Rotor Direction!
 

So ladies & gentlemen.............

Is there any conceivable reason why you would put the rotors in backwards; ie the front in the rear and vis a versa?

PS Its a race engine!

Y

NO, never do this ever.

it depends. on the 13B engines, from 1974-2003 the front and rear rotors are the same, so nothing happens.

on the 76-85 12A engines, they have an LDR combustion recess so if you put em in backwards, you change it to TDR, which should just suck.

the Rx8 engines have a little cut on the side to open the ports a little early, so if you put em in backwards you loose there too.

Its as 1980 12A engine with scallop'd edges to increase effective inlet.
scalloping is in wrong place if we put rotors back the right way!

Not a cheap engine from a 'renown' US builder.
Guess he had a 'bad day'

How do you know they are in the wrong place?

did you ask the builder if he intended to open the port sooner or to close it later? that can determine if the scallop is on the leading edge or the trailing edge and will affect torque and the power band depending on the build's chosen purpose.

in reality it is a very minor difference either way

They were installed this way round,with the chambers upsidedown.

Ahhhh so the scallops were on the leading edge but the combustion chambers are backwards.

Hmmm interesting.

As door stops they have a certain attraction; one that one can stub one's toe on and remind oneself of the 'wonderful individual from the free world who built it'/'the consummate professional who values his reputation'.

Calm - Calm - OMM - OMM - OMM - OMM - OMM - AAAAAAAAAAAAAARRRRRRRRRRRRRGGGGGHHHH !

1) Talk to the builder first to resolve the issue.

2) If it was indeed an oops, have him machine the other rotor flanks for early opening as well as late closing and press for a full rotating assembly balance in the deal.

MDR, LDR, TDR seem to just affect the timing of peak charge velocity in regards to the gas charge switching from the trailing to leading side of minor axis.

They experimented with all three styles and it is just as likely that Mazda used the LDR rotors and the LDR motors unique ignition configuration for emissions alone.