Interesting hr in the shop

[D-17_Dave]

I finally had a few minuets in the shop this evening and spent it tearing down the generator I got off eBay last month. This is the pic off eBay as I still don't have a camera.
[img]http://i1.ebayimg.com/07/i/000/80/1c/1de5_2.JPG[/img]
I knew it had problems and paid accordingly for it. When I picked it up I got a close up view of the hole in the side of the block.B) I figured the crank was toast and this being one of those dreaded tapered shafts I figured I was in for a costly repair. BUTwhen I took it all apart I found that the piston had stuck in the cyl. due to some corrosion from sitting and when they started it up dry and at full throttle the piston seized and broke the rod. The block is toasted and it busted the cam and split several parts of the casting around the cam bearings. BUTthe crankshaft was perfect. Now it won't be too hard to find a good block for this is a very common 8HP engine. I'll most likely bore whatever block I get so it's all fresh inside and it won't be nearly as costly to repair as I first thought.8DdOd I just couldn't let this rare gem fall into oblivion.

[Roy]

Dave, What model number is the engine? If you're not in a hurry and the engine I'm putting in my B-1 runs OK I have a spare short block and head. It is missing most of the tin, the flywheel, carburetor, intake, governor linkage, etc. but has the head on it. It is a model 252417. Hopefully in another week or so I will have mine running so will know if I need the spare or not.

[BLT]

Dave first of all, it was one built by Generac. I had one with a Tecumseh 7HP engine. My guess from picture is 3500 watt. If it has a 7 HP Briggs(17CID)the piston is cut straight opposite the ring end. If it is an 8 HP (19CID) it has a scalloped piston to clear (longer stroke) the crankshaft counter weights. The bore is the same. What Roy has (25CID) is to big unfortuneatley.

[FastPaul]

Nice find Dave. Like you said, very common engine ,Should'nt to be to hard to find another motor,Good luck

[D-17_Dave]

Bob, 3750 Watt. 8HP engine with the piston skirt scalloped as you mentioned. Roy, if you'll look at some of ny other projects lying around you'll know I'm not in any hurry.B):O:D

[ehertzfeld]

quote:

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Originally posted by D-17_Dave
Roy, if you'll look at some of ny other projects lying around you'll know I'm not in any hurry.B):O:D

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Now you sound like me!:D

[MPH]

Maybe I was miss lead back when I lived with a generator for power, but I understand the 8hp IC Alum engines cannot even be honned, much less bored. The cyl wall is basicly a coatting and if you take any off the piston will sieze as soon as it gets warmed up. Hope someone tells me that's wrong, have 3 or 4 of them ole blocks laying around yet I think.

[Ketchamized]

Dave, Maybe you could put a pulley on the generator part and build a frame for just the generator part of it and hang it on the rear of a tractor and run it off the rear PTO? Or off the front pto? Maynard has one of these with a frame meant to go on a tractor. It'd eliminate the need for a new engine... More "implements" for your tractor, and less space taken up in the garage. :o)

[D-17_Dave]

Marty, the aluminium engines can be bored and oversized pistons are common replacements. I've done dozens in my early years. NEVER had any negative problems. I hope someone will correct me if I'm wrong but I seem to remember the Briggs book saying that the aluminium bore engines used a special alloy piston to deal with the bore issues. Erick, this is the same gen pack as they used n the 5000 watt pto gen sets. It's derated a bit for the smaller engine. I did contemplate just going to a pto unit but these seem so rare and I seem to have so many odd AC represented pieces of yard stuff in my shed I felt I should restore it to it's orriginal glory. I have a lot of smaller yard stuff like walk behind mowers, tillers and such. This seemed like it would complement my collection well. Shoul dbe nice for conversation at Spring Fling8D:drl

[Ketchamized]

Dave, That's very true, didn't think of that. It's a very nice generator and an excellent specimen for a collection. Have fun restoring it. :)

[SmilinSam]

I've got the opposite problem. The Devilbiss 10 HP generator i bought about 4 years ago died last Sunday morning during the second day of a 3 day power outage here. Generator only had about 30 hours of run time on it max. Took it apart Monday morning and found that 3 of the four nuts that hold the 3 piece magnet assembly to the engin had come loose and allowed the magnet to drop onto the spinning armature. Toasted it.

[PatRarick]

Marty, as Dave said, you can hone or rebore the aluminum blocks. Have done several myself in the past and it works fine. To hone safely and properly, you need a finer set of stones than you use for cast iron. In my opinion, feasibility is the issue. If you can have it rebored and do the rebuild yourself, it's worth it. If you have the entire rebuild done at a shop, you come very close to, sometimes even exceeding the cost of having the engine repaired with a new short block. Dave, yes, the pistons for the aluminum bores are plated. To minimize wear, you need to have one surface harder than the other. Cast iron and aluminum bores both use aluminum pistons. Bare finished aluminum for the cast iron bores, and plated aluminum pistons for the aluminum bore. I believe tin is the plating material.