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Sierra Emax in ill health


SeanRG

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Bit of a request for advice, also a bit of a vent.
 
Buggered:  Ford Sierra following an unleaded conversion last year.  It's the one concealing a 1.6 Emax lump under the bonnet. 
 
My garage, who have maintained the car for the (near) five years I've owned it, put in new valve seats etc as part of the conversion to unleaded it had.
 
When the car was returned to me it ran brilliantly, far more sprightly than in recent times... funnily enough.  Garage recommended running it on 98 OCT or higher - I've been using the locally available Tesco Momentum 99 OCT, sans lead additive of course.
 
Very soon after, a metallic rattling sound began when being driven at low revs or uphill.  Back to the garage...
They adjusted the timing and solved this problem (hurrah) however now it wobbles on idle.  Back to the garage...
They adjusted the timing again and gave the (Webber) carb a clean inc. new jets.  Result:  no difference. 
Now it's spitting oil from one side of the engine - rocker cover gasket I suspect (could however be unrelated).
 
And that's the Sierra in its current state.
As I say, the wobbling problem didn't exist until the timing was altered to overcome the rattling sound (pinking...?) issue.  
 
Any advice on how to achieve a 'rattle-free engine' which will not wobble on idle?

Perhaps I ought to try a new garage too - on the Nottinghamshire/Derbyshire boarder if y'all can recommend a mechanic out there. 

Thanks for reading!

pic sierra.JPG

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Many many years ago I had a 1.6 Pinto Sierra, which suffered bad pinking that could not be cured by adjusting the ignition timing.

I pulled the head off and found massive carbon build up on the valves and tops of the pistons. Once cleaned, the engine ran sweet.

This information may be of no use if you’ve had your engine rebuilt and de-coked.

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My 1.6 MK1 Sierra also pinked no matter what I tried. Wobble sounds like a misfire, probably a carb problem. 

May be worth trying a different one as it's probably got its share of wear and tear - if it's a VV chuck it away and fit a Weber - VV is good until it goes wrong then they never work properly again

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Just a thought but, when they did the valves did the skim the head as well?  It seems a tad 'odd' that tey should say use high octane fuel but if they did skim it and a bit more than is good for it then the compression ratio would be higher which would explain its sprigtly performance and the pinking.

Do a compession test and compare to what it should be. If it is too high then you can do it the proper way by expensive machining of the head or the quick and dirty way with a thicker head gasket (if they exist for Pinto engines?) on bikes we sometimes used two head gaskets of the heads had been skimmed too much.

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I would suggest the following need to be looked at; 

1. Ignition timing - check what advance it is running and compare that to the factory default. Pinking is caused by either: too much advance causing combustion too early and trying to force the piston down whilst its on its way up, OR by auto-ignition of the fuel/air mix. Higher octane fuels have a higher resistance to auto-ignition, so as you have been running a cocktail of octane I would suggest it ain't that. So, you may have too much advance.  Incidentally, why have you been running lead additive in it after its been converted to run on un-leaded fuel? Unless you need to use it as an octane modifier. However, it should run perfectly fine on standard 95 RON pump fuel - unless the garage have dialled in a shed load of advance, I'm somewhat baffled as to why they would suggest running it on 98 or more as standard. 

2. Fuel - specifically the carburettor.  Now, changing from one octane rating to another should not affect your fuelling at all - petrol is petrol, it has the same calorific value regardless of its octane rating and so the baseline air/fuel ratio will stay the same, However, worn throttle spindles, leaky gaskets, and general poor condition can lead to that mixture being thrown out - either by unwanted vacuum leaks drawing in too much air and leaning the mixture out, or by fuel getting to where it isn't supposed to and not atomising properly. Vacuum leaks are a very very common cause for lumpy idle, so check all the rubber hoses to and from the carb - vacuum advance line, brake servo, manifold etc - go through them one by one and trace them from one end to the other - check for leaks, cracks, broken bits and poor sealing on the spigots the hoses plug onto.  

- HOWEVER, you say you have been using Tesco Momentum 99? I would seriously suggest you avoid this stuff. It is not a true 99 octane fuel, rather a blend of petrol and bio-ethanol. The additional ethanol in the fuel can cause havoc with older cars as it eats away at seals and diaphragms (ask me how I know....). It could be that it has eaten through something in the carb. 

3. Compression - as said by fellow shiters above, it could be that if the head was skimmed and the wrong head gasket put on (not accounting for the loss of material) then you could have the wrong compression ratio - either too high or too low. Both will produce their own symptoms. Easiest way to tell before you delve further is to run a compression test as stated.  As the car did not misbehave when first rebuilt, I kinda doubt that it is this though. 

4. Arguably the worst case scenario: one of your hardened valve seats in your new unleaded head has fallen out - if it is off this type.  No real way of telling with this unless you have a borescope - ask a friendly mechanic to take a look in the bores and see, you may well find evidence of pinking on the piston crown too. The solution to this, unlikely as it is, is another engine rebuild I'm afraid. 

My money is on the Momentum 99 having buggered up a seal or diaphragm somewhere. 

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It's worth noting that it seems that all pump fuels have had a degree of ethanol added over the last couple of months. 

Every pump at the filling stations around me now has a marker on it indicating a minimum 5% ethanol blend.

Shame as I used to always stick with Shell V-Power as (as of a few years ago anyway) it was one that could always reliably be known to be ethanol free.  Especially where it's likely to be sitting around for a while when the ethanol tends to absorb moisture (eg cars doing low mileages or garden equipment that's only used periodically).

Funnily enough I've had fuelling issues with the lawn mower, chainsaw and hedge trimmers in the last couple of months, which I have a feeling may have something to do with this having washed stuff out of the tanks and fuel lines...maybe unconnected, but it just seems a bit of a stretch of a coincidence...

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It is rather irritating - it can catch you out if you're running old or original rubber fuel lines. Easily corrected with new SAE spec rubber hose - most autofactors will do it - but it's still a pain and an expense that otherwise you wouldn't have needed to go through! 

I recently was handed my fathers trusty Stihl chainsaw, which is a good 25 years old, because it had mysteriously become a complete pig to start (a 2 stroke chainsaw of course being normally the easiest thing to start in the world, much easier than starting a conversation with that tidy blonde girl in the barbershop.....that turned out to be 15 and now your worried the rozzers are on to you, but thats another story...). Anyway, rambling aside - he'd recently been running it on 2 stroke mixed with Momentum 99  and it had rotted out the main fuel hose from the tank so it was pulling in air. 

Slightly off topic there, but hopefully of use to the OP. :) 

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From having pfaffed about with my timing last night this made me think. I'd wager at slight throttle the vacuum advance is dialing in too much of a change in timing for modern fuel.

I would wager they had initially set the timing to factory 4-star spec and under light throttle the timing was too far advanced so it was pinking (the metallic plinking noise) so they backed the ignition way off so the maximum vacuum advance at light throttle stops it from making that racket but now for idle the timing is way off making it all wobbly.

 

Way to test that theory is really easy- have them set the timing to factory spec at idle and then disconnect the vacuum line from the vacuum advance module (the little flying saucer thing on the distributor) and plug the pipe up and see then if a) it idles nicely and b) doesn't make any untoward noises at light throttle/uphill (you will see a slight decrease in performance, that is expected). If so, the vacuum advance needs to be trimmed out so it doesn't apply quite so much timing change at light throttle as modern fuel is all terrible (remember the "bring your car in to have it set up for Unleaded" programs dealerships did back in the day?).

--Phil

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3 hours ago, PhilA said:

From having pfaffed about with my timing last night this made me think. I'd wager at slight throttle the vacuum advance is dialing in too much of a change in timing for modern fuel.

I would wager they had initially set the timing to factory 4-star spec and under light throttle the timing was too far advanced so it was pinking (the metallic plinking noise) so they backed the ignition way off so the maximum vacuum advance at light throttle stops it from making that racket but now for idle the timing is way off making it all wobbly.

--Phil

An excellent suggestion I reckon. My Land Rover has various timing marks for different fuel grades, mine also suffered from a sticky advance/retard mechanism which sometimes stuck in the advance position causing running problems, stalling and difficulty starting.

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Here I am, but what help I can be is debatable.

Problems we used to have with pintos. Rotor arm, the two wires to the dizzy can break, difficult to spot, the plug is often towards the back.

Dizzy cap,  ignition module, plug leads, filter at carb. We ran new carbs so no wear on ours.

Cam belt jumped 1 notch? They still run but wobble a bit and down on power. Am wondering if the belt jumped and they adjusted the dizzy to compensate, but the crank to camshaft is still out?

Plug leads crossed, they can still run, but not well.

Oil blowing out, would hope it is the rocker gasket and not the breather box on side of engine.

Unleaded inserts do come loose, but would affect valve clearance/compression.

Should run on any fuel.

Check crank, cam and dizzy are set correctly static. Check advance with strobe.

Check compression. Change rotor arm.

I'll think of some more in a while no doubt.

Yes, take rocker cover off, check valve clearances, fit new gasket.

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Firstly, please excuse my delay in responding.  I've been away with work since posting this. 

Thank you for the comments all, some most in-depth stuff.  The car did suffer from a vacuum leak around 2015 but that was long since remedied.  RE fuel hoses, dizzy cap etc - I've no idea how old these parts are, I suppose that's one of the downsides of an original/low mileage car as nothing gets replaced!

I wish I could provide a more informative response but this stuff is totally out of my depth.  I'll relay it back to my garage and see what they say.  I hate to be the guy who rocks up and says "I asked this question to people on the internet and here's what they say" but your words will no doubt mean more than mine!  

sierra two.jpg

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A moderately interesting update: 
Driven again, from storage to home, in prep for tomorrow's handover at the garage.  I poured in a jerry can of BP Ultimate, rather I extravagant for a road car I hear, based on the feedback RE Tesco Momentum 99 which is currently in the tank.

The idling?  A big difference.  The Sierra seems to be idling far smoother than it has for most of this year.  There's still a slight wobble but it is minimal - in fact, I will sit and idle the silver Sierra (which is problem-free) for comparison.  It'd certainly like to drive it a little more than today's 4 mile journey to see how it progresses but with oil still spitting out of it I figure that's unwise.  It'll still be going to the garage tomorrow for a good check over, oil and idling anyways. 

Here's a photo of it in situ - thanks for reading.

DSC_3315~2.JPG.jpeg

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It’ll be interesting to see what the cause actually is with this...

Occasionally I used to get a slight stumble on my 1600 Pinto engined Capri, never did find the cause even after replacing the points, condenser and much of the ignition system but it never completely went away. It wasn’t particularly bad anyway so I just ignored it! I’ll soon find out if it still does it once I get it running again!

 

Gorgeous pair of Sierra’s btw!  

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Great pic of a two Sierra family circa 1986! 

What spec is the silver one, it looks a bit sporty with the black rear panel and spoiler.  I remember there was a 2.0 ‘S’ model available around the B/C registration time, quite rare even when new.

Hope the running problem gets fixed, maybe it was the Tesco fuel. 

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On 10/15/2019 at 12:00 AM, AnthonyG said:

Great pic of a two Sierra family circa 1986! 

What spec is the silver one, it looks a bit sporty with the black rear panel and spoiler.  I remember there was a 2.0 ‘S’ model available around the B/C registration time, quite rare even when new.

Hope the running problem gets fixed, maybe it was the Tesco fuel. 

Thanks! It's one of these:

https://www.flickr.com/photos/61090099@N04/7538974764/in/album-72157630432904188/

...with optional 1.8, 5speed and spongey spoiler. 

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I avoid Tesco branded fuel like the plague. My e28 is very picky on fuel and hates Tesco stuff. 

My company Volvo V40 went in for its first service last week and I mentioned a slight and temporary performance issue which happens once every morning and the first thing the dealer asked was whether I used Tesco fuel!

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I avoid Tesco branded fuel like the plague. My e28 is very picky on fuel and hates Tesco stuff. 

My company Volvo V40 went in for its first service last week and I mentioned a slight and temporary performance issue which happens once every morning and the first thing the dealer asked was whether I used Tesco fuel!

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