5 Cylinder radial (winter's project)
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Hi Peter,
You're correct on the combustion chamber tool. It was machined from a piece of drill rod with the hemispherical shape on it. I then roughly relieved the flutes staying away from the cutting edges. With a magnifier I then file almost to the cutting edge leaving just a small amount to hone once it's been hardened.
The cylinder head/cylinder mating face should seal with no gasketing. The threads on both were machine cut so everything is very square and the two surfaces should run up tightly.
I didn't figure the compression ratio as I used the basic Morton dimensioning for bore, stroke and combustion chamber shape. Looking at it I would think it will be quite high, somewhere in the neighborhood of 8:1.
Pictured is the tool I made for cutting my valve seats. I must have 10 of these things now in almost every conceivable size variation for everything from hit and miss engines to my V-twin and now the radial. It is turned from W-1 drill rod with the pilot machined as part of the cutter. I set my compound over at 45 degrees to cut the angle. There was some question in another thread about trying to match the valve to the seat, angle wise. My register marks on my compound are far enough apart that I shouldn't be more than a tenth of a degree out of match. There's one thing I do when making the tool, instead of cutting the flutes at 90 degree increments I make one about 10 degrees off, so that would be -0-, 90, 180 and 260. The reason for this is if they were evenly spaced and a small chatter developed you wouldn't be able to get it out because each tooth would fall into the same chatter mark but with one tooth out of sync it seems to prevent this from happening. Once the tool is machined, hardened and honed I chuck it up in a small drill chuck and cut the seats by hand. Once the seats are cut I lightly lap each valve to it's seat until I see a dull finish all around the seat. As a double check you can put some ink marker on the seat and lightly turn the valve against it. If there is a low spot it will show up.
Once I have the valves lapped and mounted with the springs I suck on the port to see if it will hold a vacuum. As in the case of these heads I can't get my mouth up to the port so I make a tube up with a slight taper and wedge it into the port. I then put a piece of tubing on it and suck. One more thing I might add, put a small ring of grease around the valve stem/valve guide joint to prevent any leakage from there. If your guides are a little loose you can pull air through them.
George
You're correct on the combustion chamber tool. It was machined from a piece of drill rod with the hemispherical shape on it. I then roughly relieved the flutes staying away from the cutting edges. With a magnifier I then file almost to the cutting edge leaving just a small amount to hone once it's been hardened.
The cylinder head/cylinder mating face should seal with no gasketing. The threads on both were machine cut so everything is very square and the two surfaces should run up tightly.
I didn't figure the compression ratio as I used the basic Morton dimensioning for bore, stroke and combustion chamber shape. Looking at it I would think it will be quite high, somewhere in the neighborhood of 8:1.
Pictured is the tool I made for cutting my valve seats. I must have 10 of these things now in almost every conceivable size variation for everything from hit and miss engines to my V-twin and now the radial. It is turned from W-1 drill rod with the pilot machined as part of the cutter. I set my compound over at 45 degrees to cut the angle. There was some question in another thread about trying to match the valve to the seat, angle wise. My register marks on my compound are far enough apart that I shouldn't be more than a tenth of a degree out of match. There's one thing I do when making the tool, instead of cutting the flutes at 90 degree increments I make one about 10 degrees off, so that would be -0-, 90, 180 and 260. The reason for this is if they were evenly spaced and a small chatter developed you wouldn't be able to get it out because each tooth would fall into the same chatter mark but with one tooth out of sync it seems to prevent this from happening. Once the tool is machined, hardened and honed I chuck it up in a small drill chuck and cut the seats by hand. Once the seats are cut I lightly lap each valve to it's seat until I see a dull finish all around the seat. As a double check you can put some ink marker on the seat and lightly turn the valve against it. If there is a low spot it will show up.
Once I have the valves lapped and mounted with the springs I suck on the port to see if it will hold a vacuum. As in the case of these heads I can't get my mouth up to the port so I make a tube up with a slight taper and wedge it into the port. I then put a piece of tubing on it and suck. One more thing I might add, put a small ring of grease around the valve stem/valve guide joint to prevent any leakage from there. If your guides are a little loose you can pull air through them.
George
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Winter is not over until March 19, so you can slow down a bit. ;D
Great work, thanks for showing.
Great work, thanks for showing.
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Awhile back in the postings I mentioned that I had to order a 64 pitch internal gear for the cam ring. It came last week and I set about making the cam ring. The gear was made from mild stainless steel and had enough material around the outside of the gear to machine the entire cam ring. I first had to make a backing disc to mount the gear to. This disc has a bronze bushing in the center as it needs to rotate freely on the crankshaft. I turned up the disc and drilled and countersunk for the 0-80 Phillips head screws. I also drilled and tapped the gear blank for the screws.
As most people know a counter sink is not a great method for locating one part to another so I made up line-up bushing that would fit snugly inside the gear and located the mounting disc exactly. I then lightly tightened the screws to hold the 2 pieces together. I then drilled 5, .040 holes to put small dowel pins into so that when the flat head screws were tightened the two parts couldn't shift.
In the second picture you can see the small holes, some adjacent to the mounting screws and the others at different locations around the diameter. They all have brass pins in them but they all didn't com flush before getting tight that's why you only see a couple of brass spots in the picture. The small dimples in the screws were made by a small staking tool. This was to prevent the screws from coming loose or at least backing out.
The small gear you see is the 25 tooth gear that starts the gear train to drive the cam ring. It is keyed to the crankshaft. Here again in the second picture you can see the key just peeking out of the top of the gear. I cut this gear from 303 stainless with a home-made hob. I then had to make a special bushing to broach the keyway as the crank diameter is metric to fit the small bearings that the crank rides on. The key is .025 deep in the gear and .035 deep in the crank.
In the final 2 pictures you can see the intermediate gear. This is another 25 tooth gear and a 10 tooth gear on top of it. I ordered the 10 tooth gear along with the internal gear as the small number of teeth prevents the hob from making a good involute curve on the teeth. On the top of the 10 tooth brass gear you can see some 50/50 solder. The reason for this is because the gear came with a .094 diameter hole in it. The dedendum or root diameter of this gear is .120 so that only leaves .013 metal wall. I was afraid if I tried to press it onto the shaft it would surely distort so when I made the shaft I filed a flat on it, made the gear hole and shaft size for size and then filled it with solder. This gear combination runs the cam at 6:1 which with the 3 lobes makes the timing right for this 5 cylinder engine.
In the bottom right corner you can see 2 of the roller lifters poking through the case. These will be located true by small set screws in the crankcase. The set screws go through the bronze lifter bushing and up against the flat on the lifter, minus enough for movement.
George
As most people know a counter sink is not a great method for locating one part to another so I made up line-up bushing that would fit snugly inside the gear and located the mounting disc exactly. I then lightly tightened the screws to hold the 2 pieces together. I then drilled 5, .040 holes to put small dowel pins into so that when the flat head screws were tightened the two parts couldn't shift.
In the second picture you can see the small holes, some adjacent to the mounting screws and the others at different locations around the diameter. They all have brass pins in them but they all didn't com flush before getting tight that's why you only see a couple of brass spots in the picture. The small dimples in the screws were made by a small staking tool. This was to prevent the screws from coming loose or at least backing out.
The small gear you see is the 25 tooth gear that starts the gear train to drive the cam ring. It is keyed to the crankshaft. Here again in the second picture you can see the key just peeking out of the top of the gear. I cut this gear from 303 stainless with a home-made hob. I then had to make a special bushing to broach the keyway as the crank diameter is metric to fit the small bearings that the crank rides on. The key is .025 deep in the gear and .035 deep in the crank.
In the final 2 pictures you can see the intermediate gear. This is another 25 tooth gear and a 10 tooth gear on top of it. I ordered the 10 tooth gear along with the internal gear as the small number of teeth prevents the hob from making a good involute curve on the teeth. On the top of the 10 tooth brass gear you can see some 50/50 solder. The reason for this is because the gear came with a .094 diameter hole in it. The dedendum or root diameter of this gear is .120 so that only leaves .013 metal wall. I was afraid if I tried to press it onto the shaft it would surely distort so when I made the shaft I filed a flat on it, made the gear hole and shaft size for size and then filled it with solder. This gear combination runs the cam at 6:1 which with the 3 lobes makes the timing right for this 5 cylinder engine.
In the bottom right corner you can see 2 of the roller lifters poking through the case. These will be located true by small set screws in the crankcase. The set screws go through the bronze lifter bushing and up against the flat on the lifter, minus enough for movement.
George
Bill Gruby
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Man, you are fast. You must have a different amout of hours in a day? Very nice work.
"Billy G"
"Billy G"
Regarding your valve seat cutter, I like the idea of having one tooth out of sinc. Hogging in has always been a problem for me so I always suggest driving the cutter with a mill or drill press to better control the depth. I've got 16 seats to cut coming up on a v8. I'm gonna try this tip.
Thanks,
Thanks,
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With all the valves assembled and vacuum tested for leaks it was time to permanently (semi- permanently) assemble the heads to the cylinders. The cylinders were chucked by the short spigot at at the bottom of the cylinder in my 5c collet chuck. The mating surfaces on the head and cylinder were cleaned and a very light coat of high temperature silicon was applied. The head was then tightened to what I felt was tight but not to the point of stripping the small 40 tpi threads.
Another fixture was now required to drill all the mounting holes in the flange. It had to be done after the heads were installed to keep everything lined up with the crankcase holes. I made a simple fixture from 3/8 aluminum plate. The top plate was bored for the cylinder spigot and the mounting holes were drilled. The bottom plate got a 1/4-20 tapped hole to tighten the aluminum block against the head to hold everything in place. To keep everything in register I used an adjustable parallel against the port face and the inside wall of the fixture. I would put each cylinder in the fixture, lightly tighten the fixing screw so that I could adjust the cylinder head square against the parallel and then snug up the fixing screw.
Once the cylinders were drilled they were then moved to the dividing head to get the lower to fins relieved for the 2-56 socket head screws. These can be seen in the next set of pictures. After I relieved the first cylinder I tried assembling it to the crankcase and found out that there wasn't enough room for the ball end Allen wrench so a little engineering was needed. I had originally cut the fins at a 10* taper so a quick calculation showed that I would need 17 degrees to give ample room to get the wrench in. While the 5c collet was still in the big lathe I mounted each cylinder and recut the tapers. As if find things like this that need fixing or changing I mark my working drawings in red so at the end of the day I can go into Autocad and correct them.
The cylinders were all mounted with one screw and then it was on to the next parts, the rocker posts. I had 10 of them to make so I thought about the easiest way I could get the job done. With the .125 slot needing to be almost as deep as my end mill I wasn't looking forward to that job. Instead of using an end mill I used a larger block of aluminum and cut the slot with a slitting saw. While in that position I drilled and counterbored for the rocker arm studs. The hole on one side is drilled for a 2-56 thread while the other side is opened up to .125 diameter. The problem is the .125 diameter goes .02 deep into the threaded side to keep the rocker stud lined up and secure. I had to make up a drill rod counterbore to do this job.
Once all the stud holes were finished the strip was sawed from the block and finished to width. The strip was then turned up to to cut the width of the circular boss and put the countersunk holes in for the 0-80 mounting screws. I laid out the parts on the strip with enough spacing so that when the machining was finished I could cut safely cut them apart on the bandsaw.
Once cut apart the radii on the posts was filed round and all the edges were filed and cleaned up.
The final set of pictures shows all the rocker posts installed and the one view shows the 0-80 screws used to mount them.
gbritnell
Another fixture was now required to drill all the mounting holes in the flange. It had to be done after the heads were installed to keep everything lined up with the crankcase holes. I made a simple fixture from 3/8 aluminum plate. The top plate was bored for the cylinder spigot and the mounting holes were drilled. The bottom plate got a 1/4-20 tapped hole to tighten the aluminum block against the head to hold everything in place. To keep everything in register I used an adjustable parallel against the port face and the inside wall of the fixture. I would put each cylinder in the fixture, lightly tighten the fixing screw so that I could adjust the cylinder head square against the parallel and then snug up the fixing screw.
Once the cylinders were drilled they were then moved to the dividing head to get the lower to fins relieved for the 2-56 socket head screws. These can be seen in the next set of pictures. After I relieved the first cylinder I tried assembling it to the crankcase and found out that there wasn't enough room for the ball end Allen wrench so a little engineering was needed. I had originally cut the fins at a 10* taper so a quick calculation showed that I would need 17 degrees to give ample room to get the wrench in. While the 5c collet was still in the big lathe I mounted each cylinder and recut the tapers. As if find things like this that need fixing or changing I mark my working drawings in red so at the end of the day I can go into Autocad and correct them.
The cylinders were all mounted with one screw and then it was on to the next parts, the rocker posts. I had 10 of them to make so I thought about the easiest way I could get the job done. With the .125 slot needing to be almost as deep as my end mill I wasn't looking forward to that job. Instead of using an end mill I used a larger block of aluminum and cut the slot with a slitting saw. While in that position I drilled and counterbored for the rocker arm studs. The hole on one side is drilled for a 2-56 thread while the other side is opened up to .125 diameter. The problem is the .125 diameter goes .02 deep into the threaded side to keep the rocker stud lined up and secure. I had to make up a drill rod counterbore to do this job.
Once all the stud holes were finished the strip was sawed from the block and finished to width. The strip was then turned up to to cut the width of the circular boss and put the countersunk holes in for the 0-80 mounting screws. I laid out the parts on the strip with enough spacing so that when the machining was finished I could cut safely cut them apart on the bandsaw.
Once cut apart the radii on the posts was filed round and all the edges were filed and cleaned up.
The final set of pictures shows all the rocker posts installed and the one view shows the 0-80 screws used to mount them.
gbritnell
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These last 2 pictures are close ups of the rocker posts showing the 0-80 mounting screws. There's actually 2 of them. You can just make out the second one inside the two uprights.
Tomorrow I'll have to come up with a way to mass produce the rocker arms. These will be made from 1018 CRS for a little bit of strength and wear.
gbritnell
Tomorrow I'll have to come up with a way to mass produce the rocker arms. These will be made from 1018 CRS for a little bit of strength and wear.
gbritnell
Killer work, as the norm from you. One thing that I learned from how you work is taking the extra time to make fixtures/jigs. As always, thanks for sharing your work. Now, sometime you'll have to cover the basics of making cutter heads, counter sinks, etc. I say this because to countersink the holes in the rocker posts HAD to be done with something homemade. Looks great!!!
Craig
Craig
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Hi Craig,
Yes the countersinking tool was another homemade affair. The slot in the rocker posts is .125 so I turned up a piece of drill rod .124 dia. with an 82 degree tip on it. I have found that when hardening drill rod it will grow slightly so that's the reason for the undersize. From there it went to the dividing head and had 3 flutes machined into it and then it was hardened. On tools like this I don't spend the time to draw them out because the load on the cutting edges is minute and I'm cutting aluminum. I ran the spindle about 150 rpm and lightly pecked down until I got to my depth reading.
I have a drawer that is filled with homemade cutters. Most are one application tools but without them it would be virtually impossible to do most jobs. Usually I have my dividing head and vise set up on the mill so if I need a special tool I can turn something up and then flute it without too much trouble.
George
Yes the countersinking tool was another homemade affair. The slot in the rocker posts is .125 so I turned up a piece of drill rod .124 dia. with an 82 degree tip on it. I have found that when hardening drill rod it will grow slightly so that's the reason for the undersize. From there it went to the dividing head and had 3 flutes machined into it and then it was hardened. On tools like this I don't spend the time to draw them out because the load on the cutting edges is minute and I'm cutting aluminum. I ran the spindle about 150 rpm and lightly pecked down until I got to my depth reading.
I have a drawer that is filled with homemade cutters. Most are one application tools but without them it would be virtually impossible to do most jobs. Usually I have my dividing head and vise set up on the mill so if I need a special tool I can turn something up and then flute it without too much trouble.
George
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Continuing with the valve train I started on the rocker arms. Although I love working with 12L14 steel I wanted the rocker arms to be a little tougher so I dug out a piece of 1018 CRS. I know it's 1018 because I just ordered it for another job last month. Boy it sure seemed easier to work with the last time I used it.
Anyway, I cut and squared the stock to the necessary dimensions. I had done the rocker arms for the Holt this way and it seemed to be the easiest way to make a whole bunch of them. I left about .75 extra stock to clamp in the vise when it came time to cut the parts off.
As with all jobs I had to plan my attack so that I would have something to clamp to after each step. With this in mind I drilled and reamed the .125 hole and then cut the 6 degree angle on the top surface first, leaving the extra .75 length square for clamping. I made two pieces of stock as I don't like vertical pieces standing that far out of the vise when cutting off, beside that I would have to drill and ream too deeply to trust it being straight.
After the angled top surface was cut I flipped the pieces over and cut the shape on the bottom, this includes stepping off the .25 radius using my standard step-off method and reducing the radius in the corner to .062.
The next step was to stand the piece vertically in the vise and start sawing off pieces. I used a .04 HS steel slitting saw at about 400 rpm.
Anyway, I cut and squared the stock to the necessary dimensions. I had done the rocker arms for the Holt this way and it seemed to be the easiest way to make a whole bunch of them. I left about .75 extra stock to clamp in the vise when it came time to cut the parts off.
As with all jobs I had to plan my attack so that I would have something to clamp to after each step. With this in mind I drilled and reamed the .125 hole and then cut the 6 degree angle on the top surface first, leaving the extra .75 length square for clamping. I made two pieces of stock as I don't like vertical pieces standing that far out of the vise when cutting off, beside that I would have to drill and ream too deeply to trust it being straight.
After the angled top surface was cut I flipped the pieces over and cut the shape on the bottom, this includes stepping off the .25 radius using my standard step-off method and reducing the radius in the corner to .062.
The next step was to stand the piece vertically in the vise and start sawing off pieces. I used a .04 HS steel slitting saw at about 400 rpm.
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Now it was time for yet another fixture. As you can see by the picture I have used this poor old piece of aluminum many times. I drilled tapped and reamed for the the center mounting hole (2-56) and then drilled and tapped 2 holes at .75 away from center for little clamps that I made. With the holes in I milled away material leaving little stop posts to keep the rockers square in the fixture. The first picture show the fixture and the second show one of the rockers in place. I started with the center screw and one clamp in place. The rockers were cut off .156 wide to accommodate the eventual radius for the pushrod end. The center boss and valve end are .125 wide so I made my initial cuts at .015 deep, removed the center screw, put on the other little clamp and then finished the center boss area and went down an additional .015 for relief.
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If you will notice that when I made the fixture it had locating lugs on both sides of center. The reason for this is so when I finished the first side milling I could flip the part on the center dowel and use the same dimensions from center to do the other side. Being that the center boss is now .015 thinner I made up a little shim to keep the wide end at the rear in it's proper location. The milling procedure was the same as the first side.
A piece of .25 rod was turned down to .125 and threaded 5-40 to hold the rockers to turn the bosses. I set up my dial indicator, touched both surfaces on either side of center, backed up .0005 from the highest reading and cut the bosses. The height varied a couple of thousands on some and others it was darn close. It's easier to stay a little high and file the material down to match rather than cutting an arc in the part and having to file a lot, or make over.
gbritnell
A piece of .25 rod was turned down to .125 and threaded 5-40 to hold the rockers to turn the bosses. I set up my dial indicator, touched both surfaces on either side of center, backed up .0005 from the highest reading and cut the bosses. The height varied a couple of thousands on some and others it was darn close. It's easier to stay a little high and file the material down to match rather than cutting an arc in the part and having to file a lot, or make over.
gbritnell
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Still a long way to go on these little rascals. I have to make another small fixture tomorrow to mount on my rotary table to spin the end bosses and also put the pushrod recesses in. Then comes the filing and sanding. I'm sure glad I don't have to pay by the hour to have these things made.
gbritnell
gbritnell
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Very neat. Well, here I am... taking notes ;D
So with 303 valves & 1018 rockers, is any hardening required, or thats how it will run? I seem to recall some miniature engine article that volunteered rocker faces should be harder because it's more difficult to re-dress. But it seems to vary by builder.
Will you have rocker covers or exposed mechanics? Reason I ask is about lubrication oil up there. My only experience is RC glow ignition 4S & pretty much anywhere raw fuel mist reaches gets a light coating, so its kind of maintenance free from taht respect. But Im always interested in how the gasoline & oil pump boys do it.
So with 303 valves & 1018 rockers, is any hardening required, or thats how it will run? I seem to recall some miniature engine article that volunteered rocker faces should be harder because it's more difficult to re-dress. But it seems to vary by builder.
Will you have rocker covers or exposed mechanics? Reason I ask is about lubrication oil up there. My only experience is RC glow ignition 4S & pretty much anywhere raw fuel mist reaches gets a light coating, so its kind of maintenance free from taht respect. But Im always interested in how the gasoline & oil pump boys do it.
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Hi Peter,
Well that valves can't be hardened but the rockers could be case hardened. With the amount of running and work these engines do it should hold up a very long time. On my V-twin I put oil on the valve tips, rocker shafts and pushrod tips and run the engine for hours with no noticeable wear. An option would be take make a rocker box with the same basic dimensions as the current rocker posts and then oil could be pumped up there but then it would need pushrod tubes for the oil to have a return route to the crankcase. Too much work on something this small. Yes I know there are fellows out there that build smaller more complex models but I don't have 7-8 years left to devote to a single model. I would like to end up with one of several types of gas engines. I now have 5 and this one will be 6. I'd like to take the basic dimensions for my 4 cylinder ohv engine and turn it into an OHC engine, maybe even a DOHC engine. Time will tell.
As a side note this engine has a pressurized feed and scavenge oil system. It won't rely on oil mist from the fuel. The secondary crank has a gear machined onto it that drives the oil pump gears and the distributor gear. They reside in the fuel feed chamber and will get a little lubrication from the fuel/oil mix, otherwise everything will be bathed in oil.
George
Well that valves can't be hardened but the rockers could be case hardened. With the amount of running and work these engines do it should hold up a very long time. On my V-twin I put oil on the valve tips, rocker shafts and pushrod tips and run the engine for hours with no noticeable wear. An option would be take make a rocker box with the same basic dimensions as the current rocker posts and then oil could be pumped up there but then it would need pushrod tubes for the oil to have a return route to the crankcase. Too much work on something this small. Yes I know there are fellows out there that build smaller more complex models but I don't have 7-8 years left to devote to a single model. I would like to end up with one of several types of gas engines. I now have 5 and this one will be 6. I'd like to take the basic dimensions for my 4 cylinder ohv engine and turn it into an OHC engine, maybe even a DOHC engine. Time will tell.
As a side note this engine has a pressurized feed and scavenge oil system. It won't rely on oil mist from the fuel. The secondary crank has a gear machined onto it that drives the oil pump gears and the distributor gear. They reside in the fuel feed chamber and will get a little lubrication from the fuel/oil mix, otherwise everything will be bathed in oil.
George
