Briggs and Stratton genny project

[gazjon]

Been lurking for a while and thought it was about time I contributed to the forum

Yesterday I acquired this Briggs and Stratton engine for ebay for the sum of £20. My aim is to clean it up and connect it to an alternator/generator so I can have some power in my garage.




It turns over nice and freely but I could see that there was some crud in the cylinder, so whipped the head of to find this.




After a bit of elbow grease the block and head came up lovely. You can't really see in the picture but the bore is in near perfect condition. The piston also has .20 on it, although I'm not sure if this means it has been bored out or not.

Anyways, I moved on to checking the ignition system. The first obvious problem was that someone had put too long of a spark plug in and the spark plug gap had closed up when it came into contact with valve. Connecting up the spark plug, i turned the engine over, but still no spark. So I checked the coil and found that the contact breaker points were not opening. After a brief strip down of the flywheel/fan, I found that the dowel that opens and closes the points had swollen up and seized into the hole.

After a quick bit of drilling a managed to remove the old dowel and replaced it with some brass rod I had lying around.



And thats as far as I got today, hopefully put it back together tomorrow and see if I can get it running. Anyone have any info on these engines? Especially why there would have been a wooden dowel to open the points?

Gary

[lewist123]

At a guess it is wooden to make it electrically isolated from the crank or whatever actuates it.

Lewis

[gazjon]

I thought that at first, but have tested it and the ignition circuit works perfectly with the brass rod

[lewist123]

Perhaps a traveller repair in its past life?!

Lewis

[datman]

hi, would it not be easier to just buy a £50 generator? I think you will have so much hassle getting that to successfully make mains.

[lewist123]

Where is the sense of adventure in that? Combining random tat into a working contraption/abomonation (sp) is always a worthwhile endevor!

Lewis

[skodagimp]

just to say that engine was built to run on 4star fuel ..not unleaded but all you need to do is decarbon it fit the later type head gasket and the later typespark plug.[ngk B2LM i think] the other thing that you should do is reseat the valves..the older type engine has knock in vale seats..and thay tend to work lose..thay have punch marks on them to hold them in..if you need any bits pm me . as ive worked for a briggs dealerfor the past 30 years..

[jrevillug]

I too suspect that the wooden dowel was a dodgy repair - I've a similar engine and it has a steel dowel. IIRC, it's length adjustable, too.

It was made to run on 4star, but I had no trouble running mine on unleaded - valve seat recession isn't a big problem (low temps, low revs) and the compression is so low (6:1) that it won't knock.

The biggest issue that you will have is getting the generator head - have a look at making self excited induction generators from induction motors. It will work out a lot cheaper than buying a synchronous generator from epay.

The other big issue is how to couple the two parts - belt drives seem simple, but getting the pulleys to fit and then getting (and keeping) them aligned isn't easy. V-belts also loose quite a lot of power through friction. Direct shaft couplers can work well, but again aren't cheap.

[Deleted]

Aug 31, 2010 22:06:28 GMT lewist123 said:

Where is the sense of adventure in that? Combining random tat into a working contraption/abomonation (sp) is always a worthwhile endevor!

Lewis

An excellent reply if I may say so ;D

.20 means it's had a 20 thou overbore. Watch out for the extra horsepower now, don't want anyone getting hurt ;D

What's the plan, alternator, battery and something like a Maplin inverter?

[gazjon]

Thanks for the comments.

This is the route Iwas planning on going down to generate electricity

www.qsl.net/ns8o/Induction_Generator.html

I work in a bus garage, so have access to various high output alternators and large motors.