Alfa Pages

[chpinto]

I have a problem with my alfa car 33 1.350cc dellorto carburators year 1991. It idles ok but when i start accelerating from 2000 rpm to 3000 rpm, it sort of runs irregularly, falters and chokes, but as soon as i go over 3000 rpm it comes back to normal. What can be wrong? I took the car to a mechanic and he battled for days but could not sort the problem. Anybody can help

[Kevin Smith]

I had a similar problem with my 1700cc Cloverleaf 33 Sportwagon. It turns out that the acceleration circuit spray nozzzles that sit above the main venturi's were gummed up. They looked clear, but the gum was transparent and obviously prevented the mixture richening properly as the throttle was depressed. My engine also had the symptoms that the revs fell back to idle very slowly
Once the engine was at higher revs the main fuelling circuit was it full operation and the effect was reduced.
It might also be the non-return valves in the acceleration circuit have jammed, or the pump diaphragms have split, or the return valve in the circuit has jammed open.

[chpinto]

Thank you for the information. I am going to start dissassembling both carbs and i will let you know of the result.
regards
chpinto

[cpinto]

Finally because it is a long weekend here in portugal and the weather is bad i decided to have a go at this problem. I have noticed along all this time what appers to be an oil leak at the base of the left manifold gaskett.
Every time i clean this leak it returns again and the spark plug on that side is swiming in oil all the time.The gaskett must be bad. So i took that carburetor out and tried also to take the manifold out. I have disconnected all piping and taken out the 3 nuts holding it but the manifold does not want to come out. I pull it , i have sprayed with penetrating oil the studs, i have hammered lightly it, but to no avail. Looks like its welded to the engine. Anybody can help ?
How the hell do i take the manifol out ?
regards
chpinto

[cpinto]

Finally i got the manifold out (had to hammer it), and the gaskett did not look too bad. Put a new one, cleaned and reassembled both carburetors and tuned the engine. The problem is still there. Between 2000 and 3000 rpm the engine works unevenly. After the 3000 goes ok again. This uneven running is not too bad and i can live with it but one can feel that something is not right in that range. I have noticed that the last mechanic that worked on my car about 2 years ago put ngk or champion spark plugs (still there) instead of the lodge ones . The question is : can this cause this problem ? Because i remember that after this last service, when i took the car out of the garage It was showing this problem although it was not easily discernible. It got worse slowly with time.

[paddy granger]

Well, I would recommend that you fit some Golden Lodge plugs (25HL). These seem to the only spark plugs that actually work properly on the 8V Alfa boxers. Don't ever buy Bosch plugs for your boxer - the results are surprisingly poor.

Out of curiosity, is the faltering at its worse at 2,200 rpm?

Have you taken the plugs out? Are they clean? I seem to remember with the Bosch plugs (which I tried out for 10 minutes), that the engine didn't run quite as smootly, with quite a few 'pops', as if the fuel wasn't quite combusting properly during all cycles. The Golden Lodge surface-gap plug has 4 ground electrodes for better spark propogation and combustion. I can imagine that a different spark plug design could lead to carbon build ups over time? This might be why the problem seemed to get worse with your engine?

[cpinto]

Well i have replaced all 4 plugs with brand new golden lodge but did not make any diference. Since this problem is not a matter of life and death i will carry on eliminating the possibilities one by one. I have rebuilt the carbs, substituted the manifold gasket, put new spark plugs and the next step will be the ignition system. Because my other twin alfa (the red one) does not show this problem i will start by swapping the distibuitor and see what happens.

regards
chpinto

[knight]

Kevin - was your problem also on a set of Dellortos?......or Webbers?......I have a very similar problem on my 1.5 Alfa-sud motor at the moment......miss-fires up to about 3000 rpm, then OK.......its on 36 IDF's .......the spray from the acellerator pump looked OK on all 4 cylinders when I checked the other day.......I am changing the Golden Lodge plugs for a set of NGK's.......as I'm suspecting thats where my main miss-fire problem lies.......but if it persists, I think I will buy a re-build kit for the webbers, as the engine is 20 years old now, and I dare say the seals and diaframs could do with replacing!

so what carbs are you running?.....

[knight]

I fixed my missfire .......but it was not the plugs which were the cause ........it was the fu*&ing air filter!!!!!!......I changed the GL plugs for some NGK's , and the exhaust temp on cyl 3 was still only about 40-50DegC.......as soon as I popped the cover off the air box all exhaust temps at idle were between 100 and 120 DegC......so I jumped in the car, blipped the throttle and it was revving like never before.......sweet as a nut......I have left the NGK's in as I still believe the GL's are crap, but thats just my personal preference!......am now sourcing a proper K&N cotton-gauze filter which will not cause so much of a pressure drop......JR also do a cotton-gauze filter......depends which is cheapest.......the air-filter in question was a yellow paper type, with a green rubber foam frame, made by a company called Crossland.......you have been warned!!!!!......a new paper one will probably be OK, but I think it will soon block up and the problem may return......hence, I'm going the cotton-gauze route

[ChrisC]

I can assure you that the induction noise with a k&n pancake style filter on each carb is seriously fearsome. In fact, I might even consider popping on a stock airbox for occasions the car needs to be a little quieter (i work at an accountancy practice )
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Alfa Sprint QV - Gone to a better home and in happier health for it
Silver Lancia Beta HPE Volumex - under restoration

[LDA]

i had twin pancake filters on my Arna. i loved the noise
but i spose if you are worried about weather people think your car is too loud then maybe not the best option.
they do make a lovely sound tho. but i have a feeling that they tend to draw a bit more warm air in than the stock box, as they dont have twin cold air feeds supplied with them. i had to make up some pipe work to direct some cold air at them.

glad you got it sorted !!

L.
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A good workman allways blames his sh*t tools.

[Sergio]

[ChrisC]

Lets hear it then - you must repeat 100 times :
I must read before I post
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Alfa Sprint QV - Gone to a better home and in happier health for it
Silver Lancia Beta HPE Volumex - under restoration

[Sergio]

[ChrisC]

Gah. How stupid am i? I got confused between this thread and a recent one in general where someone was going to great lengths to fix a misfire and then replaced ht lead and fixed the problem..

Im off to go repeat something 100 times...
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Alfa Sprint QV - Gone to a better home and in happier health for it
Silver Lancia Beta HPE Volumex - under restoration

[Sergio]

[Eddie W]

This is such a nice polite forum compared to some others. Self mutilation is not required for minor offences Cris.
Eddie
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A LITTLE FURTHER A LITTLE FASTER

[Dreamracers]

Thanks guys! Just the advice I needed....

Mis-fire on the road-going Sud upto around 2.5k - 3k revs, less in 3rd, 4th or top.

I'm off to buy some filters, leads and plugs...
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Alfasud 1.7Ti & Alfasud 1.3Ti