Author Topic: Side Valve i.c. engine from Bar stock  (Read 88430 times)

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #150 on: September 24, 2014, 08:41:01 PM »
Not much machining accomplished today. I'm a bit overwhelmed by 'real' work right now, plus making a wooden cabinet to hide an ugly wall mounted 100 amp electrical service at my son's house. I did manage to steal 20 minutes out of the day to hone the cylinder/valve chamber with my 3 stone brake hone, and to lap it using a piece of 1" aluminum round bar and first #400, then #600 carborundum paste.  Sometime in the next few days, I will use the other end of the 1" aluminum round stock which is not polluted with embedded carborundum paste to make a piston. Good Heavens!!! If I get a piston made, then I am getting awfully close to a finished engine. Oh yeah, I forgot---I still have tappets to make.---Brian

Offline DavidA

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Re: Side Valve i.c. engine from Bar stock
« Reply #151 on: September 25, 2014, 05:40:58 AM »
It's coming together nicely.
Makes me feel guilty every time I look at my part finished Jan Ridders engine.
When the weather turns bad again I will have to make some progress on that front. And the Fowler 4F loco.

Dave.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #152 on: September 27, 2014, 06:51:03 AM »
I haven't had a very "machiney" week due to other obligations. I hope to make a piston sometime today, and I have realized that due to adding the 1/32" gasket between the valve chamber and the cylinder body, I will have to make the piston 1/32" taller between the gudgeon pin and the top surface, in order for it to come even with top of the "deck" when at top dead center.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #153 on: September 27, 2014, 01:48:46 PM »
Hey Hey!!! we got a piston!!! That's two things accomplished today. Machined a piston and got a haircut. Damn, I'm a good looking fellow when I get a haircut.--Look just like Elvis---sorta---


Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #154 on: September 27, 2014, 05:34:50 PM »
I'm very pleased to announce that with rod and piston installed and all gaskets in place, the crankshaft does indeed go "round and round". No matter how much fancy 3D cad modelling I do and how many calculations I make, this is always the moment of truth for me. I actually had one little heart stopper---the crankshaft wouldn't make a full 360 degree rotation when I first assembled everything. I took out the bolts that hold the cylinder to the crankcase one by one, but it wasn't that. Then I pulled the head off----and discovered that the top of the piston actually comes up about .013" higher than the top of the deck. That would have been okay, I have .060" clearance milled into the head.---But--I had cut the gasket hole a bit small, and the piston was hanging up on the gasket material. A bit of very careful exacto knife work to trim the gasket, and that fixed things. A big sigh of relief----Brian

Offline Stilldrillin

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Re: Side Valve i.c. engine from Bar stock
« Reply #155 on: September 27, 2014, 05:41:40 PM »
Well done, Brian!  :clap:   :clap:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline awemawson

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Re: Side Valve i.c. engine from Bar stock
« Reply #156 on: September 28, 2014, 02:26:07 AM »
 Looking good Brian

Is that con rod the finished article or are you planning to slim it down a bit? It's certainly chunky as is.
Andrew Mawson
East Sussex

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #157 on: September 28, 2014, 07:07:19 AM »
I'm going to leave it chunky. This is not a high speed engine, so the mass of an aluminum connecting rod is not really a big issue. On higher speed engines, where the weight of a a connecting rod can cause balance problems, slimming the rod down has advantages. It also has advantages for the manufactureres, where cast rods are used, because it saves material.---Brian

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #158 on: September 28, 2014, 07:55:34 AM »
Jeez, we're really coming down to the wire here folks.The two knurled items in this post will be what allows me to grip the ends of the camshafts and rotate them by hand after loosening of the set-screws in the timing gears to adjust the cam timing. They also limit the axial movement of the camshafts in their bushings. They will be bolted and Loctited to the ends of the camshafts.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #159 on: September 28, 2014, 08:03:48 AM »
These are the parts I've been saving until last, for two reasons. First reason is that 95% of the engine has to be built before their is a place for them to go, and the second reason (the real reason) is that I'm not sure how I am going to make them. The method outlined by Malcolm Stride in his Bobcat/jaguar/Lynx series works very well, but involves an awful lot of mill cranking. The second method which I believe Chuck Fellows made a video of and involves doing them in a rotary table on the mil looks a lot simpler, but I'm not certain about being able to hold the accuracy with the Chuck Fellows method.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #160 on: September 28, 2014, 06:15:25 PM »
So--What did I do wrong? I just used the cam-calc program http://modelenginenews.org/design/CamTable.html to create this cam profile. My inputs were --cam angle=120 degrees--valve lift 0.080"--flank radius =.640" --base radius =0.240" --engine rpm 3000, and 2 degree angular increments. It created a profile that dishes in rather than out like it is supposed to be. I am not sure I have laid it out correctly but I think I have.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #161 on: September 28, 2014, 06:27:29 PM »
And just for interests sake, that generates a nose radius of a whopping great .1815" . I'm sure I must be doing something wrong. Maybe the calculator doesn't like such a slow engine speed. The only really major difference between the inputs for this cam and the one Malcolm Stride generated for his Bobcat and Jaguar engines was that he used an engine speed of 5000 rpm for his inputs, and his cam profile turned out like one would expect a cam to look like.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #162 on: September 28, 2014, 06:42:03 PM »
I must be doing something wrong in my layout. I just reran the cam-calc program using a 5000 rpm input and it spit out exactly the same numbers as for a 3000 rpm input. The output for both 3000 rpm and 5000 rpm inputs  is also telling me that the nose radius will be .080" which I expected it to be. I'm doing something wrong in my layout. I just have to figure out what it is.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #163 on: September 28, 2014, 08:04:07 PM »
Okay--I'm sorted out. I have figured out that my layout was incorrect. I am currently working on a 3D cad model which will give me the proper profile when finished, but it's not quick nor easy. I have to create a solid, then rotate it and machine away portions of it exactly as I would in the machining process. I will post the profile when I get it finished.---Brian

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #164 on: September 28, 2014, 09:25:12 PM »
This was a battle royal, but I got it sussed out. The end result is happy!!! The cam profile generated by using all of the inputs for machining from CamCalc is a VERY VERY close match to what I had originally designed. I feel confident that if I use the generated numbers when actually machining my cams, I will end up with the result I was after.

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #165 on: September 28, 2014, 09:28:43 PM »
Yowzahhhhhhhhhhhhhh!!

Offline philf

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Re: Side Valve i.c. engine from Bar stock
« Reply #166 on: September 29, 2014, 01:40:53 PM »
Hi Brian,

I thought I'd replied last night but it must be stuck in the ether somewhere. (We're on holiday in our touring caravan and the wireless broadband connection has been very dodgy until 2 BT OpenReach engineers turned up this morning.)

I drew out your cam on Autocad using your figures of 0.24 base radius, 0.08 lift and 0.64 flank radius and it comes out with 0.08 nose radius. So, how the program generated a profile with such a huge nose rad I don't know. (It wouldn't display anything on my PC complaining of a Java Security issue.)

By the way - the speed has nothing to do with the profile the program generates. It's only used if you need to know accelerations.

For your 3d model why couldn't you just extrude the profile?

A very simple machining job for a CNC mill!

Phil.
Phil Fern
Location: Marple, Cheshire

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #167 on: September 29, 2014, 04:50:36 PM »
Philf--I did exactly that (extruded the profile) on the green cam. On the grey cam, I used the machining sequence generated by CamCalc to create the profile. That is why you see the side facets in the grey cam. It is a rotary table job with a cut taken every two degrees of rotation.---Brian

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #168 on: October 04, 2014, 07:34:43 AM »
I have had a crazy busy week, and haven't had a chance to play machinist very much. I did come home last night from the factory where I've been consulting for a couple of weeks, and got a good start on the tappets. I figure that if I have to set the rotary table up on the mill to do the cam anyways, I might as well cut the hex shapes on the tappets, which are being made from 1/2" 01 drill-rod. I hope to get the cams done this weekend as well. You are probably right about the shape of the cams not being all that critical. They are very "not critical" if using a follower wheel on the tappet, but for a flat bottomed tappet, if you don't get the curve right on the cam flank, they will 'slap' the bottom of the tappet on every revolution.----At least that's what the books say.-----Brian

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #169 on: October 04, 2014, 12:21:27 PM »
This morning I made the tappets from drill rod, which is a "water hardening steel". The machining went reasonably well, until I realized that I had tapped the wrong end of the larger diameter which rides on the cam!!! After remaking the large ends and getting it right the second time around, I carefully fit everything, then took the pieces out to my big garage for hardening. I heated the pieces one at a time with my oxy acetylene torch until they were bright orange, then tipped them into a can of water. I hoped that I wouldn't get much heat distortion which would have buggered up either the internal or external threads, but I must have lived right this week, because everything went back together fine. The outer diameter of one of the large parts may have grown a little, as it was a tight fit into the bronze guide block and I had to set it up in the lathe and polish it a tiny bit with some 280 grit paper. I decided at the last moment to use mild steel #10-24 locknuts, because it was less work, and I figured when used as a jam nut the mild steel would grip better and not back off while the engine was running. In the picture, one valve is open and one is closed, but the cams are still not made. That will be tomorrows job. The blob of stuff on top of the left hand tappet is some oil I had used when assembling things and then forgot to wipe off before taking the picture.

« Last Edit: October 04, 2014, 01:12:41 PM by Brian Rupnow »

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #170 on: October 04, 2014, 07:34:05 PM »
We have a cam!!! Actually, we have two cams, once I get them parted off. Everything went very well, and the profile looks perfect. I took a cut every two degrees of rotation in the rotary table. This leaves only microscopic ridging, which will clean up very easily with a fine diamond file. However, no matter how you do the math, that is 180 trips back and forth with the manual table. My right shoulder will be sore tomorrow from crank turning. Old dogs do learn new tricks---this time after the profile was cut, I left the cam in the rotary table set-up and continued taking cuts every two degrees until I had completed the full 360 degrees. This is an excellent method of making cams, but it is tedious. Tomorrow I will dress things a bit with the fine diamond file and part the cams of from the parent stock. Then they will be flame hardened and quenched, then silver soldered to their individual camshafts.


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Re: Side Valve i.c. engine from Bar stock
« Reply #171 on: October 05, 2014, 04:14:45 AM »
Hardened and quenched then silver soldered

Bit odd there Brian surly the SS unles you quench it again will soften them ?

Stuart

Offline chipenter

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Re: Side Valve i.c. engine from Bar stock
« Reply #172 on: October 05, 2014, 05:22:19 AM »
Hardened and quenched then silver soldered

Bit odd there Brian surly the SS unles you quench it again will soften them ?

Stuart
Even soft solder will soften to spring steel , will requenching crack the joint ?
Jeff

lordedmond

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Re: Side Valve i.c. engine from Bar stock
« Reply #173 on: October 05, 2014, 05:45:12 AM »
Not sure

But I wonld not SS them but pin them and fix with Loctite ,put the pin in from the large rad portion where the Tappit has its clearance so that it will not affect the cam profile .

Just my 2pence worth

I think G Meek put this method forward when he did his cams made easy write up

Stuart

Offline Brian Rupnow

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Re: Side Valve i.c. engine from Bar stock
« Reply #174 on: October 05, 2014, 07:56:15 AM »
The outside diameter of the cam, in the non lift area is only .480"  (12.2 mm).  The bore is 3/8" (9.5  mm).That means that the wall of the cam is only .052" (1.3 mm). not much room for a pin in that. I will be a doing a bit of experimenting with this and let you know the results.