Forum for air cooled diesel engines and clones

[90cummins]

Dumb question - how do you separate the generator from the engine? I got the big main bolt that runs through the rotor out, loosened the 4 long external bolts that seem to hold the stator to the front cover that bolts to the engine. But nothing seems to be coming loose? It's 7 degrees out in the barn right now, so I'm trying to be careful not to break anything, lol. Am I missing something other than a bigger hammer? Any parts diagrams anyone has would be helpful and much appreciated!

TIA...[/QUOTE

Not a dumb question!!

To seperate the generator from the engine first remove the outer (external) generator housing to expose the rotating Field unit.
Then remove the center screw that secures it to the engine crankshaft, the OD of the bore you removed the long bolt from should be threaded.
Now find a screw that has the same thread as the long screw up hat was previously removed and cut a threaded section to insert into the crankshaft to protect the internal threads and provide a surface to push on. Cut a slot on it to slow you to thread it into the crankshaft and turn it in until it is slightly above flush.
It the OD previously mentioned is not threaded you must tap it with a 1/2-20 tsp to allow use of a 1/2-20 screw to use as s pushed device.
With the insert threaded into the crankshaft cut a length of solid rod as a spacer that can be inserted in the hole so you can use the 1/2-20 screw can to push the unit off the crankshaft.
Use caution this process could take time and require some shock with s hammer and possibly some heat.
Seperating them can be very difficult and time consuming to avoid damage.
My personal unit was not tapped which required me to do and took considerable time and force to separatem from the crankshaft.

Be patient.
90cummins

 

[BeeferMan]

Thanks for the help "90", but I think your detailed response indicates my question was indeed a dumb one, lol, as I'm stuck on your first sentence: "first remove the outer (external) generator housing to expose the rotating Field unit." I've got the long center bolt out, although it sounds like maybe I should reinstall that until I have the "outer cover" (what I called the "stator") off?

Are the four long bolts the only thing that holds the outer cover (what I called the "stator") on? (The picture below shows 3 backed out, but I've got all four loose.) I couldn't see anything else holding it on, but it didn't want to budge and I didn't want to use too much force until I knew I had all the required fasteners loose. From your description it would seem the silver colored cast end housing and the black metal outer cover should just slide off revealing the rotor/rotating part still fastened to the crankshaft? Once I have it to that stage the rest of your directions make sense!

Thanks,
- Jim

Dumb question - how do you separate the generator from the engine? I got the big main bolt that runs through the rotor out, loosened the 4 long external bolts that seem to hold the stator to the front cover that bolts to the engine. But nothing seems to be coming loose? It's 7 degrees out in the barn right now, so I'm trying to be careful not to break anything, lol. Am I missing something other than a bigger hammer? Any parts diagrams anyone has would be helpful and much appreciated!

TIA...[/QUOTE

Not a dumb question!!

To seperate the generator from the engine first remove the outer (external) generator housing to expose the rotating Field unit.
Then remove the center screw that secures it to the engine crankshaft, the OD of the bore you removed the long bolt from should be threaded.
Now find a screw that has the same thread as the long screw up hat was previously removed and cut a threaded section to insert into the crankshaft to protect the internal threads and provide a surface to push on. Cut a slot on it to slow you to thread it into the crankshaft and turn it in until it is slightly above flush.
It the OD previously mentioned is not threaded you must tap it with a 1/2-20 tsp to allow use of a 1/2-20 screw to use as s pushed device.
With the insert threaded into the crankshaft cut a length of solid rod as a spacer that can be inserted in the hole so you can use the 1/2-20 screw can to push the unit off the crankshaft.
Use caution this process could take time and require some shock with s hammer and possibly some heat.
Seperating them can be very difficult and time consuming to avoid damage.
My personal unit was not tapped which required me to do and took considerable time and force to separatem from the crankshaft.

Be patient.
90cummins

 

[90cummins]

The outer housing is attached to the engine with 4 screws. Remove those and the housing can be removed.
The long screw holds the rotating Field unit on the crankshaft.
90cummins

 

[90cummins]

It is a snug fit so use a soft malet to free it.
90cummins

 

[90cummins]

In your photo where the long screws thread into the aluminum housing there is a notch barely visible that you can use a screwdriver to pry the black housing off.
Work it side to side unti loose and carefully slide it off taking care not to damage the windings.
90cummins

 

[BeeferMan]

Your descriptions gave me the confidence to get a little more aggressive, and it finally popped apart. It didn't take *that* much force, and mine came apart somewhat differently than you described. The housing and rotor came off as a unit rather than separately. The rear rotor bearing didn't separate from the rear housing.

Thanks for the confidence boost. Now to find out what went "bang" in the engine. I had the head off and there was no sign of traumatic damage to the valves or (top of the) piston. When spinning the crank and watching the valves everything seemed mostly in time, although it's hard to tell exactly. I'm suspecting broken rings or ring lands at this point.

 

[90cummins]

I've repaired a lot of generators and never had one separate from the crankshaft as easy as yours!!
Now you can dig in and find your clunk.
90cummins

 

[xp190]

Great timing BeeferMan, I was just about to attempt the same thing on my genset.
Mine seems to be very similar to yours and I spent quite a bit of time looking at it as well to try and figure out how to separate it from the engine, but didn't get far.
I did twist off one of the long screws that holds the housing together, I will have to replace it.

Any chance you could upload a few more pics of how you got it all apart?

xp

 

[BeeferMan]

Great timing BeeferMan, I was just about to attempt the same thing on my genset.
Mine seems to be very similar to yours and I spent quite a bit of time looking at it as well to try and figure out how to separate it from the engine, but didn't get far.
I did twist off one of the long screws that holds the housing together, I will have to replace it.

Any chance you could upload a few more pics of how you got it all apart?

xp

I can get some pictures later when I get back at the shop if needed, let me try some text first..

There are three main parts involved in this step: 1. The housing that bolts to the crankcase of the motor, which I'll call the front cover. 2. The outer housing of the generator itself, properly called the stator, I believe. This part also includes the rear cover. And 3. the rotating part of the generator, the rotor.

The rotor rotates on a bearing in the rear cover, but has no front bearing - it it bolted to the crankshaft via a long bolt all the way through the rotor shaft and uses the crank bearing in place of a front bearing. Remove that long bolt.

The stator and rear housing assembly are fastened to the front cover by four long bolts on the outside of the stator. You can see those in the picture I put in post #322. Remove those.

A little prying between the stator and the front housing should allow those two to separate slightly, but they may not come apart more than a fraction of an inch at first. Now it seems there are two ways this might come apart.

A. In 90Cummins experience (see his posts) it seems that the rear bearing of the rotor separates from the rear housing, and the rear housing and stator slide off over the rotor leaving the rotor stuck on the crankshaft. Remember there is no front bearing, so take care sliding the stator off the rotor. Then the job is removing the rotor from the crankshaft.

B. In mine, the rear rotor bearing didn't separate easily from the rear housing. With enough prying the rotor eventually separated from the crankshaft, and the stator/rear housing and rotor came away from the front housing as one unit.

A caution: the front and rear housing are cast (aluminum?) of unknown quality, so I'd be very carefully when you're prying or putting pressure on them. Best to pry in a few spots at the same time to reduce the risk of cracking one of the castings.

If this doesn't suffice, ask more questions and I'll get some pictures.

- Jim

 

[xp190]

Thanks a lot for the pointers, that helps a lot.
I will be trying this in a few days if weather allows.
I twisted one of those long bolts, so the housing has to come out to get the broken piece of the screw out so i can replace it.

xp

 

[bennyboy95]

Does anyone know if a Yanmar L90 and be bored to fit a L100 piston?

 

[90cummins]

The L100 bore is 0.080 larger than the L90.
Not sure there’s enough material there. If your choice is to scrap the block or bore it out for the L100 try it.
90cummins

 

[90cummins]

If the L90 has a standard piston why don’t you install an oversized piston.
They have .25 & .5mm (0.010 & 0.020) inches oversize available.
That should cleanup any rust pitting.
90cummins

 

[bennyboy95]

I know they have the two oversize but I can only find them available in Europe for far more than I can get an aftermarket L100 piston off ebay. Is there a place for the pistons for a L90 in the states? The water made some deep pits and I'm not sure how much will need to be bored out to clean it up.
Thanks Ben

 

[90cummins]

Call Jameson tractor.
Bought quite a few Yanmar parts nice people!!

http://www.tractorbynet.com/forums/asset.php?fid=478224&uid=109723&d=1518903641

 

[xp190]

Howdy folks

I managed to get in some wrenching time this weekend.

I am down to the difficult bit, separating the rotor from the crankshaft.
This is what I'm looking at:




Now comes the part where I need to pop the rotor off of the crankshaft.
I think I understand how this is supposed to happen, it looks like it will take effort on my end, a project for next week.

Looking everything over, I noticed that the wire connected to the fuel pump solenoid was quite loose.
Is it possible that the solenoid was being activated and deactivated as the engine vibrated causing the stuttering?
I'm not quite sure of the functionality of this solenoid, but it sounds like it cuts off fuel when not energized and needs to be energized to allow fuel to flow?

If that is the case, if it was jittering, it would cut the fuel every few revolutions causing the engine to start slowing down, but as soon as it reconnected it would fire up again.
Perhaps this is why I didn't see anything unusual about the smoke coming out of the exhaust?
Just speculating here, but I'm starting to think maybe my problem isn't as complicated as I initially though it could be.

Appreciate any input from the experts.

Thank you

xp

 

[frugalangler]

...........
Looking everything over, I noticed that the wire connected to the fuel pump solenoid was quite loose.
Is it possible that the solenoid was being activated and deactivated as the engine vibrated causing the stuttering?
I'm not quite sure of the functionality of this solenoid, but it sounds like it cuts off fuel when not energized and needs to be energized to allow fuel to flow?
...........

Being that the solenoid is the shut down mechanism if it's interrupted the engine would attempt to die, if rotating enough to sustain restart on the solenoid re-opening, then that could very well cause it to 'sputter' as you describe. Too bad you've got it torn down to where you can't test that theory on your motor.

 

[90cummins]

Looks like you are on the right track.
To protect the crankshaft I cut the head off a grade 8 screw and threaded it into the crankshaft then inserted a spacer so my jack screw could push field unit off.
Mine did not come off easily.
It took considerable force and careful application of heat (to avoid electrical damage) near the engine end of the generator to get it to separate.
It was on so tight I had to use my air impact to tighten/loosen/tighten /loosen many times.
I even let it set overnight with pressure on.
When I exhausted all options I ram my air pressure up to 200 psi and let-er rip.
Finally came off with minor crank thread damage.
Your symptoms could be the loose wire or a couple other issues I've seen.
Once you open it up we can diagnose.
90cummins

 

[BeeferMan]

I'm not impressed with that tapered shaft design - I'm feeling very lucky my rotor pretty much fell off the crankshaft.

I got some time in on mine last weekend, opened the engine up and pulled the piston - I found that the piston lands were broken, as suspected, so I think I'm at root cause for its sudden lack of compression. Also, my unit had very low hours on it, so I was surprised at the amount of wear on the rod bearings. I ordered a new piston and some rod bearings, hopefully they'll show up while I still remember how to put this all back together, lol.

 

[xp190]

I'll keep working on this, but in the meantime, do you guys have a place to order parts from for these engines?
I wanted to get a gasket set for it once I pull the head to see what things look like on the inside, maybe a real glowplug as well. I have a feeling that the coil under the air filter might have been responsible for why the air filter burnt up to begin with resulting in all the other issues.
I'll have to jimmy up some sort of a jack screw to get this thing off.
Since it's a tapered design, has anyone tried the tierod trick? I always struggled with tie rods until a friend of mine who just finished shop class told me that you don't hit it from the top or bottom, but you hit the side to shock the tapered surfaces causing the tierod to pop out, it works quite well, but I'm not sure I would know what to hit on the rotor, or if it is strong enough to make this work, just an idea really.

xp