Long story short, just put together a motor. It's a half bridge S4 T2 with side cut and tip clearanced rotors. Irons have also been lapped.

After stacking everything tonight, cranked it over by and and the compression is BEAUTIFUL. 6 crisp pulses.

However, when I turn it on it's head, there is absolutely zero play up and down on the e shaft. What could be the cause of this?

Also, side note, it takes about 20 ft lbs to turn over. Someone did the research and found it should take no more than 15.


Is there something wrong? If so, what could it be?

 

If youre turning it over with no front stack then you have a pinched seal somewhere, if I had to guess a side seal came up out of its groove or you may have overtightened the keg. IIRC its 12 ft lbs, 18ft lbs, 27ftlbs?

 

Oh you're not supposed to turn it over without the front stack on? I was unaware of this. I tightened the keg to 40 ft lbs.

 

so you're definitely over torqued. go ahead and loosen them all and reset to this and try again. this says 23-29 ft lbs.

 

I've also read that my stat gears could need shimmed. Since my plates have been lapped and the rotors are side cut, could it be possible the stat gears are bottoming out on the e shaft/rotors? If so, how would I go about shimming the gears?

 

Did you try loosening the keg and retorquing to the picture above? Are you aware how much material was removed from the plates? I have a hard time believing so much material was removed that you would bottom out on the stat gear.

 

if you loosen the front pulley bolt does it have endplay?

is the endplay zero because the rotors are stuck, or because there is no endplay?
we say endplay but its really the thrust bearing preload.

 

So I figured it out, and the answer was painfully obvious. First I loosened the tension bolts to spec, and tried again, still no endplay.

It was the front stat gear. I snugged up the bolts on the front stat gear WITHOUT the front stack on. Since the front bolts are so long, it was bottoming out the gear, causing 0 endplay. If I loosened them just a bit, so that they were hand tight, there was plenty of endplay. Assembled the front stack and got .002" of play, which is perfectly within spec.


In hindsight, the thrust plate must space out the bolts enough so that they don't bottom out and allow the e shaft to float.


Now, follow up question. I was turning the motor over with no front stack (given, without any endplay, but still). Could this have caused any issues that would require disassembly (ie. side seal popping out of the groove, or oil control rings)? Engine takes 15 ft lbs to turn over now that endplay is set.