Rehab of another lost cause

rsv1cox Thu Dec 07, 2023 9:34 am

This might be my most dumb attempt. Well abused "thin wall" that came with the Atwood outboard.

I should have just tossed it but didn't. Looked at it - well maybe it's a Space Bug or Space Bug Jr.cylinder/head, you can't tell just by looking. But, the shoulder just above the case threads has been ground off along with much of the already thin cylinder wall. First thing I did was look up through the cylinder to see if I had a "W" element glow head. Nope, drat!

The usual - heat to get the glow head off and buffered Cox wrench through the exhaust ports. It didn't work. I wound up damaging the already damaged head to the point where I went the Wen Mac route filing the head down to where I could get a wrench on it. Still stubbon but it worked.

Disappointed, no SB SBJr. Plane old thin wall early Babe Bee but with a surprise.

Alcohol soak and a pick got the caked on castor out of the fins and a dip in gun blue restored the finish after a long time spin on the drill press to file/sand off the tool marks.

Ok, so I have half an engine. Looking through parts I found one of Bernies old poorly anodized cases that he sold at a reduced price. I bought a few. Then a crank shaft from Matt, a plastic backplate, a 8cc tank from Bernie. Rest - pick up tube/spring, drive washer, prop., gaskets came from parts on hand. Worst was the case screws for the tank. All I had were to long with the large phillips heads. Heads had to be ground down and the shafts shortened. Four of them - painful!

But, I have an engine with compression that any Cox fan would be proud of and enough subduction, SPI, PDQ that may make you engine guys happy.

Wondering about that compression. Remember this cylinder has no shoulder to provide a stop. Regardless it screws down to a point and stops that does not interfer with the operation of the piston/connecting rod. But, when rotated there is a hitch in the pull-through. Remove the head and rotation is fine. My answer was to add a couple of gaskets which solved the problem.

The needle is for show, it's missing the tip and the threads are messed up. I ran out of needles so it's back to Bernie or Matt along with most everything else.......... Sad

rdw777 Thu Dec 07, 2023 2:00 pm

Nice work up and save of another engine Bob… I like the new flats on the head in order to save it Thumbs Up

….. That one deserves a crank and run!!…. Engine day for me too… Running a PeeWee .020 with a throttle barrel….That may be the one for my Ace Littlest Stick rehab I’ve been putting off for awhile….

rsv1cox Thu Dec 07, 2023 6:33 pm

It looks like you placed a grommet in the tanks hole Robert to hold and protect the fuel line. Perhaps a gang of D cells to the right to supply power.

Stick series. Das Little Stick and others. Popular a few years (decades) back.

I do intended to run that put-together engine. It just feels so right when you flip it. It has more potential than the one on the stand next to it.

BTW, even with what I put that glow head through, the element still glows. I have used that method before to remove damaged Cox glow heads.

getback Fri Dec 08, 2023 6:56 am

Good Job on the restore , hope it runs good for you also ! That is cool with the filing of the glow head I have seen this before in sales on the Bay . Is that the cly that came with the outboard engine ? Snowman

rsv1cox Fri Dec 08, 2023 7:07 am

getback wrote:Good Job on the restore , hope it runs good for you also ! That is cool with the filing of the glow head I have seen this before in sales on the Bay . Is that the cly that came with the outboard engine ?

Yes, it was a nasty little thing. You can just see the ridge where the shoulder stop was.

Seems funny, but it has a "flip" equal to my best Cox engines. Nice POP and no snap, crackle............

admiral Fri Dec 08, 2023 2:14 pm

Thanks for the tip on removing Damaged glo heads, bought a job lot of .049's a couple have damaged glo heads, got one off after a struggle , wish I had seen your method first.

rsv1cox Fri Dec 08, 2023 2:43 pm

admiral wrote:Thanks for the tip on removing Damaged glo heads, bought a job lot of .049's a couple have damaged glo heads, got one off after a struggle , wish I had seen your method first.

Heat always helps. Complete circle Cox wrench works best but some glow heads are just beyond saving in original condition. Had I filed a bit more a 3/8th" open end wrench would have been a better choice so I used an adjustable/cresent wrench instead.

Good luck with your building and flying experiences and let us know how you're doing.

rdw777 Fri Dec 08, 2023 5:28 pm

It looks like you placed a grommet in the tanks hole Robert to hold and protect the fuel line. Perhaps a gang of D cells to the right to supply power.

Yes, That tank had a hole in it so I enlarged it enough to install an old servo grommet to protect the line… Also a couple of springs for fuel pick lines to keep it from kinking…. Runs a good long while with 6 cc’s from a balloon tank Thumbs Up

rsv1cox Thu Dec 14, 2023 6:40 pm

This cylinder/headless engine is kicking me around a bit.

Not all Atwood/Wen Mac engines are created the same and this outboard has a different case which requires a different cylinder. I think that Wen Mac just milled off the skirt of the cylinder to accept the odd case. I have tried most of my Wen Mac engines swapping cylinders and heads around to get this thing going with no + results.

The problem is......the cylinders skirt extends down into the case to the extent that it blocks the connecting rod to make a full rotation. I have cylinders to spare so I'm going to sacrifice one just to find out. I already sacrificed (ground down) one of my good screwdrivers to fit in the cylinder exhaust ports to unscrew it.....yes, I know fear the burr but so far using a lot of heat - no problems just burned fingers.

A mess, but I'm leaving it for tonight.

rsv1cox Sat Dec 16, 2023 8:05 am

Fooled around with it a bit more this morning.

Check out that piston at TDC. Shows about an eighth" above the top of the cylinder. Must be a different case or connecting rod. I have got to dig out all my Wen Mac engines and do mix and match until I find the right combination.