RX7Ratty

hey, im having my 93 fd rebuilt at the mo and i have been told that the crankshaft might need replacing. this is because it went through the bearing, which was filled with piston rings so that it could pass its compression test, and they are goin to try and repair it but i was wondering if they can't then does any one know where i can get one or would an rx8 one be alright.

Thanks

thatpoorguy

ok where to start............



on a rotary engine the crankshaft is actually called the eccentric shaft, or e-shaft for short. spinning a bearing is nothing uncommon and you should be able to get a bearing spacer (correct me if i'm wrong guys i have yet to rebuild a rotary, i'm a diesel mechanic for christ's sake), the rotary also doesn't have piston rings as it doesn't have pistons at all. it has numerous seals though along the edges of the rotor and the faces. the ones on the edges are called apex seals and are the most common to **** the bed. i don't have any parts that you need but knowing what to ask for should help you find stuff easier. best of luck and check out the site attached.



HowStuffWorks "How Rotary Engines Work"

Speeder

Whew! Think my "Shtuff" detector just went off the scale!

No pistons in a rotary.

No crankshaft.

filled with piston rings so that it could pass its compression test????



Someone is stretching things a bit.





& no. From what I understand, you can`t use an eccentric shaft from an RX8.

Someone is trying to take you for a ride. Watch your wallet.

If you want to, look around on EBay for an eccentric shaft. I have seen them & they are usually cheap. The bearings they ride in sometimes go too if the E shaft is trashed. Usually oil starvation is what does it.



Check the blinker fluid also while you have the car apart.

thatpoorguy

and don't forget to check the muffler bearing

Signal 2

Actually, you can. They're nominally lighter, but identical in all other respects.

Other parts will also interchange...thrust bearings, main and rotor bearings and IIRC stationary gears.

thatpoorguy

didn't know that, are there any advantages to doing that?

Speeder

Seems like I had read somewhere it wasn`t recommended. I hate getting old as the memory loses specifics. I am not sure I would want to mix parts of one model in another. Just my opinion. Doesn`t mean much! LOL! I know on the RX7 models, rotors & such are interchangeable from varying years as are side housings & gears. Just depends on what you are trying to achieve during an engine build. Sure is alot to have to keep up with!

Signal 2

Obviously the lighter weight is some advantage. They drill one additional hole into each lobe of the RX8 e-shaft...which is not a high stress area. IIRC, it's not a lot of weight...about .5 lbs. How much difference that makes is a matter for speculation.



As for things like the Torrington (thrust) bearing, I used it on my rebuild a couple of years ago, along with the washer and plate. As I recall it had the same part number as the FD bearing with just a different letter designation and was about 1/3 the price. Not sure about the price difference on other parts, but if that's any indication, it's an advantage.

RX7Ratty

Hey all engine has been rebuilt had to get a new e-shaft but its all good now. Piston rings were used to make it pass compression test bast*rd before i bought it must have been lookin for a quick fix. Its also been rebuilt with pineapple racing tips and am now looking to single turbo it. many thanks for all the comments much appreciated