Nemett Lynx 15 cc 4 Stroke I/C Petrol Engine

Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

gus

Well-Known Member
HMEM Supporting Member
Joined
May 27, 2010
Messages
2,999
Reaction score
1,171
Plan to build this engine next year .Bought plans and the Best of Model Engineer,100 Page special Autumn 2013 Magazine.
Still wondering am I chewing off too much more than I can swallow and digest.Have I the all the required skills/determination to complete from scratch. Have not jumped in yet. Having very bad cold feet.
Engine is about same overall dimension of Rupnow's Hit & Miss Engine but with overhead cam drive . Overall height is 165mm.
The magazine has very good write-up take reader thru step by step or rather
foto by foto.
Hi Meisters/Maestros. Your kind advice is requested.

IMG_2320.jpg
 
Last edited:
Gus:

Only you could know your comfort level.

How bad could this build be? If you ruin a part, re-make it from bar-stock. If you run into bad problems, the forum members will help you solve them. I have these plans and even with my very rudimentary skills, I would attempt it. The only parts that cause me some concern would be generating/profiling the cams, and maybe, the carb....oh yeah, valve seating and leaking. But look at the beautiful engine that you'll be making, and all the new skills you'll be gaining.

GO FOR IT!



Frank
 
Gus - from what I've seen of your work so far, I definitely think you can build this engine (although I'm not familiar with this engine at all). Plus, I find it very rewarding to learn new skills and do things that I haven't done before.

Speaking for myself, once I finish all my current engine projects , my next build will be a multi-cylinder 4 stroke. I'm not at all comfortable with my choice and I know I don't yet possess all the skills to build it, but I know with help from the forum geniuses, and with enough effort from me, I will get it to run.

Good luck with whatever you choose.
 
I have looked over the plan and articles, and hope to build one after I retire. It is a litttle complicated, but the very complete builder notes that the articles give should make it a lot easier. I'm sure you can do it, Gus, but I think it will be a big time commitmernt. It sure is a beautiful engine.
 
Gus, did you ever get the Firefly going? There are far more important fits in the Lynx than the Firefly that you will need to achieve if it is to run OK.

J
 
Gus, I think that I've mentioned before that we need challenges to hone our machining skills. I'm amazed by what you can produce with a balcony workshop. You should go for it, were all here to help.

I'm off to the newsagents this morning to see if I can get a copy of the magazine with the plans.

Paul.
 
Checked several local shops that sell the magazine, but none have the special edition, so have placed an order to have one posted out.

Paul.
 
Last edited:
Gus, did you ever get the Firefly going? There are far more important fits in the Lynx than the Firefly that you will need to achieve if it is to run OK.

J

Hi Jason,

I have two very unforgiving engines to rework and get running.
The Bolero and the Firefly. After this engines are up and running,will go on to
the Nemett Lynx. Both Bolero and Firefly have some critical fits to meet.

With experience gained from both these two engines plus the Webster and
Brian's H&M Engine,I would gain confidence to embark on the "Lynx" in 2014.

Thanks for the expert advice.
 
Hi
I see no reason for you not to have a go at this engine.
I managed to build it and I class myself as a rank amateur,in fact its only the second engine I have made.
see here...http://www.homemodelenginemachinist.com/f14/nemett-15cc-4-stroke-engine-14425/

I might add that I built mine from the magazine articles and not the overexpensive book.

good luck.
Roy.


Hi Roy,
Saw your engine running beautifully sometime ago and I just could not resist not building this engine. The Model Engineer article has very comprehensive Work Instructions as though written by ISO 9000 guys.
This will be the first time I will be cutting cam shafts with two cams.
Plan to run with petrol and CDI.Promise I will take time to make this engine and no rush.Will take time to read article and scrutinise prints.

With the Firefly I went in like a Kamikaze fighter w/o comprehending the prints and crashed. Same engine has some very unforgiving fits.The Bolero too.
As of last six months with the building of Webster and Brian's H & M Engine, my turning skills has improved vastly.

Now pondering to buy a new lathe now that Bernanke is behaving and the local market shot up. Gus made a good bundle.Also been spending on good turning tools and measuring instruments.Plan to throw away all the cheapy
China Mikes and Calipers that eat batteries and indicator panels flash like Christmas trees.
 
Me too

I've got the best of ME articles, have sourced the bar stock and did the cylinder liner the other day. Small beginnings.

However, I'm now sourcing the bought in parts I went to HPC for the timing pulleys and belts and they are very expensive. Digging around I came across the 3D printing Wiki http://reprap.org/wiki/Belts_and_Pulleys and a good write up on various vendors. Take a look at www.beltingonline.com only 10quid for both the pulleys and belt.

For the bearings Arc Eurotrade prices look OK but they don't have needle roller inner sleeve.

My question; would it be OK to make the roller inner sleeve from a 10.5mm length of 10mm Silver Steel, 7mm reamed hole, heated to cherry red and quenched in water?

Pete
 
HI
Nice to see you made a start.
The bearing part really depends on what you are going to do with the engine when its finished. ( note I said when not if) :)

If you are going to test run it the just display it silver steel should work , you'll have to temper it as well or it'll shatter.
If you intend to run it in a model I would go for the proper thing.

Have you looked here http://simplybearings.co.uk/shop/index.html.

I get most of my bearings here.

Good luck with the build and we want lots of pics.

If I can help in any way just yell.

Roy.
 
Me too

I've got the best of ME articles, have sourced the bar stock and did the cylinder liner the other day. Small beginnings.

However, I'm now sourcing the bought in parts I went to HPC for the timing pulleys and belts and they are very expensive. Digging around I came across the 3D printing Wiki http://reprap.org/wiki/Belts_and_Pulleys and a good write up on various vendors. Take a look at www.beltingonline.com only 10quid for both the pulleys and belt.

For the bearings Arc Eurotrade prices look OK but they don't have needle roller inner sleeve.

My question; would it be OK to make the roller inner sleeve from a 10.5mm length of 10mm Silver Steel, 7mm reamed hole, heated to cherry red and quenched in water?

Pete


Hi Pete,

I am up to my neck with Webster IC Engine and The Rupnow H & M Engine.
Got the H&M Engine going but I still have the Hit & Miss parts to be done. Will do it leisurely. Will be March 2014 before I start buy the timing belts.

Will be following your threads building the Nemett Engine. Plan to cut the timing belt wheels because they cost an arm and leg to buy. Cutting these wheel will be fun though I have successfully cut some small gears for the above engines with Harold Hall's Dividing Head.

Wish you all success.

Gus Teng,from faraway Singapore.
 
Plan to cut the timing belt wheels because they cost an arm and leg to buy..

I dont know much about these timing belts & pulleys supply, but I have seen smallish sized ones like this in robotics kits suppliers, link below. They seem very reasonably priced if they would work. The smallest circumference of toothed belt is 120mm (4.72"). Judging by the Nemett engine size, maybe something could be made to work from this selection?

http://www.robotmarketplace.com/products/timing_belts_fingertech.html

http://www.robotmarketplace.com/products/timing_pulleys_fingertech.html

At the end of the day, I imaging all that's required is 2:1 gear ratio for the cam. It doesnt mater if they are metric or imperial, as long as the tooth pitch match the corresponding belt & gear ratio is 2:1?

Another possible source might be RC helicopters & cars. But I suspect the belts might always be too long for that application ... unless there is a reliable way to splice & join them?

http://dx.com/p/esky-ek1-0503-belt-parts-spare-for-belt-cp-v2-rc-helicopter-80cm-33375

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDHU7
 
I dont know much about these timing belts & pulleys supply, but I have seen smallish sized ones like this in robotics kits suppliers, link below. They seem very reasonably priced if they would work. The smallest circumference of toothed belt is 120mm (4.72"). Judging by the Nemett engine size, maybe something could be made to work from this selection?

http://www.robotmarketplace.com/products/timing_belts_fingertech.html

http://www.robotmarketplace.com/products/timing_pulleys_fingertech.html

At the end of the day, I imaging all that's required is 2:1 gear ratio for the cam. It doesnt mater if they are metric or imperial, as long as the tooth pitch match the corresponding belt & gear ratio is 2:1?

Another possible source might be RC helicopters & cars. But I suspect the belts might always be too long for that application ... unless there is a reliable way to splice & join them?

http://dx.com/p/esky-ek1-0503-belt-parts-spare-for-belt-cp-v2-rc-helicopter-80cm-33375

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDHU7

Hi Peter,

You are a gem. Thanks .The timing wheels are so cost effective. Will buy and study.

Now looking for belts. There are many belt shops here in Singapore.Failure of which will pay more for the UK source,
 
hi
I have just bought the latest model engineer with Lynx 15cc petro engine . I have checked the drawing and could not find any DIM tolerances for any dimensions. question is that anybody built this engine before and could help me to solve the problem? many thanks mike
 
Mike

As the guys have said over on Model Engineer. Unless you are making more than one and all the parts need to be interchangeable make one part to dimension and make the other part fit. You are your own Quality Controller.

Pete
 
Zega79, I have the drawings for this motor and will start later this year. As Mike said, you have to make your own tolerances. Just work out what is easier, to make bores on size or to make the parts that go in them on size, and make other parts to suit.

Paul.
 

Latest posts

Back
Top