Onan W2C Fairbanks Morse Repair

AngrySailor

Subscriber
So I'm finally home from 4 months on the Great Lakes and I'm rearing into my Great Grandfather's Onan. He stopped running it after it was frozen by an early frost. Back in the 80's my father and grandfather used Devcon on the cracked cylinder head but never got it running. I got it running last year, here's the first start up video: https://youtu.be/OzD8eBWDT-A

It ran a couple hours before the cylinder head started leaking externally, then she started burping coolant on start up signaling an internal leak:( I hadn't held out much hope for the repair lasting so I wasn't surprised.

I've just pulled the head hoping it was a gasket problem but it seems ok. There is also severe rust damage in the forward cylinder. I'm thinking the cylinder is cracked but can't see anything obvious. I wonder if there is enough meat to sleeve it?

Anyways, here's some pics!
 

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AngrySailor

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Re: Onan W2C Fairbanks Morse repair.

More pics of carnage. Also a shout out to Dan H, sitting on my kitchen table when I got home was a nicely packaged new head gasket:)

The pic of the head with the screw driver pointing at it is where the crack is under the epoxy repair.
 

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AngrySailor

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Re: Onan W2C Fairbanks Morse repair.

Nice! These machines have a lot of character, and built heavy! I'm going to clean up the head and have a good look at the gasket, I'm hoping the head is cracked into the combustion chamber and not the cylinder. I think I will sleeve it and hopefully reuse the piston.

I MIGHT have valves and guides NOS somewhere but haven't seen them in years so they're buried at my dads shop.
 

AngrySailor

Subscriber
Vacation cut short:mad: only have a few days left so I'm thrashing in the shop to organize this week. Bought an air compressor at a price I couldn't refuse, building a stand to set it on and use the floor space underneath as a new home for my W2C and Wisconsin/Hobart welder

Going to call LA sleeve and order up a universal sleeve. They're long enough I can sleeve both bored with one sleeve:brows: can't wait to pull her apart and see if the piston is salvageable, she ran great and even had decent compression considering how rust pitted the front bore is!
 

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AngrySailor

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Almost too big:uhoh: I might set up a small head (maybe 1hp) and stepped pressure switches... couldn't pass it up for what I paid for it though.
 

AngrySailor

Subscriber
Oh yeah, gotta have shop tunes. She bi-amp 2400w low frequency and 300wpc stereo high frequency. Got some old phase linear stuff in the house :D
 

AngrySailor

Subscriber
Sleeve ordered from L.A. Sleeve. I'll tear her down and get the cylinder up on my mill when I get back from work after Christmas. I'm hoping the piston is salvageable, but will surely need to source some rings. Any ideas? She's 3.005" measured in the good used bore, I don't know the thickness yet. Buried somewhere at my fathers shop is a box with some NOS parts,mostly valve train though and I don't recall seeing rings but it's been years since that box saw the light of day!
 

AngrySailor

Subscriber
I'm told a package from LA Sleeve is waiting at home for me:D. I should be home in a couple weeks and the Old Onan is high up on the list for repair. I'd like to find some other parts for her if anyone might have any for sale let me know...

Possibly a piston
Definitely a complete set of standard rings (3.000)*- see edit
Cylinder head (mine is cracked, might attempt a stitching repair)
Coil box (missing)
Rad cap (I'm going to machine/fabricate a copy if not available)

Thanks guys.

Andrew

*Hastings lists a ring set for this engine. 3/32 3/32 1/8 3/16". Is it a four ring piston? I've never had a piston out? I'll order it if that's the correct ring package. Thanks
 
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From the manual I have there are two 3/32 compression rings and one 3/16 oil ring. Wonder if different year had extra ring or one 1/8 instead of one of the 3/32. Either way looks like the Hastings set would have you covered.
 

AngrySailor

Subscriber
From the manual I have there are two 3/32 compression rings and one 3/16 oil ring. Wonder if different year had extra ring or one 1/8 instead of one of the 3/32. Either way looks like the Hastings set would have you covered.

Thanks, I'm away from home working for a couple more weeks so I don't have the manual handy. I ordered the Hastings set this afternoon, it was in stock but at over $70 USD plus shipping and exchange I'm into $150 ring set:eek: small price to pay I guess as I'm sure Great Grandpa will be smilling from above when she's up and running proper.
 

Power

Active member
Sweet running unit.
Hope you can get it running.
Do not forget to clean and repack gen end bearing, clean out sludge and crud from fan bearing casing and put fresh oil in it.

Looks like radiator and air cleaner top came from other units.
 

John Newman Jr.

Subscriber
I'm confused...:shrug:
Engine has 3" bore. Sleeve is 2-7/8" x 1/8". I will assume that means it has 1/8" walls, so outside diameter would then be 3-1/8"??? How much material is there in the cylinder walls of the engine? Can they be bored 1/8"? Then when you bore the sleeve to bring it up to 3", there will only be 1/16" wall left in the sleeve. Is this enough?
 

AngrySailor

Subscriber
Power, the Rad cap is just sitting there (doesn't fit) and it's from a Ford N series tractor. I play to build a reproduction of the original cap. The air cleaner top is original to the unit.

John, the cylinder walls appear though the water jackets to be able to easily accept a 3 1/8 bore. Remember it's only .0625" per side, there will be a step left at the bottom for the sleeve to rest on. Looking for .003" interference then the sleeve will bored to within .008" of the finish size and finished with a portable sunnen hone I borrowed from a friend. LA sleeve is confident that 1/16" wall is suitable for this application, they just didn't have a 1/16" wall sleeve that size in stock.
 

Power

Active member
Power, the Rad cap is just sitting there (doesn't fit) and it's from a Ford N series tractor. I play to build a reproduction of the original cap. The air cleaner top is original to the unit.
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There are quite a few folks who have several of these, running and parts machines. You may be able to buy a rad cap at reasonable cost.
If you really want to make one, and need pix, let me know, I will take pix of mine.
 

AngrySailor

Subscriber
Power, If someone has an original rad cap forsale I'd be interested but most rad caps have a machine they go with and I don't blame someone for not splitting them up!

Today was my first solid day in the shop, after grocery shopping and homemaking duties (I live alone so no sandwich maker). Mostly organizing and making room for real work... I plan to have the cylinder on my mill soon and install the sleeve. Pics coming.
 
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