PCV Valve

Technical Area Engine, Transmission, Exhaust etc
2

Hi all

I am new to this group and indeed MX5s too! . I have just bought a six speed MK2 Icon W reg and one of only 750 worldwide apparently with the full leather interior.

This is the 1.8 injection 16 valve engine but finding it not to be as quick as 8 seconds 0-60 time as stated. I know older engines loose horse power with age. and my car has currently done 95K miles

I read that the PCV valve should be replaced about every 50k and that if blocked or just worn not allowing the correct suction rate from the crank case that the car can burn oil quicker and loose some power. I have ordered a new valve from Mazda as Mx5 Spares online will not be getting any more of these right angled bend ones for the MK2 for another month. I will check the hose too for crud build up.

Has anyone else had experience with noticing more oil burning and a loss of power due to this valve?

I have arranged a  full service for in a weeks time too . It maybe worth having a compression test done 

Thanks

3

hi and welcome

4

Soak it it white spirit overnight.

Let it dry well, then give it a shake.

You ought to hear the valve rattling, in which case just refit.

New ones are dirt cheap though. Our 98ooo miler is still original…since I cleaned it twice.

Yes, it is known to promote consumption if really goosed which I doubt yours will be tbh.

Best done in private in case the neighbours think you’ve lost the plot.

 

With regards to oil “burning” yes it can happen for a variety of reasons.

Give it a long drain from hot, new Mazda filter, and quality oil. Then you have a benchmark to measure over time.

Around a half litre per thousand miles is par for the course. Or, nowt…unless it looks like Bismark trying to escape the Royal Navy. 

You could always ask the previous owner how it was…assuming you did’nt when you bought it.  

If you notice blue smoke on “the over-run” eg engine breaking down gears, there may well be an oil ring issue but again, I believe our later engines are somewhat less prone than Mk1 1840cc mills.

If…they have been serviced properly that is. Don’t worry unless it’s blowing smoke on start up…not to be confused with water vapour on cold starts…which will be whitish. 

As for 0-60 figures, they are marketing poppy cock frankly gained by dropping clutches at high rpm and caning it silly.

Ignore.

Just keep it on the boil between 4-7k rpm and have fun.

It’s a revvy twin cam after all, not a long stroke slogger.  

5

Thank you for all of this info Scottishfiver!

I should be getting the new pcv valve from Mazda on Tuesday. My car fortunately makes no smoke and was interested to hear that generally these cars need about half a litre of oil every thousand miles anyway. I have only owned my car for four days now and really enjoying it !

6

If the engine runs without any unpleasant noises and doesn’t smoke on startup or under load there is probably nothing to worry about.

This has the beautifully smooth engine as fitted to all MK2/MK2.5 1.,6 cars 1998 - 2005. It is not a racing machine and only 110bhp.

Not sure of the 0 - 60 for the 1.6 but the 1.8 with about 30 more bhp is about 8 seconds so I would expect the 1.6 to be somewhere around 9.5 seconds.        

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thanks Rhino666. Yes mine is the 1.8 injection, I believe rated at about 144bhp. My other non Mazda car is rated at 9.5 seconds 0-60 and does have more pull during acceleration than my MX5. I am hoping that after the full service and the new pcv valve that it will pull a little better. I am by no means a racer but it’s nice to have that power for overtaking etc!

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Almost the equal, in fact, of the ‘long stroke slogger’ Triumph GT6 of 20+ years prior, which didn’t require keeping the thing on the boil to make it go. 

 

 

9

Sorry Dave - for some reason I got it into my head that yours was a 1.6.

Yes, 1.8 is much more powerful but the 0 - 60 time quoted would be very hard to achieve, especially with the 6 speed(extra change required)  without hammering the clutch, etc.

The 1.8 is much more sensitive and needs to be looked after. Check the oil level regularly and Keep it topped up. They do burn oil unlike the 1.6 and can have emissions issues. Check the MOT history on yours to see where you stand on this. Lots of owners have run cranks on these MK2 non VVT 1.8 engines where oil starvation has occured.   

 

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If you can blow through it one way, but not the other, it works.