Ever have one of those engines?

fit90 Sun May 01, 2016 7:37 pm

I have. a couple months ago I purchased a Silver Swallow 1.5cc Diesel engine form ebay. It looked pretty but was frozen and had some odd wear marks. Anyhow, I got the engine moving nicely and decided to try it out, today. I got it going easily enough. But, I was having trouble getting a good, steady needle setting. After a little look I discovered that the nut holding the spray bar was loose. I started to tighten it and then discovered that the spray bar was badly cracked and ready to break in two. After replacing the whole NVA I got it runnng again. It isn't a monster performer but it still ran very nicely. I decided to shut it down and try a hot start. Whoa, what is this? Suddenly, the prop is spinning withut turning the engine over. A little more investigation revealed that the crank shaft appears to be tapered and the threads that hold the prop nut are also tapered and badly worn. A thread file did little more than make the threads shiney. I sent an email to Mr.Carlson of Carlson Engine Imports to see if he has a crank shaft and prop nut. If not, does anyone think it is worth it to rethread the crank? I really don't want to have to go that far for an inexpensive ebay engine. But, I don't know if I am capable of leaving an engine so close to running condition without repairing it. Also, does anybody know how hard the metal for the crank shaft on this engine is?

Ken Cook Sun May 01, 2016 8:09 pm

Bob, the Silver Swallow ( Yin Yan ) diesel engines were pretty low in quality. I happen to have one here that actually runs real well. I think it would be easier to find another engine opposed to finding a shaft. My example here seemed to take forever to break in. The piston was amazingly unstable and would grow. I had to lap that piston into the liner several times until it stopped becoming problematic. It now starts quite easily and reliably. Ken

fit90 Sun May 01, 2016 8:33 pm

Ken,

Thanks for the insight regarding the piston fit. That might explain why my engine would suddenly shut down like it was over conpressed after runing for just a few seconds. I thought I was doing something wrong but couldn't figure out what. The engine always started right back up without issue so I didn't give it too much thought. If Mr.Carlson doesn't have a crank shaft available I will probably take a crack at rethreading the crank shaft myself. If the crank material is soft enough for me to do it then I know the engine will be very delicate and probably have a very short life. Oh well, I guess it is all part of the learning curve. From what I have read these engines are really hit or miss. Looks like I might have gotten one of the rotten ones. I am glad yours runs well.

Have you had any further luck with the dieselized black widow?

Bob

Ken Cook Mon May 02, 2016 4:17 am

I had the Black Widow running with the Davis Diesel head pretty reliably. I found that I just need to quickly reduce compression once running and richen the needle. After about 30 seconds I have to back off the contra piston a bit more and all seems to stabilize. I feel there's enough rpm's to fly a 1/2A with a bit of authority. The exhaust residue appeared to be not showing signs of over compression. Ken

fit90 Mon May 02, 2016 6:52 am

How does the exhaust residue look when over compressed?

fit90 Mon May 02, 2016 9:08 pm

Ed Carlson of carlsonengineimports.net has saved the day. He has everything I need and at a very reasonable price. As always, he has been great to work with, as well. Thank you Mr. Carlson!

Ken Cook Tue May 03, 2016 4:09 am

Bob, typically when over compressed the oil residue is usually very dark. I look for more of a dark honey rather than a blackish Coca Cola look. I'm glad to see Mr Carlson is still doing well, he's been very supportive to the hobby. Ken

fit90 Tue May 03, 2016 7:38 am

Ken thanks for the tip. Since I am still learning about diesels tips like that go a long way to helping me be better to the engines. Yes, Mr. Carlson has been great for the hobby. Every time I have talked with him he has been incredibly knowledgable and helpful. Plus, he is just a nice guy. I hope he enjoys what he does.

fit90 Sun May 08, 2016 1:00 pm

Got the new crankshaft and prop nut. Before I installed them I drilled out the venturi, cut it down a bit and installed a PAW 1.5cc carb. Everything is all put back together. In spite of all I have to do today, I am hoping to run it this afternoon. Of course, I am hoping for a strong runner with impeccable throttle response. I am expecting an ok runner with recognizable throttle response. We will see.

fit90 Sun May 08, 2016 4:35 pm

I don't know what the standards for good and bad diesels are yet, but I know what makes me happy. This engine makes me happy. With a MAS 8x4 it had an ultimate high end of 11,500 RPM. After I backed the compression off a bit it was running between 11,300 on the high end and idling between 5,400 and 5,500 RPM with a clean throttle response. This is way better than I ever hoped for. I am really starting to dig the diesels. Now all I have to do is learn to tolerate the smell associated with them. Does anyone have a solution for that?

Pictures coming.

Ken Cook Sun May 08, 2016 5:21 pm

Bob my friend Dennis suggested to me to use lamp oil scent and mix it into the diesel. Apparently they make lemon and vanilla. I never tried it, He says it works great. Ken

fit90 Sun May 08, 2016 6:08 pm

Thanks Ken. I need to try something. I made a meat loaf tonight but could only smell the diesel residue. It broke my heart. Maybe I can find a meatloaf scent.

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