Swifty's build of Nemett Lynx

[Swifty]

I thought that I would just touch base, I have disassembled the engine to finish off bits like chamfers on corners, removing some machining marks etc. I'm not going for a lot of bling, a matt surface finish suits me. I noticed that the oil in the crankcase was already a very dirty colour after it's few short runs.

I have a piece of oak for the base, but after spending quite a while trying to find my router bits, I finally recalled that I had lent them to one of my sons, I think that he is trying to build up his tool collection piece by piece at my expense. Anyway, after a quick phone call he will try to find where he has put them, so hopefully that won't be too long and I can continue with the base.

Paul.

 

[Swifty]

I'm still working on the engine, I have reassembled it again after polishing machining marks out etc. I reset the cam timing, even going to the extent of using a dial indicator to check when the exhaust valve starts to move at the correct angle of rotation. I also set the ignition timing using a plunger style dial indicator fitted with a long point to poke down the spark plug hole to check TDC of the piston. The crankcase has been refilled with fresh oil and the flywheel refitted for starting. I now only have to finish the board to mount it on, stay tuned.

Paul.

 

[Swifty]

Here is the final assembly of my engine, I will also post the photo's in the "Finished Projects" section. I will add a new video shortly.





Thanks everyone for following along, I hope to pull out a couple of part finished projects and finish them off next.

Paul.

 

[Brian Rupnow]

Paul--It is gorgeous!!! Congratulations from Brian.

 

[johnny1320]

That is one beautiful looking engine!

 

[Swifty]

Thanks Johnny, I had a few short runs with the propellor yesterday but I will put the flywheel back on today so I can adjust the carburettor safely. I will then replace the prop and take a video.

Brian, I'm really flattered, you have given me 2 likes on this build. The further I got into this build, the less I explained and photographed the machining methods, I must try to show more methods in my next build. I took all the photos with my iphone except for the final ones, it was just so handy with the phone. I think the final assembled photos came out well, I'm pleased with them anyway.

Paul.

 

[AussieJimG]

That's one for the mantlepiece where everyone can see and enjoy it. Congratulations.

Jim

 

[gus]

A MasterPiece by a Maestro. Hopefully my Nemett-Lynx can match.

Cam Cutting and heat treatment will happen today.

 

[doubletop]

Love it!!

I may just have to replace my plastic prop with a wooden one.

Pete

 

[Swifty]

All those that said that a spiral style starter drive was best are proven correct. With the propeller on, as soon as it fires it tries to drive the battery drill that I am using to start it, I generally cannot pull it away fast enough for it to continue running. It was no trouble when using the flywheel as it had enough momentom on to keep running, but the prop weighs practically nothing. I am currently modifying the starter drive plate to have ramps to allow it to uncouple easily.

Paul.

 

[Swifty]

I've come to the conclusion, for the time being, that the propeller is just too light to keep the motor running. If I put the flywheel on, it starts and runs straight away, but when I change over to the prop on a still warm engine all it does is fire a bit and stop. It appears that it just needs the weight of the flywheel to keep it running. It doesn't matter, as I know it runs and the prop is only for display anyway. I might keep tinkering a bit longer, but I am calling it finished anyway.

Paul.

 

[Swifty]

The tachometer finally arrived via that slow boat from China, it was simply a matter of plugging it straight in to the ignition. The maximum revs that I could get was just over 12,000 rpm, with idle speed just under 2000rpm. It looks like it is idleing slower, but I trust that the tachometer is correct. It still burn a lot of oil and does not appear to be very fuel efficient, but what the heck, it's only a model.

Paul.

 

[fishy-steve]

Hi Swifty.
I've been directed here by Jason. Thanks Jason.
I'm in the process of buying all that I need to make the Lynx. It will be my first build.
I've read the complete thread from start to finish and will now read it again but this time with a note pad to jot down the gems that it contains.

Thanks for taking the time to post this thread. I really enjoyed it.

Steve.

 

[Swifty]

Hi Steve, I hope that you are going to post on your progress with the build. Please ask any questions that you like and I will endeavour to help.

Paul.

 

[gus]

Hi Swifty.
I've been directed here by Jason. Thanks Jason.
I'm in the process of buying all that I need to make the Lynx. It will be my first build.
I've read the complete thread from start to finish and will now read it again but this time with a note pad to jot down the gems that it contains.

Thanks for taking the time to post this thread. I really enjoyed it.

Steve.

Hi Steve,
Paul Swifty is the best mentor Gus ever had. I tagged along with his post on Nemett-Lynx Engine so that I need not re-invent the machining/fitting skills to cut some very difficult components. Machining,drilling and tapping the Petrol Spray Bar today. Same part is so small and I get worried.

 

[fishy-steve]

Hi Steve, I hope that you are going to post on your progress with the build. Please ask any questions that you like and I will endeavour to help.

Paul.

Hi Paul.
You might live to regret that.
Thanks.
Steve.

 

[fishy-steve]

Hi Steve,
Paul Swifty is the best mentor Gus ever had. I tagged along with his post on Nemett-Lynx Engine so that I need not re-invent the machining/fitting skills to cut some very difficult components. Machining,drilling and tapping the Petrol Spray Bar today. Same part is so small and I get worried.

Hi Gus.
I've read your thread from start to finish also. I'm trying to glean as much info from both threads before starting my build.
I'm using the drawings from The best of model engineering magazine.
I've purchased the timing belt/pulleys and the bearings. I also managed to get the crank pin sleeve.

Steve.

 

[Swifty]

Fishy-steve, if you can go to the Welcome area and tell us a bit about yourself, it will help other members to have an idea of your skills and equipment. You will find members very helpful with any questions that you may have, no matter how simple you may think they are.

Just a bit of a heads up about the drawings in the magazine for the Lynx, there is no distinction between solid, hidden or dimension lines. This makes it very difficult if you have limited experience with reading drawings, however if you take your time and check pictures on other builds, all should be ok. The only part that I had problems with was the carby, but nothing that ended up being a problem.

Paul.

 

[fishy-steve]

Hi Paul.
I'll pop over there now.
As far as the drawings are concerned. I'm finding the crankcase drawing "challenging"
If I'd produced a drawing like that when I took my Tech drawing O'level I think I would have failed.

 

[gus]

Hi Paul.
You might live to regret that.
Thanks.
Steve.

Hi Steve,

No worries. Paul is very helpful. He would have kindly mail over a very small/intricate/delicate part to Gus if Gus was about to throw in the towel and hang up the unfinished engine.
The Nemett-Lynx Carb Spray Bar was very scary to drill the 0.8 mm i.d. hole which happened to be 10 mm deep. This part now done and assembled.

Retirees have plenty of time.