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Engine troubles, Diagnosis help required
https://www.ausmini.com/forums/viewtopic.php?f=2&t=58646		 Page 1 of 1
Author:  NAV [ Tue Nov 10, 2009 10:25 am ]
Post subject:  Engine troubles, Diagnosis help required
Started NAV up to go on a cruise, he was chugging like a chaff cutter :evil: . Compression checked out as even except cyl 4 which was h handful of psi higher (tested with plugs out). checked dizzy, leads & plugs all in good order. Housemate claimed he can smell coolant in the exhaust. Could a leak into the water galleries do this and would it cause the radiator to boil over even though the car is not hot with a new radiator cap?

There was no notable change in rpm (even on the tacho) when #2 lead removed, a small rpm drop when #3 removed and the engine tried to stall with #1 or #4 lead removed.

What's the go? I'm getting the feeling I'll have to remove the head to figure it out.
Author:  Blokeinamoke [ Tue Nov 10, 2009 10:51 am ]
Post subject: 
dizzie, rotor or cap
Author:  NAV [ Tue Nov 10, 2009 11:05 am ]
Post subject: 
blokeinamoke wrote:
dizzie, rotor or cap


changed leads and plugs around, no change in symptoms
Author:  Mike_Byron [ Tue Nov 10, 2009 2:39 pm ]
Post subject: 
Tappet lock nut come undone and allow a rocker not to push down a valve ????

Mike
Author:  Harley [ Tue Nov 10, 2009 2:49 pm ]
Post subject: 
What sort of distributor do your have?
Author:  NAV [ Tue Nov 10, 2009 3:03 pm ]
Post subject: 
Harley wrote:
What sort of distributor do your have?


Pulsar dizzy. the one the doc reccomends for smallbores d4r83 i think
I've checked the leads and cap for resistance and no issues there.
Author:  VicMini13 [ Tue Nov 10, 2009 3:12 pm ]
Post subject: 
- rough running
- problems with 2 & 3 (no change when leads are off)
- coolant smell to exhaust
- blowing water out

I'm tipping a blown head gasket between 2 and 3, or a cracked head around the same place.
Author:  NAV [ Tue Nov 10, 2009 4:29 pm ]
Post subject: 
VicMini13 wrote:
- rough running
- problems with 2 & 3 (no change when leads are off)
- coolant smell to exhaust
- blowing water out

I'm tipping a blown head gasket between 2 and 3, or a cracked head around the same place.


On a small block??
Author:  awdmoke [ Tue Nov 10, 2009 4:33 pm ]
Post subject: 
Common on a small block, even more common on big bores.
Blowing coolant out with the motor still cold = head gasket
Author:  peterw [ Tue Nov 10, 2009 4:36 pm ]
Post subject: 
If you have a blown head gasket between the cylinder and a water gallery the combustion gases can be getting into your cooling system causing bubbles to come out the top of the radiator which can seem like boiling. When you stop the engine the coolant can then force it's way into the combustion chamber until the pressure equalizes. You would normally get some white smoke blowing if this was happening.

Sounds like head gasket to me.

Pete
Author:  NAV [ Tue Nov 10, 2009 5:26 pm ]
Post subject: 
no bubbles to speak of, although i havent had it running with the radiator cap of, and given it's worsening state i don't want to run it much more
Author:  drmini in aust [ Tue Nov 10, 2009 6:36 pm ]
Post subject: 
If you have a decent cam (say 270 degree or bigger), #2 and #3 on an A series don't pull their weight at idle when you yank their leads off.
IMO it's due to charge robbing at low rpm between the cylinders, due to the siamesed intake ports.
My 1360 (RE282 cam) does it too... yet it idles fine, and goes like a train, runs cool and uses no water.

Pulling plug leads off works on Alfas, it's recommended in their book to check synchronisation of the twin Webers/Dellortos.
Not on a 5 port A series though.

Don't sweat it mate, I reckon it's fine... :wink:
Author:  NAV [ Tue Nov 10, 2009 6:44 pm ]
Post subject: 
drmini in aust wrote:
If you have a decent cam (say 270 degree or bigger), #2 and #3 on an A series don't pull their weight at idle when you yank their leads off.
IMO it's due to charge robbing at low rpm between the cylinders, due to the siamesed intake ports.
My 1360 (RE282 cam) does it too... yet it idles fine, and goes like a train, runs cool and uses no water.

Pulling plug leads off works on Alfas, it's recommended in their book to check synchronisation of the twin Webers/Dellortos.
Not on a 5 port A series though.

Don't sweat it mate, I reckon it's fine... :wink:


It's a stock cam afiak and it's progressively getting worse. Plus it's never run like this before.
Author:  gafmo [ Tue Nov 10, 2009 7:43 pm ]
Post subject: 
have you checked if your manifolds has a leak
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