’s free at the bottom but a nice pinch at the top…. Too much actually…. But unfortunately overall length is too much…

Robert

rdw777 Sat Jul 24, 2021 2:14 pm

One bit of info I forgot to add in the sketch ….Overall height of piston from crown to skirt is .388….. Again this for one the doesn’t work but may help dial in on one that will…,

BTW…. What do you use your Wasps on?

Robert

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