i just pulled my 12A for a basic rebuild. it has 114k miles, and seemed to have very good compression. im going to clean it out and replace all the gaskets. my question lies in the rotor parts. i dont have much money to play with. Im not buying new apex seals, side seals, or oil control rings because they are too expensive. the other parts arent as expensive but put together add up. of the following other rotor parts, what are the most important for a basic rebuild?...

rotor bearings
apex seal springs
corner seals
corner seal springs
corner seal plugs
side seal springs
oil control ring O rings
oil control ring springs

which parts should I definatly replace? any i can safely leave out assuming my motor has good compression?

 

I have seen rotor motors built with used apex corner and side seals & springs last a long time. I wouldn't reccomend it, but it does get done.

On the list you provided I'd definately put oil control O rings on the top of the list to buy new. Then corner seals, springs, and plug. Use 3rd gen corner springs, they are a much better design.

After that it's up to you to decide how strong and reliable a motor you want.

Might as well streetport the motor since it's all apart, and I'd also go with an 85psi rear oil pressure regulator. Helps motor live longer when revved.

Not common to replace rotor bearings unless they're beyond factory wear specs or you want it to last a LONG time.

 

ok all the O rings i need and the corner seals,springs,and plugs comes to about $138. the side seal springs arent expensive so ill get those too which brings it to around $147. I think the apex seal springs would be good to replace so now its $174. what about the oil control ring springs...could i get away with reusing the old ones?

I might do a mild streetport if I think i can pull it off without screwing anything up. the rex this motor is for is my daily driver and I wont be tearing it apart again until i save money to convert it to a 13B and get my housings pineapple large streetported, etc. (all the goodies).

 

If it's only 114k the internals are probably all still good. Invest in a good micrometer and set of feeler gauges and USE THEM. Everything that has a spec, measure it.

But if it had good compression, most likely everything is still good, and you'll only be out the cost of cleaning everything up and a new gasket kit.