Ohlsson & Rice: Type 117 Rebuild

[CNew 404]

Well, what I had hoped was going to be a quick tear down and rebuild as a test engine for new gasket materials and seal alternatives has turned into a bit more of a project. I should have known better with these older model engines...

 

This is is the first I’ve seen of a flywheel that doesn’t have a key. There is a little nub cast into the area where the key slot would normally be, very odd design concept. Mine was ruined upon removal so now I will have to pull another from a donor engine if I have one. It barely protrudes enough to catch the slot on the mating shaft. Another bad design flaw...

 

This engine also has the plastic bearing cages...

[JUST O&R 237]

I have the a-27-4 in the new metal bearing should be a-27-17 used

I have the a-27-2 in the new # metal bearing a-27-18 only in a new one

I have a-27-3 in a used one  I don't see an old # for that one

If you need one let me know

[Wallfish 698]

That "nub" looks like a sheared key to me but there was another guy before stating his flywheel didn't have a key way. The key only lines it up for the timing and the taper is actually what holds it in place. Is the crank slot normal?

 

Now I see what takes you guys so long. All of those neat little compartments for parts takes time.

Wish my organizational skills were that good

[factory 487]

I remember finding a flywheel like that with some parts engines I bought, it would be interesting to see if the crankshaft is different too.

 

David

[JUST O&R 237]

Will were new at this I like to know were my parts are not all over the table and the floor  .

I seen somewhere on here to use a big pan under the engine so you don't lose parts .

2 minutes ago, factory said:

I remember finding a flywheel like that with some parts engines I bought, it would be interesting to see if the crankshaft is different too.

I think the one on my s/saw was that way can't remember for sure it was1961 I think is what you said.

no looked back at the s/saw post it had a key

[factory 487]

I hope he knows that the shaft seals are different in these early engines.

The carb with the red needle valve, I'm sure I seen that on the Creme Lure generator, mine doesn't use a Type 115 117 though.

 

David

[JUST O&R 237]

good eye didn't see the red needle valve ( but that way we have you ) .

[Fishnuts2 22]

The taper is what holds the flywheel, and the key is only there for setting the timing.  Just make sure the tapered surfaces are ultra clean, and the flywheel is torqued properly.  I've known guys to skip the key on modified chainsaw engines to get the timing where they want.

[factory 487]

Correct torque tightening is very important, we had someone injure themselves when a flywheel came off, not sure what they were doing but I suspect the starter housing was not attached.

They changed the flywheel keys from steel to aluminium for later engines (again the sizes are different) this would allow the key to shear off & prevent keyway damage if the flywheel became loose.

 

David

[CNew 404]

I think the shaft slot looks normal. I’ll take a photo later tonight. 

[CNew 404]

2 hours ago, Wallfish said:

That "nub" looks like a sheared key to me but there was another guy before stating his flywheel didn't have a key way. The key only lines it up for the timing and the taper is actually what holds it in place. Is the crank slot normal?

 

Now I see what takes you guys so long. All of those neat little compartments for parts takes time.

Wish my organizational skills were that good

Yeah, I made the mistake thinking it was sheared and initially tried to remove it and that’s when I found out it was part of the design. 
 

I use to be more organized but now that I’ve done a few these you start to know each little piece pretty well.

1 hour ago, factory said:

I hope he knows that the shaft seals are different in these early engines.

The carb with the red needle valve, I'm sure I seen that on the Creme Lure generator, mine doesn't use a Type 115 117 though.

 

David

The seals are different sizes or design?  I haven’t removed them from the housings yet.  I was also wondering about the little red cap on the needle valve- I hadn’t seen that before.

[CNew 404]

6 hours ago, factory said:

I remember finding a flywheel like that with some parts engines I bought, it would be interesting to see if the crankshaft is different too.

Shaft looks normal to me.

 

[CNew 404]

18 hours ago, JUST O&R said:

I have the a-27-4 in the new metal bearing should be a-27-17 used

I have the a-27-2 in the new # metal bearing a-27-18 only in a new one

I have a-27-3 in a used one  I don't see an old # for that one

If you need one let me know

Can the plastic bearings actually be swapped out with metal ones on these early model engines or is the design too different?

[JUST O&R 237]

From what I see they should fit a price list I have the numbers supersede

I'm not sure on the a-27-3 I have no # change but it has a metal case.

David will know for sure

[CNew 404]

Ok, cool that’s good to know - it would be much better with metal bearing cages.

 

[CNew 404]

On 2/18/2020 at 12:09 PM, JUST O&R said:

I have the a-27-4 in the new metal bearing should be a-27-17 used

I have the a-27-2 in the new # metal bearing a-27-18 only in a new one

I have a-27-3 in a used one  I don't see an old # for that one

If you need one let me know

 

If you have a couple minutes can you send a photo of these? I’m curious to compare the design of the metal to the plastic ones? Wondering if I can find a metal version off a donor engine or something and it would help to have another visual reference since they won’t be NOS with part numbers.

[JUST O&R 237]

Here's some pic's hope this helps I had plastic and metal for all

this is the order a-27-4 & a-27-17

                             a-27-2 & a27-18

                              a-27-3 that's the only number I could fine but i did have a Plastic and a metal

[CNew 404]

This is awesome! Yes, very helpful, thank you!

[factory 487]

A couple of sources (1971 price list & 1965 parts list) give the following bearing changes, of course it all depends on the age of the engine as to which are used, the changes started happening around 1963/64 following the NIAE test report;

 

Crankshaft main* bearing: A-27-4 use A-27-17.

*When they changed the crankshaft main bearings in August 1964 they used part no A-27-8 for this one, for A-27-8 use A-27-16.

 

Backshaft (PTO) reed* & induction housing bearings (2 sets): A-27-2 use A-27-18.

*When they changed the PTO shaft reed valve bearings in August 1964 they used part no A-27-4 for this one (1 set), again A-27-4 use A-27-17.

 

The A-27-3 bearing never changed part number for both the plastic & steel cages, I did note the steel cages are slightly thicker than the plastic ones, this may have been because they were used of course (it was a while ago I checked).

 

David

[CNew 404]

Thanks for all the research on this David, very helpful knowing the progression and changes in part numbers. 

 

Do do you know if the bearing swap is all that’s needed or are there any spacer washers or other pieces requires drivers to fit the metal bearings with the various shafts?  I will try to add a photo in a little while of one in particular I’m thinking about.

[factory 487]

On 2/19/2020 at 2:27 PM, JUST O&R said:

From what I see they should fit a price list I have the numbers supersede

I'm not sure on the a-27-3 I have no # change but it has a metal case.

David will know for sure

 

By the way the 1971 price list fails to mention* anything about the A-27-11 main con-rod bearing change to A-20-5-13-7, that must be used with a slotted con-rod and also a change of piston & wrist pin, here is the April 1964 parts list information;

 

 

 

From the August 1964 parts list,  the con-rod main bearing was changed to A-20-5-16-7 with 7-25 washers.

 

David

 

*Which is why it takes a long time to cross check to find the correct information, also note you will find more bearing differences with engines below SN 006072.

[factory 487]

23 minutes ago, CNew said:

Thanks for all the research on this David, very helpful knowing the progression and changes in part numbers. 

 

Do do you know if the bearing swap is all that’s needed or are there any spacer washers or other pieces requires drivers to fit the metal bearings with the various shafts?  I will try to add a photo in a little while of one in particular I’m thinking about.

 

I will need to do more research to check about the thrust washers, adding a picture will help confirm which ones you are thinking of too.

David

[CNew 404]

Here’s one of the shafts and it has a flat washer with the plastic bearing. If I switch to a metal bearing I’m wondering if this washer will still work or if a different set up is needed.

 

[JUST O&R 237]

That must be an early one I think my c/saw had that washer/spacer

[Wallfish 698]

Click through the manuals David has posted. There's drawings of the different engines