What he said.
My only other advice, since I just did 4 of these:
This got long... sorry. Just started typing and before you know it...
1. You need good technique for pulling and reinserting the crankpins. That is the trickiest part of
the job, I think. To do this:
a) lay engine on its back
b) apply power to get the crankpins all at the bottom on one side
c) lay engine on it side with the bottomed crankpins facing up
d) slip Xactro knife blade under rod and pin head, gently pry up to start raising the pin out of the driver
e) place finger over crankpin, pry a little more (so the pin can't go flying if you pry to far)
f) when it is 1/2 to 3/4 of the way out, slip very fine pointed tweezers in around the pin,
and gently push so that the head of the crankpin rides up the tweezers as they are eased along
KEEP FINGER OVER CRANKPIN while you do this
when it comes out, place in a cup, repeat.
2. Lay all the rods as you free them in the order they need to go back on that side. mark them,
label them , or take a photo so you will remember how they go back on!
3. Once all rods are off, lay engine on its back, remove the 3 cover plate screws.The one under the pilot truck can be reached with a little effort by swiveling the truck out of the way,
but be careful not to snap it free from it's pilot arm and send the spring flying
4. Remove cover plate5. Pluck out the 4 old driversNote: #1 will be harder to pull out and push in than the others. Unlike the others,
it plants firmly into the frame and locks in the slots with no wiggle. You may have to work it
a bit to get the old one out.
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As Victor suggests, if your #1 or #4 are not cracked, I would use the non-cracked one
in the #4 position, and only replace the other 3. This is because I have been seeing spotty behavior
with the new-style driver bearings being able to stay in the frame slots without popping out
and going cock-eyed against the axle while running.
6. Look at the crankpin holes. #1 and #4 are the same. Put those in. #2 and #3: one has the gear
and can only go in one slot. And that leaves the remainining one.
Put the geared driver in so the crankhole will be at the dead bottom, when the engine
is turned upright. This will make it easier to get the 1st 4 crankpins back in7. Make SURE you get the "ears" or tabs on each bearing into the little slots in the frame
on both sides of each axle. This is particularly tricky on #4 because of the sprung fingers under it.
But if you use an older axle tube driver, it is easier.
8. Put the cover plate back on, being careful that all 8 bearings stay in their slots as
you get it in place. It is easy to bump a wheel and knock a bearing out of the slots.
This is especially true on #4 with the spring fingers under it. You may want to hold that driver down
into the very bottom of its slot with your thumb/index finger of one hand while you put the cover plate
back on with the other, and don't let go until you get the plate all the way down so it can't pop out,
or move its bearings out of place.
9 Replace the screws.
10. Now... to replace the rods and crankpins. Driver #1, rotate hole to bottom, engine on its side. Lay rod over hole.
Gently get the pin in some tweezers, locate pin through rod and into hole.
Try to get a finger tip or finger nail onto the tip of the pin before you let go.
Push a little, try to get the pin just started.
Now, with slightly wider-jawed tweezers, one jaw behind the wheel, other one on top of the pin, squeeze.
KEEP FINGER or hand over the pin while you do this to help stop it if it goes flying.
Driver #4, same process as #1
Driver #2, get rod from #1 swung up onto #2, place SECOND rod on top, get pin through both rods
and into hole. This takes patience and it is very important to have the engine lying dead horizontal
in a foam cradle so that the rods don't keep trying to slide around while you work.
Now swing rod from 2 up onto 3, swing the one from 4 over onto 3. This is the hardest one because
the two siderods plus the main rod from the valve slider, all have to stack up over the hole.
Once you get all 3 (use a toothpick through them all, into the hole to get them lined up),
put the crank in. The crank/eccentric rod end is square, so it can only go in one of 4 possible
ways. Starting from the left end, it has 2 joints. It should go down, turn right, over, turn downward,
and then the crank goes through the 3 rods stacked up over the driver.
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Turn engine on its back. Apply clip leads to just get the drivers rotated so that the
crank holes on the OTHER side (without rods) are all at dead bottom. Be careful. It's easy to
jam the rods when only one side is connected. Just touch for an instant, then re-line-up all the wheels,
touch again, until you get the holes bottomed out.
Now lay on its side and put the rods and pins into the other side.
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Except for the issue with the bearings that won't stay in their slots, requiring me to make a special piece
to keep them in position, this method served me well. I did 4 of them and I'm 0 for 32 on lost
crankpins (meaning there are 32 of them and I didn't lose any).
Good luck!
