The new adventures of Brownnova! Another Saab joins the fleet… 13/10/24

[SiC]

Make sure you're not using a cheap no-named red/blue box compression tester from eBay or Amazon. I'm sure many a engine has been written off by one of those shit gauges. 

[SiC]

Was this scummy wet/oily plug the one from the cylinder reading low?

[brownnova]

Yeah it was... ironically the one which appeared to be missing had the best compression... 

Apparently liberal application of WD40 has got it going on all 4.... I’m stuck in work but will go and see later on. 
 

[DoctorRetro]

I'm going to vote timing belt jumped a tooth. 

The symptoms you're describing are exactly the same as the 323 I had, and I tried alsorts to get it sorted. It gave me various misfire symptoms! @BlankFrankmanaged to sort it very quickly!

Now someone will correct me and say mx5s have a chain or something ?

[Tickman]

7 minutes ago, TheDoctor said:

I'm going to vote timing belt jumped a tooth. 

The symptoms you're describing are exactly the same as the 323 I had, and I tried alsorts to get it sorted. It gave me various misfire symptoms! @BlankFrankmanaged to sort it very quickly!

Now someone will correct me and say mx5s have a chain or something ?

You are correct with a belt and also non interference engine

[paulplom]

Have you checked the piston return springs? The one for that cylinder might have stretched/snapped.

 

[brownnova]

So the 5 is home and got there under its own steam. 

 

I left the keys with my BiL who said he’d get his uncle to pop up and do a compression test whilst I was working. He applied a Liberal application of WD40 onto the coil and it seems to have jumped all 4 cylinders into life! So clearly some electrical shenanigans.

However the compression test shows low compression in the three apparently working cylinders, all of which had fouled plugs.

Being around 15 minutes drive back home I thought I’d chance it and see. And we got home No problem. Engine running grand. But a glance in the rear view showed very blue smoke emitting from the rear. So we’re burning oil.

But at least it’s home now! So I’ve parked it in the naughty corner... I’ll investigate next week. 

Also pictured ShiteCamperMk2, she Roffle Clio WarmHatch.

I also created Saab corner. 

I wanted to do a few car jobs this week, but that was on the 2CV and Yugo projects not the MX5!! 

[camryv6]

See if the smoke clears, it might just be oil that has leaked into the cylinders, from a leaking cam cover gasket when you removed the spark plugs ?

[brownnova]

Sometimes having two of the same car is quite an advantage... a for nicking parts from one for the other as a temporary fix, and secondly comparing when you’re not sure if something is right.

 For example, the throttle on my 2CV has been sticking open a little. And with a club run tomorrow I thought I should look at it before I go.

Now my throttle return spring seems to have some kind of wire extending it... therefore making it less springy... hmmm... don’t think that’s supposed to be there. I’ll check the other 2CV... 

Nope.

Could it really be that simple? So I’ve hooked the throttle cable to the actual hook. And we’ll see in the morning if that cures the issue. Is there a reason why this would be done? 

In other 2CV news the fuel gage on the green one still isn’t showing any fuel despite gagging tightened the Earth from the sender. Not sure if that’s because the 3 litres I sloshed in isn’t enough to show or because I’ve done something wrong... 

More fuel in this week and then a little run to get it out and about.

 Then I really must get on with renovating it. With early negotiations into another project begun I need to get on with getting at least one done in case I end up with another project to do! 

[brownnova]

Throttle behaved itself as we led a convoy of 2CVs round the Nant Y Garth pass and up to Flint Castle today... 

[Frogchod]

I'll admit it.

I like those go faster wheels

 

[500tops]

22 minutes ago, Frogchod said:

I'll admit it.

I like those go faster wheels

 

Not cheap though

 

https://www.burton2cvparts.com/rolling-chassis/wheels-and-tyres/poedercoat-sportvelg

[brownnova]

1 hour ago, Frogchod said:

I'll admit it.

I like those go faster wheels

 

I wasn’t convinced, but having had a good look at them today they’ve grown on me... 

[wuvvum]

And they increase the top speed to at least 72.

[dollywobbler]

Moving the spring attachment is a common mod, to try and stop the throttle jamming wide open. Most people use a cable tie though... Usually combined with moving where the spring fits on the throttle.

If the throttle does jam open, and stamping on the pedal doesn't release it, the 2CV is at least a car where you can turn the engine off at speed and still have most functions working 100%. (needs ignition back on for lighting, though some will have permanently live brake lights, so don't need ignition.

[brownnova]

1 hour ago, dollywobbler said:

Moving the spring attachment is a common mod, to try and stop the throttle jamming wide open. Most people use a cable tie though... Usually combined with moving where the spring fits on the throttle.

If the throttle does jam open, and stamping on the pedal doesn't release it, the 2CV is at least a car where you can turn the engine off at speed and still have most functions working 100%. (needs ignition back on for lighting, though some will have permanently live brake lights, so don't need ignition.

Oh ok, so the wire was to stop it jamming open?

Will keep an eye on my next few runs. I’ve left the wire in place, just hooked the cable on to the normal hook. 

[dollywobbler]

The person who did it may have thought it would help. With the engine off, may be worth stamping on the throttle to see if it jams open. If it doesn't then you should be ok.

[brownnova]

Today I needed to rearrange the drive to accommodate the new vehicular arrival tomorrow... I had to use the road as a car park for a bit. 

This also meant starting the Mazda for the first time since I got it home

It started well, and ran well... I was feeling optimistic. So I let it get to temperature and still it seemed ok... no blue smoke no misfire. Maybe it was just one if those things.... 

So I braved a little run to the road... within a quarter of a mile I got the feeling that something wasn’t right... it was popping and banging on any slowing down. A quick glance in the mirror showed blue smoke billowing... Shitsticks... 

Turned around and made it to the drive where as I turned in it died.... I got it going again and parked it up in its new spot. The smoking was pretty bad... so bad that it disturbed a was wasps nest in the Bush behind its parking space... 

Bugger. 
 

Is it fucked? 

[loserone]

You should put a B3 engine in it from a Kia Pride.

[SiC]

If low on compression measured with a decent compression tester, chucking out blue smoke and PCV is good, low down on power and misfiring enough to bang ... then it does sound fucked. 

How much do you love that particular car? If a lot, then engines look to be available for under 300 quid. 

If not, then sounds like it's at the end of its life. There are plenty of good MX5s still around and affordable if you wanted another. 

[High Jetter]

Nah, quick strip down and re-build, right as rain M9

[dome]

Yeah, if the MX5 is solid then it needs to live on! It should be easy enough to get an engine from a rusty one.

[brownnova]

8 hours ago, SiC said:

If low on compression measured with a decent compression tester, chucking out blue smoke and PCV is good, low down on power and misfiring enough to bang ... then it does sound fucked. 

I’m not certain of the quality of the compression tester as I wasn’t there when it was done, so I think I’d want to do another one to be sure. But to be honest my wife’s uncle who did the compression test is likely to have done it properly, he really does know his way around an engine!

Excuse my thickness (it’s early and I haven’t had much sleep) what’s PCV? 

Whatever the weather be a shame to scrap, it’s one of the 200 oldest ones in the Uk and it is generally pretty solid. Whether it’s me that fixes it is another question... 

[SiC]

I’m not certain of the quality of the compression tester as I wasn’t there when it was done, so I think I’d want to do another one to be sure. But to be honest my wife’s uncle who did the compression test is likely to have done it properly, he really does know his way around an engine!

Only say, as said earlier in the thread that the generic red/blue box unbranded ones off eBay are crap. Usually give inconsistent readings and a good 50+psi out.

Excuse my thickness (it’s early and I haven’t had much sleep) what’s PCV? 

Lives in the rocker cover.
https://www.mx5parts.co.uk/valve-mk1-25-p-783.html

Wiki offers the best description:
https://en.m.wikipedia.org/wiki/Crankcase_ventilation_system#PCV_valve

[brownnova]

Cheers, I’ll check that next. ?

[brownnova]

Actually a quick google at failure symptoms suggests that’s a real possibility.... 

Thanks @SiC. 

[chompy_snake]

Three main issues that will cause these oil burning antics I reckon.

Bad pcv (least likely but possible)

Knackered valve stem seals

Worn and past it oil control rings on the pistons 

Or you have really crap oil in that's sat there for a century and it's gummed the rings. Engine flush (with flushing oil) and a decent thick oil may fix.

[brownnova]

As the PCV is likely the cheapest option I’ll fix that first! ?

[Zelandeth]

Also check the timing.  If it's jumped a tooth or two that can cause all kinds of antics.  Including low compression obviously, and can massively exacerbate any other weaknesses of the engine.  It can also play havoc with the fuelling so smoke can be a symptom... doesn't take much oil getting in to make that more blue than black.

Do you have or can borrow a timing light?

[brownnova]

Another good suggestion... timing is something which has been suggested by my tame MX5 specialist too (I’d forgotten that suggestion in the excitement of new acquisitions), although seems odd that it would run fine until warm. But I’ll check it nonetheless.

 Don’t have a timing light... I’m sure I can either purchase or Borrow one. 
 

Thanks.