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Discussion Starter #1
Hi guys, I have a 1975 Australian delivered RHD 2000 GTV with the factory twin Dellorto carb set-up.

Cylinders 1 and 4 seem to be running at a pretty good mixture, yet 2 and 3 seem to be running pretty rich and foul spark plugs very quickly.

Does anyone know a good combination of mixture-screw turns for this model car that leads to a consistent and safe mixture to all four cylinders?


Also, my dashlights, parklights, tail-lights and number plate lights all work fine, but when the switch is turned to the position to engage the headlights, all others go off. I have traced this to a fatigue in the mechanism of the switch itself. Has anyone had a similar problem, and if so, how did you address it short of replacing the entire switch mechanism?

Thanks for your help. All the Best, Andrew.
 

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Before you start diddling the carbs, you might want to make sure your compression and ignition system are OK. Maybe compare how far the idle screws are in 1 & 4 and set 2 & 3 in the same ballpark.
Andrew
 

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You sure it's the mixture? I had an Alfetta GTV that used to foul plugs two and three. Eventually I traced it to excessive crankcase breathing into the airbox (worn out piston rings).

The breather pipe fits to the airbox between cylinders two and three so they were dealing with more oil fumes and suffering more than one and four.
 

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Discussion Starter #4
I have checked my ignition leads and distributor, everything seems to be fine there, will check the compression.

what is the factory compression ratio?

There is either fuel or oil coming out the exhaust pipe and "popping" on over-run. Does the popping indicate that it is unburnt fuel rather than oil?

I'm also conscious of not making the mixture too lean as i was under the impression that running rich is safer than running lean for the engine... is this true?

Thanks for your contributions, the help is greatly appreciated.
 

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Discussion Starter #5
Thanks to everyone for their advice and suggestions. A special Thank You to Robert from Manning Motors in Sydney, Australia for his time, effort, passion and positive attitude to helping people with their alfas.

Being a total novice, it was an absolute pleasure to be able to talk alfas with someone who races, rallies and builds these beautiful machines.

I highly recommend anyone (especially in Sydney) to give him a call and learn from his experience and knowledge.

Thanks again to everyone. This is the first post I have made here and the help is greatly appreciated.
 

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Does anyone know a good combination of mixture-screw turns for this model car that leads to a consistent and safe mixture to all four cylinders?
Every engine / carb setup requires a unique set of idle jet adjustments and jets. So, just because my car has its idle screws 2-1/2 turns in (say) means little for your car.

Also, my dashlights, parklights, tail-lights and number plate lights all work fine, but when the switch is turned to the position to engage the headlights, all others go off. I have traced this to a fatigue in the mechanism of the switch itself. Has anyone had a similar problem, and if so, how did you address it short of replacing the entire switch mechanism?
The headlight/TS switch can be disassembled, tinkered with, and reassembled, though it's not an operation for the faint of heart. Used switches come up on ebay from time to time - of course, who knows whether they would be any better than your old switch.

To disassemble a switch, drill out the four rivets holding the two halves together. Be prepared for an explosion of springs and small brass contacts, all held together by dirty grease. Watch where all the parts go! Hopefully you can just re-bend the tail/parking light contact so that it works with the headlights on.

Reassemble the tiny parts into the housing, and re-attach the two halves of the housing with two machine screws through the smaller pair of the four rivet holes. Mounting screws go through the larger of the larger rivets, so there is no need to replace those - the mounting screws will compress the housing pieces together in that area.
 

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Relays

Mounting screws go through the larger of the larger rivets, so there is no need to replace those - the mounting screws will compress the housing pieces together in that area.
After you've followed Jay's advice and your lights are working again, take the car to your favourite Autoelectrician and get them to fit some decent relays in both the light and starter circuit. The Oz delivered 105s were never fitted with relays in these places and as a result the full current load goes through those delicate little contacts causing them to pit over time. It is the same with the ignition switch, though its construction is more robust. Once fitted with relays, your Alfa will be a paragon of electrical reliability :p
Regards,
Chris

PS: Enjoy your car, they really are great little automobiles and they are getting rarer and rarer.
 

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Hey Guys.
I was going to let Andrew (bubys 54 ) reply to this,but thought i would do it for him.
I sent a PM to Andrew to bring his car here with 2 cans of coke and I would tune his carbys.
As the car drove up the driveway,I said,I CANT tune that.
Reason was,induction leak-squeel.
Anyway,on opening the bonnet,2 new Ram flow air filters were installed by the owner previously.
Carby to engine mount support was removed also.
There was also no support plate on the front of the 2 carbys to keep them together.
Well,its a bit hard to tune carbys that are not supported together.
Both carbys were bouncing around independently from each other.
Carby Squeek,well,Andrew removed the carbys,,,,,didnt he.
Welli got a 12mm spanner,and tightened the carbys to the rubber mounts.4 were 12mm nuts,,,4 were 13mm headded nuts.HATE THAT.Squeek gone now.
Anyway,after a quick carby syncronisation,idle mixture and idle adjustmet,there was a major improvement in idle.
We had a discussion on what needed to be done = put the carby stay back on and support the 2 carbys at the front.
Andrew has put it all back to original= carby stay,carby tray-support,and air filter and has advised a major improvement.
He will come back again with 2 cans of coke for another quick carby tune.
The above responce is not intended to make anyone look stupid,but to advise others that more information is required for us to answer questions on here,especially when we are not aware that anything has been altered,and we are trying to help fellow BB people.
Everyone,please advise if you have modified anything before we all open our thinking tanks.
Was a pleasure to meet Andrew,and help him with his problem.Had a great chat with him.He owns a very nice 2 litre 105,in original condition.
Hopefully Andrew has learnt from his mistakes,and will enjoy his car more in the future.
Andrew also advised that the car was running great before he modified it.
Its all good fun.
In Andrews case,it will all be fine,and not expensive.
We also discussed the healight switch problem and options.
Yes,Relays were drummed into him about the benefits they do.
All in all,about 3 + hours spent fixing and talking for 2 cans of coke.
Well he did bring more.
Was a pleasure Andrew.
OH,his mate came with him.In a fantastic looking Trans Am firebirdy thing in RED.
Niceeeeeeeeeeeeeee.
Hopefully will get to tune the Trans Am one day too.
That costs 4 cans of coke.
Anyway,hope you guys enjoyed reading this,Great typing practice.

cheers,

Robert
 
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