short story bought a 2007 191 instead off a 231 total mistake got delivered when check i was errr
any way can i put in a 231 i no it will fit in but with been 5 speed instead of 6 do i need gear box to just yes or no really and sorry i know this will have been asked a lot


when got car oil light was on put almost 4 litters in it light went off looked at top were meant to be .

2 days after doing a 30 mile drive light came on stooped at garage put more oil in with engine on took 3 litters light went off


when i checked when cold next day there is far to much oil in the car .doing oil change when home tonight to fix this

but after my long story (sorry) i know its not leaking cos theirs far to much in

where is the censer so can clean or replace it

(car will not start when hot )

 

The real problem you have is the car won't restart when hot. That's a sign of low compression, which would mean the engine is toast. The oil light can come on without any real cause, it's a known issue (a TSB actually) on 04-05 RX8s.

The fix is to replace the sensor and the oil pan (inside of which the sensor sits). But focus on the compression issue.

You want a rotary compression test to confirm the state of the engine. Only Mazda or a rotary shop can do that, a regular compression tester won't work.

If you need to swap out the engine, I don't have all the info, but at a minimum upgrading to a 6port "231" engine requires the 231 ECU and another oil cooler. And a known good (tested!!) 6 port engine. Pretty sure the 5 speed trans can stay.

I don't know how the prices are out there, but it might be cheaper/faster/easier to just buy a (tested!!) 231.


Also you're from the UK, please use those english skills, it's hard to follow what you're saying.

 

Since I am currently in the middle of a "low power" 191 4 port removal and a "high power" 231 6port installation, I will chime in here.

You will need:

A complete high power 231 engine, with lower and upper intake manifold, fuel rail, and fuel injectors. A second oil cooler is recommended but not strictly required. You will also need a high power 6 port ECU, and its paired ABS box. It is very difficult to pair these, most dealers will refuse to do it, or claim ignorance, so its much much easier to bring a matching pair. You will also need the engine harness for the 6 port motor (they are different, as the 6 port has more injectors and more accessories).

You could leave the 5 speed transmission, but I have read that it is a poor match for the 6 port. (The gearing is different between them, and the 6 port makes more power up high). Speaking of more power up high, you will also need a 6 port dash cluster, in order to have an accurate tachometer. Yes, you can leave your current one, but it will look strange, and it will appear that you are revving into the red, when you really are not. Please be advised, the mileage for the car is stored in that dash cluster, so a swap may cause a mileage discrepancy. Use caution.

As Loki pointed out, it would be best practice to do a rotary specific compression test on the new motor before it goes in. A coolant system pressure test is also not a bad idea.

As with all rebuild / replacements, you will want to flush oil and coolant, and replace the ignition system: spark plugs, ignition coils, and wires. These are wear items on these cars, and they start to fade after approximately 20,000 miles.

Good luck!

 

thank you for that i do not think i will attempt to change the engine type