How to / DIY > Engines

HR2

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cobbadog:
It is details that can resolve issues. I don't have an answer but maybe as suggetsed it is not big enough or there is an issue with the setting up.

scott p:
OK, We start from the beginning and perhaps something will emerge.

I purchased the engine from a fellow who set out to rebuild it for a generator. He suffered a medical situation and was not able to finish the job. He had a machine shop do some of the work and did some himself.

Unfortunately he apparently let the engine be at least partially exposed to the weather or at least some of the parts, which were rusty. When I got it home I found a large mouse nest in the air cowling and the crankcase was contaminated with rodent waste and spider webs.

At that point it seemed appropriate to dismantled it completely and start from scratch. The piston cylinder assemblies were new. All of the bearings were new and assembled correctly.

Installed the crankshaft and set the end play. Installed the cam and the pistons, made sure the pistons were orientated correctly and the cam meshed with the crank. I set the piston to head clearance as per the manual. I adjusted the valve clearance as per the manual.

The fuel pumps are new and I messed around with the timing procedure until I had a good idea on how I could do it correctly.

The injectors didn’t look so good so I sent them off to be cleaned up and rebuilt.

The governor weight numbers matched the numbers for weights designed to run at 1800n as per the manual. The speeder spring had lost its color so I don’t know about that; it appeared to be in good condition, the windings nice and tight.

This I believe brings us to the part dealing with the fuel pump and governor setting, which I have already covered.

The sawmill is actually sawing wood probably less than half the time that the engine is running due to various reasons So I attached a small air cylinder to the speeder spring so that the engine idles down to about 1200 rpm when not sawing and 1800 thereabouts when sawing. I am using the 1800-rpm weights and spring. When the air cylinder hits the stops it does not move, guaranteed.

I did purchase a set of variable speed weights and spring, haven’t tried them yet. I believe this is a build 20 engine designed to run at constant speed. Perhaps a engine that is variable speed capable has a lighter flywheel or some other design function different than this engine?? My train of thought is that once this engine is revving at 1800 with the proper weights and spring it shouldn’t matter if I idle it down between runs.

The weather has been less than pleasant and I haven’t really used the mill much since my last post. From what little I have seem I am relatively certain the HR will handle the load but that remains to be seen for certain. I have been looking through the steps for setting it up and will look things over again when the weather warms up.

cobbadog:
Mate, it sounds as if you should have a brand new engine ready for any use.

More things to consider are,

What HP is required to run the hydraulics when loaded and does it match your engine?

Maybe the issue is you need a 2200 RPM governor setting

When you over rode the 'overload trip' that allowed the engine to rev over the 1800 RPM. Maybe and that is why it appeared to work.

It will be interesting if you get the chance to change over those variable springs and weights to see what happens.

I am only throwing ideas out there that may help you out, so hopefully something might twig for you and all come together and work.
Good luck and keep us informed.

scott p:
Thanks for the input dieselgman, old goat and cobbadog.

The formula I use to get a hydraulic PSI to Horse Power is as follows.

HP = (PSI X GPM) / 1714

The hydraulic pressure usually doesn’t go beyond 1500 PSI. It would be ideal to have a constant saw feed speed but that is not the case here. I can vary the saw feed.

21 GPM at 1500 PSI comes out to around 18 HP/ 22 HP at 1800 PSI, much beyond that and the pressure relief valve opens.

Concerning the variable speed setup. I’ve been looking at the various builds of these machines in the manual I have and have noticed some builds use a standard flywheel and others use a high-speed flywheel. It seems for the most part high speed flywheels are used for machines that can be revved to 2200 RPM but some 60 Hertz machines also have the high speed. If this engine is a build 20 it comes with a standard flywheel. Is it wise to run it beyond 1800 RPM? It looks like 2000 would clear all losses and have room to spare.

cobbadog:
Going by what you have resolved is that you need a minimum of 18hp therefore a near maximum RPM of your engine so it should be running at or near the governed speed to operate.
I would not recommend the running of it over and above the recommended RPM. I know that in some cases engine manufacturers will lift the RPM to get that extra HP to be able use their engines on items that require that extra HP, not always a good idea as it could end up in shortening the engine life over time.Also by what you have told us is that a similar engine can be upgraded to a higher RPM BUT they did fit a differnt flywheel. The heavier flywheel helps in maintaining the revs under load but requires more fuel to get to that point and maintain that level of HP.

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