Saving Old Seagulls

I've just been given a non runner that I'm going to take to bits to familarise myself with the full make up of a gull
Clanger number 1
I attempted to remove the flywheel without putting the piston at BDC
I realised this after half a dozen blows and stopped
The flywheel didn't come off
How will I know if I've damaged anything

Lucy S wrote: I attempted to remove the flywheel without putting the piston at BDC
I realised this after half a dozen blows and stopped
The flywheel didn't come off
How will I know if I've damaged anything

I do not bother with piston position, if you were hitting it hard, after 12 blows you may have bent the crank.

What size hammed did you use? and were you holding the full weight of the engine by the flywheel.

If the crank is bent, you may feel the engine is a little tighter when you turn it over with the plug removed.

H-A

My lad was holding it clear off the ground, I held a piece of 3 by 2 on the dome nut and hit it with a claw hammer maybe 6 or 8 times and it didn't budge
It still seems to turn over just as easy
If I did get it running, what would the symptoms/outcome of a bent crank be

You do not need the piece of wood, claw hammer size is good.

Remove the nut, wd40 down the keyway in the flywheel, replace nut loosely

(use a spare old one if you have one) warm it up with a hot air gun, it can't hurt bit of thermal shock.

Suspend by flywheel and give a sharp tap on the nut, sometimes takes two hits.

Thin webbing straps can be threaded between the flywheel and the base plate, that is how I hold them.

Do not hold back when you hit it, you are not trying to bash it into the next county, but it does need a sharp tap or 2.

If the crank is bent you will feel it is a bit tight when turning over, with the plug out.

Post pictures so we can judge the condition.

If it does not look like this you should be OK.
H-A

I had faced a badly stuck flywheel to the crankshaft. Lubricants, heat, time, everything in vain. It was an MK2 magneto with one crack. After some blows I took the flywheel on my hands and the central fitting still stuck on the crankshaft. The crankshaft bent at some point so I stopped worrying about not being gentle. The only thing it worked was drilling down the flywheel key path to destroy the key. Then holding the lower end of the crankshaft in a vice and turning the fitting I managed to remove it. I may have saved both the flywheel and the crankshaft if I had drilled the key before damages occured.

You usually won't face such a situation. Follow H-A instructions, you can also leave it for some days with lubricants.

H-A
Is the give away of a bent crank being off centre in the flywheel?

Lucy S wrote:H-A
Is the give away of a bent crank being off centre in the flywheel?

Yes the crank should be in the centre of the flywheel.

Replacements are readily available and cheap.

Post a picture so we can see what is going on.

H-A

Looks ok, yes?

Unless you have a definite problem I wouldn't bother. Make it spark, that's all you need to do and that can be done 99% of the time with the flywheel on. The wipac coil is very reliable.

That looks OK, I think you should try again without the 3x2 wood .

Don't forget to put the nut back on.

H-A

As you put the nut back on, make sure you do it up just finger to hand tight so it can bottom out a wee bit. The reason why is because you wont damage the threads on both the nut and crankshaft as your giving it a hit with the hammer. Judging by your pic it doesn't seem to have any corrosion in there. Spray a bit of WD-40 down there and give it some time to soak before you go any further, that will help it.

If it aint broke don't fix it. By all means drip some pentrating oil in there and let it soak for a week before whacking it again. In the mean time clean the points, adjust and get her running. You might decide to leave well enough alone until 2030 when the wipac needs replacing.

Smart tip about the webbing straps.