^ interesting results

 

harder can also mean brittle depending on how things are tempered. But this doesn't mean its a bad thing for the rx8 crankshaft. There could have been some seriously out of balance things going on in the only 2 motors to fail with one in them. I don't know all the details so its all speculation. The hardness numbers are kinda scary on the FD shaft though

 

well we don't know if the shaft that i saw was the same one that rotarygod is talking about or not.

keep in mind that statistically, mazda has made 50,000+ e shafts (there is one in every rx8 after all), and we MIGHT have 2 bad ones, but we don't even know that.

plus the shaft i saw at sevenstock was the damage FROM a bearing/oil failure, and that would have destroyed any eshaft, this one was just damaged more.

 

Running rx8 e-shaft + front and rear stat gear and rx8 rotor bearing. all that is required is to match up the stat gear oil passage. I did not rebalance and have been fine.

 

Do you have to use Rx8 rotor bearings with the Rx8 e-shaft?

I was wanting to use 89-91: rotors, rotor bearings, counterweights with
Rx8: e-shaft, stationary gears, stationary gear bearings.

In a 74 13b block. Dremel the rear stat gear bearing to line up with the rear plate main oil galley. Street application. Would that work? And if I run it under 8500rpms would it need to be re-balanced?

Does the Rx8 front stationary gear dictate using the larger thrust bearing pack?

 

This is from one of the top US engine builders. There's so much misinformation on Internet forums:

 

This.

 

As regards clearancing...

The 12A that I killed from overrevving a couple years ago... okay the 211k mile bone stock engine that I killed from overrevving that is... finally came apart the other day.

Bearings looked perfect. Apex seals and housings, of course, are FUBAR, with a few patches of no chrome left at all (so that was why it ticked at idle...) but a few interesting things. The apex seal slots still look to be in good shape, and the bearings all looked perfect.

Mind you, this engine saw most of its life with me on 5W20, and had a beehive so it was HOT 5W20.

Food for thought on bearing clearances. (And no, I am not quite sure what it means)

 

You need to rebalance the hole assembly if you use 89-91 rotors and counterweights together with a lighter rx8 shaft.

 

I believe that to be incorrect. The e-shaft is a center piece of the rotating assembly, but is balanced on its own. I believe all the weight added to the e-shaft needs to be balanced, but I am assuming that they balance the shafts separate at the factory when they are made. This assumption comes from the balance holes drilled in the shaft at the lobes. Its my assumption that they balance the shaft separate, then balance all added weight as a group. That would be the front, and rear counterweights, and the flywheel. Makes more sense from a manufacturing standpoint, but that's just me. I could very well be wrong.

 

Anyone else?

 

I could see this as very true since the weight saved is too close to the center of rotation. therefore, it won't have much of a benefit from the weight loss. Virtually no effect on rotaing inertia.

gd

 

It does not. I used the RX8 front stationary gear and the regular thrust bearings.

 

What is a regular thrust bearing, an FD thrust bearing, or pre-FD?

 

FDs Thrust Bearing was larger then the FC Thrust Bearing. I used the FC model.

 

Weird, I was told the RX-8 stationaries use the FD thrust bearing.

 

Well, I must have phoned that order into Mazdatrix and didn't get an email for it. So I can't confirm what I ordered.

However, I thought that the thrust bearing was front counterweight dependent and not stationary gear dependent.

 

I'm planning on building basically the exact same engine this winter for my Rx-4. Bridgeported 3B 13B 4 port with S5 rotors and counterweights with renisis e-shaft, stat gears, and bearings to match. As far as I know it should work perfectly fine. I don't see any need to balance the rotating assembly. Would it be nice, yes but not necessary. As long as you don't rev it to the moon, it should hold together.

 

Any issues setting end play with an Rx8 e-shaft , Rx8 stationary gears, and pre-1986 everything else? Will the 8 partst cause any interference, cause the eshaft to hit anything and make a false reading on end play?

 

if you look at the part numbers, the FD uses the same bearings as the high power rx8. the low power rx8 actually uses the 74-91 bearings.

the rx8 front gear will have the place for the big bearing, all you would need is a counterweight that is also big bearing, since FD = late FC, then that would be an option. the bearings get held by the spacer, so you should be fine using the small ones too.

i don't know about the balancing. i built peepers with counterweights out of a pile, with everything else new, i decided to have it balanced, so i didn't have to worry about it.

i sent mine to AZ rotary rockets, glen and tom are both cool

 

People say to oval the Rx8 rear stationary gear oil galley hole to the rear of the motor 2mm. I'm using an old 3b rear plate and had to grind it at least 3mm, and not just grind the top of the hole but port the first 1/4" into the hole to get the path right.

Cone dremel bits got the shape right so it's like a funnel.

Stock rear gear for reference, and the stocker galley doesn't completely fill the oil feed galley from the filter. It needs to be match ported basiclly about 1mm to the right (or towards the flange when the gear is sitting on the table). Orange mark up sharpie about 1/2 way thru the porting process.

 

Noticed that the part numbers for the RX8 e-shaft differ between the auto and manual tranny. Anyone know the difference between the two shafts?

 

Manual transmission is "high power", automatic is "low power", work from there.

Do e-shafts come with the pilot bearing installed? Heck, that may be the only (practical) difference.

 

yep. that's the difference with the pre-Rx8 shafts

BTW 3 years on, has anyone heard of another shaft failing? or was it just that one?

 

My engine in my Rx-4 is still going strong. Roughly 10k miles on it of hard use, still builds over 100psi oil pressure above 3k rpm. No issues at all. I even over heated it once last fall when a heater hose blew. Didn't catch it until I saw the dash gauge was pegged and my autometer gauge was pegged at 250 degrees.