My Alfa Romeo 33 rebuild - FIRST TIMER

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Brit01
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Joined: June 28th, 2011, 4:54 pm
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Still not happy with the progression. Wish my lambda was working.

This weekend I will try and find time to adjust the float height.
I am going to raise it by 1.5mm or so.
Current height is 6mm.

How does the bottom float height affect the carbs? Never understood this. Once they open they are open no? If the drop height is adjusted to say 16mm what affect does this have on the running of the carbs?
Guy Croft
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Guy Croft »

I have deleted the remarks about metric/imperial. Members may post in whatever units they are familiar with.

Do your own conversions as I have to.

If you don't have the units converter from:

http://www.engnetglobal.com

..on your desktop you should have....


GC
Guy Croft, owner
Brit01
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Location: Uruguay

Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Well I've been in contact with Eurocarbs and they have been quite helpful indeed.

They also stated the 52 idles are way too lean and I should try 58 or 60 idles as the 55's I have now are still giving hesitation issues.
Also the idle mixture screws are about 4 turns out.
Ideally they should be 2.5 turns out.

I have some spares I can get drilled out to see the difference.
If that improves the progression I'll probably buy a set of originals.

Regards

Chris.

Some good new about customs here. They just passed a new bill allowing us to import 5 packages a year up to a value of 200 USD each without taxes (20kgs max). Before it was only 50 USD and taxes were at their discretion!
Brit01
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Location: Uruguay

Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Just returned from the local carb specialist and had a spare set of 52 idles drilled out to 60 and also a set of mains drilled out to 145.
(sorry Guy I didn't have my camera with me to take a photo- we have one at home semi-pro so a bit large to lug to work on the bus). Not much to photo really, just a slim door, no store front, and a small wooden top inside to serve the 1 person who can fit in. He has his machinery at the back.
He didn't want to charge me for the work so I gave him a tip!

Hopefully on Saturday morning I can find time to try the carbs out with these. Little easier than playing around with the float heights which I know are set at about 5.5mm. (factory specs: 5-6mm).

New fuel filter purchased also.
Tecfil GIO4/7
for a AR 145 1.8 e 2.0 16V.
Should give less flow restriction than the tiny cheap carb filter that I have on now.
Brit01
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Excellent!!!

60 idles and 145 mains in.
Really nice smooth progression.

A joy to drive now! Finally feels like it should.

Tomorrow hopefully get the new fuel filter in and temp gauge (sensor fitted today).

Winter sun started to set on me and was about 7 degrees working outside.
Urbancamo
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Urbancamo »

Nice to hear! If all feels good and mpg seems to stay in reasonable limits, you are good to go. As I said earlier in this topic, factory adjustments aren't always satisfying.

I just adjusted one old carburettor car, which was running only CO 0.19 in idle. It was very "thin" and hesitated in 1600-2500 rpm range where idle circuit works. Small fine tuning with idle mixture screw (end result approx. CO 1+) and it totally changed the behaviour in lower rpm range. No more annoying stuttering and hesitation.

I have 62 idles in my emission DHLA's, and it just about right. Dellorto has this has this numbering system where the number is actually bigger than true diameter. 62 idle is 0.60mm in real life.
When I had 57 idles, it was completely undrivable. Of course we cannot compare two totally different cars, carbs and engines, but this only to give perspective.

Ps. very cold there...last night it was just under 20 deg. C here in North! The best summer time is running now.

T
GC_25
Guy Croft
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Guy Croft »

Some interesting observations there regarding idle jets on Dellortos well done both.

Mercifully I am spare this as I do not - thru choice* - support Dellorto, only Weber..!


GC


* I can hear the next question already.....
Guy Croft, owner
Brit01
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Dellorto has this has this numbering system where the number is actually bigger than true diameter. 62 idle is 0.60mm in real life.
Really? If this is the case then I have 62 idles as the carb specialist drilled them out to 0.60mm.
Mercifully I am spare this as I do not - thru choice* - support Dellorto, only Weber..!
Weber vs. Dellorto...the debate begins!
Brit01
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Frustrating afternoon.

Trying to install the fuel filter from a 145 fuel injection car.

Installed it before the pump. Even after filling it full with petrol I couldn't get it to work with the engine. It wouldn't prime - but it was still full of fuel.
Placed after the pump a bit better but felt as if it was running on 3 cylinders! I thought I had a blocked jet (cleaned them all out!) but to no avail.

Filter off, engine smooth. Old filter back on, smooth!

The pipe connections on the new filter didn't have the small protruding edges. Maybe air was getting in.

BUT if it was placed after the pump then the fuel would have been dripping if it wasn't sealing properly as it is on the pressure side of the pump.
Just couldn't understand why. Old cheap carb filter back on for now.

Maybe the filter on the suction side of the pump needs to be far away much nearer the tank side?
Brit01
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Was informed by another Alfa romeo builder/restorer I know hat these type of filters do not work well with diaphragm type mechanical filters. They are designed for high flow rate electric pumps for carbs or fuel injection pumps.

Maybe there is my answer why it did not work with my pump.

Will look for a good quality washable filter now for mechanical pumps. Could be a King/malpassi or something alike.
Brit01
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

Here we have a diagram and fault of the piping from my fuel tank. The red showing extra piping put in.
A high U-bend was made behind the rear wheel arch for some reason and a filter placed there.

I will be removing this U-bend and placing a pre-filter before the mechanical pump and a fine paper filter between the carbs and pump(this is in now).
Attachments
tank%20a.jpg
tank%20a.jpg (48.67 KiB) Viewed 7686 times
pre-filter.jpg
pre-filter.jpg (15.24 KiB) Viewed 7686 times
Guy Croft
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Guy Croft »

"Trying to install the fuel filter from a 145 fuel injection car..."

what are you like Chris?!


G
Guy Croft, owner
Brit01
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Brit01 »

I know. A tad eccentric maybe!

I read Urbancamo's post about using those big beer can size filters from injection cars. But after it crossed my mind that probably he had a high flow facet fuel pump and not a weedy diaphragm pump.

Well luckily I didn't spend too much money on it and also learnt something. You learn from your errors.
Guy Croft
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by Guy Croft »

"You learn from your errors.."

judging by the hits, quite a few will be...!

G
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WhizzMan
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Re: My Alfa Romeo 33 rebuild - FIRST TIMER

Post by WhizzMan »

Those big beer can filters are mounted well below the fuel exit point in the tank on a 145 injection car. That could make quite a lot of difference when you don't have a high flow electrical pump.
Book #348
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