How to / DIY > Engines

HR2

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scott p:


Well-said Cobbadog.
      The weather warmed up so I rechecked the settings on the HR. Everything was good . It’s interesting that the first step says to set the engine to the run position. This machine does not have that type of start, run, stop device. All it has is a fuel shut off lever.
I am not going to use the variable speed weights and will stick to 1800 RPM.
The last step, which is outlined below is labeled setting engine load. It seems obvious that setting the engine load is important. As I mentioned before the overload stop does have flats like a bolt head and can only be accessed from one side so I turned it four flats down. That put the calibration marks on the racks a strong sixteenth of an inch towards the flywheel. I wrote this before but to recap.

setting engine load
Final setting for engine application is carried out by turning the overload stop downwards or upwards. Settings are as follows.
1200 to 1800 rev/min                          four flats down
2000 rev/min                                      No further adjustment necessary
2200 rev/min                                      3 flats up
Rated engines no overload
(engines driving pumps or fans
and all marine propulsion engines.)        5 flats down

When I started the engine it seemed to have a more robust sound. I cranked it up and put a six inch full speed load to it and again the fuel racks abutted against the overload trip. The speeder spring pulls the racks against the overload trip and can’t go any further, the flywheel weights simply shut the engine down, no stress no black smoke.
So I clamped the overload trip out of the way and tried again, the HR didn’t even notice, which it shouldn’t, the hydraulic registered 600 PSI and that’s only about 6 HP. The HR is, according to the manual, rated at 26 HP at 1800.
It seems to me the overload trip should be labeled the cold start overload in that when I pull it up the speeder spring snaps the racks into a full fuel position. The engine then fires at the first compression cycle and away it goes. When the rpm is high enough the overload trip snaps back down and then limits the speeder springs ability to compensate for the load.
As I mentioned before I use an air cylinder to give me a two-speed arrangement around 1200 to 1800 rpm. When I remove the air supply to the cylinder with the overload trip clamped up and manually lever the speeder spring out the spring snaps the racks to a full fuel position. The engine starts as before and settles down to the 1200 setting when I push the spring back to the idle setting.
Positive results of turning the overload stop four flats down. Is that the engine responds much better when I go from idle to full speed.
I ran some big logs through the mill at full speed and the engine handled the heavier cuts with ease The only down side to the HR is that it is quite noisy.
So whether it’s right or wrong the engine is doing what I want it to do so I am inclined not to worry about it. The only thing I wonder about is that the engine is getting more fuel than it needs, although not getting any smoke.
   The air cylinder has a stop; it can’t pull the engine beyond 1800 rpm so I am good there.

cobbadog:
Sounds like you are winning at last with all your persistence, well done to you!

I do not know too much on diesel engines but I am led to believe it is very hard to 'over fuel' them as the pump and injectors only allow a limited amount of fuel through and if you are not getting black smoke that is a good indicator of running right, (in my mind). hopefully another member with a lot more knowledge than me can help you out here. As for the noise of the engine, we have a few old stationary hit n miss engines and the ones we have have a habit of 'barking' at you when running. Sounds great at first BUT you sit with it for a few hours and your soon looking for some head ache tablets. To resolve this I made a new muffler out of different diameter pieces of exhaust pipe. Started with a pipe flange that had the right 3/4" pipe fitting for the short 3/4" pipe that came from the head. I then welded a flat piece of steel to it to give me 4" OD. However a short piece of 2" OD pipe was welded to the inside of the flange so that the gases would travel towards the other end and was around 3" in length. Using a 4" OD pipe at 4" long I welded that to the end where the flange was and on the outside I started drilling 1/8" holes around the outer section. I worked out that I needed 12 x 1/8" holes to allow the gas out. End result was a lovely quiet engine that causes no headaches. The more you make the gases flow in opposite directions before exiting the quieter it will be so you could put a third pipe inside to make it really dizzy before exiting.
Another option is to put another muffler other than original on it and try it. Hit up a junk yard and try a small car muffler. I have also read of exhausts being run underground on stationary Lister engines and there were some plans for this on this site somewhere, but basically it was run underground to a box under ground and had gravel piled up on top, from memory.

Keep up the good work and have some fun with cutting of firewood.

scott p:
Thanks for the input cobbadog and glort. It seems you both have different ways of saying the same thing. Slow the exhaust down and do that by redirecting the flow. I like the idea of fabricating a custom muffler out of exhaust pipe material. I would think it would be lighter than a regular muffler and then could be wrapped with a heat resistant material. I kind of shy away of getting to much weight on the exhaust manifold. This HR does like to vibrate. Unfortunately it is currently fitted with a simple straight pipe but as you said Glort, the mechanical noise from these old air-cooled engines is also considerable. I will probably deal with that first.
I have a ST2 that came with a good muffler and a special wrap. It is housed in a insulated shed so the mechanical noise is cut way down but the exhaust was still quite loud. When I put that wrap on, the exhaust noise fell off considerably. The ST2 runs at 1500 RPM and is belted to a 6.5 K Onan generator that I bought from a salvaged RV. I tossed the Onan engine and machined a bearing to the gen head.  The Onan has a nice feature in that it has the starter built into the generator so the prime mover does not need a starter.  These Onan RV generators are a dime a dozen on the local Graigs List and if your patient you can pick one up for a song.
The ST is one of my best buys; it offsets some of my (inexperienced, didn’t really need) worst buys. The lift pump was stuffed full of junk and couldn’t possibly work and the pumps needed to be primed. Other than that it started right up and runs fine no smoke. Handles a full load like a champ, very light on fuel, gota love it.
I think you raised a good point, Cobbadog, about fuel consumption with diesels. Turning the overload stop four flats down on the HR improved its performance and was per the Manuel. The governor is set to 1800 RPM. Follow the timing layout from the manual and it should be all-good. I did a sniff test of the exhaust, just a clean, light diesel smell. 
I am sorting through your explanation of how you built your muffler Gobbadog. I think if I read it enough I will get the picture.

cobbadog:
I will take a pic of it on my engine and will describe it again. Wont be before tomorrow though as its out in a shed.

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