Rover Metro 111 farting noises & history lesson

[Isaac Hunt]

5 hours ago, Skut said:

Thanks - maybe a better use of my time would be to drill some holes in the original stat or do a second completely unnecessary head gasket change for the sake of a rubber grommet. 

I seem to recall QED Motorsport do a nice Alloy stat housing that enables the stat to be situated in the top hose near the engine, but it isn't cheap.  

I also seem to recall that folks have also used a Renault 5 (Might be Renner 4, so check) stat that pushes into the top hose.   The idea being that the stat is moved into a position that exposes it to warm coolant 'sooner'

all variations of the PRT in hose stat idea.

the alternative K Series theory, is to set the heater to hot and keep the revs and engine load down until it warms up.

[bunglebus]

12 hours ago, N Dentressangle said:

More or less, yes. I think.

Thanks - need something like that for something else

[Zelandeth]

2 hours ago, bunglebus said:

Thanks - need something like that for something else

Lada used a similar setup for the Riva and Niva for years too. 

Possibly cheaper to acquire for experimentation. Usual going rate is £10-12 I believe.

This is all metal (brass I think) which I inherently trust more than plastic...

 

[N Dentressangle]

Reading through bollox's giant thread of K porn makes me realise how OK this particular engine is. No oily milkshake, runs fine and even the coolant's pretty clean. Must have been the first beginnings of oil oozing into the water, but good to catch early I guess.

The aux belt was knackered anyway so a few quid made this turn up in the post yesterday. Here it is making friends with the cambelt it's shortly doomed to spend the rest of its life with:

Moving on I did ghetto head skim & block decking, AKA rubbing down with 1200 WnD with plenty of WD40, and then tapped in the two new steel dowels which came with the gasket set:

My feeling is that this is now all ready to go back together.

I've left the manifolds on the head because the HBOL suggested it was fine to do so and it seemed less work that way. I'm now wondering if the head would be a damn sight easier to seat on the dowels without all the unwieldiness, and risk of buggering up the new gasket. Ho hum.

[N Dentressangle]

And the head's back on!!!!!

All torqued down according to the book, with new head bolts.

Now, where do all those friggin hoses and wires go?

[Angrydicky]

Great work! This is coming together nicely.

[N Dentressangle]

55 minutes ago, Angrydicky said:

Great work! This is coming together nicely.

Thanks ?

Decided to lob it back on in one lump, and it wasn't too bad. I'd checked the steel dowels first to make sure they fitted, and slotted them into where they felt best. They do actually locate the head, unlike the sloppy plastic things that came out. Makes you wonder why they decided to try and save what must have been pennies that way...

Did the angle tightening with a 2' breaker bar - easier to gauge the angle of turn and keeps me looking effete and sensitive

[Mr_Bo11ox]

Good luck man!!!! I love a good K-series fettle!!!!

[N Dentressangle]

11 minutes ago, Mr_Bo11ox said:

 I love a good K-series fettle!!!!

Do you? I hadn't noticed 

[N Dentressangle]

Much to my surprise all the wires n hoses were pretty self-explanatory - the only cunty ones are the bolts for the inlet manifold stays - and everything else seemed suspiciously straightforward:

Mostly all back together - I've re-routed the yellow pipe to where it should be, don't worry!

Now, onto the cambelt. Here's the field of battle:

I followed the Haynes for putting everything back. The cam sprocket is supposed to have a special tool to allow you to tighten it to 35nm or whatever, but I improvised with a big screwdriver jammed in the spokes. Cam sprocket was then carefully reset to align with the timing marks.

I used the video I mentioned earlier to refit the belt. More details shortly...

[bunglebus]

Any bits left over?

[N Dentressangle]

Nothing obvious yet...

[dc2100k]

Good stuff. The K-series is a great little engine. It's amazing to think Minister could get a *reliable 250 bhp out of this little Metro engine.

God bless Norman Tebbit.

[N Dentressangle]

Fitting the cambelt actually turned out to be a bit of a PITA

I first tried getting it on with the tensioner in place, as Haynes and other sources suggest this should be doable. Well, I found it about as much fun as jelly wrestling Michael Gove, and eventually I gave up. Many years of spannering have taught me than when something ain't going right, the best thing to do is go and have a cup of tea. In olden days I'd have had a coffee and a fag, but they're long gone ?

I watched the video again, and tried to do as he did, but just couldn't keep the fucking belt on both crank and cam pulleys taut at the same time. Fucker always slipped off when I tried to get the tensioner on. Another cup of tea... ? and ?

Eventually I thought of a plan. I used some gaffer tape to hold the belt onto the crank and cam pulleys. It didn't need to be strong - just enough to hold them would do. It only fucking worked!!! I refitted the tensioner (not much slack with a new belt, surprise, surprise) and success was mine!

I've rotated the engine since the belt was fitted so that's why the cam timing mark's no longer where it should be. Don't worry.

Getting the aux belt on the crank pulley was the next challenge. The tensioner adjustment for the alternator on these cars is probably OK if you have the car on a lift in front of you, but if you don't then you're reduced to grovelling under here, trying to unscrew the tensioner bolt enough for you to get the frigging crank pulley back onto its woodruff key type thingy:

Bastard. I got there in the end, and re-torqued the crank pulley to 165nm, with the car in 5th and Mrs D's foot on the brake. Nearly there!

[Mr_Bo11ox]

On 3/21/2020 at 12:02 AM, Mr_Bo11ox said:

 As for 82 vs 88 deg, I can't think of a practical reason why 82 is 'better' than 88, if the cooling system is all behaving itself it could regulate to any temp setting, I would rather have 88 myself!!! I suppose a few degrees lower operating temp might give you an extra 30 secs before damage gets done if the impeller drops off the water pump or something.

Actually I rememebred a good technical reason why you might have a cooler stat in an engine. 

One thing you want to avoid in your cooling system is 'cavitation', this is basically localised boiling which can happen below 100 deg C if there is a region of low pressure (usually just upstream of the water pump as the pump 'sucks in' the coolant). If the cooling system is poorly designed in terms of maintaining even flow round the whole loop this can happen. When it happens you get weird pressure fluctuations that resonate and can bust water pump impellers and cause all sorts of mayhem. So changing to a cooler stat gives more 'margin' before this boiling can occur and can make a cooling system operate satisfactorily in higher ambient temps than would otherwise be the case.

But if you're not operating close to the max cooling capacity of the system (e.g.  youre driving steadily round cold miserable Britain) the cooler stat doesnt really gain you owt.

[dc2100k]

4 minutes ago, Mr_Bo11ox said:

But if you're not operating close to the max cooling capacity of the system (e.g.  youre driving steadily round cold miserable Britain) the cooler stat doesnt really gain you owt.

In the world of water cooled Porsche flat sixes it is estimated that a low-temperature thermostat (a common mod to try and prevent cylinder bore-scoring) gains you approx. 5bhp due to generally cooler engine temperatures.

I'm *sure the same applies to a 111GSi.

[dc2100k]

Further to this I have run through in my head how a well designed cooling system works and the logic of why the stat is placed where it is (a location that seems counter-intuitive). I find it is easier to conceptualize if you think back to air/oil cooled engines first to understand that they shed heat through airflow over the engine and that the pumped engine oil assists by moving heat from hot parts (block and head) to cooler parts (sump). If you take this one step further and introduce a pumped water jacket for additional cooling you can seen the basic operation of a cool engine. The closed stat sits right beside the water pump at the notional coolest part of the water jacket and forms a T with the return loop of the radiator circuit, the outward loop being at the far side of the block. As the temperature of the engine/water jacket increases the element of the stat gradually opens allowing some flow through the radiator loop. However, the cool water from the radiator loop cools the element slowing the rate at which it opens. Therefore that stat actually opens slowly or not entirely under normal circumstances depending upon engine speed and load, external temperature, airflow over radiator/engine, etc. It's all very complicated and as Mr. Bollox says you could do with a degree in fluid dynamics to really understand the detail of cause & effect. I think the important point is that the thermostat (unless fully closed) always measures a mixture of water jacket and radiator loop coolant.

[Mr_Bo11ox]

The stat just sees whats coming out of the cylinder head and decides whether to send the flow through the radiator or through the bypass pipe directly to the WP, varying the proportions to try and achieve the required temp setting.

[dc2100k]

10 minutes ago, Mr_Bo11ox said:

The stat just sees whats coming out of the cylinder head and decides whether to send the flow through the radiator or through the bypass pipe directly to the WP, varying the proportions to try and achieve the required temp setting.

The stat sees a mixture of whats coming out of the head and whats coming round the radiator loop in a quantity proportional to how open it is. Therefore I think the temperature at the stat is always lower than it would be if located at the other side a la PRT, and the engine runs hotter as a result. This gives a good quick warm up and should be fine with a well functioning cooling system (which we know is the usual problem). With the 996 the problem is that the higher global engine temps lead to a temperature spike on the thrust side of one bank of pistons (due to the flat six design) and the 0w40 oil cannot handle it; the low temp stat reduces global engine temps to a point where this spike is within the oil's capabilities.

[N Dentressangle]

Whatever the faults of Haynes, I often find it's good at keeping you honest.

Before I tightened up the cambelt tensioner backplate and main bolt, I took the Haynes advice and checked the timing marks were still in alignment, and ....

? ? ? ? ? ? ?

They weren't. They looked way out, but in fact were about 1 tooth out, I think. I'd already rotated the engine a couple of times without any horrid noises, so it can't have been much further out than that. I presume the cam pulley had shifted as I put the belt on: the valve springs mean it's not always keen to stop spot on at the timing mark. So, I set the crank pulley to the timing mark, unbolted the tensioner assembly again so the belt was loose on the cam pulley, and moved the pulley to spot on its own timing mark. I kept it real and used the same method as before to refit the belt where it should be, but took a pic for you this time:

Next, everything re-torqued. Managed to do the crank pulley single handed with a cacky arrangement of bits of wood holding down the brake pedal:

OK Mr Haynes, what's next?

[N Dentressangle]

Ah yes. The upper cambelt cover. All a piece of piss, apart from the shitty fucking inaccessible bolt behind the water pump which I've just dropped behind the thermostat

[N Dentressangle]

It is done.

[N Dentressangle]

Tomorrow's job:

 

[rainagain]

Great job, I use tie wraps to hold the belt on when changing. A lot easier to loop round the pulley than tape and you just clip  them off with side cutters when finished. 

[N Dentressangle]

22 minutes ago, rainagain said:

Great job, I use tie wraps to hold the belt on when changing. A lot easier to loop round the pulley than tape and you just clip  them off with side cutters when finished. 

Yes, that's a good plan too.

I don't know why I'd never seen dodges like this on the net. Belts are such a cunt to fit, otherwise.

[rainagain]

Tie wraps for the top pulley(s) and then a piece of cardboard folded over to hold it against the crank pulley. Makes it much easier. 

[N Dentressangle]

Turns out the bleeding time is about 45 mins - that's how long it took to warm up enough at idle for the electric fan to cut in.

All seems OK so far. Update when I can get pics to upload.

 

[N Dentressangle]

As promised, a few more pics.

The old water pump pulley looks worse for wear:

The new one didn't have this kind of taper, but I don't see how the belt could have worn it like that.

I made a mix of this stuff plus some washing powder to start degunking the cooling system. I've ordered some Radflush off Ebay to give it a proper flush next week, but hopefully my mixture will clear the worst of the crap out first. It took 4 litres pretty much straight away, and I kept opening the two bleed points as it warmed up and releasing any bubbles, before I was finally able to top up to 4.5 litres this morning:

It was an anxious wait as the car gradually warmed up. Took about 40mins to get to this stage, at which point, thank fuck, the electric fan kicked in:

I'd kind of sooner it did its stuff a bit sooner, but maybe it's just one of those gauges. The engine didn't seem especially hot, and the bottom hose had only really just got too warm to hold a hand on it for any length of time.

All sounds sweet, and Mrs D has taken it to work this morning:

 

[Marm Toastsmith]

Well, it didn’t make it to the red... 

This is all making me very nostalgic. I learned to drive in a k series metro. My first car was an a-series one... I spent a lot of time fixing it and generally fiddling about with it. My best mate had one too. And I had another later. In my teens I was driven to school in a rover metro “clubman”. I remember gazing at the dash, thinking how fresh it seemed compared to my dad’s old chod.

I think I need another. I even quite like the idea of it pulling an omghgf on the way to work.

keep up the excellent work.

[egg]

Was the old water pump leaking at all do you think?