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Home > Help Needed / General Tech Chat > Not much happening on Number 2 Cylinder

Graham T

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604 Posts
Member #: 1106
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Hungerford, Berks

Guy’s,

I’m just looking for some advice before I start a strip down.
I’ve just swapped the Mini over from Injection to Carb and taken it out today for it’s first run, hoping I could get it to the dyno before the really cold weather gets here.

However, all is not well apparently.

Last run out with injection was around 2 – 3 weeks ago and I certainly never noticed anything odd.
I should have realise it was not running properly before I set off, because the engine had a different noted to normal on tickover, but I just assumed the changes I have made were responsible for the difference in sound.

I’m not running any boost at the moment (or very, very, very little) and have not been for several months.
Anyhow, the car ran shockingly badly, very sluggish and just no real power there.
Ultimately I realised the odd note of the engine and lack of performance meant a problem, so I started pulling HT leads when I got back from my drive out and it appears Number 2 cylinder is not doing very much at all.
In the below you can see a log where I have pulled each HT lead in turn, 1 to 4 and the result: drop in Rev’s, rise in MAP and lean Common AFR each time.
That is all except where Number 2 HT lead being pulled should be. The Marker line should be centre of the 5 second interval the lead was pulled.







So I’ve swapped HT leads 2 and 3 around, swapped spark plugs, put in new plugs, replaced leads and even swapped the coil pack.
Always the same, so I’m convinced it’s not Spark related.

I’ve run compression tests on all cylinders.

1 = ~150PSI
2 = ~150PSI
3 = ~155PSI
4 = ~155PSI

I’m not seeing any signs of coolant in the oil, coolant being blown out the radiator or anything sinister.
So has anyone any idea’s on what could be going on or what else I could try before pulling it apart?

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


robert

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uranus

dp

Edited by robert on 17th Nov, 2017.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


robert

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uranus

too lean ? tried winding down the jet or pulling the choke on ?

not a chance or blue paper towel of death stuck somewhere ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


Turbo This..

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Previously josh4444

Australia, brisbane

something in the valve terrain gone a miss?

the jam nut on the rocker back out and self adjust losse?
worth a check under the rocker cover for anything strange lash? bent push rods? eyeball on full lift?

id assume an air flow problem might show up on the comp test but the engine is turning slow compared to running speed so perhaps something is open just enough to show a good read but not to the extent it should be?
ive never found any difference with the throttle open or closed for instance so there only needs to be a tinny gap for air to show a good reed


Graham T

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604 Posts
Member #: 1106
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Hungerford, Berks

On 17th Nov, 2017 robert said:
not a chance or blue paper towel of death stuck somewhere ?



I hope not! But looking at the plot again with a fresh set of eye’s a bit earlier this morning, the effects to AFR on pulling the HT lead for Number one are nothing like that of 3 and 4 Cylinders, so this could be a blockage in the inlet tract for 1 / 2 cylinders, affecting 2 more than 1.

It looks like I need to pull the inlet manifold off as see if I’ve been a complete cock and left something like rag/ towel in the port on Number 1 / 2.


On 17th Nov, 2017 robert said:
too lean ? tried winding down the jet or pulling the choke on ?


I have not since discovering this problem. I’d do that after I’ve looked in the ports.


If not, I’ll pull the rocker cover and look at the valve train.

Thanks for the suggestions.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


Graham T

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604 Posts
Member #: 1106
Post Whore

Hungerford, Berks

Sorted – or at least I know what’s wrong now.





I’ve been able to partially rectify the problem, but not fully.

At least now pulling the HT lead for Number 2 registers, though it is far from right.

Also, pulling number one HT lead shows more of an effect than it did, but more significantly tick over MAP has dropped from 38 – 41Kpa, back down to its usual 29 – 33Kpa.

It was not blue paper towel and not a problem with the valve train.

There was a rather large air leak on the inlet Manifold flange to head.

Basically, it looks like the flange is crooked on the runner ( It looks like it has been welded up in a previous life), hence it was not pulling down flat on the gasket.

I’ve carefully filed the flange so that it is square with that of Number 3 / 4, but ultimately I need to get the flanges machined properly. Something I cannot do as I do not have a mill.

Anyhow, I now know what the cause is so at least I can move forward!

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


wil_h

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Betwix Harrogate and York

Had I read this before you found it, I'd have guessed air leak on the manifold.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


robert

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uranus

rub it down on a sheet of glass and some 40 grit ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


Graham T

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604 Posts
Member #: 1106
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Hungerford, Berks

So just to close this off.

I followed Robert’s advice above and rubbed down the Inlet manifold flanges, but decided I would also replace the manifold gasket.
When I stripped down to get the exhaust manifold off I found A LOT of oil in the Turbo to intercooler pipe. Stripped the turbo out and found the turbine shaft was slightly buggered.
So now I have a new Turbo and finally have the car back together.
I’ve only just got it started up tonight, but logging looks much better:



Hopefully I can now get the car out for a run in the next couple of days, as long as the weather is nice to me, ready for a Dyno Session this coming Friday. *smiley*

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Home > Help Needed / General Tech Chat > Not much happening on Number 2 Cylinder
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