Q: Using a 30, 40gb Hard Drive in 20gb 4th Gen iPod Clickwheel

Hi- I can't rattle off everything that you have to change over to upgrade the hd,but it can be done. Been a few years since and I've forgotten all the details...

Yes, you can put a larger drive in  the 20gig click wheel. Besides the HD, you need to replace the back case with a deeper one that the larger hd click wheels came with…and something else like the earphone jack or some other internal bit or piece….But you can read all about it over at iFixit.com to get the whole story.

I've thought of upgrading my dead 20gig 4th gen clickwheel for a few years now. But the hd's are no longer in production, and can be pricey. If you can find one.

I just happened to see some kid post his plans to mod his old-school iPod. I guess people are modding out their iPods with ssd's or another flash-drive type technology I can't remember at the moment…but basically, you can get an adapter on ebay or wherever for 3 or 4 bucks that lets you put in a flash drive of some make or model. Same type they have in some cameras. I've got some basic info and some sites to research the exact details of whats needed and where to get it. I keep forgetting to do it, getting sidetracked by something else...

So iFixit was where I read that it is possible to upgrade the click wheels HD, and what is needed to make it work.

40GB is the thicker 2-platter hard drive, so it won't fit (unless you get the thick iPod back casing).  30GB can be either one-platter (like your 20GB hard drive) or two-platter.  The older 30GB hard drive is the thick type.  The newer 30GB hard drive is thin.  So you need to fine out the specifics from the supplier.  You can put any thin iPod hard drive of the same type (not the more recent type with "ZIF" connecter used in 5th gen iPod and later) in your 20GB 4th gen iPod - They are all the same physical size starting with the 5GB hard drive in the original iPod.  The largest capacity (that is thin) is 30GB.

I have a 64GB compact flash card on an adapter in my 4th gen iPod (thin model with monochrome screen).  It mostly works great, except that it occasionally starts skipping through songs continuously.  Haven't figure that out yet.  As a test, I let it play by itself all day on shuffle until the battery ran low, with no problems.  I may be pushing the hardware; 32GB CF card would have been a more logical choice, except I wanted to fit my entire iTunes music library which is about 50GB currently.  Or it  may the particular brand or model if CF card that I chose.  It is reliable enough for my use.

Another option is the smaller SD card, which is usually cheaper for a given GB size.  But you need to put an adapter on an adapter, because there is no adapter that goes directly from SD card to iPod hard drive connector for the older "classic" iPods.  And some of those SD to CF adapters are too thick for the thin iPod model, when you stick it on the CF to iPod adapter.  Haven't tried it, but seems to work for some folks who write customer reviews.

What I just tried a few days ago works REALLY well on an iPod mini (not nano).  iPod mini uses an IBM MicroDrive, which is a really tiny spinning hard drive.  It is the same form-factor as the thicker compact flash card type.  That adapter for SD to CF is exactly the same size, with the same connector.  Along with a 64GB SD card, my 4GB iPod mini is now a 64GB iPod mini.  Restored smoothly, and synced to my entire iTunes music library.  I did not try it with my 64GB CF card, because that one's in my 4th gen iPod right now.  Still testing it out, but this mod seems to be ultra-reliable.

If you want the more details about specific products I used, please post back.