1985 ATC 250 engine orientation

[Lcarter114 4]

I recently purchased a Cushman truckster project where the prior owner removed the batteries, constructed a rear suspension and motor mounts, then installed the engine and swing arm out od 1985 ATC 250.  When doing this they rotated the engine back appropriately 15 degrees,  (the piston is pointing straight up).  The problem I discovered is if the oil is filled to the correct level on the dip stick it will blow out of the crank case vent.  The engine has a knock so I pulled it out to rebuild it but I am worried about the oil issue.  From what I can see from the shop manual the oil pump is toward the front of the engine.  I fear that when the oil blew out of the crankcase vent it was too low for the oil pump to pick it up.  I can't turn the engine back to original position due to the angle of the swing arm.  Am I correct in assuming I am losing oil suction with the engine tilted?  If so can I make a taller vent tube with a couple of 90 degree turns to keep from losing oil and not have any issues?

Any advice would be greatly appreciated.

Edited November 7, 2023 by Lcarter114

[shadetree 5,869]

50 minutes ago, Lcarter114 said:

I recently purchased a Cushman truckster project where the prior owner removed the batteries, constructed a rear suspension and motor mounts, then installed the engine and swing arm out od 1985 ATC 250.  When doing this they rotated the engine back appropriately 15 degrees,  (the piston is pointing straight up).  The problem I discovered is if the oil is filled to the correct level on the dip stick it will blow out of the crank case vent.  The engine has a knock so I pulled it out to rebuild it but I am worried about the oil issue.  From what I can see from the shop manual the oil pump is toward the front of the engine.  I fear that when the oil blew out of the crankcase vent it was too low for the oil pump to pick it up.  I can't turn the engine back to original position due to the angle of the swing arm.  Am I correct in assuming I am losing oil suction with the engine tilted?  If so can I make a taller vent tube with a couple of 90 degree turns to keep from losing oil and not have any issues?

Any advice would be greatly appreciated.

well..i see you are trying to take a square peg..and fit it into a round hole ?!..lol. here's an idea. maybe try adapting a roller guide for the chain, this way you can put the engine back at the correct angle. the oil pump is on same side as the clutches, which in this case, are on right hand side.

[toodeep 1,758]

Do you have any pictures? There has to be a way to get the motor and swingarm sitting in there correctly. Being shaft drive they can take on a pretty good angle but sometimes the u joint needs ground a little for clearance. The case of the motor is the pick up for the oil pump so not much to modify there and messing with the crankcase vent I would think would just give you seal problems which would be a new oil loss issue. Once you start tearing the motor down you will know if it was ran low on oil or if it's just in a place to not get enough air flow to cool properly.

[Lcarter114 4]

I didn't get any pictures before I took the motor out.  The silver square tube is the mounting for botlting the motor plus one more at the bottom.  The way the engine is sitting on the bench is how it sits in the vehicle.   If I rotate it forward I will have to redo the mount (which is not out of the question) and the drain plug will be straight down in u channel.  Don't know if I should cut my loses and sell off the parts or try to make it work. It does have an electric fan so I think the temp is ok.

 

It will be a fun project my wife said...🙄

[Lcarter114 4]

58 minutes ago, shadetree said:

well..i see you are trying to take a square peg..and fit it into a round hole ?!..lol. here's an idea. maybe try adapting a roller guide for the chain, this way you can put the engine back at the correct angle. the oil pump is on same side as the clutches, which in this case, are on right hand side.

The peg was already there.  Now trying to fix it.

[toodeep 1,758]

Interesting project. It looks like they are using 2 driveshafts between the motor and final drive? There looks to be many options to correct what is needed if you have the time and tools. The time and want would be if it's something you plan on keeping and using or just something to cruise a few times a year. If using as a yard machine (work) I would think about boxing the frame and sitting the motor back so it could hook back to the swingarm like it did in the 3 wheeler. That would make the drive line tougher, take care of motor mount issues plus give extra weight on the rear wheels for traction. Possibly the motor does sit back farther than it looks in the picture???

[shadetree 5,869]

2 hours ago, toodeep said:

Do you have any pictures? There has to be a way to get the motor and swingarm sitting in there correctly. Being shaft drive they can take on a pretty good angle but sometimes the u joint needs ground a little for clearance. The case of the motor is the pick up for the oil pump so not much to modify there and messing with the crankcase vent I would think would just give you seal problems which would be a new oil loss issue. Once you start tearing the motor down you will know if it was ran low on oil or if it's just in a place to not get enough air flow to cool properly.

ty toodeep, i forgot it was shaft drive ?..dang i hate getting old !.

[shadetree 5,869]

1 hour ago, Lcarter114 said:

I didn't get any pictures before I took the motor out.  The silver square tube is the mounting for botlting the motor plus one more at the bottom.  The way the engine is sitting on the bench is how it sits in the vehicle.   If I rotate it forward I will have to redo the mount (which is not out of the question) and the drain plug will be straight down in u channel.  Don't know if I should cut my loses and sell off the parts or try to make it work. It does have an electric fan so I think the temp is ok.

 

It will be a fun project my wife said...🙄

if you can weld ?, weld up a drop tubbing under the drive shaft , this will let it clear the output shaft.

[Lcarter114 4]

The front of the motor bolts to the upright square tube.  There is only 1 drive shaft.  It would probably be used for a little yard work but more of a toy.  Originally it had a throttle lever on a homemade shift knob.  I added a gas and brake pedals and fixed the rear  brake.  It still need front brakes, that one drum brake doesn't get it.  I also changed the swing arm seals and bearings, new tires and wheels.  I am pretty good at mechanical and electrical, but welding is my weak suit.  I could maybe go bigger wheels and tires and shorten the springs to try position of the swing arm, then change the motor mount. Alot to think about.  I don't want to go ahead and fix the motor if I could potentially damage it in this configuration.

[shadetree 5,869]

36 minutes ago, Lcarter114 said:

The front of the motor bolts to the upright square tube.  There is only 1 drive shaft.  It would probably be used for a little yard work but more of a toy.  Originally it had a throttle lever on a homemade shift knob.  I added a gas and brake pedals and fixed the rear  brake.  It still need front brakes, that one drum brake doesn't get it.  I also changed the swing arm seals and bearings, new tires and wheels.  I am pretty good at mechanical and electrical, but welding is my weak suit.  I could maybe go bigger wheels and tires and shorten the springs to try position of the swing arm, then change the motor mount. Alot to think about.  I don't want to go ahead and fix the motor if I could potentially damage it in this configuration.

have you thought about adding shocks to the swing arm to raise the swing arm up some ?.

[Lcarter114 4]

It has one shock.  I have thought about putting in coil overs and removing the large springs.  I will have to check tire clearance.  I know I will have to move the inner fenders up.  I want to keep the it pretty level and not have it being lower in the rear.

[jeepwm69 7,611]

Neat looking project.   Could you add a second ujoint where the shaft goes into the swingarm?  That should solve your angle problems. 

[shadetree 5,869]

2 hours ago, jeepwm69 said:

Neat looking project.   Could you add a second ujoint where the shaft goes into the swingarm?  That should solve your angle problems. 

if you look closely...he's already got two drive shafts going to rear end as it is. most drive shafts stop right at the end of swing arm, he's got an extension tapped into the swing arm drive shaft.

[jeepwm69 7,611]

7 minutes ago, shadetree said:

if you look closely...he's already got two drive shafts going to rear end as it is. most drive shafts stop right at the end of swing arm, he's got an extension tapped into the swing arm drive shaft.

 

Yeah, I was thinking if he put a ujoint between that joint where the shafts come together, he'd had enough flex to set the engine level.

[shadetree 5,869]

4 hours ago, jeepwm69 said:

 

Yeah, I was thinking if he put a ujoint between that joint where the shafts come together, he'd had enough flex to set the engine level.

if he can get a u-joint to spline both ends there at the swing arm..this would work.

[Lcarter114 4]

I pulled the plastic boot off the swing arm.  I see what you are saying now.  Whoever done it before welded the shafts together.  I would have to source some shafts.  One surprise after another...lol

[shadetree 5,869]

1 hour ago, Lcarter114 said:

I pulled the plastic boot off the swing arm.  I see what you are saying now.  Whoever done it before welded the shafts together.  I would have to source some shafts.  One surprise after another...lol

yikes !...lol. yeah..now yer gonna have to locate a couple drive shafts on top of a couple u-joints.