That's the 33hp V-twin right? Looks like this inside. Note where the case gasket fails, and sort of falls into the engine, leaving a .020" opening for the cam gear to sling oil right out of the engine onto the upper corner of the front facing cylinder. The fan then blows this oil all over the engine and inside the generator housing. As you can see, the gears are steel, so I doubt yours has cam timing that's out of sync with the crankshaft:

 

The cam is off, enough to reverse the intake and exhaust events. Reason I asked about the two piece cam, only things that could move would be the crank gear or the cam gear if it was a two piece with the gear keyed/ pinned to the cam. Should know in the next week or two what let loose, if the weather holds out so I can get the engine out.

I didn't believe it either but the intake isn't supposed to open while the piston is heading from bdc to tdc, exhaust opens on the downward stroke, same for both cylinders.
Happened after a PM, warmed it up, changed oil, fired it back up, strained to get to 1800rpm, stalled and that was it.

 

Sounds like the key in the lower crankshaft broke, that will affect cam timing directly.

Dan

 

That's what I was assuming, unless the cam uses a separate gear, then I have another area to look at. Surprised there isn't more pictures or details about the internals online.

 

There's almost zero info online about the engine and other components inside these standby units. You can see more photos of mine in the thread I started a few months ago...http://www.mytractorforum.com/showthread.php?t=670825

I had to learn by doing. Tried to get advice and learn more from the huge online forum dedicated to these, and wound up getting kicked off and banned, and my threads with photos deleted, because I was doing all the work myself, and not hiring professionals and contractors. "They" didn't want others learning how to work on these, or install them.

Here's a pdf manual that includes the 15kw unit and on page 50 is the exploded engine parts drawing. Shows the crankshaft as one piece w/ the crank gear that drives the cam. http://www.pmtech.org/document_center/4389_4456_4390__3__Owners_Manual.pdf

Here's a link to the big diagnostic repair/service manual: http://www.zabatt.com/generators/productmanuals/0e3586.pdf

 

I would suspect that the gear either split or is slipping on the crank.

 

Finally opened up the engine last night, doesn't look like it'll be with repairing. Appears there was a metal shield riveted to the oil pump and the rivets let go, guessing it was banging around in the sump for a while before it made its way between the cam and crank gears. Also broke the bottom of the skirt off the front piston.
Not to happy about losing an engine after 200 well maintained hrs. All because of 3 cheap rivets.

I don't think we are going back with Generac for the replacement.

 

I wouldn't worry about the piston, but I'll bet that gear slipped on the crank when it tried to digest that baffle. If you can find another crank, or reposition and secure the gear, it's probably worth fixing.

 

There's a tooth broken off that gear, and I don't recall seeing the gear available separately, so that means it would need a crank......and if you're spending that money, you'd replace that piston. The cam gear may also be too damaged to mate with a new crank gear, AND it needs an oil pump assembly because that gear is wiped out.

What a drag. And what a poorly designed engine. But, this is the kind of stuff you read about when you get online anywhere, and take a look a customer feedback on Generac quality.

It'll be interesting to see what the OP finds as a replacement engine, with the correct tapered shaft. The Kawi V-twins have a plastic cam that explodes at 400-450hrs. The Briggs V-twins love to blow head gaskets and intake manifold seals and bend pushrods.

If it were mine, I'd probably contact Generac and see if I could either get a warranty engine, or if they make me some sort of deal on the parts.........and then build it better than they did.

 

Proper rebuild would mean an oil pump, cam, crank and piston plus gaskets etc. And that's providing there wasn't any damage to the cam journals when the metal went through the gears. By the time we buy a replacement engine and spend the time to install it on a 10 year old generator assembly we might as well look for a replacement. Probably from another manufacturer..... to bad I already have a 17kw Generac I'm in the process of installing, doesn't make me too confident in it.

 

.... too bad I already have a 17kw Generac I'm in the process of installing, doesn't make me too confident in it.

I was going to mention something similar, but didn't want to sound like I was starting a pity party.

I just got done resurrecting and installing...including all the gas piping, and all the electrical....a 12kw Generac. Towards the end of that process I landed on all the online stories and realized my unit was no different than all that I'd read. I don't know it's history, as I bought it used on CL, laying in a pile in pieces, BUT....blown gasket between the crankcase halves, and a failed battery charger.

 

If you want something good, resurrect an old Onan.

 

Have you made any progress on this little project?

Reason I ask, is I just picked up a 12kw unit like yours (but yours is the 15kw version...same GT990 engine) and it has a blown engine. Both connecting rods are shattered into umpteen pieces, and the bottom of the front facing cylinder, near the camshaft, is blown off. If you're not going to rebuild your engine, I could use your engine case and rod/piston assemblies. Or conversely, if I replace this engine with a complete good used one, I'd offer you the crankshaft and camshaft out of this engine, as both are perfect. Appears the the rod bolts loosened up.....or the over-speed shut down was disconnected and the thing was running at 4 grand+ and grenaded.

I've been shopping parts, and will share a couple options, in case it helps you rebuild or repair.

I spoke with Kelly, owner of Ziller Electric in Michigan. He's well known as ground zero for Generac standby's, and has a huge web presence. He's got a 15kw unit with a failed generator section and a good engine. He's willing to sell the whole thing, on the cheap. He'll also drop it on a crate, and ship it. He's got a 12kw as well, but I can't remember what he said was wrong, but it was similar money. I guess you could pay him to have a tech harvest the engine, if that's all you wanted. I offered to go that route, as I really don't want a complete unit shipped from MI to CA, but I'm still trying to decide which way I'm going with this project.

The best online parts prices so far, are from Lawn Mower Parts, for purchasing engine parts.

 

Thanks for the info, haven't had time to mess with it yet, I found a clean looking engine on craigslist but haven't gotten around to calling on it. Came off a 20kw which has a little more displacement but appears to work on the older 15.

I haven't even gotten mine up and running yet, hopefully in the next couple of weeks I can finish it. I think this era of engines had more problems then the newer ones.

 

Well, let me know if you want to sell your engine case, rods, and pistons.