1967brutus

The supported crank made me hit the "buy now" button, and I think I see possibilities to even support the cams in a similar way.
The idea is to repurpose the (positive displacement) cooling pump to lubricate the cams. Oil supply the same way, by means of fuel/oil mix and seepage past the rings, the pump drawing an oil/air mix from the oil discharge point , that mist being blown into the camboxes mist-lubricating the cams, rockers and valves, and draining back to the sump, very similar to what I do with my airplane engines, only a different way of generating the oilmist. The seepage past the rings keeping the oil pan "full", and a slightly higher oil discharge point added.
The cooling water circulation is way too low. Going by what I saw in the vid, that is maybe 500 ml/minute, which at full chat would result in a delta-T of well over 50 degrees. That is unacceptable given that in the original design the cold water enters the right bank, heats up 25 degrees then enters the left bank. I cannot help but thinking that a warping engine block is inevitable. The idea is to mount a belt driven centrifugal pump somewhere and fit way larger in and outlet ports, feed the banks in parallel and try to keep the delta-T limited to maybe 10 degrees or so.

Right now, my ideas wander in the direction of a boat, probably with a closed circulation and bilge-cooling, and a "thermostat" function programmed in the TX over telemetry. The idea is to circulate from tank to pump via the bilgecooling, with a controllable bypass of the bilge cooling, over the engine and back to the tank. Measuring the return temperature, and have the bypass valve open or close proportionally on a return temperature of 80 (bypass fully closed) to 85 deg C (fully open). That should lower the inlet temperature of the cooling water accordingly and result in an average and "constant" engine temperature of 80 deg C. I could try to create some sort of thermostatic element, but those are slower in response than a temp probe and a servo and the engine is in its final installation anyway never going to run without TX/RX and functional telemetry, so I am not that worried about that. A failsafe can open the temperature control valve to full in case of loss of signal.
Not sure yet about the bilge cooling as the boat probably is going to be rather quick and bilge cooling gets vulnerable with increasing speeds. It could also be an internal heat exchanger fed with outboard water via a pick-up. Also not yet decided on a reversing gear or permanent drive. I do have a Controllable pitch propeller, but that one is nowhere near suitable for the power I expect.

But that is all rather premature, to be honest, I first have to have both hull and engine in my hands, then see what (if any) of the above is actually going to be possible.... Probably going to be a wild ride...

Cat 1

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Will be an awesome project Bert... The sound is worth the price of admission Im partial to V8's having sat behind many in my day.. Had a couple of quick ones.

John_M_

Yeah, those cams are only supported at the ends. why they didn't go with split shells. they bored the bosses, just a few more machining steps is all it would have taken. it would only have raised the cost of the engine by a couple hundred bucks, but it looks like it can be modified. Conley made a nice 1/4 scale blown V8 model engine, but they were several thousand dollars. I don't know what happened to Conley, but I haven't seen anything recent.

1967brutus

I am afraid that the "not very scale" high RPMs basically will ruin the typical V8 growl...
But I hope for a great sound in the midrange.... Especially with a bit of load on it to keep the cylinder pressures up...

Probably going to take a large muffler volume to keep out the high frequency noise and beef up the low frequency noise a bit...

1967brutus

That was my idea: make threaded holes in the bulkheads to clamp down CNC made bearing shells. Assembly is going to be a nightmare, but it should be doable...
Thinking of making shallow oil grooves in the bearing shells of the crank in order to promote oil access to the running surfaces, not sure yet...

John_M_

Well you could also have the bosses for each bearing location machine down 50% of their bore diameter, have new bearing caps made ( with threaded fasteners ) and then line bore the cam bearing caps. Have the bearing shells made as you planed too, and you'll have what they should have done in the first place. Depends on how far you want to take it I guess.

John_M_

Interesting , I just noticed the cam ends are machined with drive dogs, I wonder what they had planned, distributors maybe. Could make a cam position / engine phase sensor and use multiple ign coils, 2 hv cdi boards ( 1 each bank ), and an arduino to switch each coil. My head is already starting hurt

1967brutus

From the FAQ on the website where these things are sold, the impression is given that Toyan has no direct plans for a gasoline version, but has at least considered the option during design.
I am not going to mess about with designing or having a custom made ignition system, I am just going to use two "four-inline" ignitions. This is possible due to the 90 degree crank interval and the 90 deg bank angle, which makes for always two pistons in TDC at the same time. Going to be a bit of a puzzle which lead goes where, but that is no big deal. It does mix up the leads from one unit over both banks though, but I can get away with only one pair of magnets 180 degrees diametrically opposed on the flywheel (unless the flywheel is made of steel, then I have to figure out a timing disk on the NDE of the crank, where the belt is).

EDIT: I just realized that most likely the whole thing is set-up such that by turning one camshaft over 180 degrees, the engine becomes a "big Bang" with two cylinders firing simultaneously, OR an engine that fires one cylinder every 90 degrees of crankrotation. The latter should make extremely low idle RPM possible, and COULD be the reason why the engine in the vid apparently is hesitant to idle really low....

John_M_

The dual inline 4 CDi's should work. That engine design is basically an odd fire twin 4, has 4 rod journals with 90 degree crank angle. Jag refereed to their V12 as a twin 6. it also had shared rod journals, same crank angle as the straight six. The firing order should be easy enough to figure out... keep in mind these CDi's are referenced to crank rpm in the program coding, referencing off the cam will change the ign advance timing... Set it up on the flywheel, one ign system setup to trigger on the south pole magnets, and the other setup to trigger on the north pole magnets, that way they'll ignore each others trigger, or stagger the magnets and hall sensors.

I think one of the reasons it won't idle very well is, there is a lot of internal resistance, especially on the piston rings, Ol jonnyQ nearly broke the first one putting in the ring groove, made a horrible crapping sound as he pushed the piston into the cylinders, I suspect those rings will take forever to bed in. Possibly a bit more mass on the flywheel will help the idle

John_M_

You'll have to stagger the magnets and hall sensors so they are on their on plane of rotation.. I forgot these inline 4 CDi's use both magnet poles and the "dual" hall sensor.

John_M_

Looking at the RCExl inline 4 CDi, it looks like you can get away with mounting the Dual hall sensors ( one for each CDi box ) 180 degrees, and share the magnets, I'm a bit anal, and like to keep split systems isolated, but this should workout just fine. Adding CDi alone will improve the running characteristics of that engine, those glow plugs get extinguished easily with the wet fuel.

cmulder

My car has a ignition system where 2 coils provide spark for a 4 cylinder engine. So one plug gets fired when the piston is at the botom and as result there is no ignition there.

If this engine can be seen as 2, 4 cylinder engines combined?
Then one coil could fire 4 plugs at once and the other coil the other 4? This assumes 2 cyclinders fire at the same time and there are 2 other cylinders at 180 deg.

To simplistic or might work?

1967brutus

I was aware of that...
I was indeed a bit surprised how he mangled that ring pushing it over the crown, that is not how I fit piston rings...
He also fitted the pistons into the cylinder dry, or so it looked to me. Also something I would not do.

Actually, no... I should be able to run only two magnets (one North and one South) in the same plane, and fit the sensors 90 degrees to one another.
A bit like this. If Cylinder 1A is in TDC, so should be cyl 2B. These two cylinders should be connected to the northpole firing leads of ignition one. Cyl 3B and 4A should be in BDC and be connected to the southpole firing leads of igition 1
90 degrees of crankrotation further, cyl 1B should be in top together with 3A, those should be connected to the northpole firing leads of Ignition 2. Cyl 2A and 4B should be in bottom and connected to the southpole firing leads of ignition 2
No biggie. I have done that kind of thing before. All that needs to be done is checking whether the cams are in such position that when Cyl 1A is in firing position, Cyl 2B should be in scavenging position. If that is not the case, one camshaft should be rotated 180 degrees under the belt.

Especially in the location where the plugs are, they are basically in the wettest spot of the combustion chamber....

1967brutus

Actually, no, that is not how that works... The two plugs at the same coil are basically a plug, coil and 2nd plug in series, and both fire at the same time, and both fire with the piston in top. One cylinder is in its firing position (both valves closed), the other one in its scavenging position (both valves slightly opened), so one spark is actually igniting something, the other spark is the so called "wasted spark".
Check it if you don't believe me: Cyl 1 and 4 are on the same coil, and cyl 2 and 3 on the other coil. Pull the plugs of 1 and 4 and check piston position, and you will see that they are both in TDC at the same time.

That is correct, but...
this is not, and indeed just a touch too simplistic.

Regardless of how many cylinders a multicylinder has, if it is a fourstroke, the maximum number of plugs on a coil is 2, and if the bank angle is not 90 degrees, or the crank interval is not evenly spread around the 360, then only 1.
In this case it is just a matter of luck that the bank angle is 90 and the crank division also is 90. That makes for an even division of 90 degrees per ignition and 4 pairs of sychronous running pistons. Therefore 4 coils. I can opt between 4 twin ignitions, or 2 fourcylinder ignitions. I prefer the latter.

John_M_

What are you striving for, the "big bang" approach, two cylinders firing simultaneously. I haven't seen how they setup the CDi on the inline 4's. it should be straight forward, no fancy coding, I don't think they use an end of phase reset, just alternating 180 degrees,south then north pole, so you can pretty much set it up depending on the orientation of the two dual hall sensors, and the number and orientation of the magnets,

1967brutus

??? No? I want one cylinder firing at a time. Hence the remark to check the camshafts to see if (for example) 1A and 2B are NOT in the same phase. If that is the case, then all the other cylinders will also be in the right sequence.

John_M_

Right, with the sensors 90 to each other, and the magnets at 180. what was the reference to the "big bang" setup you mentioned earlier, I thought you were going for the exhaust sound from two cylinders firing simultaneously.

John_M_

Your mind is like a cocaine addicts Bert, running a mile a minute, I can't keep up with your accelerated thought processes, I'm 74 Bert, not as sharp as I was

1967brutus

I apologize for that... I try to contain myself, but it is a thing that has caused me quite a bit of trouble including and up to a point where my employer had me examined to see if there was something wrong with me... My brain simply is wired that way.

Nah, there are a lot of 90 degree angles and 180 degree angles involved in fourstroke engines , and I suddenly realized that the belt-pulleys of the camshafts can be fitted to those shafts 180 degrees out of position, which would mean that despite the pulleys being on the marks, the "phase" of each bank is undefined. That in turn means that unless I am mistaken, it is possible to run the engine either as "big bang" OR "small bang" and for the engine it would not matter since there is no ignition system or distributer, Only glow plugs.
It was merely the realisation that that was a possibility, that made me post it. From how the engine in the video runs, I would not be surprised, that Johnny's engine is (unknowingly) in the big bang configuration.

Effectively, the way I envision the ignition set up, it won't matter either, the engine will run in both cases because of the wasted spark principle

John_M_

No need to apologize, So your employer had your head examined did they , sorry I had to chuckle, you don't hear, or read that often. Most intelligent people can multitask with their mind, some may think its a form of ADD, but its just having an overclocked brain, processing multiple threads / or ideas... like the "nutty professor"

I was getting my head wrapped around what you were describing with the "big bang" configuration, and phasing the camshafts, I understood the logic what you were saying, then you went back to the firing every 90 degrees setup, which is the way I prefer the ign to be setup. There are a few ways that can be setup, but the two hall sensors set 90 to each other and the two magnets north & south is the easiest way. It will run well, completely different than Johnny'Q's... If you recall that large scale 18 cylinder radial engine ran on glow ignition, which I thought was just ridiculous, good for demonstration purposes, but not practical or reliable without onboard glow drivers.

Don't mention wasted spark With the back ends of those camshafts with the drive dog ears, could easily make cam position / phase sensors, and fire each cylinder without wasted spark, like I did with the OS twin boxer. all I did there was to use a dual hall sensor as a cam phase sensor, and used its output signal to switch the ign coil output pins of the arduino coil A / coil B. Timing still referenced from the crankshaft, so it has the cam phase sensor as well as a crank sensor. It starts on the first flip as long as it has a good prime, If you remember our prior conversations, I had it setup were it would go out of phase, and become a PITA to start.

cmulder

Another thought.
There are these hall sensors that can measure rotation. One use is in the sticks of our transmitters,
What if you stick a magnet on a output shaft and then you know exacly what position the crankshaft is at.
Feed that data in some proccsing unit like used in the solenoid system and then have a (or several) output that commands a coil to fire.
Then you can adjust the timing of each coil in software (rpm based?)or even remote. Things like rpm telemetry are then also possible.

1967brutus

Yeah... but way to complicated for me to execute. Not going that route if I can buy a set of ready made ignitions...

John_M_

There's gentlemen that built 1/3 scale V10 engine, and used a full scale stand alone fuel injection system, I believe he used a mega squirt system. he used the ECu,and then made his own miniaturized fuel injectors and modified the ignition coils, and sensors. He's very skilled, Built a 1/3 scale RC car to put it in. The mega squirt is fully programmable, it runs quite well, but I can only imagine what he has invested in it, the time he put into the project is obvious from the fit & finish.

1967brutus

That's the thing: I do not want to go there... that is completely beyond the original scope of my project: Running simple small scale planes on gas...

John_M_

Well its all relative isn't it, maybe that's part of his bucket list. If he's in the business, then he has some "do me a favor" resources, but he could easily have $60'000 invested in it.

If you watch the other video, "Model V10 Engine Build compilation"... that's his son narrating for his father trying to explain each process in the still images, obviously he hasn't got a clue what hes looking at, but he wanted to document his fathers work. He mentions his father lost a few of his fingers while machine the crankshaft for that engine. That's a little too much invested for my liking, nothing is worth loosing ones dexterity over, and with his skill set you would think safety first and foremost.