Author Topic: Two Cylinder Engine  (Read 21378 times)

Offline Roger B

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Re: Two Cylinder Engine
« Reply #165 on: March 17, 2019, 08:18:26 AM »
Thank you Dave  :ThumbsUp:

Next up were the various brass electrodes for the distributor. I did consider making the centre electrode from graphite but didn't have any suitable material. The output electrode were turned just using a parting tool. I made a spare as they look like something for the swarf Gnomes  ::) The rotor electrode was hand filed to shape and superglued in place. Finally I set the phasing between the cam and the rotor arm and drilled and tapped the fixing hole. The RT was used as it was already fitted and is a good way of holding round things.
Best regards

Roger

Offline Ye-Ole Steam Dude

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Re: Two Cylinder Engine
« Reply #166 on: March 17, 2019, 09:26:18 AM »
Hello Roger,

Looking really good :ThumbsUp:

Have a great day,
Thomas

Offline Zephyrin

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Re: Two Cylinder Engine
« Reply #167 on: March 17, 2019, 10:23:30 AM »
very interesting job on the distributor, thanks to share !
first class use of the small tooling you have, this mill looks quite accurate.

Offline Kim

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Re: Two Cylinder Engine
« Reply #168 on: March 17, 2019, 03:32:03 PM »
Nice work on the distributor, Roger!  That's lots of shiny little bits you made  :)
Kim

Offline fumopuc

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Re: Two Cylinder Engine
« Reply #169 on: March 17, 2019, 05:45:04 PM »
Hi Roger, always watching every progress.
Kind Regards
Achim

Offline Roger B

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Re: Two Cylinder Engine
« Reply #170 on: March 18, 2019, 06:00:59 PM »
Thank you all for your support  :ThumbsUp: Zephyrin, I have found the small Proxxon drill and mill very useful. I have a very small workshop they will sit out of the way on a shelf when not in use. As my main machine is a combined Lathe and Mill I can do small milling jobs without having to convert from lathe to mill and back again. I am currently investigating the FD150/E micro lathe so I can make small bushes and adaptors whilst I am in mill mode.

Next up were the clamps for the distributor cap. These were made from 8mm aluminium bar drilled 3mm and then half milled away. I was quite impressed at the accuracy of the two parts  :) Two clearance flats were then milled on the same side. I then faced the water pump gears to size, giving about 0.1mm clearance to allow for thermal expansion (found the hard way on the horizontal engine  :( ) The key way was cut with the broach I made for the previous pump. Now I need to make a 2mm stainless steel key.
Best regards

Roger

Offline yogi

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Re: Two Cylinder Engine
« Reply #171 on: March 18, 2019, 06:55:49 PM »
Looking good Roger!  :ThumbsUp: :ThumbsUp: :ThumbsUp:
The engine is coming together nicely.  :popcorn: :popcorn: :popcorn:

Offline bent

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Re: Two Cylinder Engine
« Reply #172 on: March 20, 2019, 05:14:51 PM »
Cheers from the popcorn gallery, it's looking good Roger! :popcorn:

Offline Roger B

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Re: Two Cylinder Engine
« Reply #173 on: March 31, 2019, 10:10:32 AM »
Thank you for your interest  :ThumbsUp:

Finally a bit of workshop time on this. The water pump drive key was milled from a length of 3mm stainless steel and the ends were rounded by filling. When I assembled the gears they didn't turn smoothly and on close inspection the force of cutting the keyway had stretched between two teeth  :( I tried again this time with the gear held in a 14mm collet as I did for my horizontal engine, all ok  :)

I had decided I didn't really need to flange the water inlet as things were a little tight so I Loctited a stub of brass pipe in place. Finally I used my new toy to put cones in the end of some 4mm grub screws for the tappet adjusters starting with a centre drill and following with a 3mm drill.
Best regards

Roger

Offline yogi

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Re: Two Cylinder Engine
« Reply #174 on: April 03, 2019, 11:24:46 PM »
Coming together nicely Roger!
I like your new toy!  :popcorn:

Offline Roger B

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Re: Two Cylinder Engine
« Reply #175 on: May 19, 2019, 04:58:52 PM »
Thank you  :)

I have done a few little bits on this one. The distributor connection have been soldered onto the HT wires and I have started making the punch template for the head gasket. This is two pieces of 3mm thick aluminium with a couple of 4mm dowels for location and two M3 screws to clamp it together. The 3mm holes for the head fixing bolts were marked in red to reduce the chance of mistakes and together with the 4mm holes for the water passages were drilled and reamed on the bench drill. The two cylinder holes were made on the mill, starting 6mm drill then 15.5mm drill and boring to 20.6mm. The actual bores are 20.15mm after lapping. Next I need to make the punch for the bores. I already have 3 and 4mm ones from other engines.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #176 on: May 25, 2019, 08:09:36 AM »
The punch was turned from a short piece of 22mm mild steel with a chamfered cutting edge. This will then be case hardened which needs to done outside.

The next step was to set up the timing and cut the keyways in the two 40T gears. Problem  :( I couldn't turn the camshaft  :headscratch: I dismantled the cam assembly and found the camshaft had bent 0.2-0.3mm, I guess due to residual stress from hardening. I could have annealed it, straightened it and then re hardened but the same problem would probably occur  :thinking: I decided to take the high risk route and try and straighten it while hard. The pressure was applied using the cross slide so I could increase the deflection in small controlled stages. As expected it broke  :toilet_claw:  I will make a new one from 10mm mild steel and case harden the lobes rather than using silver steel and hardening it through.

The gaps between the lobes were cut using a replaceable tip parting tool I purchased for making crankshafts which worked well without chatter. There was one small calculation error but this won't matter as I will reduce all the lobe below 10mm to give clearance in the housing.
« Last Edit: May 25, 2019, 08:51:22 AM by Roger B »
Best regards

Roger

Offline Florian Eberhard

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Re: Two Cylinder Engine
« Reply #177 on: May 25, 2019, 08:48:20 AM »
Hi Roger

Straightening of hardened steel seems to work only a very short period of time after hardening.
What can work is if you temper the workpiece under preload into the direction you want it to go. I have already successfully done that. In my case to a light straw color - and in the oven, using a thermometer to make sure the oven wasn't getting too hot.

Florian

Offline Art K

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Re: Two Cylinder Engine
« Reply #178 on: May 25, 2019, 04:19:37 PM »
Roger,
I have to admit to never having hardened a camshaft. I think I have used stainless steel in both my engines. Sorry to hear about the broken cam, maybe a grinder on oversized shafts would work. That is if you have a grinder.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Roger B

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Re: Two Cylinder Engine
« Reply #179 on: June 18, 2019, 06:51:39 PM »
Thank you both  :ThumbsUp: The problem was that the tip of the cams were almost the full 10mm diameter of the tunnel that the cam fits in so 0.2mm deflection caused everything to jam up. I decided to reduce the diameter by 0.4mm for the next version to give some clearance. This kept the base circle still larger than the 6mm shaft. Time has been very limited in the last month or so but I have finally machined the blank read for hardening.
Best regards

Roger