compression test results opinions

[cat_nipples]

So this is the result of the test.
Apparently they done a rebuild the company that tested it 2k miles ago.
Car is being sold £1900 with clean mot with no advisories , just looking if its worth taking it.
Based on the other sheet i have seen 7.0 isn't worth picking up.

[rameshr]

I would at 7.0 was the rebuild at LC Rotary? It’s important who did the rebuild


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[cat_nipples]

I would at 7.0 was the rebuild at LC Rotary? It’s important who did the rebuild


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I just realized its in bar , so its actually 7.4 to 8.0 right?

[acegeezer]

The front rotor all equal 7.0.. and uneven on the rear

[Harrizone]

Those results look doctored IMO. Just because they look like the sort of result which would persuade you to buy, just too even.

[cat_nipples]

Well turns out the car is being sold by lc rotary itself , lmao that was weird.
So yeah I will most likely pick it up today , and the person I talked adviced he will give warranty invoice as well.

[New Duke]

What evidence is not picking something up with comp readings below 7s based on then? Some Mazda blurb somebody once read? Mazda are the ones who spec 5w30 oil (even thinner in the USA) and set very wide wheel alignment margins.

7s is a ludicrously high bar (geddit?) to set for a car worth under two grand.

[SeriousSam]

If it's an LC Rotary car, you should be fine, they're trusted around here. The results do look a bit curious, but over 7 on all faces is pretty damn solid, especially for that money. If it comes with their warranty, give them your money - that's a good buy.

Haydn, the Mazda advice is that anything below a certain level (6.7 if memory serves) is a failure, and many prospective owners have used that as their benchmark. The fact is that many of us drive cars that are significantly below this level that start every time, hot or cold, and make full power. I'm one of them, my car was recently tested in the mid-5s and I'm pretty happy with that.

[mi60o0]

I pic mine for a 1k with better readings done two comp test Essex and Lc rotary car was from a car sale place part exchange I still use 10w30

[Nerdstrike]

The readings match the graph spike pattern for the rear rotor, but the front rotor is not recorded matching the pattern. That said, it doesn't look awful. 7 bar dead is probably the lowest of the readings if my guess at the scaling is right.

I wouldn't be sad if my car had returned those numbers at 50k miles. It went another 40k miles in the 6's before I sold it. This one has just been rebuilt and run in, so maybe the results are disappointing, but compression in the 8s is probably fantasy on anything other than brand new irons and housings, which are not a given on a rebuild.

I'd take those odds if the rest of the car is straight and not too rusty on the sills.

[cat_nipples]

The readings match the graph spike pattern for the rear rotor, but the front rotor is not recorded matching the pattern. That said, it doesn't look awful. 7 bar dead is probably the lowest of the readings if my guess at the scaling is right.

I wouldn't be sad if my car had returned those numbers at 50k miles. It went another 40k miles in the 6's before I sold it. This one has just been rebuilt and run in, so maybe the results are disappointing, but compression in the 8s is probably fantasy on anything other than brand new irons and housings, which are not a given on a rebuild.

I'd take those odds if the rest of the car is straight and not too rusty on the sills.

Yeah I agree , only reason decided go for it cause they will give a warranty on the rebuild if something goes wrong I dont have to worry about £
They have actually sent me a video as well from the test.
And looking now they sold quite a bit of rx8 with their rebuilds , so I suppose people don't have any massive issues with what they do.

[PeteH]

You will rarely hear any issues with LC Rotary. They are a trusted bunch of people round here. In fact, if we see compression results that look "dodgy" our advice is often to take the car to LC Rotary to get it independently tested. You can buy that car with confidence.

[13Black]

Not to doubt LC or anything but the peaks for the front rotor should all be level on the graph, which I assume is the top plot... but it goes 'up down down' instead it seems?

Rear readings seem to match the lower plot, with an 'up up down' pattern.

I wonder if that plot is for those readings?

Either way it probably doesn't matter as those figures on the sheet with the registration number seem good to me.

[Harrizone]

If that is LC Rotary readings then I take back what I said about them looking iffy as they are a trusted source . However some dealers have been known to doctor test results on paper to make them look more attractive .

[cat_nipples]

Well the car is home , the car was fine on 40mile ride.
I revved it quite a bit , wasn't doing anything funny.
It did fine on hot and cold start.
Obvious rust around the skirts , and bodywork surprisingly just had one 2mm dent on the door.
Is it common for the gear knob to vibrate very slightly , u only notice it if you keep your hand on it.
Other thing was it looked like fans are running in slow even though it says there are off , any idea on that ?

[Scartlead]

I'd advise to get the skirts off the car and do a little rust prevention, as the 8 can rust badly behind on the sills. Do you have the aero skirts fitted or full length ones? Vibration on the gear knob, shouldnt be too bad, but have a quick look at engine mounts, as when they're worn, vibration can be much more noticeable, but without being specific there could be a few reasons as to why.

Ref the fans, are they running continuously?

[cat_nipples]

It sounds like they are , but I might be wrong unless its meant to make low hissing noise as something is spinning at high speeds.

[New Duke]

It sounds like they are , but I might be wrong unless its meant to make low hissing noise as something is spinning at high speeds.

Could be a few things, even air intake pipes or the gearbox spinny bearing thingy (technical term). Post some decent audio if you can. There's a lot spinning at high speeds on this car

The air vents will allow airflow out of the vent even when the fan is off. They don't 'lock off' like most cars. I set the vents to exit out the floor if not using them.

Is it common for the gear knob to vibrate very slightly , u only notice it if you keep your hand on it.

Yep. Totally normal and only mildly erotic. As previously said it's worth checking your engine mounts when you can anyway. But it doesn't sound excessive. Congrats on your purchase.

Haydn, the Mazda advice is that anything below a certain level (6.7 if memory serves) is a failure, and many prospective owners have used that as their benchmark. The fact is that many of us drive cars that are significantly below this level that start every time, hot or cold, and make full power. I'm one of them, my car was recently tested in the mid-5s and I'm pretty happy with that.

Totally Sam. I think that old Mazda compression benchmark has become a nuisance as the target level for comp tests, hence the amount of dubious results we see. It's also leading used RX8 buyers to expect cheap as chips cars to hit that Mazda compression benchmark, which was clearly never meant with the used market in mind. I understood Mazda applied it specifically for dealership warranty claims.

[cat_nipples]

Both rear wheel arches has some rust closer to the ground , any idea if thats expensive to sort out?
Looks like it went around 4-5cm deep

[Dan-Lincs]

Got some pictures?

[akhan48]

LC Rotary are a trusted specialist here, I doubt they would be willing to damage their reputation over a dodgy compression test and £1900 worth of car. Those results are pretty good anyway, better than my R3.

[cat_nipples]

So there was only one key with the car , i just put the new battery in the fob.
I can hear the motor moving when u press the central locking on the fob but it wont lock the doors - any advice on that?
If I want another key fob + programmed , where abouts I can get it done. The only key i got looks quite tatty as well.
I'm based in Kent.

[Dan-Lincs]

You can get a used fob off ebay (£10) and program it to work with the central locking your self (instructions how to do so are accessable if your a club member), ordered a new fob case and blank key blade off eBay (£4). I then got my transponder in my current working key 'cloned' (£30 and local key cutting place) and blank key cut, works like perfect being able to start the car aswell.

[Dazza44]

Door not locking/unlocking could very well be a sticky door actuator.

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[cat_nipples]

Door not locking/unlocking could very well be a sticky door actuator.

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It locks manually , actually boot opens on fob.