New here, looking to buy my first RX8

[ColSonders]

I'll be taking all the obvious things when buying a car into account, you can see rust visibly, low compression isn't quite that obvious and can be masked with an uprated starter motor.

[acegeezer]

Your mind seems set.. good luck.

[Nickp47]

I think buying a comp tester now is a very good idea as it will come in handy in keeping an eye on engine health as your ownership progresses as well as help you find a nice example of the RX-8, I am certainly glad I bought mine.
Let us know how you get on .

[New Duke]

I'll be taking all the obvious things when buying a car into account, you can see rust visibly, low compression isn't quite that obvious and can be masked with an uprated starter motor.

Don't let compression in the 6s put you off. You'll be lucky to find an engine in your budget with excellent compression.

My engine was mid 6s in November and is very happily working as both a daily and track car. Engines with comp below 7 can still be good for years. It's a lottery, just like the silicone lottery when buying a CPU.

[ColSonders]

Some varying opinions here about the compression test issue.

I don't understand why you wouldn't get a test done if you can do it cheaply and avoid buying a car with a dud engine....I'm not buying an RX8 without a compression test on the basis that I don't have to.

It's interesting to see opinions on what numbers should be considered workable, everything I've read in a weeks worth of research on tinterwebs would suggest anything below 7's you should walk away....My thinking is that if the owner is suggesting they don't redline it everyday then it's likely the engine has carbon buildup and the compression could well improve simply by driving the car hard and as long as a test drive shows the car pulls well through the whole rev range then it's probably fine.

So what numbers on a compression test would people here be looking for?

[Dazza44]

Everyones view will be different on that one, anything around the mid 6s is fine and as long as there all pretty even across all the faces.

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[PeteH]

You will be lucky to find any RX-8 (R3 or s1) that is well above 7 on all the chambers. The compression of a rotary naturally drops a bit as mileage increases, and even the youngest and best cared for RX-8 is now 7 years old and likely to be over 30k miles.

When I tested my well looked after and well driven s1 at 35k miles it was around 7 to 7.2. I considered these good results. As a general rule you might consider the following:

In the 8s: A new unported engine!
In the 7s: A very healthy well-cared for, low mileage engine
In the 6s: A "normal" medium mileage engine that has plenty of life left in it. And a very healthy ported engine.
In the 5s: An engine that is coming to the end of its life. Probably still fine for a few thousand miles, but start saving for a rebuild.
In the 4s: It might still run, but it will definitely let go at some point. Best get an immediate rebuild, to avoid further expense of broken seals.

This is based on a few years of seeing many people reporting their compression test results. It's not cast in stone, but should give you a better idea. If you hold can find an engine in the 7s then happy days. But if you find one in the mid to high sixes then you'll probably be fine for tens of thousands of miles.

[ColSonders]

You will be lucky to find any RX-8 (R3 or s1) that is well above 7 on all the chambers. The compression of a rotary naturally drops a bit as mileage increases, and even the youngest and best cared for RX-8 is now 7 years old and likely to be over 30k miles.

When I tested my well looked after and well driven s1 at 35k miles it was around 7 to 7.2. I considered these good results. As a general rule you might consider the following:

In the 8s: A new unported engine!
In the 7s: A very healthy well-cared for, low mileage engine
In the 6s: A "normal" medium mileage engine that has plenty of life left in it. And a very healthy ported engine.
In the 5s: An engine that is coming to the end of its life. Probably still fine for a few thousand miles, but start saving for a rebuild.
In the 4s: It might still run, but it will definitely let go at some point. Best get an immediate rebuild, to avoid further expense of broken seals.

This is based on a few years of seeing many people reporting their compression test results. It's not cast in stone, but should give you a better idea. If you hold can find an engine in the 7s then happy days. But if you find one in the mid to high sixes then you'll probably be fine for tens of thousands of miles.

That's really helpful info cheers

[ColSonders]

Along with what Pete says, the indicator that I would be looking out for is the difference between the numbers

- all six numbers within 5% is great
- rear three the same but all lower than front three = rear stationary bearing failing (reverse for front bearing)
- one in three low = bad news
- one in three high = two in three low = different bad news.

As for an upgraded starter "masking" compression issues, this is a little misleading.

The early starters were really slow and would become even slower over time and with tired batteries.
As such, an engine with even good compression can take a while to fire-up when heat-soaked.

The later starters were better and it would take a more significant drop in compression before hot restart became a problem, all other things being equal.

The R3 starter and many aftermarket starters, spin the engine faster and therefore aren't quite as sensitive to compression during hot start.

Therefore a pre-2006 car that's having a bit of a problem with hot starts can be "cured" by fitting a better starter, but that doesn't mean that it's got compression issues that are now being "masked" - it just means that the early starter wasn't up to the job.

I've seen people refuse to buy a car "because it has an upgraded starter, and therefore must have a compression problem" - which is a nonsense.

If you see a car that's had the starter, and anything else replaced, then it *might* have had parts throw at it to attempt to cure a problem, or it might have been owned by someone that recognised where the weak links are and was avoiding a problem. Same for coils.

I'd be more worried about new (cheap) coils or aftermarket O2/MAF sensors being fitted recently.

[ColSonders]

I've seen people refuse to buy a car "because it has an upgraded starter, and therefore must have a compression problem" - which is a nonsense.

If you see a car that's had the starter, and anything else replaced, then it *might* have had parts throw at it to attempt to cure a problem, or it might have been owned by someone that recognised where the weak links are and was avoiding a problem. Same for coils.

This is the issue for me, I WANT a car with an upgraded starter, but a car with this upgrade would mask hot start issues to a degree....this is where the compression test comes in handy.

If I get a car without an upgraded starter it'll be high on my list of things to get done....after making sure i've got fresh plugs/coils/leads and fresh fluids throughout.

[ColSonders]

So I'm ready to pull the trigger on an RX8.

I'm looking at 2 that both look to be in pretty clean condition.

An 05 (cheaper tax) with 75k on the clocks... Pictures show bubbling around the boot light.
It's easily within budget too.

An 06 (higher tax bracket) with 100k on the clocks but an engine rebuild around 6k miles ago. Pictures suggest it's in cleaner condition than the 05.
Slightly over my planned budget but certainly won't break the bank.

Would I be stupid to pass up on a clean car with such low mileage since the rebuild even if everything else is pretty much stock?

[Nickp47]

How much are the cars and do you know who rebuilt the higher miles one?

[ColSonders]

£1300 and £1800 and the rebuild was done by rotary revs with all the documentation.

[Nickp47]

A recent RR rebuild is certainly attractive, though personally for £1800 I would hold out for a lower mileage example with a compression test showing good results.
Does the 05 have a recent compression test?

[ColSonders]

Check with RR if there's any warranty left on that engine and if it's transferable.

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[ColSonders]

Check with RR if there's any warranty left on that engine and if it's transferable.

There certainly won't be any warranty left as the rebuild was done in 2014.... The mileage all checks out though, following the MOT history looks like it's just been a summer car since the rebuild

A recent RR rebuild is certainly attractive, though personally for £1800 I would hold out for a lower mileage example with a compression test showing good results.
Does the 05 have a recent compression test?

The 05 doesn't have a compression test, although I can perform one when I go to view.... Do you think I'm likely to find a low mileage 231 for that sort of price?

I'll really leaning towards the 06, it looks clean, it's barely been used over the last 5 years, the only bad things I can find are the higher tax bracket and looking at the MOT history there's a repeating advisory for windscreen damage.... Which I'm guessing isn't cheap to replace.

[ColSonders]

If the screen were to get damaged then it would be replaced for the cost of the windscreen insurance excess.

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[ColSonders]

Thanks everyone who's commented on my thread, I appreciate all of the advice.

I picked up a 2006 231 yesterday, 100k on the clocks, 6k on the engine, bodywork in really good condition (once I've got it polished up nice I'll get some pics).

I gave it a look over and no rusting anywhere other than a touch on the rear wheel arch. The windscreen damage on the MOT history has been repaired too.


Had it in today for MOT today and apart from needing the rear coils replacing it's all good.... But I'm gonna have to wait for that before I can have it back and it might be days!

[Nickp47]

Congrats on becoming an owner and look forward to the pics, was it a straight rebuild or was a bit of porting involved?

[ColSonders]

Standard rebuild looking at the paperwork from rotary revs... But I'm over the moon with getting an engine with such low miles since a rebuild.

Oh and it's Velocity Red

[Shagrington]

Congratulations and now you have one I'll post my usual list ...
Have a good read through whatever in the FAQ section you didn't already read and then (and just ignore me if you know all this already) here are my best tips for keeping it all running sweetly:

1. To start up turn the key to position 2, wait for most of the lights on the dash to go out (I watch the airbag light by the glove box), press the clutch to the floor (optional, but reduces drag), turn the key to start and do not touch the throttle until it has started. You can drive off straight away, just keep the revs down for a bit (see #4 below).

2. Never turn off the engine before it has reached at least somewhere towards normal operating temperature (should only take a minute or two, but best to go for a short drive if just swapping cars round on the drive etc). Switching off cold risks flooding, which is a real with a rotary engine. Mazda recommend rev to 4k and hold it for 8-10 seconds switching off while still revving if you have no option but to switch off cold (it is not necessary to do this in any other circumstance).

3. Check the oil level regularly (use the dipstick - the oil gauge tells you nothing other than that you have or don't have pressure) and top up if necessary with semi synthetic 5w30 (most people and specialists are advising to use 10w40 now though) ... small amounts at a time, no more than ½ a litre then check the level again before adding more as you don't want to overfill it.

4. Use all the revs once the engine is nice and warm (don't sit idling to warm up, start up and drive but keep it below about 4k until the needle on the water temperature gauge is pointing straight up, then give it another 10 minutes for the oil to warm up too before really thrashing it ) and hit the beep often. Best acceleration is from 4k revs up - to pull away you really need to rev to 2k - you can let the revs drop after lifting the clutch if you are in traffic, cruising steadily at 3½k revs and changing down to go up hills or accelerate gets you the best mpg ... which still won't be great.

5. Join the club for discounts on all sorts of things (you will very quickly get the cost of membership back - and then some), loads more info in the members only sections, local meets (or if you can't find one exactly local it is a good excuse for a drive if you come to one a bit further away), a sexy keyring just for joining and more.