Post by: Stilldrillin on January 04, 2020, 04:08:03 pm
This engine arrive from Jin, today.
Only, nine days from China! That is very speedy service......
(https://i.postimg.cc/7PtHv3Mv/IMG-20200104-200434.jpg) (https://postimages.org/)
The only "problem", is the usual split woodwork, due to the fuel tank screws. Easily fixed....
Also. The end of the h/t lead is just snipped off. No clip of any sort, to locate onto the plug!
Is this usual?
Post by: RedRyder on January 04, 2020, 07:10:33 pm
If you get it close but not quite touching the plug tip, it will still work.
I would like to see a more proper brass tip to clip on but it does work as is.
You might want to swap out the springs for softer ones or stretch a bit to run it slower.
You can also remove one spring to help slow it down.
I also like to get the piston out and place in my lathe chuck to shave 50-100/1000 off the top and make sure there is just one O-ring. If you have 2 o-rings, remove one. The bore is very smooth and it is near impossible to get any oil between 2 o-rings.
I recommend white gas (Coleman fuel) or similar mixed 15 to 1 with Marvel Mystery Oil. I like Mystery Oil because it doesn't burn and it is passed through and out the exhaust while keeping the upper cylinder well lubricated.
Enjoy!
Gil
Post by: Stilldrillin on January 05, 2020, 05:04:04 pm
Thank you, for the list of tips and mods. I have been reading all I can, on forum, while awaiting delivery.
Bought myself an 8mm a/f, deep socket. (Thought I was on safe ground, 'cos 8mm is slightly larger than 5/16"). ;)
The plug measures 8.2mm!! Whatever size is that? ???
I spent 1/2hr this morning with a diamond file, opening out the chrome vanadium socket......
I intend to insert a piece of brass wire, into the end of the ht lead, to positively hook onto the plug.
Don't like the idea of the ignition module being stressed, making two sparks, if the lead comes adrift.
Lighter springs? Heavier weights might be worth exploring. Eventually.
.100" removed from piston crown, and a single O ring sounds good! Seems quite high compression, at the moment.
We can't easily get hold of the liquid fuels, which you have over there, Gil.
So I have bought a can of Clipper, lighter fuel. Several people on YouTube use it.
As on all my hot air engines, I intend to use my usual, 5-W30 engine oil, at least until I learn otherwise...... ;)
I'm really looking forward to starting yet another, another long term engine adventure.
P.S.
Mine has a pull cord, for starting. First one I've seen.
Post by: RedRyder on May 28, 2020, 04:43:29 pm
For the off sized plug I would have shaved the plug to fit the socket. Jin's plugs are of inconsistent finish and do not take to wrenches and sockets as nicely as a standard 1/4-32 spark plug from nearly any hobby store or ebay. Just about any other plug from any other supplier will fit perfectly in a 5/16 or 8 mm tool.
Did you get after shaving the piston top?
Post by: Stilldrillin on May 29, 2020, 05:08:30 pm
Thanks for remembering me!
No progress has been made! But, all is on schedule.....
Since last autumn, I have been working on re-furbishing this mini lathe....
(https://i.postimg.cc/nrgD9M86/IMG-20200529-175426.jpg) (https://postimages.org/)
It once belonged to a good friend, on the other forum. I carried out several mods to it, over the years.
Before he died, almost two years ago. He asked me to sort it out, and move it on, to another member.......
It is now finished. Allowing me the chance, to machine some of the components in my 16yr old mini mongrel....
(https://i.postimg.cc/wxGJG4t0/IMG-20200529-175738.jpg) (https://postimages.org/)
The engine?
It is still living on the shelf, just above my computer, as I'm typing this. Not been run, as yet.
I have had a peep inside. Really beautiful components.....
(https://i.postimg.cc/G2MYrqX3/IMG-20200226-095339-2.jpg) (https://postimages.org/)
Fully agree with you, (now), over plug hexagon tolerance. It just didn't occur at the time.
Give me a few more days/ weeks.... This engine will be my next job. When the yellow lathe has gone to Scotland.
Still considering heavier weights. Also, a ring groove at the bottom of the skirt. To allow oil further down the piston.
As, and when. Success, or fail. I will post progress on here.
Post by: RedRyder on May 29, 2020, 07:00:36 pm
Gil
Post by: Swift Fox on June 04, 2020, 11:56:09 am
Post by: Stilldrillin on June 04, 2020, 02:14:51 pm
Thanks for your confidence, in my future fumblings....
Post by: 70Rcode on June 05, 2020, 11:32:46 am
Lubricant to avoid eventual frictional scoffing damage & present conflicting type manually applied lubricants. The long piston itself requires no direct friction generating to cylinder wall contact & and an additional piston near bottom end ring groove & similar rubber o-ring would let the piston almost frictionally "float" being physically isolated from the cylinder wall. A Dry, rubber o-ring compatible, ptfe telflon long lasting dry lubricant applied to the cylinder wall would greatly reduce manually applied lubricants & further reduce non-desirable, upper cylinder soot generating "wet" sparkplug exhausting fuel mixed lube concoctions as the piston's upper & lower rubber o-ring lube requirements would be completely addressed by the lowest measured, friction coefficient, dry ptfe telflon cylinder wall coating. Commercially made, Dry ptfe diy lube are readily available. This cleaner running, non-fuel lube mix, lowest friction, dry lube approach came about with your mention of adding a lower piston ring groove & could optimally address the M-90's unique rubber o-ring/ metal on metal piston to cylinder wall friction scuffing lubricant needs finally eliminate the messy oily spitting exhaust issue..tom.
Post by: 70Rcode on June 05, 2020, 12:19:25 pm
Post by: Stilldrillin on June 05, 2020, 04:48:25 pm
Thanks for your thoughts.....
My idea was to move the single O ring, to the base of the skirt. Lubricating with two stroke mix.
Dry ptfe, sealed between top ring and skirt base sounds a great idea!
S/S Machine? I'm afraid, I'm on the wrong side of the Atlantic.
Will have to see what's available over here, when the time comes....
Post by: 70Rcode on June 05, 2020, 06:27:23 pm
is super compatible with rubber on metal sliding applications Without any additional wet lubricant needed. That entirely eliminates the need for
Any fuel-lube mix and/or any direct applied to piston-cylinder wet lubes & lets the pure clean white fuels combust cleanly as possible without "passing" thru wet sooting plug & valves fouling oil based wet lubes. Retain the stock upper O-ring & add your 2nd additional rubber o-ring & piston groove to allow the entire piston to float non-contacting any part of cylinder wall like piston to wall isolators without need to worry about getting any "liquid" lube between the o-rings & eliminates any metal piston skirt frictional scuffing to cylinder wall issues. A non-metallic o-ring at far opposite ends of the fully "floating" piston to speak....just a few thoughts to let the 4 stroke fuel & run like well lubed 4 stroke without the 2 stroke lube mess i plan to impliment on my M90...Regards,...tom.
Post by: 70Rcode on June 05, 2020, 06:30:44 pm
Post by: Stilldrillin on June 17, 2020, 04:57:59 pm
I won it on Ebay, for a bargain £160.
Must have been something to do with it being Boxing Day, at the time.....
Intending only to have a few seconds proving run. I just fitted batteries, and filled the tank.
Set the needle to 1/2 turn open. Gave it a pull on the cord......
https://youtu.be/24I47knrqdI
That will do nicely. Lots of experimenting to come.....
Post by: Nick on June 17, 2020, 05:45:33 pm
That will do nicely. Lots of experimenting to come.....
Thanks for the video David and I will be watching for your future experiments ;)
Post by: RedRyder on June 18, 2020, 07:25:01 am
Make sure you mix Marvel Mystery Oil, 2 cycle oil, or Castor oil with your fuel.
It is cheap insurance and will run better, last a lot longer.
Most of all.... Have fun!
Gil
Post by: Stilldrillin on June 28, 2020, 04:16:54 pm
.100" faced from piston crown, to reduce compression ratio. Plus an oil groove, at lower end of piston skirt.....
(https://i.postimg.cc/tR6p0hGQ/IMG-20200620-163841.jpg) (https://postimages.org/)
Unfortunately... A fumbled insertion of the piston, nipped the O ring, and it broke!
Four days later. I had a pack of 10 new rings, and a 12mm high, aluminium block.....
(https://i.postimg.cc/h45cnkND/IMG-20200626-091919.jpg) (https://postimages.org/)
The block is to guide the piston straight into the bore, with no need for any wiggling.....
(https://i.postimg.cc/GhTrmM1k/IMG-20200626-091753.jpg) (https://postimages.org/)
When fitted to the crank assembly, the piston just slid straight in!
The block then is taken out, from underneath the crank, before the bearings are settled into their seats.
I've mixed some two stroke oil, with the lighter fuel 20/1.
Slightly smokey. I think it is a little rich. Will try 15/1, later.
Also. I'm going to retard the ignition a little. It is hitting a little too hard for me.....
I love fiddling/ bodging/ experimenting/ getting it wrong/ putting it right, (usually). With our small engines....
Post by: RedRyder on June 29, 2020, 06:34:18 am
I may need to start addi g that lower oil groove. Great idea!