Crankcase Repair Method

GallopingGhostler Mon Feb 02, 2015 7:59 am

I disassembled one of my dirty Enya 09-III CL engines, a used auction buy. It was definitely used but with very good compression. (These Enyas are long lasting if cared for.) Soaked it in Acetone for a day. Cylinder liner wouldn't budge. In my jing hamdiness using a screwdriver to pry, I broke out a small part of the exhaust!

Having to blink twice over disbelief for what happened made me realize how brittle aluminum really is. With further cleaning with antifreeze in an old electric Poly-Perk coffee pot, the cylinder liner easily pulled out while hot. (Got an old percolator? It works as well as a crockpot! Very Happy

)

Taking a tip from engine guru Joe Wagner in one of his magazine engine columns (can't remember which), I repaired it using a J.B. Weld like Epoxy product by Pacer called Pro Seal Pro Weld. It cost me $3 US at Big Lots.

As a form I used masking tape rolled around the outer edge of the exhaust outlet. It pulled off without leaving paper, so I didn't have to do any filing on the exterior, which would ruin the original bead blast finish. I also filled small nicks in the exhaust rim with it, caused by someone's careless use of a screwdriver to install and remove engine mount screws. After curing for 10 hours prior to full hardening in 24, I filed the exhaust edge smooth. This will allow a good seal for a muffler if I so choose.

As you can see, so far the repair has went well. I figured I'd have to buy another crankcase, a well known seller on E-Bay fortunate has the part for a reasonable price. I just hate to otherwise abandon an otherwise acceptable crankcase.

Since Pro Weld is gray rather than J.B. Weld's black, it better matches the aluminum finish.

roddie Mon Feb 02, 2015 9:47 am

That sure is a neat repair George. It took me a few minutes to notice the spot! Bridging the gap with tape on the outside worked surprisingly well.

If you had another parts engine needing a larger repair (possibly a broken beam-mount?) You could maybe use the thin plastic from product packaging to form around the area to make a "well" and fill it with the epoxy? I wonder if such a repair would stand up to engine vibration?

Sort of along this idea..

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GallopingGhostler Mon Feb 02, 2015 10:08 am

Thanks, Roddie for the kind comments. Joe Wagner showed in his motor mount flange repair a paper form attached with tape to contain the Epoxy filler during curing. If one was careful to very lightly coat the form with a medical/cosmetic petroleum jelly like Vasaline (without getting onto the suface to be glued) would help to prevent stick.

These type Epoxy filler putties have been used on motorcycle cases and engine blocks with success. I would think they would be able to hold up to vibration stress. However, they may break if there isn't enough metal for an engine mount screw to clamp on. Best way would be a try, there is nothing to lose and more to report.

I would think that the success of the repair would be on a case by case basis. One thing important is a very clean and reasonably rough surface for the Epoxy filler to bond to. I used Acetone to clean any remaining residual oils prior to do the repair.

andrew Mon Feb 02, 2015 10:31 am

George -
Very well done -- many of these metal filled epoxy's can be difficult to work with since they're so sticky. Your's is a great looking repair.

I also have several Enya's. They're not stump pullers; they are heavy and none of mine have mufflers, but they will last as long as rocks if cared for.

andrew

roddie Mon Feb 02, 2015 10:52 am

Hi again George Smile

I've had these 2-part "putties" in my "glue-box" for quite some time. The PC-7 states "cures to a uniform grey color".. The PC-11 is white. These are made by "Protective Coating Co." of Allentown, PA. I've yet to use them though. Rolling Eyes

I often purchase things like this, so I'll have them on hand if I ever "do" need them. I would imagine them to have an indefinite shelf-life.

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GallopingGhostler Mon Feb 02, 2015 12:20 pm

andrew wrote:George - Very well done -- many of these metal filled epoxy's can be difficult to work with since they're so sticky. Your's is a great looking repair.

Thanks, Andrew.

I also have several Enya's. They're not stump pullers; they are heavy and none of mine have mufflers, but they will last as long as rocks if cared for. andrew

Interestingly enough, I've found that the Enya's do really well if one matches a prop to their power curve. Use a 7x3, it flies like an 049. A 7x6 wood prop works really well with the 09-III, it really moves out. An 8x6 Masters plastic prop on my Enya 15-III TV (throttle wired open) had the same lap speed on my Ringmaster Jr. as my OS 15FP-S with a Masters 8x4.

Power curve maxes out at a lower RPM. Thus a prop that works well on a same displacement Schneurle doesn't necessarily work well on the Enya. Popcorn

GallopingGhostler Mon Feb 02, 2015 12:28 pm

roddie wrote:Hi again George I've had these 2-part "putties" in my "glue-box" for quite some time. The PC-7 states "cures to a uniform grey color".. The PC-11 is white. These are made by "Protective Coating Co." of Allentown, PA. I've yet to use them though. I often purchase things like this, so I'll have them on hand if I ever "do" need them. I would imagine them to have an indefinite shelf-life.

Roddie, PC-11 would probably work. I'd think the main thing is ability to handle heat. I think this is what makes J.B. Weld so successful is it has been tried in hot applications like oil pans, motorcycle engine cases and transmission cases. If one fails, it doesn't take much to chip it out and retry with another. I'm just looking into ways to keep these old engines running.

I did have some Epoxy go bad on me. I've had 10+ YO tubes of Epoxy go hard on me. They will thicken over time, but they do have a reasonably long shelf life.

getback Mon Feb 02, 2015 1:21 pm

fine looking job George , I repaired my 250yz case housing some 30 yrs. ago with jb weld and is still holding !! the casing 1/2 was 89.00 then . yea the epoxy will harden after some time have one up stares now never opened Mad

Eric

Ken Cook Mon Feb 02, 2015 5:27 pm

George I strongly feel your repair is going to be short lived. I've witnessed this many times with JB-Weld and similar products. The case rarely sees a lot of heat down near the lugs. The problem is vibration combined with stressing due to the bolts. Scott Dinger of Simi Valley California could weld that lug for a very low cost. Scott's work is impeccable. Scott can be found in the members section of Stunthangar. Scott has welded my broken magnesium and cast aluminum speed pans and broken engine cases for me in the past. Not too many can weld the materials that he does. Scott being a modeller and a hobbyist himself usually does this for very few $$$$. Ken

GallopingGhostler Mon Feb 02, 2015 6:03 pm

It wasn't the mounting lug, it was the exhaust exit flange area. Flash photography is less than ideal, if you look you will see it. This area gets little or no stress on it. Heat, yes, but the only way to truly find out is through flying it. That will be a ways off for now, but thanks, Ken, I may get the crankcase part so its there when I need it.

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