Quarter Scale Merlin V-12

[mayhugh1]

Peter,
Your questions are certainly relevant, but I'm afraid I don't have enough experience to answer them. Maybe someone else could? I'm not aware of what the effect of rake angle is on free machining bronze, but any modifications would have to be done carefully in order to keep the tip symmetrical. Most of my reamers came from surplus outlets, and they are a mix of both straight and spiral. I've not seen much difference between the two types in the holes I've reamed, although if I were reaming a cross-drilled hole my preference would be a spiral reamer. On the cages I've done I've used a ball mill to ream the large opening for the seat since it gives a nice transitional region between the port and the valve. The exact diameter you end up with depends on how precisely it is aligned with the axis of the lathe, and so it should be gripped in a tapered collet holder for consistency. Grinding down all but one cutting edge will reduce chatter and give a nice surface finish. I would then normally design the valves around the seat i.d. that results. - Terry

 

[mayhugh1]

I took a final look at my valve cage design just before setting up to machine them. After some more thought I don't believe it's safe to use them in these heads after all, especially after I increased the valve stem diameters. Once the head castings are machined for the cages there may not be enough material left to reliably support them. The cages would also be very close to an internal coolant passage that runs the length of each head, and my modeling of this portion of the casting isn't accurate enough to insure they won't break through.
So, I'm going to focus on using the seats and guides that the heads were designed to use. Instead of the wide 30 degree seats against 45 degree valves as shown in the drawings, though, I'm using 45 degree valves against narrow 45 degree seats as I've done in my other engines. The seats and guides have already been machined, but I went through each seat one last time and turned a steeper bevel on its bottom outside corner. My original shallower bevels created a lot of difficulties earlier when I tried pressing some practice seats into a test block.
I also machined a back-up block to support the heads while they will be upside down in a vise having their seats pressed in. The castings' thin walls behind the combustion chambers seem a bit fragile for the pressure they may have to sustain during the seat installation. I also made a tool for installing the guides. The guides must be pressed in from the tops of the heads after counterbores for the spring perches are machined into the heads' top surfaces. I also made new pilots for my seat cutters to fit the Merlin's guides. These cutters are the same 45 degree Brownell's counterbores that I used on my T-18 valve cages:
http://www.brownells.com/gunsmith-tools-supplies/barrel-tools/barrel-chamfering-cutters/45-chamfer-cutters-prod41716.aspx
The valves, themselves, are the last valve train parts to be machined. I made only two pairs for now to debug and verify my valve-making process. Since machining two dozen valves will be a big deal for me, I want to test fit a couple of them in the actual valve train before spending a week making the rest.
I slotted the stem of one of the valves so it can be used as a test valve for checking the seals. A Mity-Vac can be used to pull a vacuum on the rear of each installed guide with this test valve temporarily installed. With the test valve closed against an installed seat the leak-down time can be measured and compared with results obtained from similar measurements in previous builds. I should be able to apply this technique to the Merlin's heads once I figure a way to reduce and seal their humongous ports. The remaining three valves will be used as piloted laps that will be used to remove the machining marks left by the seat cutters.
It's been my experience that nearly all valve sealing issues are related to the seats. I've been able to machine valves with enough consistency so that practically any valve will seal against a good seat. It's not difficult, on a lathe, to turn the correct geometry and a sealing surface that is free of tooling marks. I don't lap my valves to their seats since this can damage the finished surfaces of the valves. I also don't try to correct geometry problems with lapping. I use manual piloted seat cutters to cut the seat and to establish the proper geometry for the sealing surface. The pilot ensures the contact patch will remain circular even if the seat and guide are not perfectly concentric. A 360 degree circular contact patch is a fundamental requirement for a seal. The seat cutter will leave behind microscopic machining marks, though, that will limit the integrity of the seal. During my T-18 build I found that using two seat cutters on each seat leaves behind a smoother surface than using either one alone. I use lapping to remove these marks, and I use a separate spare valve to lap all the seats. Automotive valve lapping compounds are designed for hard seats and valves, and they will typically embed in softer metals like the bronze I use for seats. I use TimeSaver lapping compound which breaks down during use and does not embed. I can usually lap ten or more valves with a single lap. I lap for only 30 seconds or so, and if I'm not happy with the leak-down results, I'll lap a second time. Finally, I manually polish the seat using a felt bob and a dab of metal polish. This last step brings the seat to a brilliant shine without removing metal, and it usually improves the leak-down time a bit. Generally, narrow seats have fewer machining marks to deal with, and so I like to use .005" as a seat width. If the seat and guide are not concentric then the width of the seat will not be uniform. The seat may have to be cut deeper than desired in order to obtain a complete 360 degree contact patch. If the concentricity is poor enough one side of the seat can end up very wide and require a lot of work to clean up.
My leak-down criteria are my own numbers on my own set-up derived after lots of late night hours experimenting with seat making on my two radial builds. These times are dependent on the volume over which the vacuum is pulled and are most meaningful to my set-up. Using my Mity-Vac on a freshly cut .005" wide seat I expect a 10 second leak-down time from 25 inches Hg to 15 inches Hg. Lapping and polishing can extend this time up to a minute or even more. My criteria is over-kill, but I like to squeeze out all the performance I can get so that compression doubts aren't on the table later. In order to get an engine started the leak-down time needs to be short compared with the time the cylinder is under compression during cranking. With a 120 rpm cranking speed, a four-stroke cylinder will be under compression for something just under a second. Loss of cylinder pressure during this time (from two leaking valves) reduces the effective compression and steals torque during the power stroke.
If the engine can be started, the seals in a model engine will improve over time as the seat material yields to the extreme pressures created by combustion, and the pristine valve surfaces pound the remaining machining marks out of the softer seat faces.
While waiting on an odd size reamer that I need to properly install the guides (I should have checked my reamer inventory before finishing the diameter of the guides) I decided to assemble a few reject guides and seats into a scrap block of aluminum just to see what results I could get. The TIR of the guides was .001", and with the reamer I had on hand the hole they went into was .002" oversize. By this time, though, I had forgotten the reasons for scrapping the particular seats I was about to use. For these practice parts I wasn't expecting much, and so I didn't bother to purchase any dry ice; but I did use the high temperature Loctite. The two seats I pressed into my test block appeared to go in smoothly with moderate effort, but the guides ended up with sloppy fits as expected. I accelerated the guide's Loctite cures with heat so I could get some quick measurements.
Unfortunately, the seat cutter initially left chatter marks on the very first seat I tried. It may have dug into a burr that I neglected to remove on this rejected part, or it may have been caused by my rusty technique. The pilot was .001" under the i.d. of the guide which is what I normally use, but I swabbed the pilot with some thick grease to reduce the clearance. By the time I had cleaned up the seat its width had grown to some .050" - much too wide for my taste. Its measured leak-down time was 3 seconds. The result for the second seat was a little better at about 5 secs, but it was obvious that this particular seat and guide were not concentric. The seat face width varied from .030" to .010". The guide's TIR and its sloppy fit couldn't fully account for the error, and so there was probably also a drilling problem.
Thirty seconds with TimeSaver extended the leak-down times to 15 seconds for the first pair and to 30 seconds for the second pair. The metal polish extended the time to 20 seconds and 45 seconds, respectively. I stopped at this point and declared them 'good enough' and was very surprised that these seats cleaned up as well as they did. When I start out with similar problems on a valve cage I normally just discard it rather than put any effort into saving it. I won't have that luxury, though, with pressed-in seats on these heads. - Terry

 

[gbritnell]

Terry,
For the life of me I don't understand why they would stipulate 30 degree seats and 45 degree valves. (seats) Common practice is to have the seats and valves at the same angle to insure that there is a good seal. Just as a point of information, if the seat was 30 degrees and the valve 45 degrees where were they expecting the valve to sit on the seat, at the top of the valve angle, the bottom or where. I just can't picture this working.
gbritnell

 

[mayhugh1]

George,
When I first saw what they were recommending I envisioned the valves sitting deep down in the seats. When I sarted working on this portion of the engine I modeled what they were doing and saw they actually had the valves sitting high up on their seats. I guess the reasoning was that the mismatch in angles would provide a thin contact patch. But they also suggested lapping the valves to the seats, and in this scheme the seat width could grow pretty quickly. I was tempted to try their recommendation, but I'd have had to come up with a 60 degree piloted seat cutter that I'd probably never use again. - Terry

 

[kvom]

There's a set of castings on eBay if you want to make a pair.

 

[mayhugh1]

Kvom,
I just saw those on Ebay! It looks like the seller changed his mind or else found a local buyer for them since the auction was cancelled.
The interesting thing I learned from his description was that the castings dribbled out from Dynamotive, their source, over a period of some five years from 1994 to 2000 as they were designed and manufactured. It took a lot of faith on the part of the early buyers to purchase them as they became available since there was probably no guarantee that the project would actually be completed. The pressure on the Dynamotive to finish the project was obviously great also - it had to have been a labor of love on the part of the owner. There was evidently a newsletter published to alert buyers to the progress of the project and the availability of castings. I'd love to get access to them. Mention was also made that Dynamotive had also commissioned the CNC manufacturing of some of the other high volume parts including the rocker arms which are the only parts still available. I read on another forum that they early in the project they were trying to cast a crankshaft which evidently was offered in very small quantities. - Terry

 

[kvom]

I wonder if in the very near future direct 3D printing of metal parts would work to replace the castings for this engine (or any other similar).

 

[mayhugh1]

The reamer that I was waiting for arrived, and so I bought some more dry ice and assembled one last pair of practice parts in a piece of scrap 6061. Interference fits are a hit-and-often-miss operation in my shop. I usually err on the loose side and end up augmenting the fit with Loctite. In this case, though, I had 24 of them that had to be tight and straight in a pair of irreplaceable heads, and so I don't feel guilty about being too cautious about this portion of the build.
Everything on the last practice part went as expected, and so I set-up to start installing seats in the starboard-side head. With the head in the vise and the back-up block in place, I used a .236" carbide mill-drill to drill through the pre-cast seat opening, followed it with a .240" reamer for the guide bore, and then bored a .1" deep pocket using my .493" end-mill-converted-to-a-boring bar. The pocket was lightly coated with high temperature Loctite, and then the chilled .495" diameter seat was pressed in place using the mill's quill.
I immediately noticed the force required to install the seat in the head was much higher than needed with the 6061 practice scrap. The press factors for 356 and 6061 are probably similar, and so the extra force was probably due to a bit of additional interference. The force required to press one part into another is directly proportional to the amount of interference and the contact area between the two parts. So, if the actual seat and bore diameters varied such that the amount of interference increased from .002" to .0025" the required force would increase by 25%.
I set up my press as a back-up and continued with the next four seats which went in very much like the first. As best as I could measure, the seat i.d.'s were being shrunk by nearly .002" which was close to what I had measured on my practice scrap.
When I got to the number three exhaust seat it went in very easy which, initially, I attributed to a more thorough chill. The next couple seats returned to being difficult, but then the pocket on the number two intake seat ended up so much oversize that it would not even grip the seat. The same thing happened on the next seat for the number two exhaust valve. I turned two oversize seats to press into these locations and then went looking to see what had happened to my boring tool.
In order to quickly handle tool changes I had put the three tools I was using into Tormach TTS tool-holders for use on my Enco mill. In the middle of a process that I had carefully practiced and which had been working, I decided to make a change and start blowing chips away with compressed air. A sizable chip ended up wedged between the R-8 collet and my spindle bore, and this slightly tilted the tool holders. I seldom use compressed air around my machines, and in this case the spindle of my mill was sitting just above the workpiece when it was hit with a shower of chips.
After clearing this, the bore diameters went back to where they were supposed to be, but to be safe I started measuring each bore just before installing its seat. I was left feeling really uneasy about that number three exhaust seat, though.
After finishing the seats I installed the guides. They were Loctite'd with no interference; but a few did go in a little hard, most likely because the bore hadn't been completely deburred. These guides had to have their valve stem bores re-reamed.
After the Loctite had cured, I used my seat cutter to cut very minimal seats just to see how well the drilling had gone. Under a jeweler's loupe it was obvious that the oversize seats had a 2-3 thousandths width variation, and so the drilling at these locations had also been affected by the chip. The rest of the seats looked nearly perfect. The port side head was then completed, and the widths of a couple of those seats varied by 1-2 thousandths for some inexplicable reason. None of these variations are a major concern, but I'll likely not be able to use my favorite .005" seat width on the starboard head's oversized seats.
I trial fitted one of the test valves to a portion of the installed valve train so I could get a final measurement on the valve stem length and the spring retainer location. I also verified the valve's clearance to the spark plug. These measurements completed the valve design so the rest can be machined.
During my modeling I discovered that the channel running lengthwise through the center of my heads is actually a coolant passage and not a waste oil collection trough as I originally thought. The twelve holes penetrating this channel in the topside of each head that I thought were for oil collection were likely used to support the core for this internal passage. I don't believe this trough existed in the early heads because the photos I've seen of Gunnar's engine don't show these holes. It doesn't seem the documentation was ever updated because my drawings don't show them either. This casting change was likely done as an attempt to improve the engine's cooling issues rather than help with waste oil control.
There were a total of twenty core support holes in each head including these that needed to be plugged, and so each was reamed and counterbored for a pressed-in plug. All these holes penetrate coolant passages, but their quarter inch diameters should never see more than a pound or so of force. I installed plugs with .003" interference fits plus high temperature Loctite since there wasn't enough material for a threaded plug. I cured the Loctite overnight with the heads in my 120F welding rod oven. I've learned that curing Loctite 620 in this way will also harden any excess that was squeezed out and left inside the head by the pressing operation. I originally ran across this tip from another builder's unfortunate experience:
http://homepage2.nifty.com/modelicengine/h9120302.htm
At room temperature and with exposure to air, Loctite 620 will essentially never cure. However, overnight exposure to 120F will turn an air-exposed meniscus sitting on metal into a tenacious rock-hard solid. I was able to view the cured adhesive on the rear of the plugs with a borescope, but I didn't have any means to take a photo. There are still another 14 coolant passage penetrations in each head required for the cylinder studs. These will be sealed with yet-to-be-machined two-piece stud guide tubes.
The borescope also uncovered a large amount of residual investment hidden in the coolant passages. I removed another teaspoon full from each head with a dental pick, but there's still more that I can't get to. This has been a on-going problem with several of these castings. Some of their intricate interiors are coated with investment that wasn't fully removed by the foundry. This particular investment isn't water soluble, and is surprisingly unaffected by acetic acid. So far, scraping it out with dental instruments has been my only way to remove it. This stuff is going to be problematic in the coolant loops and maybe deadly in the oil loop, and so filters will have to be used in both. - Terry

 

[petertha]

With the head in the vise and the back-up block in place, I used a .236" carbide mill-drill to drill through the pre-cast seat opening, followed it with a .240" reamer for the guide bore, and then bored a .1" deep pocket using my .493" end-mill-converted-to-a-boring bar. - Terry

As usual, I feel obligated to precede my trivial questions with WOW! Can you elaborate on the end mills.

- the .236" carbide EM preceding 0.240" reamer. Is the EM required because they delivers straight holes or more because irregular entry surface? I always thought plunging like this was not preferred with EMs, but maybe I'm using the wrong ones. What kind of flute geometry works best for this? Is carbide vs HSS for tool rigidity?

- 0.493" EM converted to boring bar... I don't quite get what's going on.
Also does your pocket need to be flat bottomed? I struggled with this on my head preparing for square valve cage profile to sit down on. The tapered flutes cut well but left a crowned bottom. The flat bottom had a slightly different diameter. Do you have this issue & if so how did you deal with it?

 

[mayhugh1]

Peter,
The end mill I used for the initial drilling was a mill-drill. It wasn't flat bottomed but was pointed like a spotting tool, and so it is capable of both spotting and drilling in the same operation. It's shown in the first photo. I thought it would give me my best chance of drilling straight through an irregular surface.
The 'boring bar' was actually a resharpened four flute end mill I purchased on Ebay. It was grossly undersize for a 1/2" cutter and never got much use. For this operation I ground three of the four flutes down to make a single flute cutter as this tends to reduce chatter when making plunge cuts.
A flat bottom pocket is desirable, but these heads were cast with much of the seat pocket material already removed. My 'boring bar' just had to remove a bit more material. In fact, the i.d. of my seats slightly overhang the floor of the pocket. Although the cutter really didn't have a flat bottom, the bottom of the pocket it left behind was almost flat. The third photo shows just how much seat pocket material I actually removed.
The carbide was for rigidity. - Terry

 

[Ethan D]

This build is unreal! Beautiful work!!

 

[gbritnell]

Terry,
I'm following along enjoying the trip. At the start of a build like this all the superlatives get used so much that they seem superfluous after awhile which by no means diminishes the extreme quality of your work.
My deepest admiration!
gbritnell

 

[mayhugh1]

After completing the Merlin's valves I will have made a total of 92 valves, including spares, for three different model engines during the past four years. That's a lot of valves for someone who used to hate to make more than one of anything. Even though they were all made using essentially the same technique, it seems I always learn something new from each batch that helps me with the next.
I started by cutting a number of short lengths of half inch diameter 303 stainless rod so I could machine a valve on each end and waste only one spigot between them. I've used my 9x20 CNC lathe to make all my valves, and I machine them in a single batch in four steps.
The first (roughing) step is my favorite because with .020" excess stock left behind for finishing, each part can be run relatively unattended without the hand-holding required for a precision part. This step includes my screwy technique of using a greased leather pad between the end of the valve stem and the tailstock to dampen chatter. My live center is the only center I have that will give the tool holder and inserts that I use for this operation access to the end of the stem, but its run-out produces a larger taper than I can typically get with my leather pad kludge. With all the valves that I've made I probably should have created a custom center by now, but the leather actually seems to work pretty well. The blanks were all rough-machined over a couple days using a Seco DCMT21.51 MF2 TP250 insert. Each end of the blank required about ten minutes machining time, and a single edge of the insert showed negligible wear after roughing out all 28 valves.
However, I had to interrupt the build and devote some time to my lathe. During the T-18 build my 9x20 Mach3-based CNC lathe began acting up, and the spindle motor would sometimes take an inordinate amount of time to start up, or it would not start up at all. This occasionally caused the tool to crash into a non-rotating workpiece. At that time I replaced a couple relays on the break-out board that I thought might be sticking, but that didn't solve the problem. I then made a bus monitor to display the various control signals between the very expensive and poorly supported German-made Hamming motor and the Lathe's breakout board. The problem showed up only intermittently over the past year and, it seemed, only after the lathe had been powered up for a few hours. However, while turning the Merlin's valve spring retainers and clips the problem became much more frequent. According to my monitor the problem appears to be within the motor, and maybe it is heat related.
The motor inside the lathe's enclosure has a powerful fan mounted on one of its ends. Air is blown over a heat sink wrapped around the motor to which the VFD circuitry is likely internally attached. Warm air, chips, and coolant from inside the enclosure is blown through the heatsink and must occasionally be cleaned out.
In the middle of the spring retainer machining I stopped and cut a five inch vent in the rear of the enclosure and after fabricating a bezel and adapter for a large plastic plumbing elbow I had cool uncontaminated outside air flowing over the motor. This seemed to help, but while machining the valves the problem became even worse and, finishing the valves became difficult. The west coast distributer for the lathe informed me the motor is repairable only in Germany and will likely require several months, and so I've decided to order a replacement.
The next step used a Kenametal DCMT21.51UF finishing insert, and because of my lathe issues I decided to leave .002" stock instead of my normal .001" stock for later polishing. This higher precision step required more of my involvement. The lathe is typically consistent enough to hold a thousandth if I measure and readjust the work offset between each part. The tailstock wasn't used at all in this step, and I backed up the valve stem with a leather pad in my fingers. This really isn't as dumb as it probably sounds. I usually finish machine all the valves in one sitting, and after the first few parts I can usually maintain just the right amount of pressure on the workpiece to obtain final valve stem diameters that are consistent to within a half thousandth. Because the lathe now forced me to run much smaller batches there were a lot more 'first few' parts, and these diameters ended up all over the place. Typical finishing time was about four minutes.
The machining marks left by the last machining pass were polished out in a third step using 400g and 600g papers followed by metal polish. The valves' rear sealing surfaces were polished with 600g and 1000g before using the metal polish. The sealing surfaces, after close inspection, may be polished one last time later during the fourth operation when the valves are brought to their finished length and the retainer grooves are cut. The polishing time was typically eight minutes.
Before actually finishing the valve stem diameters I had to decide on a target clearance to their guides. I used .0005" +.00025"/-.0000" on both of my radials, but these engines are air cooled, use valve cages, and don't have well-defined top-end lubrication systems. A small clearance seemed appropriate for them in order to prevent un-metered air from being drawn past the intake valve stem. The Merlin's top-end will likely be well-oiled, and some of this oil will end up on the valve stem to help to seal it. If the clearance is too great, oil can be sucked into the combustion chambers during the intake stroke, and the engine will smoke.
I'm expecting the Merlin heads with their valve-cover'd heads and suspect liquid cooling system to run much hotter than the finned radial heads which sit well up in the prop wash. Since the exhaust valves will likely run much hotter, temperature expansion of the stem diameters is a concern. This, coupled with the use of individual seats and guides rather than valve cages, may result in larger temperature differentials between the stems and their guides so that binding could become an issue. As a result I chose a target clearance of .001" +.0005/-.0000" for the Merlin valve guide clearance Because of my lathe distractions, several ended up closer to .002", and they were marked with a red Sharpie so I could keep track of them during the fitting process.
Leak checking the valves in the Merlin heads is complicated by the individual seats and guides as well as the engine's giant ports. I was tempted to skip this step but finally decided it would be interesting to give it a try.
I purchased a two-part silicone molding kit from a local craft store. After shoving temporary hard rubber plugs through the valve seats and up against the valve guides to create an air space inside the silicone behind the valves, I poured the silicone into the ports. After it cured, the hard rubber plugs were (easily) removed, and I was left with silicone molded plugs that perfectly filled the ports. Just behind each valve was an open space with a volume that very closely matched the volume I would normally leak-check in a valve cage. These equivalent volumes will allow me to compare my leak down times with past results from other builds.
With the silicone mold plugs inserted into the ports, the leak-down times can be measured either of two ways. A vacuum can be drawn through the rear of the guides with the slotted test valve in place. Or, the vacuum can be pulled through a metal tube inserted through the silicone and into the air space behind the cylinder's actual valve while it is held in place. I decided to test a seat and valve pair to see just how well this second check might work.
After some measurements to verify the final valve length I realized my CAD model was accurate enough to use, and so I determined the final length through trial and error with the valve in place in the actual valve train. The lash-setting eccentrics are difficult to use and don't provide much adjustment range, and so the finished valve length needs to be fairly precise. Fortunately the valve train components seem to be consistent enough that the valves won't need to be fitted to their locations.
The total machining time per valve averaged just over 30 minutes which is probably even more than what a real machinist would need using all manual equipment.
The seat was cut to a .005" width using the manual seat cutter, lapped with TimeSaver against a dedicated steel lap, and then polished using a felt bob and a dab of metal polish. I found that greasing the cutter's pilot to reduce its clearance in the valve guide produced a better finish than I could get without using it.
To reduce the measurement to a two-handed operation the silicone plug was held in position with a pair of miniature clamps, and its integrity was verified before the measurement by pulling a vacuum against my thumb on the seat. The rear of the guide must be capped even with a valve in place. Even though any leak past the valve stem would become a part of this leak-down measurement it is not a component of a combustion chamber leak which is the leak I'm ultimately interested in.
My first leak-down test resulted in a twenty second time which seems like a reasonable goal I'll likely set for the rest of the valves. The volume being checked behind the valve is only .05 c.i. which is a small fraction of the total involved volume. The volume of the interconnecting hose between the port and the MityVac is .20 c.i. - Terry

 

[kvom]

That toss off about how fast a real machinist could make a valve made me smile. If you're not a real one nobody is.

 

[ICEpeter]

Hello Terry,
Sorry to hear about your Hanning motor problem. I have a Hanning Varicon motor on the German made mill I have been using for the past 8 - 9 years and it runs fine so far (it's out of the way of swarf and coolant)

One thing I want to bring to your attention is that you may need to program your new Hanning motor by entering the operating parameters (speed for example). Don't know whether the new motor comes pre-programmed from your supplier but it may be worthwhile to check.

FYI, here is a link to the Hanning Varicon short guide. Their website is in English. http://www.hanning-hew.de/wEnglisch/download/Prospekte/AT/BA_65158_VARICON_Part_B_Short_Guide_E.pdf

Peter J.

 

[mayhugh1]

Peter,
Thanks for the link. My motor uses a potentiometer to set the speed, and so I think I can do the comissioning per the right-hand side diagram without Hanning's digital interface. My older version of the motor has a controller board that is different from the one in the photos in your link, but I expect the replacement will match. I hope you don't have problems with yours as the price for a replacement is $2K U.S. -Terry

 

[ICEpeter]

Hello Terry,
The Hanning motor on my machine ( Type CCD-864-122 / 1.1 KW) has the electronics board, i.e. the frequency drive and controller board, incorporated into the motor junction box, similar to the link picture I sent you. It is in fact an electric motor with an incorporated VFD all in one. I assume your motors electronic controller board (VFD) is separate, stand alone, and not incorporated into the motor junction box?

In my case, I had to use what they call a set up unit to program the operating parameters (about a dozen parameters) for the VFD into the motor based on the information in the Varicon manual that came with the machine / motor prior to using the motor. Although the motor, when in use, is controlled either via manual potentiometer when used in manual mode or remotely by the CNC program.

I attached a photo of the programming / set up unit that I received with the Varicon.

I realized in the past that these motors are good quality high priced and cost more than a pretty penny, but $ 2,000.- is inflicting severe pain onto anyone. I know that Hanning has a strange sales policy whereby they only sell direct to OEM manufacturers and force retail customers to buy spares through the OEM. That and customs duty jacks up the price considerably since there are too many hands that reach into ones pocket, deeply I might add.

I keep my fingers crossed for my motor to hold up for another 8 - 9 years and put some money into savings for a future replacement.

Peter J.

 

[mayhugh1]

Peter,
Here's a photo of the inside of the controller box of my 2 hp motor. I'm told it is an older version of the one I'll be receiving as a drop-in replacement. I'm pretty sure yours is a later version that came out just after I received mine and should match my replacement. The lathe's distributer sent me screen shot of the new controller with some instructions on how to map my cable wiring over to the new controller, and it matched the pdf you sent me perfectly. I asked about the need to commision the motor with Varicon programmer and was told that will have already been done on the motor I will be receiving. I've been wondering where the VFD electronics is, myself, as there doesn't seem to be any 1.5kW components on the controller's topside pcb. Maybe they are on the rear of the board. The motor is still in the lathe, and so I haven't wanted to do much disassembly until the new one arrives since it is still intermittently working. - Terry

 

[mayhugh1]

The past week was spent finish-machining and leak-checking the remaining 23 valve/seat pairs in both heads. At about half an hour each, most of the work was pretty routine and tedious; but with all the holiday-related distractions that popped up, it took much longer to finish than expected.
Strangely, the leak-down times seem to fall within one of two groups: either 15 to 20 seconds or about a minute. With more effort I probably could have gotten them all into the one minute group, but some of the seats grew a little wider than I was used to or comfortable with, and so I settled.
The silicone plug molds worked really well, and I wouldn't hesitate doing something similar on another project. The seats and valves in each head were all finished and tested before finally installing them with the springs in order to prevent debris from the seat cutter from getting between their finished surfaces and damaging them.
I thought I was using a reliable reference on the heads for finish-machining the valve stem lengths last week when I referenced the heights of a couple trial valves to the tops of the installed guides. When I counterbored the castings for the shoulders of the valve guides I wasn't concerned with consistency, and so I counterbored just deep enough to get a clean flat surface. The few guides that I happened to check matched one another, but they were actually sitting lower in the head than most of the rest. When I began installing the rockers over the finished valves I discovered that a majority of the valves were actually too long with no clearance for lash.
The stock lash adjusters have only .016" adjustment range, but the tolerance stack-up of the valve train components appears to be eating up about three thousandths of this range. Variations in the seat depth were taking up to another seven thousandths due to the wider seats I had to cut on some of the cylinders to compensate for concentricity errors. There were actually more of these than I had originally thought. Since the seat angles are 45 degrees, 70% of the seat width variation turns into a valve height variation.
With .130" valve lift, my plan is to set the lash at .005". Ideally, this clearance should wind up in the center of the eccentric's adjustment range so the adjusters can be used to compensate for bidirectional wear. In order to avoid fitting custom rocker rollers, I decided to re-machine the length of each valve to correspond to its seat. I had already temporarily linked each valve to its tested seat location with a Sharpie, and so I went over my marks with an engraving tool as I re-cut the stems.
I made a gage to reference the valve heights to the machined cam block mounting surfaces on the heads which is the reference I should have been using. I then re-machined the length of each valve.
After correcting the port-side stem lengths I began assembling the head. Just as I was about three quarters finished I spotted a bit more investment in one of the coolant ports that I could reach with a dental pic. Picking at this stuff is like picking at a scab - its hard to quit once you get started. When I finished, I'd scraped out another teaspoonful. One of the photos shows some of the big chunks that I was still finding at this late date. I then thought I could feel grit in some of the moving parts of the valve train, and so I took everything back apart for a thorough cleaning. I went through the stripped-down head once more and re-scraped the coolant passages until I again couldn't feel anything else in them.
This whole exercise was actually fortunate because it reminded me that I needed to seal the fourteen cam block bolts that penetrate into the coolant area. This time I cleaned the tapped holes and bolt threads with acetone before reassembling the heads. When I'm finally convinced that they won't have to come apart again I'll remove each cam block bolt one at a time, coat the ends of the bolts with purple thread-locker/sealant, and then re-heat the assemblies in my rod oven. This low strength anaerobic thread locker should seal the threads against coolant leaks but allow a relatively hassle-free unplanned disassembly later.
Once the heads were assembled, it was really great to be able to rotate the cam sprockets and watch the 350 parts made during the last three months finally all working together. The feel, though, was totally unexpected. All the 'smooth as butter' motions that I had been working to achieve with the individual parts was now replaced by a stiff 'cogging' action. Having no experience with overhead cam engines, I'd never before rotated the cam in one of them, and it took a while to convince myself that what I was feeling was normal. The 'cogging' occurs between the intake and exhaust valves in each cylinder during the overlap time when one valve is closing and the other is opening. This happens at the start of each intake cycle which, in this engine, is every 60 degrees of cam revolution.
The last check was to estimate the worst-case piston-to-valve clearance in order to verify the engine will be free-wheeling with the stock pistons and rods. The remaining head-related parts are the stud tubes, intake gaskets, and the cam blocks' oil feed lines. At the rate I seem to be going they will likely require the rest of the year. - Terry

 

[10K Pete]

I've been watch the progress on this amazing engine. I'm blown away
by the level of detail and workmanship shown. Did I say amazing??

And those rocker assemblies are h**l for stout!!

Pete