Generator

I now have a portable generator for the garage. Very old, but can't complain at a 1.5kW for 80 quid.

It has no instructions, and although I've put some unleaded in and started it to confirm it runs and produces electricity, I don't know what to do about oil. It's a 2 stroke, I gather, but has a seperate "oil fill" cap. Do I still have to put oil in the petrol as I gather is normal with 2 stroke engines? What kind of oil is needed? Is there a proper 2 stroke engine oil? And does the same stuff go in the "oil fill" cap?

It's incredibly loud so I'm thinking of building an enclosure around it- essentially a frame to hold some insulation. Does anyone have recommendations on insulation I can get easily and cheaply (i.e. Wickes or Screwfix) that will bring the sound down to more manageable levels? Will expanded polystyrene roof insulation do a decent job?

There's no exhaust pipe or air pipe- just holes somewhere. So I'm thinking of a pair of holes with small-ish fans in, pushing air in at the bottom of one side and taking it out at the top of the other. Does this sound adequate? Guess I can always double up to increase the airflow through the same holes if I need to.

-- Dr. Craig Graham, Software Engineer Advanced Analysis and Integration Limited, UK.

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Reply to
Craig Graham
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Whether it uses pre-mix or it has a seperate tank for two stroke oil then it needs real two stroke oil, any garage or motorbike shop, halfords etc. will sell it.

Quietening it, without overheating will not be easy.

mrcheerful mrcheerful

Reply to
mrcheerful

It's probably loud because it's air cooled without the sound insulating benefit of a water jacket. Draw your own conclusions about trying to stop air getting in/out as you have to to soundproof.

Reply to
Dave Plowman

Well, I've already said I intend to put an air inlet and outlet on the enclosure, both forced by fans.

If the sound comes out in all directions and I can reduce all but the sound coming down the air pipes then that's pretty significant. And if there's a baffle comprising an extra sheet of insulating material a couple of inches ahead of the holes inside the enclosure then that should reduce it further. But this is all conjecture since I've never done it before, which is why I'm looking for information.

If need be I can wear ear muffs. I'm concerned about the sound level in some flats across the street from the garage, but it may be that it's not a major problem. Right next to the unit, with the sound reflecting off the brick walls, is of course going to be far louder than across the street. This means that I don't have to silence it- I just have to make sure it's tolerable away from the garage.

Reply to
Craig Graham

Material to reduce this type of sound has to heavy - e.g. a heavy grade Rockwool. Perhaps some judiciously placed on parts of the garage walls would help as well.....

.andy

To email, substitute .nospam with .gl

Reply to
Andy Hall

Driven by electricity from the generator? With only 1.5 kW available, you're not going to be left with much.

Reply to
Dave Plowman

"High Density Rockwool Slabs" from Wicks sound the thing to try then. Thanks for the responses.

Reply to
Craig Graham

If you need this as a power supply for tools then why not get an inverter or a modern quiet generator? neither have quite as much output as the genny you have but can still run all hand held tools ok. Cost about 80 pounds each.

mrcheerful

Reply to
mrcheerful

Hi,

What sort of loads will you be running?

cheers, Pete.

Reply to
Pete C

Wouldn't it have been cheaper and easier to have bought a quiet (four stroke) generator to start with?

Reply to
usenet

I considered them, but they seem to be rated only around 650W continuous. My power tools are generally in the 800-1400W range. I think the only thing I have that comes in under 650W is the jigsaw. There is quite a big jump in price to get to the 1.5kW ones. I didn't want to get an underrated one and have it keep tripping when tools start, or while a drill is in the material and a pain to remove if stalled.

Reply to
Craig Graham

Hi,

Is your garage at the end of your garden? If so would it be possible to run an extension lead out to it?

cheers, Pete.

Reply to
Pete C

Personally I think "There's no exhaust pipe or air pipe- just holes somewhere." has more to do with it, with no silencer any engine is going to fing *LOUD* even more so under load.

Of course I could be reading things incorrectly but if it doesn't have any exhaust system or silencer fabricating something to fulfill that role will be usefull...

Reply to
Dave Liquorice

I wish. I'm in a terraced house, and the garage is a brief walk up the road. No way of getting power to it unless I get the electric board to dig in a cable and install a proper supply. Which is not cheap, and given it's a rented garage it's not really worth it.

So far I've been using power tools in the garden and storing them in a cupboard in the dining room, but it's hardly convenient- especially when things need time to dry.

Reply to
Craig Graham

I've had good results with my enclosure.

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it's one thick paving slab, with 6 more arranged to form a baffled enclosure. To avoid cutting slabs, they are arranged skewed. Slabs were joined by smearing silicone liberally along the edges to be joined, leaving it to set, then applying large amounts to each edge, then clamping, and leaving for hours to set.

The generator was placed on a bit of chipboard, with thick silicone feet for vibration isolation.

The top is prepared the same way, but a sheet of cling-film placed on before applying silicone to form a gasket, and make it removable.

(I bought a lot of acetoxy silicone cheap from lidl)

Once the top was placed on, and 3*80mm fans powered from the 12V output line connected to suck air into the enclosure, this works well, and the temperature does not significantly increase over what it is in the open.

It's much, much quieter.

I suspect if it was lined with carpet, it would get even quieter.

However, this method will not work very well with generators larger than about 50*40cm.

Reply to
Ian Stirling

Sorry, couldn't resist and no offence intended.

However if you've got to go to those lengths to deal with a noise problem it does kind of suggest that thinking outside of the box might be a good thing. Does this have to be a genny? Can it be resited outside of the work area?

PoP

Reply to
PoP

Holes everywhere implies more than one. If there was no exhaust system/intake system, then there would only be a couple of holes.

It's probably just that there is no obvious pipes.

Reply to
Ian Stirling

Thanks for the paving slab suggestion.

The unit is still listed on ebay so there are useful photos;

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the first picture, the generator is to the left, the engine to the right and the fuel tank overhangs bottom right. There is a box on top of the fuel tank that I assume is the air filter, since there's an oil filling cap at the bottom of the engine (out of sight). The odd rusty-coloured box lower middle may be an exhaust- it's the only likely candidate though I haven't run the unit for very long yet- just enough to verify it starts and runs a random power tool. When I have proper oil and (to be on the safe side) some oil mixed with the petrol I'll be happier about running it for long enough to have a good play with it!

The panel on the left of the funny rust coloured box can be pressed in as if it is a button but it doesn't seem to do anything. There are holes behind it, in the rust coloured box, which is why I thought it would be the exhaust.

Reply to
Craig Graham

It does have to be a generator- it's a council garage which makes it difficult to have a main supply laid on (even if I could afford the probably horrendous installation cost!), and it's too far from the house across two streets to run a cable myself.

It can't be located outside the work area; this is a block of garages on the street. In any case, work area noise is tolerable because I can wear earmuffs- it's the noise going out onto the street and affecting nearby houses and flats that I need to reduce before I start using this properly.

Reply to
Craig Graham

Craig Graham explained on 21/04/2004 :

Not many clues there....

You need to find out whether it is definately a two stroke or not. A stroke will fire every time the pistone rises to the top of the bore, a four stroke will fire every second time the piston rises. Take the plug out and check it by cranking it over slowly. You should feel the air blow out of the plug hole as the piston rises and hear the spark. Additionally, if you have not added any fuel, dip you finger in the fuel tank, if the fuel feels slightly oily then this would indicate a two stroke. If it is very oily it is a diesel.

Only four strokes and diesel engines have valve gear, a two stroke engine will have a basic simple head with just the spark plug in it. To confuse matters there is such a thing as a two stroke diesel engine ;-)

Some two stroke engines had a petrol tank which you filled with petrol alone and the oil was added into a separate tank. Oil from the tank was pumped, metered and injected into engine.

Two stroke engine are heavily dependant upon having a correctly tuned exaust being fitted for proper operation and the exausts need to be decoked regularly due to the oil being burnt as part of the combustion process.

Early two stroke engines were designed to use a mix of ordinary engine oil and leaded petrol. 2T oil was a later development in specialised oil for the job. Even two strokes designed for 2T will happily run with engine oil for a while. The recommended mix varied from 20:1 to 30:1 (30 parts petrol), a very old one would probably need 20:1.

Most two strokes are air cooled, so will need a good flow of air past the cylinder. It would quickly over heat if boxed in.

No it does not sound anywhere near adequate, whatever type of engine it will quickly overheat and seize up.

Too be honest, all the generators I have come across are either diesel or four stroke petrol. The noise of either will identify it straight away if you know what to listen for.

Reply to
Harry Bloomfield

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