Loss of power and general unpleasantness...

[Gareth]

Hi all!

Got a bit of a problem with Phyllis at the moment, which couldn't have come at a worse time! To cut a long story somewhat shorter my laptop overheated terminally last week, so everything I've accumulated over the last 2 1/2 years is stuck inside a lump of slightly melted Fujitsu-Siemens notebook. That, and I'm stuck using the school laptop for the foreseeable future (or at least until my new laptop arrives), so I'm rather out of touch at the mo' - I'll make a point of checking back as and when I can... It's been an expensive weekend, and I fear it may have got worse.

It happened while driving home from the NEC yesterday - I had occasion to overtake a muppet in a Nissan (another 40mph sliproad jockey ). Halfway past him, she begins throwing out plumes of something unpleasant from the exhaust (couldn't see what colour it was) and the power falls off. Her engine starts knocking and, as we're down to 40mph by now, I head for the hard shoulder. Out of gear and a few hard revs later, she begins to pick up, and begins making progress once more. 60mph is attainable, but the engine still seems 'juddery'.

I'm having to use third on hills (30/40mph) when fourth would have been quite feasible.

The engine is noisy (sounds like a Beetle... ) and the exhaust 'boomy' but the note is even.

I have checked:

• Plugs (1 and 4 were light brown, 2 and 3 a little darker)
• Points (gap fine)
• Mixture (seemed ok)
• LT and HT leads (all connected and appear in good condition)
• Air filter (clean and seated correctly)
• Oil (plenty and no emulsified sludge)
• Water (no oil present and the level was close to normal - has been topped up)
• Carb' dashpot (the piston fell with it's normal 'plop')
• Fuel pump (ticks regularly and keeps up with load OK)
• Rockers (all at correct gap, no.8 appears slightly noisier than others, but not significantly)
• Engine mountings appear okay
• When driving tonight, there was no evidence of any smoke from the exhaust
• Also, travelling downhill with the throttle closed does not produce any snapping or popping from the exhaust.

To drive, she's not as smooth as she was - in the lower ranges there's a significantly pronounced judder (not present when out of gear, so I presume not driveline). As I say, she seems down on power (haven't tried to ger her above 60) and something is definitely not right.

I'm sorry for this essay, but I'm rather at a loss. Has anyone got any ideas? What haven't I checked? Could it be electrical, or something more sinister??

[Packedup]

First thing is a compression test. Not sure where the smoke came from, but I'd be looking at pulling the head as it could be the gasket's gone between 2 and 3. But a test will hopefully give you some idea in case you don't need to go to all that hassle

[rayofleamington]

Same theory and advice as above

Hopefully it is just the head gasket and nothing huge.
From memory your head was off about 18 months ago anyway, which shouldn't be very related but it would be a pain in the rear if something has failed just outside of warranty.

Do you know if #2 and #3 were darker normally or if it is a new thing? (Don't worry if you don't know - I have no clue about normal plug colours on my cars but the traveller has a wet black #1 plug and my mum's punto has a shiny steam cleaned #1 plug)

p.s. - much sympathy.

[Packedup]

Normal colour is a sort of tan, but I've found that doesn't always mean everything's running right

Wet black isn't good, it's oil burning (so rings, bore or valve guide), steam cleaned isn't good either, it's most likely water getting in there (so head gasket, cracked head, cracked block). However, if the engines run fine then best not to worry about it till everything goes up in smoke I suppose ;)

If the head was off not all that long ago, was it re-torqued after a good heat cycle? If not then it looks maybe a bit more promising I noticed the head on the Metro wasn't all that tightly held down when I took it off, and I honestly can't remember re-torquing it which might explain it. But before the buyer panics, I never once saw it run hot or had any other problems!

Many years ago I had a mobile mechanic out to my Mini, he found copmpression was poor on 2 and 3, and said these engines are prone to wear on those 2 in particular. Can't say I've ever heard that since, or had any other problems, so I don't know if there's any element of truth to it. I probably wouldn't worry about slightly darker plugs to be honest, the odd noise and lack of power is far more concerning.

[Cam]

Gareth, before I read Packedup and Ray's posts I thought the same. Gasket failure probably between 2 and 3 (the weak spot).

A compression test should reveal the problem! So, check her over and get back to us!

[bmcecosse]

Gasket failure involves drastic loss of power - the car can barely move. Maybe it's a problem with the rockers/valve gear - certainly worth a look in there.

[chickenjohn]

You could have burnt exhaust valve, and are running on only 3 cylinders- hence lumpy running.

When the gasket went between 2 and 3 on my 4-door, it could as BMC says "barely move" had to get a lift home in the Big Yellow Taxi!

I'd say you need a new exhaust valve. Still a head off job, though.

[betjent]

Hi


You write snapping and popping sounds from the exhaust travelling downhills with the throttle closed ?
Is that a sign of a failure ?
Many Minors does that including my own
What is the course of that ?

kind regards'
Carsten

[Blunt]

Also, travelling downhill with the throttle closed does not produce any snapping or popping from the exhaust.

[Packedup]

I had a head gasket go between 2 and 3 once, and for a few miles there was a bit of an odd noise, slight drop in power, and not much else wrong. By the time I'd got the 20 miles home it was very poor to drive, but initially not so bad.

When I pulled the head it looked like there was a chunk missing out the block between 2 and 3 that had been bodged enough to flog the car (I was told it had had a new gasket about 50 miles before I bought it)!

[rayofleamington]

Wet black isn't good, it's oil burning (so rings, bore or valve guide), steam cleaned isn't good either, it's most likely water getting in there (so head gasket, cracked head, cracked block). However, if the engines run fine then best not to worry about it till everything goes up in smoke I suppose

- if only! They are both dead and off the road, waiting until I have more than a few spare seconds (it may be a long wait)

[betjent]

[quote="Blunt"][quote]Also, travelling downhill with the throttle closed does not produce any snapping or popping from the exhaust.

Yes - but what if it does ? What does that indicate ?Faulty exhaust valves ???

cheers
Carsten

[Blunt]

Also, travelling downhill with the throttle closed does not produce any snapping or popping from the exhaust.

Yes - but what if it does ? What does that indicate ?Faulty exhaust valves ???

cheers
Carsten

ahhh! see what you mean

my van makes the loudest farting noise ever whenever I'm decelerating, or If I change up too soon

It's the distinctive sound of a moggy...all mine have done it (the van is the loudest ever...different exhaust?)....and AFAIK it's "normal"

[Packedup]

Leak in the mainfold to downpipe and mixture a bit out can both make lovely popping noises without it meaning anything serious

[Gareth]

There's no snapping and popping, and although she's down on power, she will actually move. I've been thinking that it could be head-related, which is not pleasant. You're right that the head was replaced not long ago - in fact she sounded truly dire a couple of months previously, but a service got her running sweetly again.

The head is hard down (don't have a torque wrench, but I couldn't budge the head nuts. She runs very much like she's firing on only three - perhaps two would be more like it - but I'd have assumed that the two plugs not firing would be highly noticeable, i.e. giving a power cycle of 1-4-rest-rest-1-4-rest-rest &c or something. Probably got the order wrong, but you get the picture. This is not the case - the engine runs evenly, without the lurching associated with reduced firing.

I can't do a compression test myself, but I'll try and run her without the rocker cover on, to see what's what. I think they were shifting up and down as expected last night, but I can't be 100% certain.

[bigginger]

Just to be the first - 1 3 4 2

[Gareth]

Ta for that.

In that case, she'd be running 1-rest-4-rest... Hmmmm.... Very interesting... I'm off to whip some HT leads off...

The plugs weren't wet but a slightly darker colour, so they were probably firing. Maybe the gasket has gone... Grrrrr....

[rayofleamington]

I'll try and run her without the rocker cover on, to see what's what.

If it is a burnt valve you probably won't see anything from under the rocker cover.
My traveller has similar symptoms (but also burns oil) and I noticed the rough running at 40mph before I noticed the loss in power. However once I got out of Warwickshire and onto a hill it was dreadful and ended up in second where 4th would normally have been ok.
The traveller is only poorly on 1 cylinder. therefore from your description of the power loss, I guess yours is either a very small hole in the headgasket (between #2 and #3) or just a fault on one cylinder.

However - check lots of things before removing the head. Even stuff like faulty electrics can cause bad running and low power. A compression tester costs not much more than a new headasket (try ebay).

A compression test will show if one (or more) is low however they don't always show up the problem - my mum's Fiat gave 210 on all cylinders despite the leaky gasket / hole in the head

[Cam]

Compression test is the way forward Gareth.

[Chris Morley]

Sorry Gareth, but to my mind the exhaust smoke and the lack of power makes it odds on favourite to be a blown head gasket.