Budget 12A SP build

[NoDOHC]

Atkins sells a kit for use in a standard press. That is what I use.

Please check everything for tolerances, you will thank yourself later.

Bearings are like $30.00 new (for 2) I think I would go that route, the chance of damaging them removing them is not entirely remote.

There should be a small ring around the metal part of the oil control ring that rides on the plate. I would expect this to be shiny (unless it rusted in the coolant).

If a seal is questionable, do yourself a favor and replace it. Better 1 seal than the whole rotor assembly.

How not to port exhaust (note many changes in taper angle and flow restrictions, early open and late close). Made 255 WHp at 10 psi.


Much prettier exhaust port (consistent, near ideal taper angle, no avoidable flow restrictions, stock open and close timing). Made 216 WHp at 0 psi.

[t_g_farrell]

Originally Posted by NoDOHC

... There should be a small ring around the metal part of the oil control ring that rides on the plate. I would expect this to be shiny (unless it rusted in the coolant).

If a seal is questionable, do yourself a favor and replace it. Better 1 seal than the whole rotor assembly.

Your referring to the 2 oil control rings on each side of the rotors right?
I'll be getting a full soft seal kit so I expect that will include the o-rings for the
oil control seals. The A engine oil control seals look brand new, no shiny area
at all. The B ones definitely look older and worn and are shiny about half way
across, probably out of spec as well.

Turns out I may be able to use the lighter weight rotors from engine A which
already have brand new bearings in them. They look almost new. In fact
everything from engine A is looking better than the B engine. The B engine side
plates have noticable grooves in them from the corner seals. I may use the
A engine front rotor housing instead of the B engine rear rotor housing which
has the chunk chipped out of the exhaust port top opening.

I'm thinking of trying out the Goopy housing resurface service. Its certainly
priced right at $125.00 for a pair.

[t_g_farrell]

Another question. My side housings show a darker coloring at the bottom
from after the spark plug hole over to where the exhaust would exit the rotor
housings? Is this normal? I'm assuming this heat from lean combution but is it
overheating damage? It certainly doesn't look like the typical iron overheat
damage they show on the mazdatrix site:



Otherwise they have almost no step wear, definitely nothing I can feel with
my fingernail. I still have to spec them out to make sure they are flat enough.

I know I need pics. I can probably get them up tonight.