Hi All,

I'm after some ideas on what to check/inspect on my car as it started making a strange noise on the way home the other day. I stopped to have a look at what it could be and it wouldn't start up again.

What happened:
Driving home it was running really well for about 10 minutes
It started making a whistling/fluffing/missing noise when under load - this seemed to me to be one cylinder only and back through the carb. I drove for maybe 1km and it started happening at lower RPM
Idling was OK
Pulled over to check everything and didn't see anything obvious. It started back up but still missing, I drove to the other side of the carpark to have another look and it wouldn't start up again.

What I checked:
Changed spark plugs - no improvement
Checked fuel pump was pumping - OK
Checked for spark at all 4 plugs - OK
Had the rocker cover off - oil is clean, rockers all seemed to be pushing down the valves
Coolant is green
Blackbox unit light still on, and I tried to bypass it and no change
Roadside assistance man (used to work on minis) checked it over, swept the dissy and checked the rotor/cap/spark from the coil. He thought the spark from the coil was inconsistent when cranking over
Battery started to get a bit flat after an hour or so of trying different things

What it's doing now:
I charged the battery yesterday so it's 100%
If I spin it over on the starter motor with the ignition off (on the floor starter button) it spins over nice and consistent speed, and has decent oil pressure
If I turn on the ignition it'll spin over once or twice and then stop - to me it seems like the timing is way out but I haven't changed anything.

My only other thought is a blown head gasket between 2 cylinders? I'm after any and all ideas so I can try and knock them all out next time I get a chance to work on the car

Engine:
1098 - high compression & RE266 cam
Original 25D with advance locked and electronic ignition + blackbox for timing + AOEW ignition coil
Dellorto DHLA

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I know you checked under the rocker cover, but it does sound a bit cam/valve train-y/cylinders not filling right to me...

Does each valve full open?
Does the cam timing match up with where it should be when 1 is at TDC?
Can you confirm a valve head hasn't snapped off the stem?
Head gasket leaking between cylinders?

Just off the top of my head. I'll have a think.

Edit: busted spark plug or not seated properly?
Edit: maybe dizzy has moved in some form...double check ignition timing

(My hope would be leak between cylinders via head gasket)



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Build thread for Supercharged 1275 1967 Deluxe Resto
Build thread for Mini ute conversion 998cc Turbo

Whistling noise? Manifold gasket? Thermostat going off/Radiator holed?

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"Show me the Mini!"

If it were a head gasket between cylinders you'd think it'd have inconsistent cranking unless it's between 2 and 3, compression test?

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Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss

My guess Black box has died. Dizzy is fixed not advancing when required. Try fitting a standard dizzy

I always have one set up and ready to go. Been let down twice by faulty electric modules in dizzys.



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hey Tim

my leccy ignition dies a few years back after a few weeks of bad performance and cutting out - random starts or no go at all then no go full stop

it was the ignition module in the dizzy that was at fault

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1968 Mini-Matic

Thanks everyone for the ideas


From what I could see all valves are opening - *I haven't checked to see if they are all fully opening the same yet
*Will check cam timing for #1 and confirm ignition timing lines up too
All the valves still had some kind of rocker arm clearance and valve stems all looked attached. Also no catastrophic noises like valve on piston - *I will check this too
I did swap the plugs and this didn't help. I nipped them up as tight as I normally do - but it was the same before and after
*Yes will double check ignition timing. I also have a dial back timing light, so I wonder if I can check all 4 cylinders are firing at the correct mark?

I did replace the manifold gasket a couple of weeks ago so it's new - *I can check to see if it's fully tightened and not leaking
Thermostat was also replaced with a higher temp one (88 deg) at the same time, the temp was fine and it reads from just under the thermostat
The radiator is still full, and coolant is green so no oil in there.

*A compression test is a good idea. I actually did a comp test 2 weeks ago and I was getting around 180-190 across all 4

Last time I had a blackbox failure (on my second unit now) the light didn't come on and bypassing it made the car start straight away. *I will connect to it with the laptop and check the timing map is still the same. If that doesn't help I will bypass the blackbox and then will test the module

Thanks Steve. I don't have a spare distributor, but do have a new set of points. I can try them if I can figure out the wiring

The strange thing is that is was running and driving fine until this happened

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I’d try a new distributor cap. I had the same thing happen out of the blue. It had a very fine crack which was hard to see.

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1970 Mk2 Cooper S under restoration

I would start with basics before you get into the detail..

Get a multimeter and check for voltage drop. You say you got battery..
Check battery leads are connect properly to battery..grounds, starter, coil, wires from coil to dizzy, ht leads connected properly to dizzy cap and check wiring to starter solenoid.. make sure getting 12 volts.. to power up the car..

Good luck

I had the same problem a month ago.It was the head gasket,blown between 3 and 4 cylinder.

I replaced gasket and all good now.

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1967 Morris mini Deluxe
1968 Buick Riviera
1979 HZ Kingswood
1979 CM Valiant
1982 Jaguar XJ6 series 3
2002 VX HSV
2013 Mazda 6
2018 Gt Mustang

Broken valve spring perhaps?

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- 1968 Australian Mk1 Morris Mini (originally a MiniMatic but a previous owner converted it to a 1275 and rod change box)
- 1964 Lotus 23B

Pull the plugs and do a compression test. Use yer thumb if no test gauge. It will be obvious if head gasket is blown.
Smallbores blow between 1-2 or 3-4. Usually...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks, *will check the distributor cap and replace if necessary

I've charged up the battery again and sitting as 12.5V at the battery and at the starter.

Hopefully a compression test will provide a clue to this. While a pain to change the head gasket at least it's a simple fix

Thanks, I'll check this too

Luckily I might even have a spare in the garage

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If you reinstall points. You need to make sure that you unlock the advance plate in the dizzy as this is controlled by the black box. It may still start but run poorly


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At the moment I’ve got it timed with zero blackbox advance at idle, so with no blackbox it will have 6 degrees or so

The blackbox should still work with points too

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