Need help with modifying a flathead engine

I can see your design alleviating a basic problem with the flathead, flow, as the space is open between the pistons. However, you will need domes on those pistons to get back to stock compression.
 
Good points 95 Shaw .
Why not run the cranks vetical .
One thing has me perplexed .how to connect both blocks through the head assembly.
With the offset the outer bolt , easy the inner bolts a different problem .
 
I wonder about a gear drive instead of a timing belt to connect the two. Then get rid of the stock flywheels and mount a cast iron flywheel to the shaft that is connected by gear drive to the engines. Fab a coil bracket and use that. I suspect only one spark plug since both share the same combustion chamber and are on identical stroke.
As for carb, I’d fab an intake manifold and use a single carb. I would straight pipe both exhaust with .890 pipe, 14” long.
 
Good points 95 Shaw .
Why not run the cranks vetical .
One thing has me perplexed .how to connect both blocks through the head assembly.
With the offset the outer bolt , easy the inner bolts a different problem .
I was thinking about this as I could not sleep this morning.

Gotta get a gasket and see if bolts are offset with bores aligned. If so, a counterbore open to outside of block could be made to work, maybe.
That would require the "head" to be thicker still, but could be doable.
 
Thank you all for all the input. It's really helpful. I'm at the University right now and will take some pictures and share all the details with you. It's going to be an extensive post but that way I think everyone will get on the same page.
 
So, from the beggining.

A few years ago, a project was carried out as proof of concept for an opposed piston 4 stroke engine. The researcher took two very basic engines and mounted them opposed to each other and went to a dyno bench to get some results. The idea was to see if the performance would be better than the two engines separate. They used a gear drive which was not the best way since it was a little complex to build and tune. It was noisy, leaked some oil and ultimately was operating the its limit.

Then, I started a new project to follow in the footsteps of that initial project. The idea is to get a baseline from a stock engine. Then, get two engines and mount them opposed to each other, sharing one cylinder. Finally, swap the crankshaft with a geared drive and see what are the performance difference of each configuration. The idea is not to see what is the maximum performance but to see the impact of each modification. As such, the goal is to modify the engines the least so that only the configuration modifications impact its performance.

Since the final configuration is an opposed piston engine, a flathead engine had to be used since the valvetrain can be used with little to no modification. I ended up having to buy vertical engines since no other option was available.

In the meantime, I ended up building a dyno bench based on an electromagnetic brake. I could have built it to test the engines in vertical position but I was asked to instead build it to test engines in horizontal position for our tests. And the engines would have to be modified from vertical to horizontal position.
A considered using a 90º gearbox but in the end we abandoned that solution to reduce complexity, mechanical losses and not easily finding one.

Now, I have the dyno bech built and ready to test the engine. I'm still considering testing the engines in vertical position but my professor keeps telling me that he prefers to modify the engines and use the dyno bench in the horizontal position. And the gearbox is a deadend, by the way.

So, now I'm strongly inclined to modify the engines. Right now, I have several options.

I removed the governor (I will cut the rod inside the crankshaft). The carb we wanted to install a 19mm carb since the intake port is 19mm to be able to tune the carb and more easily install a throttle cable. The choke is built into the carb so that's a plus since we'll only use it in the beggining to start the engine.

The exhaust is to be kept stock. One pointing up and the other down. We'll use a fan to help in cooling and clearing the gases coming off the exhaust that's pointing down.

To lubricate it, one of the engines will have a small aluminium piece to splash the oil when it's running. The other, the rod itself will hit the oil splashing it. My professor says that since it's only for testing purposes, it's not a big issue as the engines will only operate for short periods of time (30 min if it can't run any longer).

So, I wasn't going to mess with the lubricating holes in any way. Just move and install a new carb, keep the exhaust, install a dipper to splash the oil if tested in one orientation and leave it be (for the stock engine).

For the opposed piston, I chose to use a timing belt with a tensioner since it's simpler, requires little to no maintenance and is, in my view, preferable to installing a gear train to connect both crankshafts. By syncronizing the crankshafts, I guarantee that the spark and valve timings, and power output is connected and syncronized.

The adapter connecting both engines is an aluminium piece that was designed to be able to install a M10 spark plug, one close to each exhaust port, which will be connected to the magneto. It was also designed to keep the compression ratio the same as stock (6:1). In fact, the engines will operate both as flatheads and OHV, in a way. And there's communication ports between each cylinder which is not a complete hole to be able to keep the combustion volume.

I've been looking at the engines and am wondering if I should not put some JB Weld on the crankcase breather hole and install a breathing plug to put the oil in the engine. The reason for thinking about deleting the stock breathing crankcase hole is to avoid oil accumulating in the valve springs are and, ultimately, going up the breathing tube.

Once again, the idea is to get a baseline of a stock engine, then modify them in different ways and measure the internal cylinder pressure, obtain torque and power curves and compare them. So I only need the engines to work fine, not achieve the best performance possible.

I'll leave some pictures to help understading my explanation.

So, my main issue is regarding the horizontal modification. How to ensure proper lubrication, solving the issue with the oil level which will be low, specially when the camshaft is over the crankshaft (As I said before, I was thinking about letting the rod and counterweights splash the oil and for the other orientation I was considering installing a dipper). Also which carburetor is suitable to make the engine work fine (if PZ16, PZ19, PZ20, PZ22 or something else). Finally, if the crankcase breather tube will give me any issues.

PS: For the carbs, I'm considering using a cable that is used in scooters for the oil pump and throtle which has one end for the throttle and when you pull it, it pulls two cables at the same time. The main jets are something that I want to take into consideration. Also, my goal is not to increase rpms. In fact, it may be a good thing to not go over the stock rpms of the engine to not stress the parts and demand even more lubrication of the moving parts.

And thanks for all your input! I really appreciate all the help you're giving me and all the experience you're sharing.
 

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The complications of mounting a vertical engine in a horizontal configuration.
Vs ease of connection to the test device , seems disproportionate .
Considering the submerged valve train .
 
It appears you have tried to address some of my concerns.

The flywheel I still see as a problem area. To me, it appears rather simple to convert your dyno setup to vertical shaft, making it doubly useful.

Plugging the oil hole will only slow the oil getting into the valve spring chamber. It will still slip by the lifters, especially when hot.

I too see way more complication and chances for failure by trying to switch to vertical configuration. Might as well make it a durable configuration, rather than living on the edge of failure. You will likely need more testing time than you are allotting.

I like the head concept, except you have not yet designed a way to effectively connect both blocks to it. You may get to the base compression ratio, but I'm still having doubts.

Fun to think about, though.

https://www.ebay.com/itm/UNIVERSAL-THROTTLE-CABLE-FOR-MIKUNI-DUAL-CABLE-922-923/280857413029

Here may be a way around the dual throttle issue.
 
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I too am trying to convince my professor to understand the ease of adapting the dyno bench instead. However, it seems a little like a lost battle. And in a way I understand his concerns but I know it seems disproportionate.
However, I'm almost certain that it will be the engines that will be modified and not the other way.
Following on that path, I am still thinking about installing a throttle and choke cable to the stock carburetor instead of mounting a different carb. I hope it's an easy modification.

The cylinders will be bolted to the head adapter and then some rods will be bolted clamping the engines together. That solution was already used in the precious study and worked ok. As long as I ensure that the cylinders are tightly bolted and clamped, I should have no leaks.

Regarding the oil, I was thinking about JB Welding the breather tube so that the oil could flow easily inside the crankcase and the valve springs and installing a plug with breather holes at the top. That way, the crankcase would still be ventilated and I would not risk any oil being spilled out of the breather tube.
 
In that case, my advice would be to dyno both halves separately in the configuration you intend to use. Ie, cam up or down.
That will give you a chance to address the potential issues before you get to the point of no return, not that anything bad will happen.
Except waste a lot of time and not get usable data.

I see oil slipping past the valve guides and contaminating the intake charge, killing power.
 
In that case, my advice would be to dyno both halves separately in the configuration you intend to use. Ie, cam up or down.
That will give you a chance to address the potential issues before you get to the point of no return, not that anything bad will happen.
Except waste a lot of time and not get usable data.

I see oil slipping past the valve guides and contaminating the intake charge, killing power.
The more I think about it, the more I get nowhere.

If I indeed end up testing the engines in the vertical position, I may end up having issues with the dyno and also I still have to find a way to lubricate the engine when I install the geared mechanism since I can't use the stock splasher. And it's even more complex than just putting a piece dipping into the oil since the rod will be horizontal.

If I end up testing the engines horizontally, I have to address the issue of the lubrication but that is done for all case scenarios. But as you say, even if I plug the breathing hole inside the crankcase and install a breather plug at the top, I may end up with some oil coming inside the chamber. Although I think not much since the oil level would be below the lifters.
So, all I had to do would be put a dripper, plug the necessary holes, open some lubricating channels at the cam and crank shaft when and where necessary and install/modify the carbs. And the dyno bench would already be ready.

Btw, regarding the flywheel, the engines will not be used at WOT without an additional load of the dyno bench. Therefore, I don't think I'll have issues with it. But all I need to do is keep an eye on the rpms and make sure that they don't go over a safe limit, I think.

So, to sum up. Do you really think I would have big issues with the oil? That seems to be the main issue here. However, I see many people online successfully modifying their engines from vertical to horizontal and apparently no have issues with it. So all I really need is a solution for the oil and some pointers to the carb. Either use the stock ones or, if not, which do you feel are suitable. Can you give me any advice on the carbs and on the oil if I indeed end up converting the engines? Thanks!
 
^^^ any time you turn a vertical shaft lawn mower on its side or up side down / tilted funny . I have always had trouble with it filling the cylinder or port with oil . They never seem to run correct till its run out .
The fact you have done this before with some sucsess it may not be a concern .
Blocking and relocating the fill / bteather should be no trouble .
 
Possibly use a extension shaft off the flywheel side ,so as too not turn the valves down.
I like the solution for the head connection .
 
^^^ any time you turn a vertical shaft lawn mower on its side or up side down / tilted funny . I have always had trouble with it filling the cylinder or port with oil . They never seem to run correct till its run out .
The fact you have done this before with some sucsess it may not be a concern .
Blocking and relocating the fill / bteather should be no trouble .
So if I understand correctly, and with the input of 95 Shaw, as long as I have a way of splashing the oil (dipper at the end of the rod and/or the rod dipping into the oil), have the grooves correctly placed to lubricate the shafts and make sure that little to no oil gets to the valve chamber, I should be good to go?
 
When the chamber is lower, the oil may indeed come in by the blue and and red holes. Plugging them would not completely solve the issue, would it? What if I drill a draining hole at the bottom of the chamber (yellow arrow)? What do you think?
And then I could plug both holes. Maybe even the one that goes to the breathing tube just in case (green hole). The venting would be done by the breather plug.

When the chamber is higher, I don't think I would have any issue since the oil would drain back to the crankcase by gravity through the red hole, right? And in this case I would not need to JB Weld any holes. Maybe the vent hole (blue hole) by the crankcase at the most.

Also, what do you think about the dripper? When the chamber is lower, the dripper hits the oil. When it's higher, the rod and counterweights hit the oil as well so I was considering leaving it as it is without any dripper. Any thoughts on this?
 

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The red hole is not on all engines . The blue hole is a drain back hole .
Under normal conditions the oil is mostly mist or frothy in the crank case .
Plugging the blue hole addin two small holes above the lifters with a releif so oil can get into the valve chamber . Should work . Blocking the breather adding a different one .
Being new tolerances shold be pretty tight. . seepage may not be a big issue .
Still youmay need to drain the oil when it sits so intrusion isn't a problem .
Adding additional oil hole in the rod in a location to facilitate oiling from the top side would be beneficial in my mind .
Rod or dipper something to toss oil around .
 
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