help!how to locate tdc[or the rotary equivalent]
 

here is my problem.i'm putting in a new motor in my 87 rex[na].there is a punch mark on the ecentric pulley,as well as on the esentric hub,wich,one would assume,should line up so the pulley is situated properly and the timming marks are in the right spot.problem is,the punch mark on the pulley is off to one side of a hole,and on the hub its on the other..[yes,i'm putting it on the right way...]i dont know why,could have something to do with me having a 89+rotaying assembly,really have no idea.so,is ther any other reliable way to figuer out how the pulley alligns?maybe to do with the orientation of the flywheel key on the back?any help much appriciated!!
david

Ok, get a mirror and a trouble light. Remove both spark plugs from the rear rotor. Via the bolt on the eccentric shaft, turn the engine until you see an apex seal in the trailing (top) spark plug hole. Mark the pulley. Now rotate the engine until you see the same apex seal in the leading (lower) spark plug hole. Mark the pulley. TDC for the front rotor (#1) is right in the middle of the 2 marks. Good luck!

Irv, Keith's dad :cool:

thanks very much for responding,irv.i still have some qustions.what you wrote makes perfect sense....acept for the fact that there is basically 3 tdc position....wich,actually makes sense also.the question is,wich one of the 3 do i have to allign my timing marks to?does it matter?i guess there may only be 1 position that works,couse of the way the pulley has to get bolted on to the end of the esentric....or does it matter....what then,about the crank angle sensor?maybe there is only 1 position it will work too..hmm....any more help here?thanks a bunch!!
david

It doesn't matter. Every time the rear rotor is in the position described, the front rotor is at TDC. This is because the eccentric shaft will make a complete rotation for every 1/3 rotation of a rotor (a complete cycle - intake, compression, exhaust). Therefore, the front rotor will only be at TDC at 1 spot on the pulley, all the time, every time. As far as the crank angle sensor goes, it only goes in 1 way with the front rotor at TDC - align the marks and install, as per the tech. manuals.

Irv, Keith's dad :cool: