rx7racerca

iTrader: (1)

My first rebuild in 24 years of owning my RX7. I've mocked up the front stack, torqued to spec, after a rebuild (S5 NA, front iron replaced with a good used S4 one, due to a chunk of the inner coolant seal jacket breaking off near the bottom).

With the engine nose-up on the stand, I'm using a prybar to lift under the counterweight, and getting roughly 0.0018", using moderate force on the prybar, .002 if I lean on it what I think is a bit hard. This is in spec, just barely (min. 00016 listed). I used the K-spacer I had. I've taken it apart and reassembled just to make sure nothing was out of place (which would have likely crushed the Torrington bearing at any rate), same result

I'm measuring on the E-shaft bolt with a Princess Auto dial gauge (think Harbor Freight for you Americans) that has 0.001" increments, so I have to estimate the 4/5 increment between the .001 and .002 to come up with .0018, but I think its a good estimate.

Is this flirting with too little? Am I good? If I'm a bit on the too-little endplay side, what am I risking? If I've figured this right, if I get a slightly taller X-spacer, that will add 0.0008" and move my endplay around .0024, closer to the slightly high end of spec endplay. But that would likely mean waiting until Monday at the very least, and I don't want to lose 2 days of forecast good weather to continue getting this engine together and back in the car.

R-R-Rx7

iTrader: (24)

I would recommend getting a better dial indicator because with the horror freight and the other equivalent brands you dont even know if that .001" is accurate.

There are plenty of mitutoyo and other decent brands on ebay for less than a hundred bucks and they read in .0005" increments. Get a brand new one because you never know what youre getting with the used ones and how accurately they read

rx7racerca

iTrader: (1)

I was less concerned about the accuracy of the gauge (I'm pretty sure its the exact same one Aaron Cake has used in his videos) - but I see I can get a digital 0.0005" increment gauge overnight off Amazon.

I did, however, go back and recheck my measures - and realized I mis-remembered what exactly I got and how. I get 0.001 to 0.0012 with moderate force on the prybar; I only got the 0.0018 to 0.002" reading by putting a lot of force on the prybar - like, flexing the 18" bar's shaft level force. I'm pretty sure that not how it's meant to be done, so that definitely seems to mean I need the next-size up spacer - the X-size, just to take me to the 0.0018 to 0.002" range. I'm pretty sure I won't be getting that overnight from Amazon.

So, what does happen when the endplay is too-little? I gather if it's a lot too much, like if you dropped or mashed the torrington bearing, the e-shaft might even contact the bore of the centre iron, or at least the oil chain is excessively misaligned. Does too-little misalign the chain drive the other way?

Howard Coleman

iTrader: (6)

the motor likes 1.8 read with no muscle on the prybar. as things get hot clearances change and you wouldn't want bind on the bearings.