Re: 5 speed conversion question, the long story
After being on a pretty steep part of the learning curve I have completed the installation of the Toyota W58 gearbox in my BN2. As advertised, it is essentially a bolt off /bolt on conversion...with a few qualifications. I did use metric, Whitworth and standard wrenches, grinder with a cutting wheel, both mig and oxy acetylene welding, floor jack, cherry picker engine hoist, tallest drive up ramps I have and jack stands. If I had it all to do over it would have taken about a quarter of the time it did, assuming I knew what I know now. For posterity and perhaps helping someone down the road I'll briefly review what I had trouble with. Please bear in mind I have a BN2 that had the side shift gearbox with overdrive. I should also point out that Pete Delaney who supplies the Smitty 5 speed kit under the name Healey 5 Speed was helpful all the way. He was usually available by phone and made right the two parts issues I had. The kit was complete with one exception ( see below) and that was quickly corrected by Pete. The kit instructions are OK but didn't really address the issues I had.
The first issue was fitting the master cylinder for the hydraulic clutch conversion. Everything except the original clutch pedal and jackshaft goes away. It seems that on the 4 cylinder engined cars there is not enough clearance between the edge of the oil pan and where the master cylinder bracket mounts. Once I spoke with David Deamer, who had just completed his BN1 5 speed swap in Southern CA, I realized this was a feature and the bracket just needed to be notched to correct this. Not a big deal at all, just not expected. Steve Gerow was also very helpful and my thanks to both of these people for sharing their experience.
Second, it appears that there are two different engine backplates and two different bell housings that were used for the side shift transmissions in the BN2 and the 100/6s that had them. The physical difference is the location of the bolt holes on the front of the bell housing. I do not know if my back plate and bellhousing were original, I suspect they were but one can never be sure. When I put the new gearbox into position to mount it I was freaked out that some of the bolt holes were not going to even be close to lining up. A quick call to Pete and the correct back plate was in the mail. Since I had already reinstalled my lightened flywheel and installed the upgraded BJ8 style diaphram clutch assembly on it it was a bit of a pain to undo all that to put in the new back plate. Problem solved.
Third, one of the parts in the kit is a small aluminum pilot bearing carrier that you press into the center hole of the flywheel which replaces the original first motion shaft pilot bearing/bushing which remains in place in the back end of the crankshaft. There are two styles of carrier that are available in this kit. One has a flange on it and the other doesn't. Due to some confusion I got the wrong one. I got the one with the flange, which is not for the 4 cylinder cars. The flange causes the pilot bearing to be positioned further aft, by the thickness of the flange which is about 0.14", which prevents the transmission from mating with the backplate by that amount, due to interference with the taper on the first motion pilot shaft. I broke the cardinal rule of not using the mounting bolts to draw the parts together but had the foresight to check that the engine was turning freely before I torqued them too much. Low and behold, the engine would not easily turn. I was loading the first motion shaft bearings, as soon as I eased off, everything freed up. A conversation with Pete Delaney when he asked if I had pressed the bearing carrier in flush and I mentioned the flange made him realize the wrong carrier was put in the kit. I could have just ground off the flange and pressed it flush but he sent me the part. Off came the clutch and flywheel again. Correct carrier installed and that all went together just as it should have.
Last but not least, as others have found, the geometry of the clutch jackshaft lever that come with the kit with the length of the forked shaft on the supplied master cylinder, didn't quite work out for me. Going to a hydraulic clutch it became apparent that I couldn't have the proper throw on the master cylinder without having an extreme angle on the master cylinder rod. I ended up removing the rod and shortening it ( that's where the welding and grinding came in). Although I didnt have to, I also made a jackshaft lever out of steel to replace the aluminum one in the kit. Nothing really wrong with the kit lever, I just wanted a bit more strength. As a final tweek to the clutch system I made a slightly longer link from the slave cylinder to the clutch fork. This was very easy as you just cut a piece of plain steel rod and smooth the ends to a rounded shape and pop it in place. You need to make sure that 1, you have enough throw to activate the clutch properly and 2, that the master cylinder does not have a preload on it that could prevent the orifice that unports and allows resevoir fluid to flow freely in both directions. There are clutch set ups in some cars where the throwout bearing spins all the time and some where they do not. The kit bearing is not supposed to spin when not engaged so the only force on the clutch fork is from the return spring in the slave cylinder, not strong at all. There should be just a bit of free play at the clutch pedal when the master cylinder is relaxed.
The kit in general is well made and has everything you'd need to complete it, you just supply the gearbox. It is not quite " one size fits all" but pretty close. I hope this helps someone, someday. I did find that a large bottle of Ibuprophen was useful when it was too early to start drinking.