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Discussion Starter #1
I've been waking-up my Flavia Vignale after its winter snooze.

The first thing that needed rather a lot of attention was the braking system. I ended up having to completely dismantle all four front wheel cylinders to clean out all the crud that had accumulated in them (and which was causing leaks). Re-assembled with old seals (I know, but they really did look as new, and the cylinders are lined in stainless steel - though the pistons are sadly not stainless), and that all seems fine now, though the bleeding to get a good pedal took an age.

So, all that done I set off on a test drive. The car has been starting and idling just fine, but once I got some speed up, the engine started to mis-fire, with lots of rifle-shot backfiring.

Was running fine when put away in Sept/Oct last year.

Any advice on how to fault-find would be appreciated. My thinking goes thus:
- engine is over-fuelled
- choke mechanism could be jammed open (but that shouldn't be a problem when the engine is cold)
- spark is breaking down (coil or condensor)

It's a problem that has arrived suddenly, not progressively.

William
 

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i'd check to see if the spark advance is working properly. could be something crudded up in the distributor.
 

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I know I am not helpful at all but could we see a pic of the beauty?

Mike
 

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Discussion Starter #4 (Edited)
@bmarler - thanks, I was wondering if the timing might be at fault. All symptoms would seem to match that diagnosis. Will investigate and report back.

Mike, here's a photo.



Cheers,
William
 

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Discussion Starter #5
Good news - I cleaned up the bob-weights of the mechanical advance mech under the rotor arm, and the car is now running properly.

A big thank you to @bmarler for his help.

Also found a year old thread that covers exactly this malady for this type of Marelli Dizzy.

Next up, need to find out why I can't get any hot water circulation into the heater matrix (it's still d**n cold in the UK).

Cheers,
William
 

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Lovely car - where abouts in the UK are you? Plenty of Flavia owners in the UK Lancia Motor Club.

The heater will either be the valve or the matrix is blocked. The valve I think is the same as a Fulvia (see here ).

The matrix will probably have to be taken off to clean it properly although you may be able to clean it out by pumping drain cleaner through it. As both the flow and return are at the top you will need to flush it with a good flow rate otherwise all the crap stays in.
 

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Discussion Starter #7
Hi Neil,

Yes that's the same valve as the one on my Flavia. I have had the valve off and it doesn't seem to be restricting flow much, so I don't think the problem lies there. Do you happen to know if the valve is up or down-stream of the flow into the heater matrix? I ask because the plumbing of the flat-four engine is really rather complex and quite hard to fathom (Martin Cliffe did kindly send me - a couple of years ago - a hand-drawn diagram of the set-up which would have helped, only I can't lay my hands on it at this moment), and whichever of the pipes to and from the heater I disconnect, there still doesn't seem to be much in the way of flow from the loose ends when the engine (hot) is running.

I'm near Guildford.

Best,
William
 

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On a Fulvia it is before the radiator, taking its feed from the engine outlet pipe on the cylinder head, through the valve and the matrix, and returning to the bottom of the radiator. I would assume the Flavia is the same but I couldn't guarantee it.

If you need a bit of help Peter Harding is your side of Basingstoke. I'm sure he will know what's what.

Neil
 

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Discussion Starter #9
Well having said I couldn't find Martin C's drawing was all the motivation I needed to have another look... and found it!

The cooling system on a single carb Flavia appears to work thus:
- the water pump draws coolant from the bottom of the radiator
- which is then pumped into both lh and rh sides of the block
- from the block, to the head, the coolant then passes up through each extremity of the inlet manifold (where they are bolted to the heads), through two 'cross hoses', to meet at the centre of the inlet manifold, where the carb is mounted
- bolted to the inlet manifold is a junction block, from which goes the main top-hose back to the top of the radiator, and also a smaller hose supplying hot coolant to the heater (phew, got there). Just to complicate matter, there's also a bypass hose from this junction block.

So anyway, the heater valve is on the 'supply' hose to the heater matrix. The return hose from the heater matrix goes into the bottom of the rad on the lhs.

I am starting to think the water pump is likely to be the culprit, as there was very little flow from the supply hose to the heater when I disconnected it earlier this evening.

The pump was giving some trouble recently. It was in fact jammed, and while it has responded to some gentle persuasion with a 17mm spanner, and now seems to spin quite willingly (and without leaking), I'm not convinced that all is well within... Not the easiest thing to remove, from the look of it.
 

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Discussion Starter #10
Well here's more information than anyone else probably really needs (at this moment, anyway) - parts book tavola for the cooling/heating system - the first one is the most pertinent, though the junctions for the heater hoses are not clearly marked (they are on the bottom of the radiator, and just below the thermostat - 14):



Heater:



I've looked at the instruction for the removal of the water pump, and it doesn't sound too bad, 3 bolts once you've removed the dynamo. Accessibility is the issue though (Flavia is generally great to work on though).

Ciao,
William
 

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...So anyway, the heater valve is on the 'supply' hose to the heater matrix. The return ..
Seems obvious, but the heater valve is always on the engine outlet at the supply to the heater matrix; the valve's only purpose is to allow (or not) hot water to the heater matrix, and the hottest water is that leaving the engine.

If your problem is indeed the water pump, this should be reflected in high water temps on the gauge. Given your weather, though, the car will need to warm fully before this may be apparent.

BTW, the car looks great.
 

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regarding the low flow from the hose ends while running, are you bringing the rpm above idle to check? i know there may not be much relevance here but my appia engine does not really have much flow at low rpm. i have to get the motor spinning to get any heat from the matrix. if the matrix has any blockage this feeble flow would certainly be stopped.
 

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Discussion Starter #14
I have run the engine above idle speed with the 'supply' hose to the heater valve disconnected, and the engine hot, but only a trickle of coolant emerged.

This weekend I'm going to take apart the assembly that mounts to the centre of the inlet manifold, and which divides the flow into three (main top hose, supply to heater, 'bypass' hose) and contains the thermostat.

My assumption is that until the engine is up to operating temperature, the coolant passes back through the bypass to the waterpump; and that when the thermostat opens, it then allows hot coolant into the radiator (and heater, if the heater valve is open). That design would encourage a fast warm-up, which is desirable...

I've noticed in the past that the engine temperature (according to the guage) will rise and rise, and then suddently drop, which would be consistent with a 'lazy' thermostat, I guess. Time to remove it (if the brass to Aluminium gods are smiling) and get a saucepan of water and thermostat boiling on the cooker!
 

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Based on those symptoms, I'd say you're right to be looking at the thermostat itself and/or mineral build-up in the housing.
 

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Discussion Starter #16
The plot thickens!

I have now removed the casting (1 inlet, 3 outlet; as described above) and was surprised to discover it did not contain a thermostat.

The Flavia Vignale currently for sale on Ebay has a picture in its listing that clearly shows where the therm. should sit (labelled 14 in Tav. 20):



Looking at the casting, it seems that the thermostat should sit above (downstream from) the heater supply outlet (red hose in the ebay photo). The thermostat, even when open, will significantly restrict flow; so in its absence, the fluid pressure driving flow into the heater will be reduced. Does that sound right to you lot?

This could explain the lack of flow to the heater. You have to wonder why the thermostat was removed in the first place... in my experience, this is likely to be a historic bodger's strategy for coping with overheating. Strange thing is, the car hasn't run hot while I've had it, even in the extreme temp's of an English summer ;-)
 

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I think you've got it right; without the t-stat, the water will tend to bypass the outlet to the heater core.
 

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You say earlier you have had a problem with the water pump. I would check that before making any assumptions about why the thermostat was removed. The impeller slipping on the shaft would give overheating symptoms and is not unheard of.

If the pumps are the same as fulvias then they are easy to check (once off the car) but seals are NLA so if that is the problem you will either have to buy a new pump (about £100) or machine the housing to take a modern seal.

On the bright side - if the thermostat isn't there at least you haven't got to spend a day trying to get it out :D
 

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William, seems the Lancia is in the way of the Sprint project. Sounds like my dilemma. It's really not a good idea to run without a thermostat. The internal combustibles are meant to operate best with the motor toasty.
 

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Discussion Starter #20 (Edited)
Ah yes, the project queue... Really in front (proper major projects ahead in line, not poxy brake and cooling fault finding) is the Aurelia B10, and did I mention the Aprilia?

New thermostat for the Flavia arrives tomorrow. I will fit it, and see if the flow to the heater is increased. If not, then the pump comes off. No intention of running without the t'stat!

Have found several bits of hose that need replacing. This is a car that didn't need totally restoring when I bought it 2 years ago, so systems are being sorted out on the go (rolling resto as it's sometimes called).
 
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