syklone

Right after I spun in the tension bolts in I rotated the engine to get a good look at it and realized I put the rear housing in the front and the front housing on the rear. Stupid me, but I remember checking before I put on the first one, but the paint made the R look like an F.

So I couldn't really find any differance between the two, is there any? Should I just pull it apart, or leave it and call it good.

The only cost in pulling it apart would be time. The tension bolt are finger tight, so I'd just have to reset the orings, apex seal springs and corner seals, but I'd rather not if it doesn't matter.

BlaCkPlaGUE

If it were the same, it would just be listed as "rotor housing" and not, 'rear' or 'front'

I think its becuase the coolant jackets need to match up... that'd be my guess.

Bob_The_Normal

Were the housings used?

--Gary

syklone

The housings are used, but not in their current configuration. I thought that it must be something with the coolent passeges too, I have 4 bad spares floating around, I could check those out I guess.

But ya, if it doesn't matter then why are they marked F and R.

RotaryEvolution

iTrader: (30)

if you are concerned with emissions then pull it apart and swap them, the rear housing has the EGR port in it's casting the front does not so it will block the EGR flow.

here is a good thread on the subject:

https://www.rx7club.com/showthread.p...=rotor+housing

Bob_The_Normal

Don't forget he has to pull it apart now anyway... it's used so there is probably a groove from the 2nd apex seal piece, and it'll be on the wrong side now... lost compression!

So yeah I'd say pull it apart. =(

--Gary

syklone

Its all S5 turbo stuff, so no egr to worry about. According to that linked post, the housings should be funcionally the same then, right?

syklone

I thought that the apex corner piece faces the flywheel. If that is the case, the groove should be in the same place on both housings.

Bob_The_Normal

True enough!

--Gary

RotaryEvolution

iTrader: (30)

the grooves only set in with time, and the engine isn't together fully, also the boot rides in the rear portion of both rotor housings so that should not be an issue anyways.


syklone, check your exhaust manifold and see if there is any ports that match up with the passages below the exhaust ports.

syklone

Nope, the exaust manifold doesn't have any ports to match the holes below the exaust ports. It bolts up just fine, and looking at it again, I don't see any reason for the front and rear designation. They seem to be identical. I'm going to go with it in the current configuration, unless someone knows otherwise?

RotaryEvolution

iTrader: (30)

i don't think it will matter on a non EGR equipped vehicle, i wouldn't worry much about it.

HAILERS

On a SERIES FOUR, NON-TURBO the placement of the rotor housings makes a difference for sure. They are NOT the same.

The ACV feeds airpumjp air to the EXAUST PORTS.

It does this thru passages in the intake manifold that mate with passages in the front and rear SIDE HOUSINGS. The passage INSIDE the front and rear housing, travels downwards and exits facing the rotor housings passaages. If the housings are swapped, then the passages will NOT lead to the hole in the exaust ports and hence not feed fresh air from the acv to the EXAUST PORTS. The holes I'm talking about are about 1/2 inch dia and feed into the exaust diffusers.

I'm NOT talking about the EGR passage. I'm talking about PORT AIR.

Note that I stated SERIES FOUR NON TURBO. I've not looked at a SERIES FIVE turbo or non-turbo.

I posted detailed pictures of this severall years ago. They''ve been deleted from this forum.

NOWHERE in the above did I say swapping the housings makes a difference in the running of the engine in any other respect except the emissions i.e. the PORT AIR will not make its way to the exaust ports. Therefore messing up the chances of passing emissions leagally.

HAILERS

And I just looked at a turboii, series four that I just took apart. The same applies to the series four turboii. The Port Air passages are different on the turbo vs the non turbo.

On a series four turboii, the acv passage goes thru the intermediate housing straight down where it exits on the bottom front and rear sides of the intermediate housings. Its a triangular hole on each side at the bottom of the intermediate housing.

Those trangular holes mate with trangular holes in the front and rear ROTOR housings and the passages in those intemediate housings exits thru a half inch hole inside the exaust ports. I'm NOT talking about the half inch hole facing the exaust gasket.

IF the rotor housings are swapped, the acv PORT AIR will NOT go where it is supposed to go i.e. the EXAUST PORTS.

I'd bet my bottom dollar the turbo and non turbo series five are similar to the series four TURBOII in design.

Not emissions concerned? Then press on with the housings placed either way. Emissions concerned? Then arrange them per original design.

HAILERS

And I just looked at a turboii, series four that I just took apart. The same applies to the series four turboii. The Port Air passages are different on the turbo vs the non turbo.

On a series four turboii, the acv passage goes thru the intermediate housing straight down where it exits on the bottom front and rear sides of the intermediate housings. Its a triangular hole on each side at the bottom of the intermediate housing.

Those trangular holes mate with trangular holes in the front and rear ROTOR housings and the passages in those intemediate housings exits thru a half inch hole inside the exaust ports. I'm NOT talking about the half inch hole facing the exaust gasket.

IF the rotor housings are swapped, the acv PORT AIR will NOT go where it is supposed to go i.e. the EXAUST PORTS.

I'd bet my bottom dollar the turbo and non turbo series five are similar to the series four TURBOII in design.

Not emissions concerned? Then press on with the housings placed either way. Emissions concerned? Then arrange them per original design.

BlaCkPlaGUE

I say just do it right in case you need to add emissions again, or sell the car and you don't want to leave the new owner with a surprize if he/she wants emissions back.

J-Rat

iTrader: (2)

Ahhh... Memories..

HAILERS

Yep. I remember your engine. Too bad nobody mentioned denatured alky in that thread.

J-RAT bought an engine with the housings swapped a few years back and had a touch of a problem with emissions testing. He overcame it though and went on to bigger and better things (turbo)

syklone

Thanks HAILERS, that was exactly what I wanted to hear. The car is so far gone emissions wise, I'm just going to go with it as is. The engine is ported, intake and exaust, with a removed: airpump, acv, and cats, and soon to be vacume spider. Thanks.