Exhaust smoke

[greenMachine]

... get a clean tray, put under the car.

Remove sump plug, collect oil into pan.

Put sump plug back.

Pour the caught oil into the engine via the filler cap (but obviously don't put it all back, just put back enough to be at the full Mark. 3.5litres off the top of my head, but check the user manual first)

And yeah, always add less than the manual says, and slowly top up as needed.

Did you do this?

If not, do it. Then you will KNOW how much oil is in it, and if it is still smoking afterwards it is not because it is over-filled.

[93_Clubman]

He say nothing wrong.

MRDA. If you've not already done so, confirm it's not overfilled yourself - if not over filled, get another opinion on the blue smoke.

colour of the smoke, blue rather than black or white, and the fact that it only started after the last service

Did someone who should know what they're doing do the last service?

[Forgiven]

Checked the oil myself. On 'F' on one side, well above 'F' on the other.
The man now has four hats: 'mechanic', engine-rebuilder, seller of car, and man who serviced the car.
Another opinion looks like a good idea then.

[RS2000]

The oil is well over the 'F', nearly up to the top of the flat part of the gauge.

Checked the oil myself. On 'F' on one side, well above 'F' on the other.

I doubt it is overfilled with oil. To the top of the flat part is not overfilled on my NB8A

[93_Clubman]

Another opinion looks like a good idea then.

Price generous protection wise.

[Forgiven]

Price?

[93_Clubman]

For a 2nd opinion.

[Forgiven]

2nd opinion booked.

[93_Clubman]

Good!

[Forgiven]

One of the attractions of the car was that it had a rebuilt engine, rebuilt by a specialist MX-5 garage. A garage used by MX-5 club members. But the engine is no good - the rings haven't bedded. No. 3 is extremely wet, but all are in trouble.

Funny that I only noticed the smoke after the first service (by the seller). Of course, I wonder too whether an NRMA/independent mechanic would have picked up the problem before purchase? Some engine rebuilds just go wrong, despite care?

And the best offer from the seller is a small discount on the work to either install a second hand one he has for sale, or rebuild the current one. I guess it's not worth much in its current state, so even if I want to sell it (to recover some of my mistake), it has to be fixed. But first I'll see what the second-opinion man has to say about the condition of the rest of the car.

[93_Clubman]

wonder whether an NRMA/independent mechanic would have picked up the problem before purchase? Some engine rebuilds just go wrong, despite care?

Very unfortunate to hear - depends if the problem was present at a presale inspection & assessment, & what tests the NRMA/independent mechanic would have done at the time to identify any issues. Sounds like it was a quality control issue, ie the replacement parts used &/or the labour itself, so for a stock B6 motor rebuilt by a MX5 specialist & used in daily by a conservative driver 1k kms or so later, I wouldn't expect the motor to just go wrong.

[apsilon]

If it's rings a compression test may have shown it up wouldn't it? Not sure if NRMA inspections go to that extent though.

I'm sure we're all wondering so I'll ask, who is this specialist?

[bruce]

So, in fewer clearer words;
Second opinion says the motor is stuffed.
Did you have a pre-purchase NRMA inspection?
Seller is offering a tiny refund (which he does not have to)?

[hks_kansei]

stock B6 motor rebuilt by a MX5 specialist & used in daily by a conservative driver 1k kms or so later, I wouldn't expect the motor to just go wrong.

I'm suspecting that the engine wasn't run in properly.
Especially since the issue seems to have been found around about when you'd expect the run in period to be done.

Either that, or the rebuild wasnt as good as expected.
to some sellers a rebuild means full disassembly, new bearings, bores honed, new pistons etc.

to others it means open engine, check bores, put new rings on the existing pistons and put it back together.


If the bores were a bit worn, or over-honed, you usually use slightly bigger rings, or if extreme, oversized pistons.



Other option, if it's mainly one cylinder that's causing most of the problem, maybe they put them back in the wrong order?
with most rebuilds, unless you're spending big on blueprinting, each piston will be a slightly different size, and you have each bore honed to suit that piston (of course, making sure to keep each mathcing piston/bore)

maybe the builder accidentally put the wrong piston in the wrong bore? (or the machinist stuffed up)

[Forgiven]

OK, barring action against the seller, I see my choices as:
1. do nothing, and keep driving. I still get pleasure, and the smell is OK as long as I am moving.
What, if any, damage can I do?
Is there some additive I can use?
2. a low km Japanese engine, tested in the donor call, so not a complete lottery. $2500-3000 fitted (with timing belt and water pump replaced with the ones there at the moment, said to be new)
3. rebuild the engine. $3500-4000. With a warning that this could blow out, plus the result depends on the care with the build.
4. sell the car as is. $3000-3500, maybe not quickly.

I'd welcome your thoughts, especially if you have the experience to back them.