Nemett Lynx 15 cc 4 Stroke I/C Petrol Engine

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Cam rod installed and valves tuned up. Will heat treat and oil quench cam lobes shortly.

Flywheel will done tomorrow. C.I. flywheel machined on lathe is very messy.
 
Heat treatment of cam lobes done. Simple folksy equipement. Buying a whole can of SAE 20 Engine Oil would be very expensive. The 2T oil for now obsolete 2 stroke engines works fine.
Silver Steel is not difficult to heat treat and oil quench. Heat up to bright red and hold for 2 minutes and by the time cam moved to the oil,the chilly red ccloour came on. Did file test to confirm hardness done.

After clean up , did angular alignment of cam lobes as per Malcom's imperial edict. The DIY RT
with the cheapy protractor performed well.

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Cast Iron is not my preferred material. C.I. is preferred over the expensive brass/bronze. When a job gets to be too big,there is the hazard of sharp chips all over and eventually some may end up on my hands and fingers or foot.
For cast iron I get dressed up to keep away the C.I. dust on my body which is hard to dust off and the bath room gets rust stained and the boss gets mad.

For some unknown reasons,the Warner Boring Bar gave me bell mouth taper bore at the small end. The Eclipse
HSS Boring Bar saved the day. With the flywheel mounted on,job can proceed into next phase.

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Getting close now Gus, I don't know if the boss will be happy with that dirty on one side shirt. It may have been accidental, but in your last picture, you have the belt tensioner on the inside, it should be on the outside.

Paul.
 
Swifty said:
Getting close now Gus, I don't know if the boss will be happy with that dirty on one side shirt. It may have been accidental, but in your last picture, you have the belt tensioner on the inside, it should be on the outside.

Paul.
Click to expand...

My ''BOSS'' did casually asked about the very dirty shirt. My reply was -----"Its
not washable,the cast dust would ''rust'' all other clothings in the washing machine.
Its ''use and throwaway''.

There is an unending stream of mini tasks to finish up before I even dare to think of Spinning the Engine.:rant:
 
Brian Rupnow said:
Looking very good Gus. I am still watching and crossing my fingers for your first successfull run.---Brian
Click to expand...

Hi Brian,

For same reason,I am taking a short holiday in South Thailand to relax before going back to finish up and spin. Promised-------'''Gus will be very patient.''

Now enjoying tackling the mini tasks. Two subassembly to make .

The Carb and Ignition Box and the base and the gas tank.
The Carb sents shiver to my spine.All my DIY carbs went to scrap bin.:rant:
 
Swifty said:
Getting close now Gus, I don't know if the boss will be happy with that dirty on one side shirt. It may have been accidental, but in your last picture, you have the belt tensioner on the inside, it should be on the outside.

Paul.
Click to expand...


I am confused. Please enlighten Gus.

Please advise Engine direction facing the flywheel.
 
Gus, you have the belt tensioner running on the toothed part of the belt, pushing it towards the outside. It should be on the smooth side of the belt, pushing it in. The engine runs anticlockwise when looking at the flywheel.

Paul.
 
looking good Gus, getting anxious to see / hear it run.

question on the cam, do you polish or anything to remove the "scale" or oxidization caused by the red hot heat? or does that simply wear / flake off?
 
werowance said:
looking good Gus, getting anxious to see / hear it run.

question on the cam, do you polish or anything to remove the "scale" or oxidization caused by the red hot heat? or does that simply wear / flake off?
Click to expand...


No .I kind of forgot to remove the scale.:hDe:
 
Hi Pete,

I like you engine supports. Looking for ideas. May end up copying Paul Swifty's but its a lot of work.
After a weeks break in South Thailand will have batteries fully charged. I like your carby .Did you DIY it??
 
Swifty said:
Gus, you have the belt tensioner running on the toothed part of the belt, pushing it towards the outside. It should be on the smooth side of the belt, pushing it in. The engine runs anticlockwise when looking at the flywheel.

Paul.
Click to expand...


Lost a Conger Eel. A mate wants to eat it but the guy doing netting bungled and lost it. It was a very beautiful/colourfull eel with very ugly teeth.Back in mind,I rather let it go. Gave me a very good fight 50 feet from sea bottom.
This weekend fishing been very good. 8 pcs on Saturday and 9 today.All Snappers and Javekins. Good eating size to feed 3---4 pax.
Went to a very old spot that we have yet to find out the feed time. Its 1 hour before high tide!!!!. My FADs(DIY artificial reefs) now productive and kept location secret. Will be back from South Thailand next Friday and back to so many things to do!!!. Take care.
 
Gus--According to Malcolm Stride, you are supposed to carefully "dress" the machined surfaces of the cam with a fine diamond file before heat treating to remove all of the micro-ridges left by the cam machining process. Then after hardening, you can clean the scale off the faces by rubbing on a fine sheet of carborundum paper. When I made my cams, I got so excited at my success that I immediately hardened them without using a diamond file on them (I forgot that step!!). I did give them a slight wipe on some fine carborundum paper after heat treating. The fact that I missed the "diamond file the micro-ridges before hardening" doesn't really seem to have made any difference to how the cams function.---Brian
 
gus said:
Hi Pete,
.................. I like your carby .Did you DIY it??
Click to expand...

Click the link, US$17

http://www.hobbyking.com/hobbyking/store/__20455__RCG_15cc_Gas_Engine_Carburetor.htm

Of course the cam finish needed to be good before you hardened them. Too late afterwards.

To clean the scale off them just drop them into some clean citric acid mixed in hot water. The cams will them come out a light grey colour which can then be polished with some 600grit emery paper

Get the citric acid crystals from the baking section from you local store. Its what is used by the boiler makers but works on steel. Don't use a mix that copper has been in as it will eat the steel.

Pete
 
Gus---Funny story for you (fishing). I have never been much of a fisherman myself, but my father loved to fish lake trout. when I was a kid back in the 1950's my father had a 3 HP Evinrude outboard, a 14 foot wooden boat that he built himself, and he would troll with steel line for lake trout in the big lake I grew up on. He had a big aluminum handled net that he used to scoop the fish up out of the water once he had reeled in his steel line and got the fish up to the boat. I was at home alone for some reason, and a big bat got into the house. I was terrified of bats (watched too many old Vampire movies at the theater in town.) I ran to my dad's closet and grabbed his big old fish net, and used it to catch the bat out of the air. The bat immediately thrashed about and got all tangled up in the net. I carried it outside, but was afraid to try and get the bat out of the net in case it bit me. (we had all been warned as children that bats carry rabies, and not to get bitten.) I ran into the house and got my mothers big scissors from her sewing basket, and cut the end out of the net, with the bat still tangled in it. I stomped the bat to death, and then seeing what I had done to my fathers fish net, I buried the bat and put my dad's fish net back into the closet. I never told a soul about it. The next time he went fishing, he caught a big lake trout, reeled it in, and dipped it out of the water with the net. Of course, the fish went right through the bottom of the net and gave a big flop and got away. My father come home and said to my mother "I must have put the net away wet and it rotted the bottom right out of it. I caught a big fish and it went right through the net." ---I never breathed a word to my father about what I had done, and the dear man has been in his grave for twenty years now.---Brian
 
Brian Rupnow said:
Gus--According to Malcolm Stride, you are supposed to carefully "dress" the machined surfaces of the cam with a fine diamond file before heat treating to remove all of the micro-ridges left by the cam machining process. Then after hardening, you can clean the scale off the faces by rubbing on a fine sheet of carborundum paper. When I made my cams, I got so excited at my success that I immediately hardened them without using a diamond file on them (I forgot that step!!). I did give them a slight wipe on some fine carborundum paper after heat treating. The fact that I missed the "diamond file the micro-ridges before hardening" doesn't really seem to have made any difference to how the cams function.---Brian
Click to expand...

Hi Brian,
After the milling, I went over with hand smooth file,very fine diamond file and fine emery paper. But missed out the scales after heat treatment.:hDe:

No sweat. Cam shaft easily removed to remove scale. This will be done next week after the South Thailand trip. Did not realise 0.01 0r 0.02 is very minute . Gus was heavy handed. Plus the quill was not sufficiently tightened up and this gave me the heartaches and so many ruined cam blanks.:wall:Just another learning curve for Gus.;D

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Hi Brian,

Here's one story,
1. Friend of mine hooked up a 10' Shark Whale and lost it because of a bad net,the handle broke. There goes his fresh sharks fin.:wall:

2. Gus loss a 5' Cobia. The Gaff was to dull to hook up .:rant:

But your incident was very entertaining. Dad would have been mad,if he found out the bat and the truth.

Here is one last one.

Facebook friend in Thailand commented I have yet to give one of my many fish. Just imagine his reaction when
I handed him a 5 pounder frozen Snapper!!!:eek:

Had a good Thailand dinner.
 
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