1" Bore x 1" Stroke Vertical i.c. Engine

[dsage]

That's a sound procedure. One I've used many times to check final cam timing. Assuming your rockers are not a 1:1 ratio if you move your dial indicator over to the top of the valve rather than the top of the push rod and remove all the lash you can also measure your valve lift while you're at it.
BTW. If you intend to have a bit of valve lash, you should measure at the valve to get the actual valve timing since the lash will effectively alter the timing. (as I mentioned before) lash will effectively cause the valve to open late and close early.
Looks good to me.

 

[Steamchick]

Brian, I suspect we have opposite aesthetic sensibilities here, but I'd leave that flywheel painted, and run the engine long enough so that the paint is just naturally worn off by the belt.

Shiny metal surfaces that got that way by honest wear says "this is a hard-working machine" to me.

I agree Tim. - As long as the thing doesn't end-up messy with the belt slipping on young fresh and tender paint... It is only driving the little fan so probably "flea-loading". so should be OK. A bit of violin bow rosin on the o-ring will help prevent slippage as well. And if it is as precise as we all expect from Brian's work it will leave a tidy narrow line of shiny steel when the paint has worn off.
Brian,
I agree with your balancing philosophy: On more than one engine I have simply used the "unbalanced" casting" parts of the flywheel to off-set the worst of the natural imbalance. I usually get rid of most of the primary imbalance that way, and somehow it is nice to see the engine balanced, but not to electric motor levels, so there is still a tremble from secondary and tertiary harmonics, etc. but nothing damaging. I'm sure you have spun the engine by hand to check (feel) the reduction of vibration by adding those balance weights, so you know they are close enough, before you connect the valve train?
Can you let us know the valve timing, and ignition timing you will set?
Good work Sir!
K2

 

[Brian Rupnow]

Somehow, I'm not getting any joy from the cams that I made. I can set them to open at the exact time that they are supposed to, but they are staying open too long. The only thing that will account for that is that instead of having 240 degrees of interaction with the crankshaft (120 degrees of camshaft), I am getting much more than that. I have spent most of today measuring and adjusting and I have to stop now and think about what I am going to do.

 

[werowance]

Brian, its looking very impressive. for some reason i stopped getting update notices so hadnt seen updates since your carple tunnel on your hands. you have progressed alot. by chance do you have any close up shots of your new fan while its installed? it looks great and am just curious about the bends and tweaks it had to have. hoping a close up will show it better.

at any rate looking forward the running video which i know wont be long from now

 

[Brian Rupnow]

Yowee!!!--Something very, very strange is going on. I just couldn't believe that my cams were far enough out to cause the issues I've been having with valve timing. I have spent three days going over everything I have done while building this engine, and nothing jumps out at me. Then, this morning, I loosened of the set screws in both timing gears, put a mark on a single tooth of each gear, and turned the small gear by hand. Since I'm running an exact 2:1 ratio, the marks on the two gears should line up, then be out of line by exactly 180 degrees, then line up again on the second rotation.---but that's not happening. On every second rotation, the alignment marks are out by one tooth, and gaining on each revolution. How can this be??? So, next thing was to count the number of teeth on each gear. The small gear has 25 teeth just like it's supposed to have. The large gear has 48 teeth, not 50 like it's supposed to have!!! How can this be--The center to center distance on the crankshaft and camshaft are correct for a 25 tooth and a 50 tooth gear. And the two gears mesh okay!!! I've never had this happen before. Next move will be to check my drawings and engineering information and remake the big gear.--What a strange, strange thing.

 

[awake]

Oh, well, that should be no problem. The engine will be correctly timed every now and then, when everything lines up again - surely that will be good enough?

Joking aside, glad you found this - this is the sort of error that can be so hard to detect!

 

[BaronJ]

Yowee!!!--Something very, very strange is going on. I just couldn't believe that my cams were far enough out to cause the issues I've been having with valve timing. I have spent three days going over everything I have done while building this engine, and nothing jumps out at me. Then, this morning, I loosened of the set screws in both timing gears, put a mark on a single tooth of each gear, and turned the small gear by hand. Since I'm running an exact 2:1 ratio, the marks on the two gears should line up, then be out of line by exactly 180 degrees, then line up again on the second rotation.---but that's not happening. On every second rotation, the alignment marks are out by one tooth, and gaining on each revolution. How can this be??? So, next thing was to count the number of teeth on each gear. The small gear has 25 teeth just like it's supposed to have. The large gear has 48 teeth, not 50 like it's supposed to have!!! How can this be--The center to center distance on the crankshaft and camshaft are correct for a 25 tooth and a 50 tooth gear. And the two gears mesh okay!!! I've never had this happen before. Next move will be to check my drawings and engineering information and remake the big gear.--What a strange, strange thing.

Hi Brian,

It is a bit like the "out by one" error when programming !
I recall something about the number of teeth plus 2 when calculating gears.

 

[awake]

N+2 is used for calculating the OD of the gear blank - the pitch diameter is calculated from N, and the OD is calculated from N+2.

 

[Brian Rupnow]

HELP!!!---I'm losing it this afternoon. I have a 90:1 ratio rotary table. I'm using a 20 hole divider plate. My chart says that for a 50 tooth gear I need one full turn of the handle (which gives 4 degrees) and 16/20 of a complete turn. When I made this 48 tooth gear (which was supposed to be 50 tooth) I turned the crank on the rotary table one full turn and 16 open holes. Obviously, that was wrong. Doing some layout work with my cad system, it seems that The 16/20 should have been 15 holes plus one more space to where the crank pin engages with a hole in the divider plate. If I'm right, then that may account for the wrong number of teeth on my gear. Somebody sort me out please---I've looked at this until I'm going cross-eyed.---Brian

 

[coulsea]

The more you think the more confused you get. you don't count the hole that it is already in, it should go into the sixteenth hole. because you are 4 holes short of a full turn it should form a pattern and every 5th tooth you will be back to your starting hole. (it is early in the morning and i am only on my second coffee so the 5th tooth may be wrong but there will be a repeated pattern)

 

[ICEpeter]

Hello,
Brian, I am sure your dividing head is equipped with a shear on top of the hole plate that you set to include the number of holes between the two shear legs, that are required to move your gear blank in the fraction part (16/20) of moving the required distance for tooth cutting. Typically, you set the shear to include the number of holes you need to repeat (15) when cutting your 50 teeth gear whereby the left leg of the shear is against the pin that is in the current hole and the other leg of the shear is positioned clearing the 15th hole. That means the shears span includes / covers 16 holes (15 plus one where the pin is in) When you turn the handle to make one full turn of the gear blank you keep turning until the pin is over the shears other legs hole and put the pin in there. Then move the shear until its new position, left leg, rests again against the locator pin. Repeat for all 50 teeth. I am not sure if I explained it properly and understandably, if not my apology.
Peter J.

 

[awake]

90 / 50 = 1-40/50 = 1-4/5, or (since you are using a 20-hole index), 1-16/20. Thus, you need to turn one full revolution plus 16 holes, not 15 - so when the pin is in position 1, you will next turn a full revolution and go on until the pin is in position 17 - 17, not 16.

What is really confusing me is that, if you made the previous gear by using 15 holes rather than 16 in a 20-hole index - in other words, 1-15/20 = 1-3/4 turns each time - you would have produced a 51.4 tooth gear - it should have been very obvious that something was wrong when you got to the end. To get a 48 tooth gear, you would need to use 90 / 48 = 1-42/48 = 1-7/8 holes. IOW, you would need to be using a different indexing circle (e.g., a 16-hole circle, with your gap set to turn 1 revolution plus 14 holes each time).

 

[ICEpeter]

90 / 50 = 1-40/50 = 1-4/5, or (since you are using a 20-hole index), 1-16/20. Thus, you need to turn one full revolution plus 16 holes, not 15 - so when the pin is in position 1, you will next turn a full revolution and go on until the pin is in position 17 - 17, not 16.

What is really confusing me is that, if you made the previous gear by using 15 holes rather than 16 in a 20-hole index - in other words, 1-15/20 = 1-3/4 turns each time - you would have produced a 51.4 tooth gear - it should have been very obvious that something was wrong when you got to the end. To get a 48 tooth gear, you would need to use 90 / 48 = 1-42/48 = 1-7/8 holes. IOW, you would need to be using a different indexing circle (e.g., a 16-hole circle, with your gap set to turn 1 revolution plus 14 holes each time).

Well, Brian, to check how it works out you can manually turn the handle 50 times plus using either 16 holes within the shears span or 17 holes as awake says. It maybe hard on your hands since you have an arthritis condition I understand but doing it without actually cutting the gear will give you piece of mind when after 50 positions you end up returning at the starting point with 50 teeth divisions where you wanted to be. Once you went through that exercise you will have confirmed the setting for a 50 tooth gear wheel.
Peter J.

 

[coulsea]

as awake said. Looking at the charts you must have made the 48 tooth gear correctly or it would be obviously wrong as in part of a tooth. the simple solution is to re make the 25 as a 24 with a slightly shallower cut on the teeth (just make up for half the difference in OD, and have twice the backlash). no one will know.

 

[ICEpeter]

as awake said. Looking at the charts you must have made the 48 tooth gear correctly or it would be obviously wrong as in part of a tooth. the simple solution is to re make the 25 as a 24 with a slightly shallower cut on the teeth (just make up for half the difference in OD, and have twice the backlash). no one will know.

Brian,
I attached a file for you from Little Machine shop referring the use and set up of a dividing head. About page 4 or 5 there is a description about the use of the shear and how to set up the shear span. I am sure that will answer your question of the "How To" It confirms what I said in my post 271 Please take the time to read the Little Machine shop article.
Peter J.

 

[Brian Rupnow]

The little machine shop rotary table is a 72:1 ratio, not a 90;1 ratio like the one I have.--Shouldn't change the process though. My theory about this debacle is this---If, in setting up to cut a 50 tooth gear I went one hole too far each time, then the spaces between the teeth will be a very small amount larger each time I cut a space. This means that there will eventually be less room on the gears pitch diameter for teeth than was intended---but it's damned odd that it worked out so evenly to 48 teeth, and that it still meshed with the 25 tooth gear.

 

[ICEpeter]

The little machine shop rotary table is a 72:1 ratio, not a 90;1 ratio like the one I have.--Shouldn't change the process though. My theory about this debacle is this---If, in setting up to cut a 50 tooth gear I went one hole too far each time, then the spaces between the teeth will be a very small amount larger each time I cut a space. This means that there will eventually be less room on the gears pitch diameter for teeth than was intended---but it's damned odd that it worked out so evenly to 48 teeth, and that it still meshed with the 25 tooth gear.

Brian,
I realize that. I believe whats important to you is the description on page 4 and 5 relating to the number of holes to be included in the set up of the span of the shear / sector arm to indicate how many number of holes should be included when setting up the sector arm for the correct number of holes. The way you went about, you included one hole to much and should have done 15 holes plus the one the pin was in, i.e. the span of the sector arm would have included 16 holes total - 15 open holes and one hole where the locator pin is in. You weren't sure about that and I hoped the Little Machine shop article would help with that.
Peter J.

 

[werowance]

Mine is 90 to one. here is the chart for mine if it helps

 

[werowance]

and if it helps even more here is the pdf from grizley - which is the one i use but mine is a phase ii brand but the dividing plates and all seem to be the same.

g1760_m.pdf (grizzly.com)

 

[Jasonb]

Quadrant should be set to have 17holes between the fingers. 1 for the pin and the 16 you need to move

If you set the quadrant to one hole too many you would have moved 4deg + (17/20) x 4 = 7.4deg spacing which gives about 48.5 teeth so you may have had some slip an the arbour too.

here is a Video I did to go with my "Milling for beginners" book/articles you can see there are the 6 holes required plus the one the pin goes into between the fingers.