I'm rebuilding a 671 turbine engine. All has gone well until I put the side rods back on. When I start the engine they lock up. I've checked everything I know ( quartered the wheels, new side rods, old ones don't work either) but no luck. I must be over looking something. HELP!!!
I assume that it runs without the side rods.
Your quartering must be bad. What did you replace? Axles? Wheels? If you didn't replace these, did you put all the wheels and axles back in the same locations that they originally had?
Bob Nelson
Replaced axle bushings...quartered and requartered wheels. How spot on must be the quartering be? I removed the motor and the wheels on one side and tried turning the wheels with the side rod on and still the side rod binds before one complete turn. Could the line up of the wheels stil be off? Please advise. I'm really stuck.
It doesn't matter how close the quartering is to 90 degrees. What is important is that the angle between left- and right-side cranks be the same for all axles.
When wheels are first pressed onto axles, the axle splines cut grooves into the wheels. It is important when removing and reinstalling wheels to keep the wheels together in pairs, since they will tend to rotate to the closest existing grooves.
However, I think you're saying that the rod still binds when it is the only rod on the locomotive. Do you have the earliest, 1946 model of the 671? It has two worms and worm wheels on both the first and last axles. This requires that the crank angles match with the worms engaging the worm wheels, even though there is only one rod installed.
I have only the one worm gear. I replaced the worm with a new one ( the old one was worn down the middle of the gear). Could the armature end that contacts the worm gear be too worn to contact the worm gear correctly causing it to slip enough to bind the rod? Does the side rod have to be super tight to turn all four wheels? I know I sound dumb but this engine is making an idiot out me. I truly appreciate your help in this matter because I need some one with more experience than I have. Thanks again and let me know if you any ideas to help get this engine running.
Are you trying to run the loco with only one side rod? That will not work.
With one side rod on, where are the screws for the other side rod? Are they all at the same angle?
I just checked a 736 which has a similar side rod arrangement. The rear axle is driven by the motor and all the other axles are driven by the side rods. There is enough clearance between the holes in the side rods and the screws that attach them to the wheels, that the front axle will turn several degrees when the rear axle is stationary. You should also be able to turn the front 3 axles through several degrees without the rear axle turning. No matter where the wheels are, the side rod should be nearly parallel to the track.
There should be noticeable play in the side rod in all directions, up and down, forward and back, and in and out. The screws with the 1/4-inch hex heads that hold the rod onto the wheel cranks should be tight enough that they don't work loose; but the cranks should protrude far enough from the wheels that the screws, even when tight, can't pinch the rod and it has room to move around a little.
Try taking off both rods to see whether the motor can turn the one geared axle freely.
(The "worm" is the screw-like part of the motor shaft. The gear that is on the axle is the "worm wheel".)
I did not know that. I have the motor out and was turning the gear wheels by hand to see if the side rod would turn freely. I have taken the wheels off several times to quarter them and when I put them back and spin the wheels by hand they still bind up. Is there a way to check it? I want to thank everyone for their comments on this issue ( I need all the help I can get ). I won't rest until I beat this darn problem so I'll know how to fix one in the future. Thanks again
With the rods off it runs fast, smooth and quiet. The motor runs excellent. Just the problem when side rods are attached. With the side rods off all the wheels turn smooth and free. I keep coming back to the side rods as the problem.
Take off the side rods on both sides of the engine. Now line up all the wheels on one side of the engine so that the side rod screw holes face the same exact direction. Without moving the engine, look at the wheels on the other side of the engine. They should all line up perfectly also. Whichever one(s) do not line up, need to be pulled off and pressed back on again in line with the others. As Bob stated, quartering does not have to be exactly 90 degrees, but each of the wheelsets must be quartered identically to all the others, or the rods will bind.
This is probably not the issue, but since the bearings have been replaced, make sure all axles are parallel to each other, and one axle is not skewed front to back. That would also cause the rods to bind.
Larry
Try this: Get the cranks on one side to the topmost or bottommost position. Then install the rod on that side. Then go to the other side and hold a straight-edge along those cranks. They should all be in a very straight line if the quartering is consistent.
I'll try that
Ill give it a shot.
Check the smoke unit lever and piston. With the rods off, the smoke cam won't turn. So, it could be binding, and it wouldn't be obvious until the rods are installed.
Jim
Smoke lever and cam are OK. I got the wheels quartered perfectly. The wheels turn freely with the side rods on but only if the side rod screws are loose. If I tighten the side rod screws so they don't come out the the motor worm screw starts spinning on the worm wheel. Could the armature worm screw be bad? I replaced the worm wheel but when the side rods bind it just spins around and makes a growling noise. Any idea what the problem may be? This engine is driving me NUTS !!!
With the side-rod screws tight, is there any play in the rods? There should always be a little. I measure the depth of the shoulder on the cranks at .075 inch and the rod thickness at .050 inch. That leaves an in-out play of .025 inch; so a tight screw cannot pinch the rod. What do you have?
When you put on one rod at the top or bottom position and held a straight-edge to the other side's cranks, what did you see?
I wonder whether the wheels are pressed on to an inconsistent gauge. That could cause some binding.
If you put a caliper to the edge of the siderod screw mounting holes, is the width consistent?
Bur I wouldn't expect the binding to be too severe.
Pull the motor out and tighten up the side rod screws with the side rods on. Roll the chassis by hand. There should be no binding. If there is, take one side rod screw out on one side and roll again. If there is still binding, replace the screw and take another one out. Roll again. Do this until you take one screw out and the binding goes away. That wheel is not quartered properly.
With the straight edge, top and bottom are dead on. I kept working at it until they were both even across. The engine runs fine as long as the side rods are loose. They will turn a quarter turn then bind.
It's hard enough trying to troubleshoot a problem on the Internet under any circumstances; but near impossible when I can't get a clear answer to any of my questions. For the last time:
With the side-rod screws tight, is there any play in the rods? There should always be a little. I measure the depth to the shoulder on the cranks at .075 inch and the rod thickness at .050 inch. That leaves an in-out play of .025 inch; so a tight screw cannot pinch the rod. What do you have?
Does it help to see photos left, right and the gap between the rod screw and the rod?
PROBLEM SOLVED!!!!! HOORAY-HOORAY I followed your advice and found that the last drive wheel was binding the side rod. I requarted the wheel and same thing happened. I was looking at the side rod under a magnifiying glass and it looked like the side rod's last hole was a little smaller than the rest. I measured each hole (used drill bits - it's all I have right now) and sure enough three were the same size but the last one was smaller. I drilled the last hole on the side rod and put it back on and BADA BING BADA BOOM the darn engine ran like a charm. No binding. I want to thank everyone for your time and patience with me on this problem. I learned so much from all your great advice and I'm glad to see that there are so many helpful people in this hobby. I hope someday to be as smart as all you you out there because I love trains too. GOD BLESS ALL AND THANKS A MILLION AGAIN FOR ALL YOUR HELP. I'M HAPPY
Harry ( I'm still happy now )
Glad you found the problem. Wonder if that loco ever ran properly? Certainly no one would have thought that a 'manufacturing defect' would be causing your problem.
Enjoy your trains, and your knowledge gained.
Out of curiousity... the side rod with the small hole, was the hole on a motor driven wheel or a non powered wheel? or vice versa. On some of my Flyer locos the side rods have different holes at different ends. If your side rod had a small round hole on a non powered wheel I wonder if simply flipping it around to put the hole on the other end would have solved the problem. It just doesn't seem right that the loco could have enough miles on it to wear a worm and bushings with a factory defective side rod (unless of course this was the cause of the wear)
Lover of all things Gilbert, truly a man ahead of his time.
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