[Max]

I'm excited!!:woohoo1:

A quick GAS history refresher: For my first rider I started with an 816 last year and soon added 2 more non runners that I talked about in this thread.

The 16G had no engine and after searching nearly a year for a suitable power plant, one finally came along!
I found an Onan B48G that was originally on a Craftsman FF20 which was being parted out. The hour meter showed 763 hours and was still mounted on the frame when I arrived to purchase so was able to hear it run, which it did very well with no smoke or abnormal sounds. Yes!
Sometime during it's life it was subjected to a horrible paint job but other than that looks like a winner.

Of course, I need your help.
First, the search now begins for a "golden part"...an Onan engine adapter plate. If you know of one for sale, please let me know.

Second, it has a 1 1/8" x 3" shaft so will need to have a 3/4" stub added to the shaft.
Well hello there Richard ole buddy ole pal! I remember you did this exact operation on one of your Onans. Did you happen to make 2 stubs while you were at it? I could have a local shop make one, but I'd just as soon give you a bit of business if for no other reason than you have been so helpful to me with my recent CCKA troubles, plus you already know the specs.

If I can overcome these 2 obstacles with y'alls help, I believe I can take care of the wiring, the exhaust and the control cables.

Now, for grubby pics! :wwp:

 

[Richard-tx]

That sure looks like a P series engine to me. Nikki carb and all. Must be a very late B series. Boomer would know.

I did locate that bit of keyed shafting so if you need a chunk I have it.

Talk to Jamie at Richard's. He might have an adapter plate.

 

[boomers_influence]

max and richard
it deff. is a B 48G engine. ( the blower hsg. tells me that )

max
i also have the crank stubs in stock
[email protected]
i save them from cranks that are shortened for Case 448 engines.
the actual usable length of the gravely crank is 7.780.
you will also have to do some exhaust mods.
thank you. boomer ( the used onan engine parts guy )

 

[Max]

Thanks guys.
I'll call Jamie ASAP about the plate.
Richard, I sent you a PM.
Boomer, I'll be in touch.

 

[Max]

Called Jamie earlier today and he said he was pretty sure he had an Onan adapter plate and he'd call me back.
I was getting ready to leave work so I called him before they closed and he said they couldn't find it. He said he would keep looking.

Struck out!! :dunno:

Anyone else have an Onan adapter plate they want to part with or know of a source?

 

[Max]

Hey, as far as anyone knows, was there only one Onan adapter plate ever made?
I mean, will a plate from a CCKA work for bolting up a B48G to a 16g?

Thanks.

 

[Max]

I hope so, because I bought one! (A plate from a CCKA that is)

 

[boomers_influence]

max
i replied to your wanted add stating that the 816 ( CCKA )
adapter will work.
i did one for a fellow member about two months ago.
thank you. boomer ( the used onan engine parts guy )

 

[Max]

Thanks boomer. Whew! I felt pretty sure, but with Gravely, you never know.

 

[Richard-tx]

The adapter plates for Onan engines are all the same despite different part numbers. The most that has to be done with a Onan engine from another application is to drill and tap the mounting bolt holes in the Onan crankcase. It isn't hard to do but be absolutely accurate. You only have one shot when drilling and tapping. I find that a set of transfer punches are worth their weight in gold when doing an operation like that. Transfer punches are not expensive. About $16 for a set delivered to your door. Use a new tap. A dull tap isn't worth keeping.

 

[PA RedRider]

How much does a used Onan engine adapter plate sell for typically?

 

[Richard-tx]

The last one I got went for about $35 at auction on ebay.

 

[Max]

Depends on how desperate the buyer is! LOL

I got prices of 50 and 70 buying straight up.

 

[hvaboy05]

Hello to every on this thread! I see some guys on here that know a thing on two about Onan engines. Ive just recently acquired a sears with the 16 hp Onan. I have a blowby issue going on and from what I can observe I probably have some broken rings. Im trying to see what Onan engines will mate with other Onan engines. Its a bf/ms2666c model. Any help would be great! Thanks!

 

[Max]

Hi hvaboy, I'm not positive I understand the question, but if you mean "which Onan will mount up in the place of another Onan", I believe they have similar mounting configuration, but crankshaft length and diameter will vary. As I'm finding out, they are not all "plug and play" and could require some modification.

If you mean " will P or B48 rings fit a BF", I'll say no.

We need more info.

 

[Max]

I've run into an issue that I have not seen anyone post about before when adapting an Onan engine to a Gravely Rider.

It appears my B48G has some .25" "Bolt bosses" that will need to be ground off because the 816 Onan adapter plate is .25" from seating all the way.
Has anyone run into this before?

First pic show the plate in place with the .25" gap

2nd pic shows the plate lifted off to expose the 4 bosses that are causing interference.

I do have good alignment with 2 bottom bolt holes, and good alignment on 2 upper holes, but the 2 upper holes will need to be tapped.
This pic shows the lower bolt holes which are ready to receive bolts and need no modification.

Closeup of one of the upper holes that will need to be tapped.

Same hole from a greater distance. The hole that aligns with the plate is the middle hole in the picture.

I have no tap and die. I have no idea what is behind those holes, so don't know how deep to go.
Looks like I'll be taking this to someone more knowledgeable and better equipped than I. Darn, I was hoping it would bolt right up, but at least there is nothing that can't be overcome. :fing32:

Richard posted something about a situation like this in this thread, but that's all I could find.

 

[Richard-tx]

You have a strange bearing plate that I have not seen before. Call Boomer and get a regular one and it will fit just fine.

This is what you want.

 

[Kbeitz]

Also you need a bottom tap.

 

[Max]

Also you need a bottom tap.

For the bottom 2 holes? They line up and are already threaded. There were bolts in there that I removed for the pictures.
Best I can tell it's just the top 2 spots that need tapped.

Boomer if you're seeing this, do you have a bearing plate? Shoot me a PM if so.

Thanks all.

 

[lt4xtreme]

Here is a link to McMaster-Carr about half way down the page it explains the different taps (chamfer, plug, and bottoming) since the top holes in your motor are shallow and are blind (don't go all the way thru/can't see in one side and out the other) You will need a bottoming tap to thread the hole to the "bottom". I would change the bearing plate then bolt on the adapter plate using the 2 bottom bolts and use the adapter plate as a guide to help direct the tap in, keeping the tap straighter and inline with the adapter plate.

http://www.mcmaster.com/#about-taps/=ngkkbe

Jason