Australian "Dunlite" 240 volt AC querie

[Inter Bloke]

I have a 4500 watt "Dunlite" direct coupled portable generator fitted with a 10HP Briggs and Stratton engine that has chucked a rod, and I need to know how to get the rotor off the engine crankshaft to repair the engine. We managed to get the stator assembly off but can't work out if there is a trick to removing the rotor, It doesn't seem the least interested in moving ! This unit would be about 15 years old and until the engine chucked it in has been a great set up but repairing it is proving to be a pain in the neck !

BTW These things are built in Australia and I doubt they were ever sold stateside so it would most likely take someone with Australian experiance to have a chance of knowing.

Thanks Guys,
Graham

[Jim Rankin]

Most common way for these to be attached is with a taper shaft held on by a long bolt through the hollow shaft.

Loosen the bolt until there's a crack below the head (tiny crack is all you want) and smack the head of the bolt with a big hammer. You can also lay a board on the side of the rotor and whack it downward and make it come off. If all else fails, remove the bolt and tap the hole for a grease fitting and push it off with grease pressure.

Whenever you are working on it without the bolt in there, put something under it so when it falls off, it won't be damaged!

[K D Redd]

Graham,

Most generator rotor/crankshaft interface are a tapper. If so, you need to first remove the center bolt. Then what I do is thread the hole. Most are about the right size for a 1/8 inch pipe tapper thread used her in the US. I then install a grease zert/fitting and use a grease gun to pressurize the cavity making it a small hydraulic cylinder. It may need to set a will, may be over night, for a heating/cooling cycle. If it has note come lose by then re-pressurize and maybe hit the rotor with a rubber or rawhide mallet or a wooden block. BE CAREFUL TO NOT DAMAGE THE ROTOR WHEN STRIKING IT.

Kent

[Inter Bloke]

Thanks Jim and Kent,
When we started pulling this apart a taper was what I was expecting to find but there is no bolt on the end of the shaft to undo to let a taper go. Looking at it I think it is either pressed, or maybe shrunk onto the crankshaft or it may have a threaded hub and be screwed into position but without knowing which way they did it I arn't game to try and remove it because if its done the other way I will most likely wreck it. I have since been told of a contact that may know, but I won't be able to get in touch with him till next Tuesday at the earlyest so I may just have to wait.
Thanks again blokes,
Graham

[Jim Rankin]

Nothing like re-inventing the wheel! Every engineer has to earn his keep changing tried and true designs it seems.

If it's threaded, it can only be whichever direction will tighten the thread as the engine turns, (most likely clockwise threads). Are you sure there is no locking pin or setscrew to hold a threaded or keyed joint together.

I would try a bit of heat on the joint in case it is simply loc-tited so the threads don't unscrew.

[Inter Bloke]

Jim,
We can't see any locking devices on the sleeve on the crank so arn'r shure how its attached, the problem with putting heat on it is that its not very accessible in the crank area and its right next to the fan which is just soft plastic and guaranteed to be damaged if I start waving an oxy torch around inside the cavity, and the fan itself is right next to the rotor windings so if the fan were to catch fire it would likely wreck the rotor too. We suspect the rotor is either pressed or shrunk on somehow and if so I may have to make up a jig to push the engine off it with a "porta power" but if its threaded that aproach will ruin it trying to pull it off. I was hoping to find a schematic on line so I knew what was going on in there but so far no luck. I think my best bet might be the bloke I hope to talk to next week.

Thanks for the advice,
Graham

[Jim Rankin]

You might want to saw the stub shaft of the engine to get enough access to the area to do something.

[K D Redd]

Take the TYPE NO. of the engine to your nearest B&S dealer They should be able to tell you WHAT the end of the crank is like. If you do not have a Briggs dealer close post the number hear and I will ask my dealer.

Kent

[Inter Bloke]

Thanks Bloke's,
I managed to get onto the contact I was given today, and he is a font of knowledge on them !
Aparently the engine has a taper crank like you blokes are used to, but it only has a short taper adaptor fitted to the taper. This short taper has a securing bolt like some other gennys I have seen holding the taper to the crankshaft, but the end where the bolt goes through to hold it has a thread that the rotor is screwd into place on. To get it apart you have to put the rotor in a large vice, lock the engine somehow, (he says he puts a wooden block the correct size in the cylinder and then puts the head back on, but that won't work with a throwen rod) and then turn the whole engine around to unscrew the rotor off the adaptor, and then you can work on removing the adaptor off the crank.

Thanks for the offer of help and the advice, I will let you know how I get on when we have a go at removing it.

Graham,

[John Newman, Jr.]

You should be able to wedge a block of wood between the crank balance lugs & the crankcase to secure the crank while you (attempt) to remove the generator rotor.

[K D Redd]

Seen you have a thrown rod, you could remove the head,pull the piston out of the cylinder and insert a wood block into the cylinder as a wedge between the crank and crank case as John said.

Kent

[Inter Bloke]

When I get a chance I will probibally break out the back of the Briggs crankcase and insert a piece of wood in there to jam the crank. I don't think I would ever use the Briggs cylinder block again because the rod punched a 1 1/2 inch hole in the back of it under the fuel tank when it let go. It is salvagable if it were welded up, but it doesn't seem worth the effort, the bore is about worn out anyway. We have another good 10 HP Briggs I can use, but it has a strait crankshaft so I may need the crank out of the original (if its not dammaged) for the taper or alternatly I have a very nice "Robin" engine with a taper that may be able to be used, (do you have them in the US ? good quality Japanese engines ) I won't know until I get it apart but that may be a few days, we are flat out crutching the sheep at the moment and I won't have time to do anything with it until until next week.

Thanks Blokes
Graham