Hello from a prospective buyer

[PeteH]

1) I've heard some dodgy explanations for poor compression results but, "it's digital, so we randomly adjust them to be higher" is about the worst. He wrote them on a piece of paper for frig's sake....
2) Changing spark plugs to improve compression is hilarious! Spark plugs obviously have no direct impact on compression (they are not fitted when compression readings are taken....) I guess they are suggesting that the motor is clogged up with carbon due to duff spark plugs. If that's the case then the spark plugs would have to be seriously dodgy, and they would be seriously damaging the engine. That's reason enough to walk away.
3) There appear to be some odd compression compensations going on in this thread! I put them into foxed.ca (at 324 feet) and got:

Front: 6.25, 6.19, 6.37
Rear: 5.58, 5.58, 5.58

Which makes sense to me. They are the bottom end of what is worth buying. For an R3 they are poor, and for a sub-50k mile car they are very poor. Rebuilding an R3 isn't nearly as easy as rebuilding an s1, because finding R3 housings (with 3 oil ports) isn't nearly as easy.

On balance, this car is a potential money pit, and really worth not much money (only my opinion, of course).

(what WarpC0il said. I'm a slow typer today!)

[Nickp47]

It’s a difficult one, in my experience it is wholly possible that updating the ignition, oil etc and driving the car correctly can improve compression substantially, one of my previous R3s did just that - started in the 5s and improved up in to the 7s.
Thing is I bought that car cheaply due to the low figures so it was worth the risk, with this car the asking price is commensurate with a car showing very good compression.

[Ollie]

1) I've heard some dodgy explanations for poor compression results but, "it's digital, so we randomly adjust them to be higher" is about the worst. He wrote them on a piece of paper for frig's sake....
2) Changing spark plugs to improve compression is hilarious! Spark plugs obviously have no direct impact on compression (they are not fitted when compression readings are taken....) I guess they are suggesting that the motor is clogged up with carbon due to duff spark plugs. If that's the case then the spark plugs would have to be seriously dodgy, and they would be seriously damaging the engine. That's reason enough to walk away.
3) There appear to be some odd compression compensations going on in this thread! I put them into foxed.ca (at 324 feet) and got:

Front: 6.25, 6.19, 6.37
Rear: 5.58, 5.58, 5.58

Which makes sense to me. They are the bottom end of what is worth buying. For an R3 they are poor, and for a sub-50k mile car they are very poor. Rebuilding an R3 isn't nearly as easy as rebuilding an s1, because finding R3 housings (with 3 oil ports) isn't nearly as easy.

On balance, this car is a potential money pit, and really worth not much money (only my opinion, of course).

(what WarpC0il said. I'm a slow typer today!)

I figured out what I did wrong! Numpty forgot to put the speed that it cranked at in the calculator heheh. Yours seem much better Pete.

To be fair the HME said the engine is healthy and new spark plugs would improve the results. How much would this improve results by?

Humm....

Maybe someone more educated can comment on this, I cannot think of any sensible reason why new spark plugs would improve compression!

My mates mum earlier this year had a Kia Ceed with literal catastrophic engine failure. Low compression, chucking oil out the exhaust etc. Two TWO independent garages wrote identical reports as to what was wrong. Finance company refused, company that sold the car also refused. Had it taken to halfords where an unknown spark plug was changed (they refused to say what cylinder) and this apparently fixed the low compression issues... According to the "independent" mechanic either the finance company or company that sold the car had go over it... Absolute bull crap obviously.

[Honkytonk]

It’s a difficult one, in my experience it is wholly possible that updating the ignition, oil etc and driving the car correctly can improve compression substantially, one of my previous R3s did just that - started in the 5s and improved up in to the 7s.
Thing is I bought that car cheaply due to the low figures so it was worth the risk, with this car the asking price is commensurate with a car showing very good compression.

Just to derail the thread a little, I am very interested in the concept of improving compression by just treating the car right. Is this a proven phenomenon in the community? I'd like to imagine such a thing is possible, if nothing else but for my own peace of mind.

[Ollie]

The only thing I know like that would surely be an engine not fully bedded in vs bedded in? If that makes sense... But thats not going to be a massive jump upwards surely?

[Nickp47]

It’s possible, the example I have mentioned is the biggest increase I have seen but have seen small increases on others too. Carbon build-up is the reason agreed upon when I have spoken to those more in the know.

[New Duke]

Move on from this car Adam. Is it a private or trade seller? If private then there's double the reason to be careful. R3s are rare but if you can, buy from a trade seller.

If you've restricted your search radius then open it up to the whole country. It's worth travelling far to find decent one. And this one wasn't a decent one.

[nightfire10]

1) I've heard some dodgy explanations for poor compression results but, "it's digital, so we randomly adjust them to be higher" is about the worst. He wrote them on a piece of paper for frig's sake....
2) Changing spark plugs to improve compression

Can i have some of these plugs for mine ?

[PeteH]

It's absolutely a thing. One reason for low compression is that the seals become carboned up, and stop moving. There is a thing called an "Italian decoke", which just means "drive it like you stole it", which will burn off a lot of the carbon (just like setting your oven to full power for a self-clean).

[nightfire10]

I drive like that every time I get in it

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[Honkytonk]

It's absolutely a thing. One reason for low compression is that the seals become carboned up, and stop moving. There is a thing called an "Italian decoke", which just means "drive it like you stole it", which will burn off a lot of the carbon (just like setting your oven to full power for a self-clean).

Ah yes, the "Italian tuneup" as I've always known it. Nice! I better go get my car compression tested again...

Back on topic, I would avoid this car. As has been mentioned in other threads, travelling for a good car is worth it, especially with all the issues that can be lied about or masked by an unscrupulous seller. There are also members who would be quite happy to pop along and help out, no matter where in the country you end up looking, or you can get a specialist like Luke Murdoch to check it over so you get results you can trust.

[Adam41]

I've walked away from it. Thanks guys for the advice, much appreciated.

Back to the search... I'm looking in the whole country it's just they don't come up for sale too often.

[New Duke]

You're right they don't. If you have the luxury of patience though you'll hopefully be rewarded. There's no problem buying one that needs work, but parts cost so much (particularly on the R3) that if you can buy a good example to begin with it'll save you time and money overall.

Happy car hunting!

[SeeJay]

Not sure what your budget is,but a quick Autotrader search within a 50 mile radius of Nottingham threw up this red,2010,48,000 mile example..

https://www.autotrader.co.uk/classified ... ZDA&page=1

[Adam41]

Back to the black RX8 I walked away from... apparently HME used a different procedure in the compression test.
They crank the engine with no throttle, while others crank the engine with full throttle to allow air flow which will result up to a 20% difference in reading.

Is there any truth in this?

Don't want to keep going on about this but I'm intrigued now.


Seejay - I phoned that garage a couple of weeks ago. The salesman was a bit of a d**k but said he would get the engine "compressed" and give me a ring back. But he didn't then I was out the country. Might give them another go.

[13Black]

Just don't have any dealings with HME they're clearly brain dead. Nothing I ever see from them impresses me.

20% HAHAHHA maybe if the readings were 10psi with no throttle.

Utter, utter idiots.

[PeteH]

They crank the engine with no throttle

Well that would be a dumb thing to do! The engine will be sucking a very significant vacuum with the throttle shut. The result will tell you only how "shut" the throttle actually was, and how leaky your intake system was. It will tell you nothing about the engine compression. And why choose to do a test that is certain to make your engine look bad? And why not just retest with an open throttle after you questioned the results? Do they also do the test with both spark plugs removed? I thought HME were fairly OK in the rotary world, but this makes no sense at all. If I was cynical I'd suggest it's a bit like they are trying to find excuses for why the results were bad. Or maybe they had an apprentice in on that day....

[acegeezer]

You could ask them to allow an external test, someone like Luke Murdoch with his tester .. you know a Doctor's second opinion and all that
He would charge, but minimal and would confirm or deny the cars health

[PeteH]

And (13Black)

If it had an effective compression ratio of 6:1 when the throttle was shut then the engine would accelerate like mad on zero throttle. Just as if your throttle was stuck 75% open....

Don't garages realise that the days of fobbing customers off died with the arrival of the internet and forums.....?

[Adam41]

Thanks for everyone's reply. I'm in a weird position between the seller of the car and HME. The seller wanted me to speak to HME (after you guys had told me not to go with it the other day) and HME even rang me this morning. I spoke with them but nothing they said convinced me that it was worth the risk especially after what you guys have just said.

I could get the seller to get it tested again, but I'm not sure if the results would change that much (mainly the difference between front and rear)?

[13Black]

There are less riskier buys out there. Let someone else take it.

[Adam41]

The vast difference in cranking speeds F 318 vs R 288rpm suggests that either;
- the battery is dying
- the starter motor was overheating
- they had so many attempts at getting the front numbers that either the battery or starter was tired
- they did the rear first, then left that plug out while they did the front, so the starter had a much easier job

The difference in the normalised figures is harder to explain, other than there being more wear or stuck seals.
To get exactly the same numbers for all 3 on the rear is highly suspicious and suggests equipment/operator failure.

[Adam41]

Would anyone be kind enough to check out an R3 with me on Sunday? It's located in Cookham, between High Wycombe and Maidenhead. Any help would be appreciated!

[Adam41]

See this thread
viewtopic.php?f=6&t=36525
for members in the area and try a few PMs, in case people don't see your request.

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