I"m doing my first rebuild of a JDM S5 13B. I've got the engine apart and am deciding what to do about some of the parts. The front and rear gear bearings are shot. Is it better to have new bearings pressed in or replace them with good used parts? I ask because I remember reading that some builders don't like replacing the rotor bearings because they will not hold as long as the oem pressed bearings. Is the same true of gear bearings?



Front gear

http://sphotos.ak.fbcdn.net/hphotos-..._7803560_n.jpg



Rear gear

http://sphotos.ak.fbcdn.net/hphotos-...1_333458_n.jpg

i personaly wouls replace the front and rear gears with rx8 gears, there hardend and race clearanced from the factory with multi window bearings. and there half the cost of aftermakarket gears or even thirdgen gears. plus there set screwed into place wich is nice. another little trick that i have been doing latly is to dry ice the bearings and heat the gears and rotors to 300deg f. and coating the outside of the bearings with green locktite. use a heat gun , not an open flame though. since i started using this process i have had zero bearing failure.

Won't I need an RX8 E-shaft? Do you have any links where I can read more about swapping gears?



Also I noticed near mirror image wear pattern on my stationary gears. The front wear including all discoloration not just copper showing ranges between 10 and 3 oclock position. While the rear wear is between 6 and 10 oclock. Could this be from overtightening belts? or simply normal wear patterns?

i have run both the REW and the 13b and 13bt eshafts with the 13bMSP gears. have not had an issue. the only thing you need to watch for is the rear gear and some of the front gears from the MSP because the oil holes do not line up. easy fix is to elongate the gear hole so the oil passage lines up. easly can be done with a dremmal or a die grinder and a carbide 1/8" bur tool. also the rear gear of the MSP does not allow for and O ring seal so a small amount of grey sealent is needed.



as far as the ware pattern of the bearings, that seems pretty common, yes it could be because of belt tention but its also caused by deflection from the rpm and combustion.

I had a very reputable engine builder advise against using the RX8 gears. I'm told the FD were/are the best to use.

lets see here , one 13bre with an rx8 e shaft and gears making 500 plus hp no issues what so ever with bearing ware or any other issues, 4 E Production 6 port road race 13bs all running near 10000 rpm with rx8 gears one with an rx8 shaft with no problems. 2 fds running the rx8 gears again with no problems.



i think ill stick with what i said and use the rx8 gears

I'll read up on FD gears, but in an effort to reduce any chance of user errors I'm wanting to keep my first rebuild as OEM as possible. If I'm sure reliability comes first I'll consider some modifications but my goal isn't to create a frankenwankel. That being said, I do appreciate the feedback and advice and I'll research and consider all advice tossed my way.

fd gears and rx8 gears are both hardend , both have multi window bearings with set screws, the rx8 gears are clearanced for race aplications also from the factory. yes you need to mod the rear gear oil passage wich anyone can do in 5 minutes.



i choose to use the rx8 gears because of avalibuilty and cost. the fd gears where on back order for a long time and cost almost 3 times what the rx8 gears do at my dealer price. i stick to my guns and use all rx8 internals minus the rotors as the weight is less on the e shaft and the gears are clearanced better and they are more readly avalible at a less cost then the fd stuff.

I believe I have read that the Renesis has more clearance than older engines, and that either the crank or bearing has even more clearance on the rear half of the bearing then the front half. All good stuff. The crank tends to flex into an "S" shape at high revs and this produces extra wear on the outer ends of front and rear bearings. Engines run at high boost then produce wear that bends the crank away from the spark plug side of the engine. Not unusual and reduced in the Renesis bearings. Higher oil pressure and windowed bearing shells help as well.



I think the Renesis rear bearing comes in 4 sizes, and the biggest would be used in hard street use or racing.



Very few of the holes that connect the stationary gear oil hole and the one foot long drilled hole in the rear iron will line up perfectly. Use a small ball stone to enlarge the stationary gear hole to the extent that none of its edges appear in the line with the hole in the iron. The hole in the gear is plenty big enough at 100+ PSI oil pressure. The gear is hard all over and drilling it is nearly impossible. The alignment tab is still there so the reason for the set screw through the bearing has escaped me. If you loose oil pressure and weld the bearing to the crank, that set screw will be in the pan with a bunch of other swarf.



The gray stuff on the bearing is only about .0005" thick and in the old days we just scraped off the rear half of the bearing with a knife blade. Some builders press in a new rotor bearing and bore out the gray stuff a bit of the copper to get extra bearing clearance. The copper is a fine bearing material. So, when you wear through the gray stuff it looks real bad, but is of little matter performance wise.



I would use the Renesis gears, just from the cost stand-point. All of the gears have been hardened for years so not a factor.



Lynn E. Hanover

thank you lynn. this is what i was trying to say but i can never relay my point across as well as yourself.