My Hodgson 9 Radial Final Assembly

[mayhugh1]

I thought I might mention a possible problem that has been on my mind and that may be waiting for me when the engine is fired up. I have a very big unknown and that is the Walbro carb that I intend to use on this engine. I have zero experience with these carbs and I don't even know if the one I have is capable of working on this engine. So, I have been trying to be very careful up to this point to eliminate as much uncertainty in the areas of compression and spark so that if the engine has issues with running I can be reasonably certain it is in the fuel system.
I'm using the same TIM ignition in this engine as I used in the Jerry Howell V-4 that I built. An important parameter for this transistorized Kettering type ignition is the dwell since it sets the amount of energy that will stored in the coil for discharge across the plug gap. It also affects the relibility of the ignition components since significant power is dissipated in the output transistor and the coil and the dwell is a 'duty cycle' for this dissipation. I could easily calculate what I need to know if I knew the specs of the coil I'm using; but I don't and I don't have any equipment to measure the primary inductance in either the fequency or time domains. I do know, however, the resistance of the coil I'm using. Once the primary inductance is known, the slope of the rise of the current through the coil can be computed by L/R and knowing the saturation current I can compute the time it takes for the coil to just reach saturation. If I'm going strictly for performance I calculate the required dwell in degrees at the maxiumum rpm I want to run with full spark power. At lower speeds where the dwell angle is the same but the dwell time is longer, I waste power and decrease reliability of the ignition components by dissipating power in them after the coil saturates. If I'm going strictly for reliability I choose an idle rpm and compute the dwell ini degrees at that rpm. At higher rpms, the coil does not have time to saturate and the energy in the spark falls off until the rpms are increased to the point where the plug is not capable of firing at all.
I built my Jerry Howell V-4 to his specs and used the TIM ignition and 'Exciter' coil that he sold. Only the resistance of the coil was spec'd but Jerry had evidently massaged the dwell so that the combination would work with his engine. The dwell in this engine was chosen to be 40 degrees (I'll always refer to crank degrees when speaking about dwell). This dwell is set in the distributor by the time the rare earth magnets that activate the Hall effect sensor spend over the active area of the chip. This time is, in turn, set by the diameter of the magnets and their radial distance from the axis of the distributor. Jerry chose 2mm magnets and .3 inches radial distance to get the 40 degrees. When I built and first tested this engine I verified the dwell at 40 degrees. This ignition combination was adequate to support 1200 rpm to 6200 rpm and I never had any problems with overheating the output transistor of the coil.
For my Hodgson-9 I decided to use the same ignition since I had a spare original Exciter coil. This coil was designed by Bob Shores and is no longer available although a smaller cousin with different specs from the original (whatever they are.) is being sold from the Howell website. I have never wanted to make my own ignition coil because it is really difficult to do properly.) Anyway with 5 more cylinders power dissipation might become an issue for the electronics and so I decided to cut the dwell in half from my V-4 since I didn't forsee running the radial with its big prop at 6000 rpm. I went to the drawings for the V-4 magnetic disk and increased the radial distance for the H-9 magnets to .58" instead of .3". After the distributor was completed I verified the dwell measured 21 degrees which is close to what I wanted. Anyway, a few days ago I took the V-4 down off the shelf to run it. I decided to make a dwell measurement and I measured only 24 degrees! I rechecked my notes for that engine and verified that I had measured 40 degrees at various times just after finishing the engine 1-1/2 years ago. I still had several of the rare earth magnets left over from the V-4. They had been stored on a steel 'keeper' plate all this time and easured 40 deg dwell in a dummy magnetic disk that I rigged up. Evidently, over time, those magnets in the V-4 have lost strength. It is not temperature problem. The magnets are inside the distributor at the front of the engine which is water cooled with a radiator fan. The distibutor housing barely gets warm when the engine is run. I think the opposing fields of the adjacent magnetts locked in close proximity are causing the magnets to degrade over time. The four magnets on the V-4 disk are not distributed evenly around the distributor axis. This engine is actually two single pin crankshafts in tandem with an irregular firing order. This places the magnets in two closely adjacent pairs around the distributor axis whose od's are only .129" apart. The good news is that this problem offers some support for the 20 dwell choice I arbitrarily made for the H-9. The magnets in the H-9 distributor are spaced .32" apart at their od's which, hopefully, is enough so that they will not degrade and reduce the dwell even further.
The photo shows my valve cage design. I was surprised to find out that the bottom cooling groove in the valve towers that intersects of the body of the head limited the diameter of the cage. Since I hadn't thought out the design of my cages before machining the heads I had to reduce the diameter of the valves slightly to be able to use a cage. I could have kept the original valve size if I hadn't cut this bottom cooling groove. - Terry

 

[mayhugh1]

OK, after 18 months and an estimated 3000 hours of work I've finished my radial to the point where all I can now do is add the prop and gas and then spin it up to see if it will run. The engine has been sitting fully assembled for a day and even though I did empty the sump, oil continues to drip pass the lifters in the two lower-most cylinders. There is only .0003" clearance between them but overnight a puddle of oil collects under them. Some oil is also dripping out of the #5 exhaust pipe. The engine happened to be left sitting with the #5 exhaust valve open and oil has drained past the rings and into the open valve. The rings fit the cylinders at installation such that light doesn't pass by the fit, and so the oil must be finding its way past the .004" ring gaps and the clearance between the ring i.d. and piston in the piston groove. Hodgson warns that it is necessary to remove the #5 and #6 plugs after running this radial in order to prevent hydrolock in these cylinders at the next start-up. I'm hoping mine will be 'special' and not require this because the clips I used for the spark plug wires are a hassel to remove from these two cylinders.
I've installed my Walbro WT-237 carb. (This carb is no longer available but its replacement WT-345 is available on Ebay for $10-$20.) I really want to make this carb work. And I really want to run this engine on gasolene instead of the methanol that I have been running on my other engines. The problem with methanol is that it's volatility is pretty low and so something has to be added to it to get a small IC engine to start expecially when the temperature is below 65F-70F. Jerry Howell recommended 20%-30% Coleman camp fuel. My experience with the Coleman in my V-twin has been that it will not stay dissolved in the methanol. If you vigorously shake the mixture you can get it to temporarily dissolve and it works OK if you immediately use it. The Coleman that I bought also has a lot of fine fibers in it that will clog the Howell carb and so I had to filter it before using it. I went looking for something else when I built my V-4. I found a similar product Crowne Camp fuel. This stuff readily dissolved in the methanol and didn't have to be filtered. It appeared to work well. I finished this engine in mid-November 2011. I ran it for a total runtime of an hour or so over a period of two weeks or so in my reasonably well ventilated garage - door open and exhaust fan running. When the blood tests for my annual physical came back in mid-December I was told that I had a low hemoglobin count that I had not had the year before. I wasn't anemic. For some reason my body suddenlt wasn't producing the proper level of hemoglobin. For some reason, I wondered if the camp fuel had something to do with it. My doctor suggested a re-test in three months. From that point on I only ran my engines outdoors. Three months later the re-test showed that my hemoglobin had not fallen any lower but was still at the level measured in December. At that point I decided to only run my engines outdoors. When I got my blood test results back for my December 2102 physical, my hemoglobin level was back to normal. I don't know know if the Crowne camp fuel had anything to do with this but I have quit using it altogether. Some model engine builders mix WD-40 with methanol to increase its volatility. I've tried this and at a 15% misture it seems to work even better than any of the camp fuels. The only issue with it for me has been with the Jerry Howell carb on my V-4. I have to make a final run with methanol only before putting the engine away because the WD-40 will clog this carb if any trace of it is left to dry up and scum over.
I was happy to see that there is enough carb vacuum when spinning the engine with the drill to suck my thumb hard into carb intake. I shouldn't have a problem with drawing fuel from my carb bowl.
I added two photos of the internals of my fuel pump. The pump and motor were scavenged from a $20 electric fuel filler for fueling RC cars and planes and is available at hobby stores.
I've also added a photo of a neat device I bought at an auto parts store years ago to sanity check an ignition system. It is nothing more than a neon bulb with a pick-up loop. You place it near a plug wire with the engine running, and it will flash if the wire is being pulsed with high voltage. The leds I built into my firewall will tell me if my Hall device is working and this little device will tell me if the high voltage is actually firing without having to pull a wire to test it for spark. Pulling a wire in these model engine ignitions can be tricky since if you don't get it to close enough to engine ground when it fires you can damage your coil or output transistor.

 

[swilliams]

Well done Terry.

It's looking great and so many small touches you've added that all sum up to make such an impressive outcome. I really like what you've done with the nut that holds the prop on and stand you've made up to hold everything.

On another note, what do you think about the prospect of using a full size 6v coil with the Hall effect ignition you have employed? I imagine one of these can store significantly more energy than the small exciter, but will this make things easier or not? I guess with a bigger coil you need to reduce the dwell in order to avoid frying the power transistor. Is that how you see it?


Cheers Steve

 

[petertha]

I was happy to see that there is enough carb vacuum when spinning the engine with the drill to suck my thumb hard into carb intake.

The pump and motor were scavenged from a $20 electric fuel filler for fueling RC cars and planes and is available at hobby stores..

This is incredible. Best of luck on the home stretch.

Re the carb suction, can you elaborate on the Hodgson overall induction flowpath. In an earlier picture it looked like some sort of vaned cetrifugal 'booster-looking' device off the crankshaft. This gets fed by the carb outlet AF mixture, right?. Do the blades & chamber shape actually further compress intake charge by reduced chamber volumer? Ive heard people say this provides more equal distribution to the cylinders so the uppers dont run lean & lowers not more rich. That makes sense. But maybe I just dont understand the principle. It would seem to me with a centered carb, any one open inlet valve would receive almost a direct feed from carb to its inlet pipe in about the same path/distance. And at typical rpm this would happen in a blink.

I can see there is something equivalent to a hydrostatic head difference between the upper & lower-most cylinders, but does intake mixture gas actually densify or coallesce or something that much that would cause the upper/lower lean/rich? Or is it moreso slinging the charge giving centrifugal push?

Re the RC pump, that is a great idea. Im not sure if its the type I've used but typically they make a glow (methanol) & gas (-oline or exhaust smoke feed). Just mentioning because sometimes internal gaskets, o-rings, plastic parts etc. dont like one fuel or another & can swell or degrade.

 

[R Degen]

What size prop are you going to use?

 

[mayhugh1]

Steve,
That's pretty much how I see it. I haven't been able to get too quantitative about the performance of my ignition because I don't have a way to measure the inductance of my coil and he Lpri/Rpri are key factors in determining how much energy one can store in a the coil. Guess-estimating my Exciter coil primary inductance from its physical size and taking some liberties with how I think the potted case is filled with wire I get about 5 mH using a freshman physics equation for the inductance of a solenoid

L=(core permeability) (#turns^2)( core cross sectional area)/(core length)

This combined with the measured resistance of 1 ohm gives a current rise which I think is longer than it should be for the dwell time I'm using. I plan to get hold of an oscilloscope and make measurements on my ignition system soon, and especially if I have problems with getting it to run. I hate having such an important component of this project be such an unknown. I plan to stay with the same coil but may have to make some changes to the dwell time or the TIM circuit itself. I've already ordered some new magnets of various diameters so I can re-do the trigger disk in the distributor if necessary. I'm pretty sure the older style automobile coils have inductance values on the order of 25 mH or so because I measured some a long time again using equipment at a former employer's lab. (I'm a retired engineer.) They also have resistances lower than 1 ohm which means they draw quite a bit more current than I'm willing to put up with in a model. The other big unknown is how much energy is required to fire a plug in the combustion chamber. Part of my testing on my ignition will be placing a plug in a chamber under 70-80 psi and see what energy is required to fire it. - Terry

 

[mayhugh1]

Petertha,
I disassembled the fuel pump I'm using to see if there were any o-rings in there to worry about with fuel compatibility. The one I'm using is just a some sort of plastic pump with no seals. The way they seal the shaft is with a close fit in a very long neck. The fuel lubricates the pump shaft and so it probably would like the RC glow fuel better than the gasolene. The testing I did on it showed some minor seepage here and so I just added a drain tube so any seeped fuel would not accumulate in the housing. So far my testing has showed no problems but it is a bit of a question mark in my mind also.
The impeller is meant to just keep the air/fuel mixture stirred up for better diffusion. There have been three iterations of the fuel distribution system in this engine. The first had no impeller, then a small impeller was added, and in this design there is a full size impeller. These were done to improve starting and to try to get an even distribution for all cylinders especially the #5 and #6. From what I understand these have progressively helped but not fully solved the problem. Most of the engines I have actually seen running have so many oil control issues with the lower cylinders that they fuel distribution issue is in the noise. In normal operation the bottoms of those cylinders behind the piston rings are filled with oil. The oil-drip system and a recommendation of straight 50 wt oil are attempts to try to reduce this. The impeller chamber has drain holes so that accumulated liquid fuel in this area is drained into the oil sump. - Terry

 

[mayhugh1]

R Degen,
I have two props - a 26x10 two blade and a 24x10 three blade. I chose the diameters purely for esthetics and to allow me access to the throttle at the rear while holding the starter in the front with getting clipped in the face. - Terry

 

[Lakc]

Its just not a round engine if it doesnt leak oil, its part of the charm.
As to fuel, E85 has been the easiest to get here. 15% gasoline 85% methanol. No oil to worry about like model engine fuel.

 

[mayhugh1]

Lackc,
I haven't seen any E85 around here. (I think you meant ethanol.). This is Texas and we don't use no stinkin' corn gas down here. - Terry

 

[Lakc]

http://e85vehicles.com/e85-stations.html

It aint worth nothing in cars, but for models it is fine

 

[mayhugh1]

This was a very bad day...
Today, I tried for a first pop. I've started with the Walbro WT-237 carb and both the high and low speed adjustment screws are 1 turn open from full closed. I'm running 87 octane pump gasolene and timingset at 10 degrees BTDC. I thought I had set the fuel pressure at 5 psi but I later learned it was set for 10 psi. I didn't get a single indication of firing on the first spin-up with my drill starter. So, with the fuel pump running, and ignition OFF I pushed down on the diaphragm on top of the carb to prime the metering circuitry while turning the prop a few rotations by hand. (On this carb I had drilled a small hole through the center of metal cover over the diaphragm.) This time I did get a first 'pop' but not kind of sustained running. Basically after a few minutes of playing, I decided that gas is probably not getting drawn past the inlet valve on the metering diaphragm due to insufficient manifold vacuum. The venturi on this carb is .310" which I think is close to ideal for this engine. I eventually got the engine to sustain running a couple times but only for a few seconds on primed fuel. To get even this I had to close the throttle almost completely and excessively richen both fuel screws 1/2 to 3/4 turn. This is a tricky maneuver, because at the angle I have to stand to fuss with the throttle or carb adjustments while holding the drill starter, the prop is only inches from my face. When the engine first started there was a glorious cloud of blue smoke as the lower cylinders cleared the oil that had drained into them but the smoke quickly dissipated a second or two later just before the engine died. I spent a good bit of time playing with the carb screws and engine timing because it seems pretty much everything is working except for the carb and I'm not going to be able to fix that with mixture adjustments. After an unsuccessful hour or so and running down the battery on my drill starter I decided to call it quits. I was able to determine was that I could force the engine to draw fuel from the carb, and probably puddle it in the horizontal venturi, by placing my thumb over the venturi and turning the prop over by hand. The only thing this meant though was that my fuel pump was getting fuel into the metering circuits.
While my battery was charging I decided to check the fuel pressure and found it was 10 psi and so I reset it to 5 psi and made sure it was a consistent 5 psi this time. Of course if the engine isn't getting fuel, decreasing the fuel pressure is the wrong direction to go. I also double checked my ignition to make sure I was getting a spark. Even with my limited dwell I expect to be getting fat sparks at starting and idling rpms and I am getting them as expected.
Since I had tried everything else I could think of, I decided to shorten the spring behind the metering diaphragm. This is the spring that holds the inlet seat closed. My interpretation of the Walbro service manual is that manifold vacuum pulls fuel out of the carb that has been let into the metering circuitry by atmospheric pressure acting on the diaphragm which, in turn, has to overcome the force of a spring located between it and the inlet seat in order to open the seat and let in more fuel. The fuel pump seems to be doing its job. I took the diaphragm cover OFF several times, and there was always fuel under the diaphragm. I studied the Walbro carb service manual some more and to me it was just too simple. It just seems like it has to work.
This is the point where I decided, right or wrong, that the carb may not be getting fuel into the metering circuit because my vacuum signal was not strong enough to overcome the force of the stck spring. And so I decided to modify the spring.
The Walbro stock spring in this carb is .008" brass wire wound at a .125" od and free height of .330". For my first test I trimmed the spring to .255", but I couldn't get any better result trying to sart the engine. In fact I couldn't get much popping at all. Trimming again to .200" was too much and the result was gas puddling uncontrollably in the venturi. The engine wouldn't even pop off this flooding.
I figured that perhaps something is wrong with this particular carb or my re-build job or whatever. I had a second carb that I found listed as 'new' on Ebay, but I suspect it was also rebuilt. It was a Walbro WT-345 which is listed as the replacement for the WT-237 and looks identical to it. I installed it with its stock spring, but I got the same no start results as before. I pulled all the sparkplugs and cleaned them. They were all wet with gas and some had some black carbon deposits that told me they had at least briefly seen a too rich fuel mixture. While all these starting attempts are going on I'm also fiddling with the oil drip regulator because the engine is blowing alot of oil out of the exhausts of the lower cylinders and between all the fuel collecting on my baseplate from my priming efforts, I can't tell if there is also gas in the oil. I'm afraid to limit the oil flow too much because I don't want to create a bearing problem on top of everything else.
At this point I'm out in the deep weeds. I've tried many things in a reasonably systematic order that may not be apparent from my description, and nothing seems to be making sense. I seem to be able to move from no fuel flow to a flooding condition with very little small changes. Also in the mix along the way I turned a .250" reducing bushing for the venturi of the WT-345 to see if more carb vacuum was the problem and, again, no joy. I can not honestly diagnose what is going on. If I had to summarize what I'm seeing it would be that the engine isn't drawing fuel from the carb unless it is primed, and then when it is primed it draws an excessive amount and floods the engine.
At this point I decided to change to the Super Tiger carb and go back to my methanol and campfuel mix just to see if I can make any difference at all. In the back of my mind are the comments I've heard from model engine building experts that say "carb problems usually turn out to be electrical problems" and then there's the other one "electrical problems usually turn out to be carb problems." I installed the Super Tiger - I don't like this carb as much because the .350" venturi just seems too big - and changed out the fuel. In this carb setup my pump merely filIs a carb bowl to a pre-defined level and recirculates the remainder back to the tank. The carb sees no fuel pressure - just a fuel level below the venturi to draw from. I started my drill starter and on the second revolution I felt a thud and the starter stalled. The prop was locked up tight. I pulled the sparkplugs from the #5 and #6 cylinders and gasolene (not methanol) poured out of the #6 sparkplug hole. After draining the cylinder the prop turned very tightly and so something is wrong deep inside the engine. On one of my previous tests with the Walbro I had evidently managed to flood the engine and the excess fuel got sucked into the intake pipe of #6 and hydrolocked the cylinder. I was aware of the potential for this happening with oil and had been careful to check for hydrolocking after the engine has set for a while, but I wasn't expecting to see this happen with fuel literally minutes after previously cranking the engine.
So, the engine will have to come apart to see what has happened. I may have bent a slave rod or even the entire main rod assembly. Either of those would be much preferable, though, to damaging the crankshaft. I'm just hoping the crank is OK. It's a complicated part with lots of machining operations, and it will be very tough to duplicate the fit that I had achieved with all the other mating components already completed.
Now, I have to go start on my income taxes. I'm trying to decide if I should throw up before or after. - Terry
p.s.
I got to talk with Ron Colonna on the phone today after all the fuel fumes had a chance to dissipate. It turns out that Ron and I are almost the same age, grew up in the same town, went to the same high school and technical school and shopped at the same neighborhood hardware store for parts for our projects when we were kids. Ron has some experience with a Walbro-type carb on his Challenger V-8. After explaining what I had just been through, Ron suggested that my method of priming the engine by pressing down on the diaphragm was probably letting too much fuel into the engine. And now, after thinking about it, I can see his point. While I have the diaphragm depressed the fuel pump is just pumping fuel into the engine and where will it go? Of course, it will go into the bottom two cylinders. Ron also suggested that with the rpms I am likely to be turning with this engine it will probably never be drawing fuel from the high speed idle circuit and so I might try to turn that screw completely off. I studied the Walbro manual some more and noticed that when the throttle is closed, the carb is designed to also pull fuel from the high speed jet to enrich the mixture for starting when choked. Shutting off this path would elimimate another source of flooding while I am priming the carb by choking it with my thumb. I reviewed some 'first pop' videos that my wife took. (She was more excited about starting it up than I was.) They showed that with the stock carb and 10 psi fuel pressure the engine almost wanted to run. I did prime it for the first pop but possibly my mistake was re-priming it and flooding it thinking that I wasn't getting enough fuel. Holding down the diaphragm while turning the prop was a big mistake. A better way of priming it would be to partially cover the intake with my thumb. Very likely, the completely dead re-start attempts were due to massive flooding. If I had allowed the flooding to clear before trying to restart the engine perhaps my attempts to adjust the idle screw would have been more effective. Oh and one other thing: for the first several starts when I thought I was turning the idle screw I was actually turning the high speed screw. The carb that Ron used actually had .625" venturi so he made a .25" reducing bushing that went through the carb. It was cross drilled for the fuel holes and he had to make a new butterfly. At .310" Ron felt my carb was probably about the right size for this engine. After all my careful prep work I let things go to Hell in the heat of battle.

 

[agmachado]

Fantastic!!!

Congratulations... very, very nice job !!!

Cheers,

Alexandre

 

[keith5700]

Hope crank is ok.
The very first fire-up is always the worst because you have no idea where the fueling is set to.
When I eventually got mine to run I realised the settings I'd been previously using to get it to start were waaaay too rich.
The only way I could get mine to run was to pre-heat the engine to around 50 degrees c with a fan heater.
After this first run, with much different carb settings, it will now start cold (just).

Lovely engine by the way.
Keith.

 

[mayhugh1]

Keith,
What carb and fuel are you running?

Terry

 

[keith5700]

Terry, my situation is a bit different to yours in that I am hoping to go to fuel injection ultimately, so the carb setup is just temporary, just to see if the engine would run. So, I bought a small twin needle carb from a small rc aero engine. The bore is 5mm, and my engine is 40cc V8.
The engine will rev high, and also tick over at about 700rpm, although not at the same carb setting.
It served it's purpose in getting the engine to run but it's far from a permanent solution.

Fuel is ordinary petrol/gasoline.
Cheers.

 

[Swede]

Hi Terry - VERY nice build, and your descriptions of the carburetor issues and difficulties in a first run mirror my own to a certain degree.

First, I'm not sure why you feel that you need to use methanol with a stock RC model carb like the super tigre. True, often the needle valves, venturis, and carb throat diameter are engineered for methanol, but they will work with gasoline. The problem most people see when using a RC model carb is an overly lean mixture due to a large throat and low air velocity, and this can be corrected by selecting a smaller carb or sleeving the throat of a larger carb. Additionally, of course, some sort of float bowl setup needs to be engineered so that negative head pressure of the fuel line to the carb remains consistent, as needle valve adjustments using gasoline are more sensitive than the same carb when using methanol and oil.

I started with a full hall-effect transistor setup, and a carb similar to your Walbro, with almost zero success. I went to a local hobby store, and simply purchased a number of O.S. and Super-tigre carbs (3 or 4) and machined adapter plates for them, and I found that as the carb-size dropped, performance improved. In the end, the best carb I found was from a .30 sized glow engine, a very simple unit. It seems ridiculous that a carb from such a tiny engine would work well with a massive radial engine using gasoline, but for me, this was the case.

The tiny throat produces a nice air velocity, sucking and atomizing the fuel very well vs. the larger carbs. And in the end, isn't reliable running the goal, vs. wringing a few hundred extra RPM out of the engine?

If you do end up with a simple/small carb, priming requires quite a few turns of the prop with a finger over the air inlet. When mine fails to start, it's almost always insufficient prime.

The process from final assembly to a solid, running engine with no missing cylinders did take a while, and in almost every case, I found simpler was better. I went from large, complex carbs to small, simple ones, and I also changed my ignition from 6 to 12V, installed a large coil, got rid of hall chips, and used a breaker with a tool steel cam, and this has been running now for many years, starting up with two hand flips.

I'm guessing your hall system is better engineered than mine, so I suspect it'll work fine, but right now, I'm guessing your problems are fuel and carb. I hope there was no damage - rather than tear it down, I'd simply drain all fluids from it and check rotation and compression. If all is good, I'd say go for it!

You've done a beautiful job of it - keep plugging away, and you will be rewarded with a sweet running engine.

 

[mayhugh1]

Kieth,
I'm sorry I didn't recognize your screen name before. I've been following your build ever since it started. Your attention to detail and the workmanship in your V-8 totally blew me away. I don't know how many non-engine-builder friends I've pointed to your site just so they could see the realism. Some of them even thought it was a Photoshop creation. I've been especially interested in your start-up progress and am still eagerly following it. - Terry

 

[mayhugh1]

Swede,
Thanks a lot for the advice. Once I get the engine running on methanol with the Super Tiger carb I will certainly give gas a try. I've been a fan of your website for many years. I first found it when I built my oven to give metalcasting a try. I spent several hours studying your H-9 project before I started my own, and some of the changes I made to the design were based on your experiences. Lee told me at one of the shows that the changes he eventually recommended for the ignition system were a result of your experiences. - Terry

 

[mayhugh1]

Day1...
Well, I opened up the front cover - it was very difficult to pull off. I had to rig a puller. I removed the cam ring assembly and cylinders #5 and #6. It turned out that the problem was that when cylinder #6 hydrolocked, the rear crank half could no longer rotate, but my drill starter was powerful enough to rotate the front half of the crankshaft a few degrees (this front crank cheek is clamped to the crank pin with a SHCS). This rotating slip around the crank pin caused the axes of the front and rear portions of the crankshaft to move out of alignment and bind in the main bearings as well as the front cover bearing. The bearings don't seem to be harmed. Loosening the front cheek SHCS clamp allowed the two halves of the crank to self-align in the bearings and the crank could rotate freely once more. This was a great relief. Fortunately, the rotational energy of the starter was slowly dissipated in the front clamp instead of being abruptly dumped as would have happened if had pinned the sections together. If I had used a pin it might have broken or, even worse, I might have broken a rod. I decided to check the rear cheek clamp in order to see if that section had also rotated. The front and back have to be aligned in order to align the oil passages through the crank.
When I built the crankshaft I was able to easily tighten the rear cheek clamp with the crank in my hand. I then considered this a permanent assembly. When I tightened the front clamp, though, that had to be done within the engine during assembly, and I had only a small hex key that would fit through a cylinder opening in the crankcase to do it. It was difficult to put a lot of torque on the screw with the 1/2" long handle of the hex key. In order to get to get the rear section out I need to pull the seal plate and rear main bearing out. I've decided to just completely disassemble the entire engine, though, and start over.
A quick look at a couple cylinders showed something amazing (to me, at least). When I annealed my rings a light straw oxide formed on them which I did not polish off. And, my 12L14 cylinders were internally lapped and hot-blued. When I looked at two of my cylinders I expected to see the bluing worn off where the rings had been rubbing. The amazing part is that there was absolutely no wear on the cylinders. The bluing was untouched. But the straw oxide on the rings was worn nicely around the entire circumference of the rings and they were a bright and shiny bare metal. I realize that without some actual runtime and combustion pressures this is only saying that the cast iron oxide is softer than the 12L14 mild steel but even still this was pretty unexpected. I've heard many builders comment that 12L14 is not a suitable cylinder material.
I can see why the bottom cylinders are so stressed with oil in these engines and why ring sealing is so important in them. When I removed the front bearing I could see that those two upside down cylinders were completely full of oil. There is no place for that oil to go since the skirts of the cylinders sit above the drain path to the sump. The sparkplugs of those cylinders will certainly have to be removed for long term storage so that this volume of oil, which is more than enough to hydrolock the cylinder, can drain out the spark plug holes. This is also a Lee Hodgson warning.
I didn't get very far into the complete teardown since my stomach was bothering me, but I wanted to make a little more progress so I decided to make another ignition test. Since I had the distributor off the engine already anyway, I hooked it back up to the radial ignition and spun the distributor as fast as I could with a dummy sparkplug connected and the sparks looked very healthy. Then I brought down my Howell V-4 and connected my radial ignition to it to see if it would run the V-4. I'm still using the V-4 distributor, of course, but the all-important coils and dwell times are the same for both engines. The V-4 fired right up and ran at full rpm and sounded even better than I remember it sounding on its own ignition. All this testing did not actually test the plug firing path through my radial distributor and so I plan to eventually rig up a plate with nine sparkplugs and connect it to the beautiful radial ignition harness that I will have to remove. If it passes that test OK, I'm finally putting the question of any ignition problem to bed. - Terry