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SOLEX 32 DIS for R4 GTL (not original)

zsolt

Enthusiast
Messages
14
#1
Dear GTL Experts,

How bad idea is it to buy an aftermarket - not so original - Solex 32 DIS carb for a 1108 ccm GTL R4 from China?
For example this one:
solex 32 dis
Currently this car has a Zenith 28 IF. Will the solex carb make the car "fly"? Is there any other changes that is needed? (The ad link suggests it will fit.)

Thanks for opinions.
 
Messages
1,448
#2
Zsolt;
Imho stay away from Chinese -made carbs and other "delicates" -I've seen a few where jets and needles have been substituted with plastic
(I'm not talking about Zytel-Nylon etc) just cheap resirculated plastic-so brittle it broke on first attempt to adjust..how it would stand up to
E-ruined petrol is anybodys guess...-R.
 
Messages
9
Location
Glossop
#3
If you change to a 32mm carb you'll also need to change the inlet/exhaust manifold, water pump, rocker cover and air filter housing for Renault 5 items. Some of these bits are easier to find than others.
 

zsolt

Enthusiast
Messages
14
#4
If you change to a 32mm carb you'll also need to change the inlet/exhaust manifold, water pump, rocker cover and air filter housing for Renault 5 items. Some of these bits are easier to find than others.
Thanks for the information. I did not know this, in fact I thought I can swap the carb only (from Zenith to Solex).
The reason why I thought this is because the following FIA document mentions SOLEX 32 DIS for R4 GTL:
FIA R4 GTL 1.1
See page 3. Was there any R4 fitted with SOLEX 32 DIS carb in the factory?

When it comes to power output, is there any other significant difference than the carb between the R4 GTL 1108ccm 688 engine (34 HP) and the R5 mk1 1108 ccm (45 HP)? Somewhere I've read that camshaft (valve timing) is exactly the same, but I am also getting mixed information on this topic. Can someone clarify?

With other words, if I replace the Zenith 28 IF with the Solex 32 DIS (and other parts as @Cleon-Fonte pointed out), will my little R4 reach 40+ HP? (Which does not sound terribly alot, but its like 20%+ increase!)

The price of the "aftermarket" "not so original", but new Chinese Solex 32 DIS is around 100 EUR. This is way more reasonable than what I am seeing for original new solex carbs. If the "aftermarket" works okay, I am not so much concerned that it is not original.
 

zsolt

Enthusiast
Messages
14
#6
A friend of mine helped me to check the camshaft timings and it looks like (some) C1E (700, 760, 762, 764) engines are different than my R4 688 D12. So maybe swapping the carb only will unfortunately not make my R4 fly and reach 40+ HP. :(
 

mr-reno-139

AKA Paul Cunningham
Messages
1,941
Location
lancing west sussex england
#7
Don't forget the compression ratios are not the same on all 1108 engines
Years ago I fitted a second-hand cylinder head from a Renault 4 Van to a Renault 6TL rather than get the cylinder head skimmed following an overheating issue I put it back together and the car was a long way down on power and I had to swap it back as the customer not very happy
Most Renault 4 will respond too careful setting of the points dwell angle and advancing the ignition timing manually rather than relying on figures given in the book also checking that you are actually getting full Throttle opening
 

JonathanT

Not normal for Norfolk
Messages
1,205
Location
Wymondham Norfolk
#8
Check out my posts on the matter . I have recently fitted a Xenith 28if copy and it’s marvellous!
 

zsolt

Enthusiast
Messages
14
#9
Check out my posts on the matter . I have recently fitted a Xenith 28if copy and it’s marvellous!
I checked your posts where you mention that the copy Zenith 28 IF works better for you than the original Zenith 28 IF.
I wish I could try it out before spending (wasting?) ~150 EUR on the copy. After all the car (1.1 GTL 688 D12) runs fine with current (factory original?) Zenith 28 IF.
If I spend some money on this, it would be great to see a few HP increase also... Maybe (an used) Solex 32 SEIA would be a better option?
 

mojobaby

Enthusiast
Messages
1,196
#10
It would be interesting to know why exactly you are looking for more horsepower. Is it extra speed, more power for hills, or do you carry heavy loads?

The reason I ask is that I also have a GTL and can cruise quite happily at 80kmh. I don't need to go at 120kmh. She can handle 90kmh if I wanted to, but I prefer 80 as a safe driving speed. If I have a passenger, there's no noticeable difference. She strains a bit on hills if there are 3 people.

Have you considered that if you have poor compression or badly timed engine, you will still have a lack of power despite upgrading parts like carburetors
 

mr-reno-139

AKA Paul Cunningham
Messages
1,941
Location
lancing west sussex england
#11
It would be interesting to know why exactly you are looking for more horsepower. Is it extra speed, more power for hills, or do you carry heavy loads?
I said more or less the same thing inpost number 7 above I will be checking to get the optimum out of what is already under the bonnet before wasting time and money
 

zsolt

Enthusiast
Messages
14
#12
It would be interesting to know why exactly you are looking for more horsepower. Is it extra speed, more power for hills, or do you carry heavy loads?
It's more like the 50-90 km/h acceleration that is not so great on "normal" roads. Top speed is not important, to be honest the car does not feel terribly stable above 100 km/h. (My suspension is in good condition, shock absorbers are after market, original is not available here).
I think my engine is in good condition, even though power output was not measured. Still, I think the car and the driver could handle more than 34 HP. The current Zenith 28 if carb was cleaned, ignition distributor is great (Replacing the old one made a huge difference). Emissions are OK (just passed MOT without any hassle).
 

mr-reno-139

AKA Paul Cunningham
Messages
1,941
Location
lancing west sussex england
#13
Can't remember exactly what I typed above I would suggest checking valve clearances aren't too tight or loose get the dwell percentage get a compression test done then finally Mark the distributors current position with a white paint Mark between the body and the Block and experiment with advancing slightly the timing making sure you don't go too mad and end up with the engine pinking also check you have got the cold air feed for the air filter picking up from the very front of the car
It is also possible that you have too much slack on the accelerator cable which will limit performance obviously
 

David M

French car tragic!
Messages
173
#14
The common options for more power are CCCC.
Capacity
Camshaft
Compression
Carburettor

Without dismantling the engine there is only one option. The carburettor.
So go with a new carburettor by all means. No leaks is a huge benefit to smooth running.

Renault strangled the engine in the R4 to get impressive mpg figures. A small carburettor was the major change. Conservative camshaft and relatively low compression rates made a 1.1 litre motor give the economy of an 850cc engine.
The bigger capacity effectively gives more torque and makes the car more drivable.

You can expect some improvement in performance from the new carb. At the age of your car, smoother running will give you satisfaction.

There is the potential of a LOT more performance by rebuilding the engine to look at the other ‘C’s. That is a lot of money. A mark 1 Renault 5 LS or TS engine would address all your concerns.
Some 1.4 motors made 60+bhp in production cars.

So there are a myriad of choices. A carburettor in good condition is a positive first step.
 

mr-reno-139

AKA Paul Cunningham
Messages
1,941
Location
lancing west sussex england
#15
But then again a good carburettor jetted for different camshaft and compression ratio will not be at it's most efficiemt
That's presuming it doesn't mind the ethanol content either which also burns at a different rate to the fuel we used to get
Rolling road anyone
 

zsolt

Enthusiast
Messages
14
#16
I looked up some numbers to see how different are some 1108 cc engines (maybe data below is not 100% correct)

Camshaft Timing (for my car, 688 D12)

Inlet valve opens BTDC 12
Inlet valve closes ABDC 48
Exhaust valve opens BBDC 52
Exhaust valve closes ATDC 8
Compression ratio: 9, 5

Camshaft Timing (for C1E 700, 760, 762, 764, 756)

Inlet valve opens BTDC 12
Inlet valve closes ABDC 56
Exhaust valve opens BBDC 56
Exhaust valve closes ATDC 12
Compression ratio 8,8

These are all 1108 cc engines.
 

angel

Enthusiast
Messages
1,873
Location
Athens, Greece
#17
The common options for more power are CCCC.
Conservative camshaft and relatively low compression rates made a 1.1 litre motor give the economy of an 850cc engine.
The bigger capacity effectively gives more torque and makes the car more drivable.

.
At 9,5:1 compression ratio for the GTL engine was actually pretty high. Higher compression ratio = better fuel economy.

The reason behind the deliberately low output of the GTL engine was more simple. The French tax system of the '70s used a formula to determine "fiscal HP" (CV) and class the vehicles accordingly. This formula took into account, among others, engine capacity, actual horsepower, and final drive ratio (!). With its low output but torquey engine that allowed the use of a very tall (3.1:1) final drive, the GTL was classed as 4 CV, while the 845cc TL was 5 CV. This made it more attractive to buyers, but also stopped any internal competition with the (higher classed) R5.
 
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