Flywheel modification

[alexanderfoti]

Hi all

I am trying to increase combustion temps a little bit for WVO use, and have had a thought.


I would like to remove most or all of the cooling fans on the flywheel with a grinder, to reduce the amount of air it pushes through the fins, seeing as the engine isn't in a generator box, the movement of the bike should be fine to cool it. If I am careful to remove even number of fins do you think there will be an issue?

[alexanderfoti]

Of course the flywheel would need to be balanced afterwards.

[DieselFly]

Why not block off part of the air inlet for the cooling fan. I do this when the temps drop down and open it up again when its hot. If you could monitor your cylinder head temps it would help. I also tape over part of my oil cooler when temps are down to 5C

[Stuart]

Flywheels on bikes have been lightened to improve throttle response but take too much off & it may not do the job on compressing the mix. Some have said it breaks cranks as well if you don't get it right. If you take the fins off you may have to replace the weight another way?

[alexanderfoti]

My thoughts on removing the fins are that they produce quite a bit of drag to the engine, I wouldn't want to be removing that much weight from the flywheel anyway.

As I have 2 tanks, I was thinking of running a copper pipe from the Veg fuel tank, down the past the left hand side of the oil cooler/cylinder block, and either wraping the copper through the fins, or just along side it, then feeding the end into the fuel filter, this should definitely help things when switching to WVO, and would mean I dont need to waste money and electricity on heated filter setups. Thoughts?

[alexanderfoti]

I do like the idea of blocking the fins when its really cold, could prove usefull!

[Stuart]

Yes, my fins push my air through an oil cooler now so that might be a good modification to make My old Hatz 1B30 ducted some of the cooling air from the fins into the air intake to boost power.

[DieselFly]

You need to keep in mind that the Veg oil may lose most of its heat before it arrives at the fuel pump as the fuel flow rate is very low. You could try making a small lube oil to fuel oil heat exchanger and place it as close to the fuel pump as possible. You could also run the engine oil through a pipe in the veg tank to help preheat the oil. Also keep in mind you want to keep you engine oil temp at 80C to ensure proper lube oil flow.

Sean

[alexanderfoti]

Many thanks for the info, never thought about it loosing its heat in the filter, I will probably have to heat before and after the filter (initially I was only going to heat it before).

[tappy]

I think both Dieselfly's suggestions are the simplest solutions to your original problem, but I'd ask you this:

Why are you trying to increase combustion temperature? And do you really think reducing the engine cooling will cause this?

The best way to increase combustion temperature is to get more of the mixture to an homogenous stoichiometric mixture. But I suspect the only reason you're trying to increase temperature is to get a better burn of the veg oil?

The best way to get the mixture right is to heat the oil to a similar viscosity to normal diesel, so that the injectors work properly. You're clearly thinking along these lines already, but the idea of increasing engine temperature (reduced cooling) to improve the burn are a red herring.

The advantage to using electric heating elements to heat the fuel is that it's very easy to carefully regulate fuel temperature - but only at the heating element! The fuel temperature as it enters the injectors will vary a lot depending on where you heat it, where it goes after that, the bike's speed, ambient temperatures, etc etc.

I think you need to be aiming for about 80deg C just before the fuel goes into the injectors. Some kind of heating jacket around the injector pipes might be nice as this is also where the fuel would lose most heat, other than the fuel filter.

[alexanderfoti]

Ah ok, so maybe some nichrome wire around the injector line that gets activated when veg oil is selected? I also get the feeling there is fuel starvation when trying to run veg oil (cuts oi a lot at high rpm, will idle all day otherwise) So maybe a combination of nichrome wire on the injector pipe, and a 12v fuel pump from the tank into the injector pump when veg mode is selected? Im wondering if this will be sufficient.

Also noting, as per your other thread, a power usage of 3.6hp of the fan at 3600 rpm! I am seriously thinking of getting the fins turned off the flywheel, then dropping 2 teeth on the sprocket (currently at 23, and my top speed is 55 at 3600-3700 rpm and I have no problem getting there). What are your thoughts?

[old clunker]

Risky!! The Yanclone engine is perfectly designed to do what it has to, as a stationary multi purpose engine - run all day every day, at a rated max rpm, providing a rated max HP output.
The flywheel appears to act a load "shock" absorber for sudden engine load changes, and smooths out rpm fluctuations that the very basic plastic/nylon geared engine governor might not cope with, or sense immediately; and provides enough inertia for engine starting and running at low rpm.
By taking off the fins, the flywheel night go out of balance, which could severely affect the smooth running of the engine.

By sticking the Yanclone engine on a motorbike, we are already starting to take it out of its "comfort zone", and just have to be happy with whatever power output it is willing to provide us! without breaking down or wearing out too quickly.
I console myself with the excellent fuel economy these diesel engines provide.

[alexanderfoti]

I see what you mean, but a) i dont think the fins provide that .much mass and b) if i were to remove them i would get the flywheel re balanced. Thoughts?

[old clunker]

My thoughts are that; what you propose to do is very experimental, by changing the optimised designed mass of the flywheel, and it's airflow properties - it's all risk with no real idea of engine performance rewards when you do the fins mod. There's a possibility that the engine won't run as well over it's designed speed range afterwards.
Without exactly knowing what the engine designer's aims and specifications were, when they were designing the engine flywheel, it's all guess work.
The best engine mods are ones that are reversible, if you don't get the result you want or expect!! When you remove the fins, that's it and if it doesn't work out, you'll have to look around for a second hand engine to provide another flywheel!

The other bonus I have found with the existing flywheel set up, is that with the anodised small metal engine shroud fitted to the engine, it directs and provides a nice steady flow of warm air over the high pressure metal fuel pipe, warming it up nicely when the engine is at operating temperature. I think that it's a deliberate design feature, and useful on colder days, when diesel fuel tends to get a bit thicker.

[alexanderfoti]

Hmm I see what you mean, I could always buy another flywheel and swap it out if there are issues. My only thoughts are that the flywheel is designed for use as a generator to keep the revs constant. In a bike you want the flywheel to be small so that the engine revs more freely. My injector pipe already runs past my exhaust manifold so that gets hot pretty quickly

[Rhynri]

Without exactly knowing what the engine designer's aims and specifications were, when they were designing the engine flywheel, it's all guess work. The best engine mods are ones that are reversible, if you don't get the result you want or expect!! When you remove the fins, that's it and if it doesn't work out, you'll have to look around for a second hand engine to provide another flywheel!

Agreed. Well, agreed on the assumption they didn't just take a part number from another engine and slap it on there with some different drilled out spots on it. (You would be amazed at how often that's done, especially on the little engines.)

[coachgeo]

Ah ok, so maybe some nichrome wire around the injector line that gets activated when veg oil is selected?...

Been done and kits are available just for this. Wire plus insulators, (heat and spark) etc.

http://www.ebay.com/sch/sis.html?_nkw=W ... EATER-KIT-

[alexanderfoti]

Aha! Although one of those kits would defo need temperature controlled feedback or it would cook the veg oil in the line i suspect.

[coachgeo]

Aha! Although one of those kits would defo need temperature controlled feedback or it would cook the veg oil in the line i suspect.

The vegoil does not sit in the injector line long enough to get cooked is the hypothesis. It moves at to high rate of speed thru those lines. This topic has been discussed a good bit on veg. oil boards and if I recall right.... the consensus is around 60/40 on the value (amount of heat picked up by oil moving so fast thru heated injector lines makes some question the value) and the concern on cooked oil causing an injector clog about 10/90

Some have found value in just super insulating the injector lines.

It has been a good while since I was heavy into such a topic though so suggest you do search this yourself.


As to your oil filter allowing heat loss... plenty of folk have made heated fuel filters (coolant wrap fuel filter) and other similar means to avoid this.

[alexanderfoti]

okay, sounds about right, I forget that there isnt a slow flow of fuel through this pipe as there are in the others.

My thoughts are, that If I can pump the fuel into the filter using a lift pump, this should overcome the viscosity of the fuel (as it will be 50/50 diesel veg oil) and then heat the exit tube from the filter to the pump, and the injector tube (or insulate it, or heat it from the engine somehow). It may work. Not sure its worth the hassle for the engine. Might be an idea to just convert the veg into bio fuel and put that straight in the tank.

[coachgeo]

run on diesel for many months. Get a base line over that time period of speed and or acceleration over a set distance in your area. Preferably something that taxes the engine a bit such as a slight upgrade. Also get base line compression numbers on each cylinder at set intervals distance/engine hours.

THEN do the conversion. Set a standard fuel blend and stick with it for a good while again doing time over set distance and acceleration runs as well as compression checks regularly. keeping records and compare to base lines.

You want to get very comfortable adjusting the IP. Plan would be to adjust IP once you've switched fuels to get best results for the fuel in use. You adjust the IP to get best results you can in the time and acceleration runs. A setting that gets best results means you will be closer to maximal fuel combustion thus a very happy purring engine. Not talking about turning up the IP... just adjusting the timing of the IP. The IP adjustment to match the fuel's combustion characteristics is the number one missed step in converting Diesels over to a veg fuel. It is very likely the number one reason things go awry beside new fuel not being reduced to similar viscosity as diesel (rather be it via heat, blending, both orrr?)

The compression checks will give you heads up on if your coking the engine lone before you will ever feel it in the seat of your pants or worse find yourself stranded on side of the road with coked up piston rings.

PS- YOU WANT THE ENGINE TO KNOCK... The quieter engine being an added benefit to running veg fuels is a myth. If on your blend your engine has gotten quiet... then your NOT getting best combustion. Diesel's knock when they have proper combustion timing

[Diesel Dave]

Gotta push the envelope........

[Rhynri]

Or grind the envelope, in your case.

[alexanderfoti]

Thanks for the info on injection timing etc. I will be establishing a base line on my current engine of max speed up hill and top speed overall. I do know about the engine knocking sounds though.

That pic is my kind of mod!

Where did I put my angle grindeR!

[espe]

Nice going! I strongly believe this will work. I love your no -nonsense approach.

[pietenpol2002]

For the record, I weighed the flywheel after removing the fins and the total difference was 1.5 lbs. Sorry, I don't remember the total weight and thus can't give you what the percentage that is of the total weight. I'll get that next time in town at the shop.

If I understand correctly, the flywheel serves 2 principal functions.
1. Provides sufficient inertia between power pulses, especially at tick over.
2. Dampens the effect of those power impulses on the drive train.

It would seem that the additional inertia available in the accompanying components (clutch, chain, sprockets etc.) should more than compensate for the 1.5 lbs lost from shaving the fins. Understandably, the greater distance that weight is from the center of rotation, the greater is the flywheel effect. However, if you look at the Yanclone flywheel you'll notice that only some portion of the fins are at the outer limits of the 11" diameter. And yet, my 7" clutch weighs well in excess of the missing 1.5 lbs.

Once shaved on the flywheel grinder, I took the flywheel to the balance boys who build race car engines assuming they would appreciate my insistence that it be balanced. They scoffed at me. They refused to take my money for balancing a flywheel that was only going to turn at 3600 RPM's. The message was, "Come back and talk to us when you're ready to spin that thing up". They would have no part of taking my money and wasting their time. So....................................

Old Clunker's points are well taken. And yet, I can't resist the urge to experiment. It helps to have a number of flywheels held in reserve should I need them. Additionally, even though I'm not using the electric start, I've retained the starter ring that's shrunk fit to the flywheel in the hope that it might help contain things should flywheel parts get the urge to part company with one another. We'll see. The prospect of a flywheel shedding parts isn't an event I long to experience. True, I'm probably done having children, so I don't need those parts. But, I've grown rather accustomed to the use of my right leg.

[coachgeo]

....took the flywheel to the balance boys who build race car engines assuming they would appreciate my insistence that it be balanced. They scoffed at me. They refused to take my money for balancing a flywheel that was only going to turn at 3600 RPM's. The message was, "Come back and talk to us when you're ready to spin that thing up". They would have no part of taking my money and wasting their time. ...................................., I'm probably done having children, so I don't need those parts. But, I've grown rather accustomed to the use of my right leg.

soooooooooooo... hit up a generic machine shop who can do the job. Would think it not an uncommon task they are hired for. Many a machine need balanced parts.

[pietenpol2002]

For the record, I weighed the flywheel after removing the fins and the total difference was 1.5 lbs. Sorry, I don't remember the total weight and thus can't give you what the percentage that is of the total weight.

It appears the flywheel weighs approximately 20 lbs with fins intact. Thus, at 1.5 lbs the fins constitute .075% of the total mass - hardly a major consideration it would seem, when figuring lost inertia potential.

[Diesel Dave]

Erm no..........

Try 7.5%

Then it's mass at the periphery too so as centrifugal mass it has a greater effect.

[pietenpol2002]

That's why I wasn't a math major. Both points well made Dave.