Another “Tiny” I.C. My first model engine

[Scott_M]

About 10 years ago when I joined the forum, Tiny was a popular build. I was very taken with it. I also enjoyed watching all the different variations you guys came up with. Some air cooled some hit & miss some with throttle control some with ball bearing cranks and different head designs, cast iron piston…the list goes on. I knew if I ever got the time, I would build one.

The time has come.

First off, I would like to thank Arv Togus for making the plans available to all! And to sadly report we lost Arv back in 2016. Arv’s Obituary This build is for you Arv.

And for those of you who don’t know about Tiny Here is Arv’s original post

I started on tiny in the beginning of April and was not sure how long it would take so I did not start a build thread until it was done. ( just to be sure it would be done )
I got it running pretty good and will be taking it apart to “Bling” it up. I did not want to spend too much time on pretty until I was sure it would run. You know , first engine and all. So here are some finished pics. And when I take it apart I will post details and pics of some of the parts and assemblies. I would also like to thank “Gail in NM” and “George Britnell” for their outstanding contributions to the “Tiny” project.



Some pictures Click for full size image












And a crappy video, I’ll try and get better video








Thanks for looking

Scott

 

[lee webster]

That runs very nicely! Well done Scott.

 

[Gedeon Spilett]

very pretty engine, run well ! congratulations !
at the end of the video, one can listen some hunting or surging, as it the fuel becomes leaner with an increase of speed followed by a loss of speed.
one of my engines behaves similarly, and I wonder how to regularize its run...

 

[Scott_M]

Thanks Lee
Hi Gedeon
I am having 2 separate issues with the surging. The first one is " sucking air" which I have mostly solved. It was hard to track down but turned out to be sucking a "tiny" bit of air around the spray bar threads. I coated the spray bar with some grease before putting the needle in and it seems to have almost stopped the surging. What we are seeing in this video is arcing off between the spark plug and rocker arm. It only does it after it gets pretty hot and starts to go rich.
I made a mold to cast a spark plug boot. Hopefully that will help. I got it done but have not tested it yet. Maybe today.

Scott

 

[gbritnell]

Congratulations, outstanding build! I added drawings to the library to build an air cooled version.

 

[gbritnell]

When I built my versions I changed the spark plug angle to get it away from the rocker arms. The drawing should be in the drawing library

 

[Scott_M]

Hi George
Thanks !! I may be making a new head with your increased plug angle if my boot does not solve my arcing problem. I also really like the longer guides on your head design.
Air cooled was going to be my next version. This one gets really hot after just a few minutes of running.
Scott

cross posting with george

 

[GailInNM]

Your "Tiny" is an excellent tribute to Arv's memory. In addition to our banter here on HMEM, Arv and I exchanged many emails and I considered him a friend and mentor. He is missed. I knew he had passed, but had never seen his obit. Thanks for posting the link to it.

I used to keep count of the number of "Tiny" builds that I kenew of, but lost count many years ago at about 80, so I am sure that there are well over 100 now. Many by well known builders so you are in good company. I know of two more that are in progress by members that are a bit shy and do not post here on HMEM.
Gail

 

[awake]

Congratulations, outstanding build! I added drawings to the library to build an air cooled version.

George, where is the library? I looked around on the forum and didn't see it - but may have missed it ...

 

[Scott_M]

Hi Andy
It is in the downloads section.
I did a search of that forum with George's name and these are the returned results.
https://www.homemodelenginemachinist.com/search/611459/

I did not see the air cooled "tiny"

His version of the head with extra angle on the spark plug is in the original thread linked to above.
Page 11 post 210 or here is the link View attachment TINY HEAD PLUG REVISION.pdf

Scott

 

[awake]

Thanks!

 

[gbritnell]

I'm sure that when I made all the modifications to 'Tiny' head, hit and miss mechanism etc. they were all downloaded to the files section. I can't say what happened to them. I will download them again ASAP
gbritnell

 

[mayhugh1]

Thanks Lee
Hi Gedeon
I am having 2 separate issues with the surging. The first one is " sucking air" which I have mostly solved. It was hard to track down but turned out to be sucking a "tiny" bit of air around the spray bar threads. I coated the spray bar with some grease before putting the needle in and it seems to have almost stopped the surging. What we are seeing in this video is arcing off between the spark plug and rocker arm. It only does it after it gets pretty hot and starts to go rich.
I made a mold to cast a spark plug boot. Hopefully that will help. I got it done but have not tested it yet. Maybe today.

Scott

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Scott,
Have you tried a bit of silicone dielectric grease around the inside of the boot? - Terry

 

[Mike Ginn]

I also found it difficult to find the drawings and the original design. Many of the links/file locations didn't seem to work and of course we are talking about posts made some 12 years ago. If you are interested, I could upload all the original drawings (rev B and one rev C) plus the air cooled version. I guess George could do the same especially since the air cooled version is his design.
I have created a document which takes the relevant Tiny comments and photos from the 24 pages of postings. I did this for my own use and I did not capture the post numbers of the authors or their names. I have found that the photos and comments of great use although having said that I haven't started - still building the Kiwi but planning! It's 73 pages long (3Mb size as a pdf) and in the order of the postings so a little disjointed. I don't know if I can/should offer this to the forum.

Maybe the admin folks can advise. Also advise if the original drawings are available - and where!

It's a lovely little engine!

Mike

 

[Scott_M]

Thanks George that would be great.

Thanks Terry, I had not thought of that, good idea. Although I think I found another problem. I put the new boot on the plug and could not get "tiny" to start. Not even a pop. Started checking things and it turns out my plug had "some" continuity and was internally shorting. It would spark in open air. (but looked weak ). I made a new plug yesterday and it runs really good now !!! I can even set the needle at a low speed and turn it about a 1/4 turn for high speed. I ran it for about 5 minutes and it got really hot and think it vapor locked and slowed down and stopped. I think I will make some sort of phenolic spacer to isolate the spray bar/ carb from the hot head. May as well incorporate some throttle into it as well.
I did not see any arcing when running yesterday. But will use the dielectric grease from now on.

Mike
I did the same thing. I have a folder with all the "tiny" stuff in it. Stuff I knew I would forget. Like Gail's spring wire diameters and ball bearing sizes and Georges head design. And a bunch of pictures of various builds that I thought were good ideas.
It may be one of those things that are builder specific on what to save. If George can't find the drawings it is good to know you have a set. Thanks!

Scott

 

[Scott_M]

I have been putting off taking Tiny apart. I have been having so much fun playing with it that I could not take it apart. Well, I got it running really well so I figured it was time to bling it up. I also decided to leave it as it is. Pretty much Arv's original design. As my first engine I wanted to stick to the plans. Also It runs good ! So I will get it all pretty and do another video and then shelve it while I start on "Tiny 2 ". Tiny 2 will incorporate all the changes I wanted to try. Like the H&M mechanism and air cooling. I will also try and incorporate throttle.
I am having a lot of fun with this little guy !

Pile of parts ready for some TLC

Scott

 

[Scott_M]

I anodized the aluminum today. Body and tank blue and the main caps and con rod clear.
I had put some "liquid electrical tape" (dries like rubber) on the bearing surfaces of the con rod but the anodizing acid somehow dissolved it at some point, so I do not know how much anodizing is on those areas. Or if they will tear up the crank and wrist pin if I don't get it off.





Tomorrow, I hope to hot caustic blue the steel parts.

Scott

 

[Scott_M]

I did get the bluing done today.
I have 2 different types of hot caustic bluing, one is your typical " hot salts" used for carbon steels. This is the standard bluing any gunsmith would use to blue a firearm. The other type of bluing is also a " hot salts" type but is of a different formula of salts and is used for blackening Stainless Steel. This is what I used because my flywheels are 303 stainless and I wanted a 2-tone flywheel. So, blue it, then polish the rim. It also works on regular carbon steel but is not as pretty as the other type. This is blacker.
After bluing the finish is "Green" for about 24 hours and should be left alone, it will scratch very easily at this point.
Here is a picture after the parts came out of the oil tank.



I still have some brass to polish and some engraving to do. Not sure if I will get anything done this holiday weekend.
Scott

 

[Zeb]

very pretty engine, run well ! congratulations !
at the end of the video, one can listen some hunting or surging, as it the fuel becomes leaner with an increase of speed followed by a loss of speed.
one of my engines behaves similarly, and I wonder how to regularize its run...

Sounds perfectly good to me. On aircraft piston engines, you want a 50 rpm rise on shutdown when you pull the mixture. That indicates your stoichiometric is close. Not sure in these little engines though!

 

[GreenTwin]

I would think you could very lightly buff off the anodization from the areas where you don't want it.

Nice work on the engine.
I toyed with the idea of getting an anodization kit, but then changed over to all gray iron parts.

I have yet to cross into the IC engine realm, but I have high hopes of mastering that type of engine one day.
I have heard others say that IC engines are much more difficult to build than steam engines, and I have become a believer in that statement.

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