Well guys we've finally got to the bottom of Maisy's problems........

It alll started when she misfired on the way home from Darrens BBQ - although it was only brief and she soon recovered.

A couple of weeks later she started ticking over a bit lumpy so I did some investigations and sussed that there was a problem with the inlet valves - possibly cacked up with carbon?

A trip to my local garage confirmed that the inlet valves were indeed clogged with carbon, and weren't sealing correctly - and therefore the cylinders were low on compression, and the car was running rough.

Well she was stripped down, thoroughly cleaned up and had to have 1 new valve - which had worn - and various OE gaskets and seals.
When I got her back she was hesitant and smoked like hell - more so when she was cold.

Further investigation found that the car was burning oil, which appeared to be getting past the stem seals on the valves. It turns out that Mazda had supplied 16 inlet valve seals as opposed to 8 inlet and 8 exhaust seals. (Now turns out the only difference is that the exhaust ones are made of harder materials so that they can stand the heat). So the correct stem seals were installed (at Mazda's expence) and off I went. No change though, she was still hesitant and smoked when cold.

So back she went.

Well it went back to the garage and oil was still evident on the the tops of the pistons - and it was still also apprearing on the valve stems. So this time the garage tried non gen stem seals which still didn't cure the problem!

Anyway - the only other thing that could be letting oil into the cylinder was the scraper rings on the pistons. These are designed to scrape back the oil as the pistons decended.

The engine came apart again - and this time including the head - to find that the scraper rings were carboned up far worse that the valves were.

Turns out that fixing the valve problems increased the compression to where it should have been - in the case of the fourth cylinder it increased the compression from 100psi to about 250psi. This in effect put pressure onto the carbonised scraper rings and made them ineffective - which left oil in the cylinder on the down stoke, which ended up getting burnt in the combustion process - hence the burning of the oil.

Whilst they're in there they are going to be replacing the full piston ring set, cleaning the cylinders, and I think they're doing something with the 'big end'. All to do with the fact that it makes economical sense whilst they're there.

So she's still in the garage in bits, and waiting for parts. Hopefully she should be back to me by Wednesday/Thursday - and in effect be like new engine wise.

Well guys - I suppose I ought to suggest we all start using engine/petrol cleaning additives. I have been to a certain extent, and indeed always use 'quality fuel'. I'm therefore miffed as to why maisy should be so clogged up with carbon, especially after 'just' 62,000 miles. Anyway - I hope that if anyone else needs to get their valves cleaned etc, they also ask the garage to check the scraper rings on the pistons - to save them the three weeks of inconvenience that I've had!

Rich

thought this might be worth trying to reduce carbon etc.

CSMA (civil service motoring ass) give it a big thumbs up in their magazine for all sorts of cars

[url]http://www.ecotekplc.co.uk/power_boost.htm[/url]

Cheers Nick,

I've actually used that twice in the last two years - maybe it's not as good as it claims

how muchy is that lil lot settin u back then?

Arty

Dunno yet!!!!

At least Mazda are picking up the tab for some of it - having supplied the incorrect stem seals!!!

I'll keep you posted...........

Rich

[quote="nickj633"]CSMA (civil service motoring ass) give it a big thumbs up in their magazine for all sorts of cars

[url]http://www.ecotekplc.co.uk/power_boost.htm[/url][/quote]

The CSMA is a bunch of old women (even the ones that are male) who know nothing about cars. Thousands of them think the Broquet Fuel Catalyst actually works for G*d's sake. As for that spray, I wouldn't trust any product where they won't say what's in it. As very little dissolves baked carbon (and what does, you wouldn't want in your engine) I suspect con. Not a massive leap in the dark given that the main product of the same company is a con.


M

Good luck with all that Rich. You didn't consider getting the head ported while it was off then?


[color=red][b]Mark[/b][/color]

Nah - I'm not lucky like you.........

My nearest port is miles away!

Hey rich, did you get all sorted out in relation to the new valve seals and scraper rings? Was it expensive?

I have a 1.5 GLX with 75,000 miles which is quite rough when it is ticking over at idle. I asked the garage and they said the fourth cylinder is misfiring but that the car is fine when it is running. They put it down to my induction kit but I'm not convinced

I wouldn't yake any notice of them on the induction front - if one of your cylinders doesn't appear to be firing on tickover, that's exactly what I suffered.

Get a compression check done - this should confirm that your other cylinders are also affected to a lesser extent.
Here's the readings I got:
1 - 190psi
2 - 210psi
3 - 135psi
4 - 100psi

Mine was found to have the valves and scraper rings caked with carbon, which in the case of the valves was preventing them creating a seal - and therefore the compression was being lost.

It took us a while to find the full extent of my problem, to the effect that the engine came apart 4 times - hence the £1000 bill.

I'd guess that if you got a good non Mazda garage to do your valves and rings in one go, you'd be looking between £600 - £800, dependant on their hourly rate.

What I can definately say is, that now mines fixed and run in - it's like a new car again. Even my wife noticed how much quicker it was on pick up.
Maybe it's the best performance modification I've done yet!!!!!!

Rich

Ya I have a strong feeling that it could be the same thing. I suppose the first port of call is to get a garage to do a diagnostic check on the cylinder compression and I'll go from there

Thanks for the info Rich