Technical Dropping a 60 Carb on a 45

[dufty01]

Hello

I'm a fellow Fiat driver, I was wondering, does/has anybody put a 60 carb on a 45? If so, does the twin choke fit directly on the single choke inlet or is it a case of changing inlet/carb from the 1108 to the 999?

Cheers all - Need more

ElgiN

 

[(CZ)enda]

I am on a thin ice here as I have never actually seen twin-chamber carb on a 1.1 Fire engine (I believe the combination is rather rare where I live as most of the 1.1 Fire engines here are SPI), but, judging from the experience I made with certain French car, I think it will be safer to get the twin-chamber carb complete with the inlet manifold from the donor car.
However, I am not sure whether fitting a 1.1 Fire manifold to 1.0 Fire engine is an easy bolt-on job...

 

[Chas Uno]

The 1108cc FIRE engine used virtually the same single choke Weber 32 TLF carb as the 999cc engine. Only a few jets are bigger, so you can uprate a 45 carb to 60 spec by swapping a few jets over.

The earlier 1116cc ohc engine had the option of a twin choke Weber carb. This engine is a totally different design to the FIRES, and the manifold will NOT fit the FIRE engines.

What some people have done is to have an adaptor plate made up to allow the twin choke carb to fit the FIRE manifold. You will also need to swap the throttle cable over for the 1116/ 1299/ 1301 cable as the FIRE cable will not fit.

Hope this helps!

 

[dufty01]

Hi

It certainly does! Thanks, apart from the obvious, i.e seeing two barrels, when in a breakers yard what years/models of Fiats whould have the 1116 etc? Just out of interest!

Again thanks

ElgiN

 

[Chas Uno]

Hi

It certainly does! Thanks, apart from the obvious, i.e seeing two barrels, when in a breakers yard what years/models of Fiats whould have the 1116 etc? Just out of interest!

Again thanks

ElgiN

All mk1 60S Unos used a twin choke Weber carb on the older 1116cc engine, so this would be a pre-1989 model. All mk2 60S models had the 1108cc FIRE engine fitted with the exception of the Selecta models, which continued with the 1116cc engine. I'm not 100% sure, but the classic Panda Selecta might also have this engine with a twin choke Weber?

You might also get away with using the twin choke Weber fitted to the 1299/ 1301/ 1372cc engines. The 1299/ 1301 engines were mk1 Uno only, but early mk2's with the 1372cc engine also had a carb, and so did the 1372cc Tipos. It's pretty much the same as the 1116cc Weber, though it might have bigger venturis (I'd have to check the manual for specs). It could probably be rejetted to suit the smaller FIRE engine.

You could also look for a Fiat 128 carburetor, or possibly a 127. These however are very rare these days. Another option would be the Lancia Delta 1300 and possibly the Fiat Regatta. You'll be lucky to see one of these in a breakers yard though!

Alternatively, look on Ebay as carbs turn up from time to time.

Don't forget that you will need an adaptor plate made up to fit it to the FIRE manifold. The non FIRE ohc inlet manifold will not fit the FIRE engine unfortunately.

Keep the board updated if you do go ahead with the swap

 

[dufty01]

Hi

Thanks for the information - REALLY uselful

I will be doing the 'upgrade' as soon as I find a carb, (trawling the yards this weekend )

I'll let you know how I get on, take some pics of the plate i'll make and probably a url to a small vid of what she looks/sounds like

Cheers
ElgiN

 

[SuperUno]

Think i have got a 32/34 DTMR (?) off a 1300 Uno which is a twin choke one, its just kicking around at home. PM me if your interested.

 

[AliBarnett]

This seemed like a suitable topic to expand on. My 1.1ie FIRE Uno has some stupid electrical problem with the injection system which i am giving up on actually finding the real cause as it has been a major ball ache so far and it broke about 7 months ago.

That said i'm pretty fed up of driving a Renault Clio! So i was thinking about getting a carb to bang on instead of the SPI. Now this brings up several questions I don't know the answers to.

Will the original ignition system still work without the main ECU and injection system?

What carb model should I fit, and would there be an advantage/disadvantage of trying to get one of a slightly bigger engine? According to my trusty haynes manual there is the Weber 32 TLF 27/251 that was used on the 1108 FIRE, so i imagine that should be a simple bolt on jobby with maybe a different accelerator cable, but I don't know if one off a bigger enginer would fit as easily. Appears they didn't do one for the 1372 engine which is a pity as it took the same SPI, and i imagine the 1116, 1299, and 1301 engines are different.

If i did get a carb that fitted, what ways of getting some more power could I do, and would there be much more power I could get out of a 1108cc engine? I would actually love to have a hole in my bonnet for a super charger to stick out of. Haha!

Cheers guys, any info or advice will be very welcome.

Ali

 

[Uno driver]

I don't think you will pass the MOT if you put a carb in your car and you will also destroy catalytic converter.

What problems do you have with your car?

 

[FastFreddy]

The 1108cc FIRE engine used virtually the same single choke Weber 32 TLF carb as the 999cc engine. Only a few jets are bigger, so you can uprate a 45 carb to 60 spec by swapping a few jets over.

The earlier 1116cc ohc engine had the option of a twin choke Weber carb. This engine is a totally different design to the FIRES, and the manifold will NOT fit the FIRE engines.

What some people have done is to have an adaptor plate made up to allow the twin choke carb to fit the FIRE manifold. You will also need to swap the throttle cable over for the 1116/ 1299/ 1301 cable as the FIRE cable will not fit.

Hope this helps!

Do you know here I can find new jets for Weber 32 TLF?

 

[AliBarnett]

The problem is something in the fuel injector system. Some part of it is causing the signal to the injector to go wrong. Although it seems to work fine, after driving a short distance if the accelerator pedal is held steady then the amount of fuel delievered will drop off until there is not enough to keep the engine running.

This can be fixed by removing the connection with the throttle position switch, but makes the idle position incorrect and makes acceleration hard kill the engine due to excess air.
Also works for a short while if the ECU is unplugged and plugged back in.
Otherwise varying the accelerator position continuously is the only other way of keeping it running.

I've changed all the sensors, tried both a 1l ECU and another 1.1l ECU to no avail. I've also changed the entire throttle body including injectors, checked all fuses and relays, but nothing corrects the problem.
Only thing i've yet to try is to get a new wire loop incase there us a short somewhere.

Why would changing the injection system to a carb cause it to fail its MOT? The SPI is afterall just a carb with an electronic system inputting the fuel instead of a mechanical one.

 

[Chas Uno]

Do you know here I can find new jets for Weber 32 TLF?

You'll have to find a carburettor specialist. There are still some around but they are getting very hard to find now. Your other option is to acquire another (different model) Weber carburettor and see if the jets are bigger. If you're lucky you'll find some that can be swapped around.

The problem is something in the fuel injector system. Some part of it is causing the signal to the injector to go wrong. Although it seems to work fine, after driving a short distance if the accelerator pedal is held steady then the amount of fuel delievered will drop off until there is not enough to keep the engine running.

This can be fixed by removing the connection with the throttle position switch, but makes the idle position incorrect and makes acceleration hard kill the engine due to excess air.
Also works for a short while if the ECU is unplugged and plugged back in.
Otherwise varying the accelerator position continuously is the only other way of keeping it running.

I've changed all the sensors, tried both a 1l ECU and another 1.1l ECU to no avail. I've also changed the entire throttle body including injectors, checked all fuses and relays, but nothing corrects the problem.
Only thing i've yet to try is to get a new wire loop incase there us a short somewhere.

Did you ever change the vacuum diaphragm on the distributor?

Also, your problem could possibly be to do with a rusty fuel tank, a duff fuel pump or a blocked fuel filter. Have you changed these yet?

Why would changing the injection system to a carb cause it to fail its MOT? The SPI is afterall just a carb with an electronic system inputting the fuel instead of a mechanical one.

Depends if your car is fitted with a Cat or not. If it is, a carburettor will kill the Cat because it cannot meter fuel efficiently when cold compared with the SPI. You also need to make sure that a carb will meet the emission requirements for your year of Uno. Post 1993 cars have stricter emission requirements compared with earlier carburettor models.

 

[AliBarnett]

Did you ever change the vacuum diaphragm on the distributor?

Everyone always say this. I have had 4 SPI Fiat Uno's and not one of them has had a working vacuum diaphram. It was shot for the long time it did work for. Instead the tube has been blocked to stop any excess air getting into the mix. It really doesn't effect running that much.

Also, your problem could possibly be to do with a rusty fuel tank, a duff fuel pump or a blocked fuel filter. Have you changed these yet?

When i originally got the car it had a fuel leak so i have had the tank off and it is in good condition, not rusty at all. I've checked and changed the fuel pump and checked and fitted a new filter. This is a problem with the electronic injection system. I have proven it, I just don't know what the duff part in the system as I have changed all of them with no luck. In the process of making a rig to check inputs and output of the ecu which will hopefully find the problem.

Depends if your car is fitted with a Cat or not. If it is, a carburettor will kill the Cat because it cannot meter fuel efficiently when cold compared with the SPI. You also need to make sure that a carb will meet the emission requirements for your year of Uno. Post 1993 cars have stricter emission requirements compared with earlier carburettor models.

Aye, it is fitted with a cat, I'm well aware i'd probably have to remove it. Car almost failed its MOT on emmissions with the SPI not sure it could get much worse
I don't know the specs on emissions with the carb version but i'm willing to give it a try before i'm forced to scrap a car that is in good condition with a good engine thats not working for electronic reasons.

 

[Uno driver]

Except carb you will need also inlet manifold and mechanical fuel pump. You don't need to remove electric fuel pump.

Did you try to change blue temperature sensor fitted on inlet manifold?

Did you check that part where vacuum diapragm is fitted. Check for air in berings.

Check ignition module (if there is no spark, there is no fuel injected)

Is your engine in phase?

Check for leaky vacuum tubes.

Now I'm out of ideas. Sorry for some words that may be incorrect, I'm not from english speaking country.

 

[AliBarnett]

Inlet manifold should be the same for the correct carb, if not then wherever I get the carb from I can get the inlet manifold which will fit the engine.

Changed the temp sensor, checked changed and rechanged the whole distributor and associated electrical components including ignition module.

Engine is in phase, no air leaks resealed several things just in case!

I'm out ideas too!

 

[Uno driver]

I have some more ideas:

Check resistor for fuel injector that is fitted on left side of engine bay and check it's contacts.

Do you have normal voltage on your battery? It should be 14,5V.

Check grounding of electrical instalation. I'm not sure for your car, usualy is grounding point somewhere behind the engine or at left side of inlet manifold.

Try if car is working correctly without fuel cap.

Try to disconect two electric valves at left side (around black canister) and disconect lambda sensor.

Disconect the tube that goes from black canister at left side to throttle body and (temporarly) seal the hole at throttle body. Check also tube that goes from servo brake amplifier (I don't find better words) to inlet manifold.

If nothing of this works try replacing electric instalation, as it's possible that you have a broken wire somewhere. It's quite easy task, I took it out from a car at scrapyard in 10 minutes.

Do you have shematic of SPI? Otherwise I have it.

 

[AliBarnett]

I have some more ideas:

Check resistor for fuel injector that is fitted on left side of engine bay and check it's contacts.

Checked and replaced it already.

Do you have normal voltage on your battery? It should be 14,5V.

Check grounding of electrical instalation. I'm not sure for your car, usualy is grounding point somewhere behind the engine or at left side of inlet manifold.

Checked and checked.

Theres not a fuel pressure problem, fuel flow through the fuel pipes have been checked and is fine.

Try to disconect two electric valves at left side (around black canister) and disconect lambda sensor.

Done this with all the sensors, all stop it from working except the Throttle Position switch.

Disconect the tube that goes from black canister at left side to throttle body and (temporarly) seal the hole at throttle body. Check also tube that goes from servo brake amplifier (I don't find better words) to inlet manifold.

Done.

If nothing of this works try replacing electric instalation, as it's possible that you have a broken wire somewhere. It's quite easy task, I took it out from a car at scrapyard in 10 minutes.

Do you have shematic of SPI? Otherwise I have it.

This is the last thing I have to check. Unfortunatly there seems to be a lack of broken Uno's at the scrapyards at the moment.
I have a schematic thanks.

Cheers for all the suggestions.