Thursday, December 4, 2014

Spare Engine - Flywheel Fiasco

Seeing as it's winter, well nearly winter! I know it doesn't actually start until the 21st of December, but in my book it's winter already. Anyway, seeing as it's winter, I thought I'd best get cracking with the 'Grand Winter Project' of rebuilding a replacement engine.

Back in March I bought a spare engine on the cheap to see if I could rebuild it with the hope of swapping it over. I have been gradually stripping it down over the year and now I need to get the flywheel off. This is not the easiest task at the best of times, but this time, it was a nightmare...


The last time I removed a flywheel, I created my own 'super heavy duty' clutch puller which seemed to do the job. So I dug it out, dusted it off and got busy. Having removed the outer housing, slackened off the big centre nut and ensuring piston 1 and 4 were at TDC. I bolted the clutch puller in place.



But as I turned the three bolts, things didn't seem to be going as well as last time. The heads of the bolts seemed to be bending and eventually one snapped off, which is never a good thing.



The problem seemed to be that the heads of the nuts were not able to sit flat on the weight plate because of the embossed writing on the surface. So out came the angle grinder and I flattened off the lettering and tried again with new and stronger bolts, up from an 8.8 to a 10.9.




But even with this modification, there was a point where I just didn't want to turn anymore as I was worried about ripping the threads out of the holes on the flywheel. So a slight modification was needed in the shape of a fairly beefy centre nut and bolt through the hole in the weight plate.



The idea was to use the three outer nuts to get the weight plate level, then use the centre nut and bolt to do the pulling using a spanner on the nut and a breaker bar on the bolt.



Using this method I was able to crank a huge amount of torque to the centre bolt. I was sure it work now. But it didn't! I pushed the bolt to the point where the breaker bar was starting to bend, but still it stubbornly remained in place.

I tried bashing the centre nut with a hammer, more out of frustration than a belief that it would do anything. Turns out that a hammer will not fix everything!



Next to come out was a blowtorch, I hoped the heat would expand the outer part and help to free it.



Guess what? Nothing, it was still stuck fast. Getting frustrated I decided to leave it for the night and and attack it again in the morning when I wasn't so annoyed. Maybe leaving under tension overnight might just help it along.

Disappointingly when I got back to it the next day, it had not miraculously popped off, so after another couple of hours of heating, bashing and trying to turn it, I decided to try to hit it through the starter motor hole. Most things I have read about this say that it's a really bad idea as it will damage the flywheel and there is potential for hitting the housing and breaking it. But I was getting desperate and decided to sacrifice the flywheel if it meant I could get it off and progress with the engine strip.

It seems the bad things I read about using this 'bashing through the starter motor hole' method were true. Not only did it not work, I knackered the flywheel and even worse, being the ham fisted buffoon that I am, I managed to hit the housing and break it! A few choice words were uttered. I'll spare you the details, but I'm sure you can sympathise.



By now I was getting pretty desperate and was beginning to worry that the 'C' shaped washer had maybe been put on upside down and was causing the problem. There was no way of knowing really. Time for a cup of tea and a bit of a think.

After one last ditched attempt with heat and hammering, it was time to break out the big guns. As much as I didn't want to, I was going to have to grind the flywheel off the crankshaft. This was tricky and potentially dangerous both for me and the end of the shaft. As I had never done this before, there was a bit of trial and error to be had, but I knew that if I mostly concentrated on one side of the centre piece, it might just be enough to break the taper without having to grind right through and damage the crank also. I had already wrecked enough stuff!

Cutting away a portion of the diaphragm for access, I started to grind. Progress was slow, but there was a spectacular display of sparks to compensate.



Actually progress was painfully slow, but after about an hour (or two) of noise and fireworks finally a crack started to appeared in the metal as it weakened.



Refitting the crank puller, I crossed my fingers and tried again...



And sweet success at last. Well it seemed like a success until I reconsidered the destruction of the housing and the clutch assembly. I did manage to save the crank though, so one out of three, well it's better than none I suppose.



With the flywheel finally off, I was able press on with the rest of the engine strip down which thankfully went ahead without any further drama. Despite the frustrations and all the carnage, there are positives that I can take from this.

It's quite often the projects that go wrong, the seemingly impossible ones, the ones that make you work just that little bit harder, they are the ones that offer the best learning opportunities and also the greatest feeling of achievement once done. Sometimes, through bitter experience comes our sweetest reward.





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