Well thanks to Kevin yet again at Rotary Resurection for diagnosing my newbie error. I finished reassembling my s4/s5 hybrid and had 9 thousandths of endplay. I had watched the turrentine video and read the FSM the mazdatrix site and Haynes and was well aware of the need to make sure the bearing was riding on the outside of the spacer and had not fallen in behind the spacer, furthermore too much end play logically to me anyway would mean my spacer was too thin so If the bearing was behind the spacer that would be the same as a thicker spacer -- wrong on two accounts.

1. I was so focussed on the outer bearing I forgot about the inner bearing (the one inside of the thrust plate held on by the 6 bolts). And sure enough I had smashed it like a redhaired stepchild behind the spacer. (luckily they are only $11)

2. As to why a thicker spacer makes more endplay, I had to really scratch my head on that one. This may be obvious but it just seemed backwards, but if you picture the eshaft as shaft with a nut at each end, a larger spacer keeps the nuts farther apart making more endplay. I was originally thinking that anytime you put something thicker between to fixed ends that would have to make things tighter not so the ends are not fixed they are nuts and therefore it in effect makes the eshaft longer ala more endplay.

 

how did you measure the endplay?

 

Just like the turrentine video, engine pointed up with the dial caliper base on the front housing and the dial caliper on the counter weight then a screw driver wedged under the counter weight and pry it up. Kind of go up and down with the screw driver and you can see the end play on the guage. After I replaced the smashed bearing the new bearings still required the next sized spacer so I'm back waiting for Mazda parts. I can email you a pic of the measuring, can't seem to post any pics.

 

hm i guess that makes sense finally. i'd always assumed that the front bolt was torqued down as far as it could possibly go. so u're saying its not.. interesting i'll have to think about that

 

Contrary to popular belief, endplay is best measured with the engine completely horizontal, sliding the flywheel by hand (no tools to pry with). The engine is installed horizontal, not vertical, so the gravitational load of the eccentric shaft stack combined with the prying tool actually causes the front bearing thrust plate to flex, giving a higher reading of endplay than actually exists. Using the vertical prying method and setting endplay to minimum specs (0.0016", I like 0.020"), you wind up with less than actual minimum spec, and bearing wear is severely increased.

I've seen a guy with a pinched spacer (zero endplay) tell me his endplay was fine because he could get 0.0016" of movement with a crowbar on his flywheel. All he was doing was beinding his thrust plate.

 

Read my other post and re-check endplay. Set it to 0.0020".

If your endplay is still too much, then don't bother buying a new one. Put some 320-400 grit sand paper face up and put it on an old iron or a sheet of glass. (anything perfectly flat) Wet the sandpaper with some cutting oil, and then sand the spacer down in a figure 8 pattern.

To find out how much to sand it down, measure the thickness first with a micrometer. If you have 0.0030" of endplay, and want 0.0020" of endplay, sand 0.0010" off the spacer.

Simple, free, more accurate.

 

Wet the sandpaper with some cutting oil, and then sand the spacer down in a figure 8 pattern.
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Been there, done that. Works plenty good fine.

 

The forum deliver's again. I can imagine you sand very little to bring down the spacer a thou or two, and save some time and money.