3 weeks ago I installed the 45N4592 (discrete) heatsink in my T61 FrankenPad. It is allmost a straight swap in, you only need to remove 3 small fins on the top.
However, after boot up I noticed some keys of my keyboard not working.
It were some keys in the middle, the T, Y, G, etc. I figured I didnt install the connector firmly. So I reopened the laptop, reattached the keyboard connector and booted the T61. However, after the keyboard reinstall even more keys where disfunctional. Now half of the keyboard doesn't work... I've ordered a new (NNB) keyboard, as the damage seems to be permanent.
Besides this, the cooling performance was quite good. The first 40 minutes when the T61 was turned on, the fan didn't even had to spin to cool it down. Idle temperature of the cpu was around 40C.
However, 3 weeks later, the T500 heatsink performance isn't any better than it was with the T61 heatsink. Idle temp during the first 10 minutes is between 40-50C, Stressed it can climb up to 75C. Fan spins much more often now, sometimes for 10-15 minutes.
I post this as a warning for you guys who are considering to do the T500 heatsink mod into a T6x. The T500 heatsink damaged my keyboard and its performance isn't any better than the T61 heatsink. It is not a perfect fit, it's a few mm thicker. Its only advantage over the T61 heatsink is that it produces a less annoying noise when the fan spins.
The ultimate combo is a T61 discrete graphics heatsink with the T500 fan installed, just like bmwman91 did. I would advise against installing the T500 heatsink in a T6x system. At the time my new keyboard arives I will perform the same mod as bmwman91 did.
I'm glad you finally managed to get the problem with the bulging keyboard sorted. Your post got me thinking as I (think) I have exactly the same setup as you were trying and have not encountered the keyboard issues you've had. I decided to revisit my T61 Frankenpad build and whilst doing it carry out another modification which may be of interest to other Thinkpadders (I'll concentrate on the keyboard issue here and detail the other mod in it's own thread later as I don't have much time now).
To be clear I use a T60p 15" chassis, QXGA flexview, T61 intel integrated graphics with a 45N4592 discrete fan from a T500. I didn't have a problem with the keyboard distorting and keys not working when I put it together. It all seemed to go together smoothly and work well. Your post encouraged me to look back with a critical eye for my own peace of mind.
When installed there appeared to be no distortion of the NMB keyboard to the naked eye. Putting a straight edge across the top of the keyboard showed what seemed to be a tiny, tiny
, rise above the heatsink area but it was still difficult to be sure. On disassembly I could lay the straight edge across the chassis and over the GPU clamp to get a much more accurate assessment. There was indeed a small lift above the GPU section. I guess I'd never noticed this because with the keyboard on it was imperceptible to the eye or in use. The keyboard worked perfectly and it was certainly not touching the screen. Why Backslahnl1 got problems with his and mine seemed to go together better without problems I couldn't tell you. Maybe I was just lucky.
Anyway, just as bmwman91 found with his (different, NVidia) setup, I had no problems and no permanent deformation of my keyboard. I think I could have carried on using it as it was. For my own peace of mind I decided to sort it out and filed down the aluminium block on the heatsink to allow the keyboard to sit dead flat. A tip if you decide to do this is to put some tape on the heatsink over the fan vents and fan inlet. In fact I taped the whole area except for the part I was working on as it was easy to do and I was paranoid about stray filings. You REALLY don't want little bits of metal floating around inside your pride and joy when you put it all back together. The alu is fairly soft and didn't take me long to remove enough carefully with a hand file. After a VERY thorough cleanup with a vacuum cleaner, taking all the tape off and triple checking it was clean it all went back together easily and the straight edge confirms it's now perfect.
I'm very pleased with it. For my own peace of mind I'm glad I went back to it. Thanks to Backslashnl1 for posting his experiences which even with the same setup and for whatever reason seemed much worse than mine but it encouraged me to check.