opel cub fuel usage help needed

Draconia2

Draconia2

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Howsit folks


i had my 1.3 cub's engine rebored to 1.6 (everything bottom end replaced with new ) and left the top end of the engine stock 1.3 ... Now i haven't tuned the carb in 2 years, and have done lots of gravel roads on the farm.

recently i smelled petrol and checked, tightened pierburg 2e diagram screws and a overall check carb clean and the leaks stopped. gaskets still 100%. She is running a bit rich though and idling seems to be SLIGHTLY off, but will this affect fuel consumption a lot ? will replacing the jets help ? the carb doesnt seem to have a flap on one of the left ports, assuming it was the auto choke ?

or is it just me looking for excuses to blame it on the high fuel price :D

im using both LRP and unleaded from shell, i first run the car empty then put in another grade, or should i mix it ?


recently changed oil castrol gtx 20w50 multi grade
changed spark plugs
fanbelt

currently if i work it out 9.2 litres per 100km
 
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Draconia2 said:
Howsit folks


i had my 1.3 cub's engine rebored to 1.6 (everything bottom end replaced with new ) and left the top end of the engine stock 1.3 ... Now i haven't tuned the carb in 2 years, and have done lots of gravel roads on the farm.

recently i smelled petrol and checked, tightened pierburg 2e diagram screws and a overall check carb clean and the leaks stopped. gaskets still 100%. She is running a bit rich though and idling seems to be SLIGHTLY off, but will this affect fuel consumption a lot ? will replacing the jets help ? the carb doesnt seem to have a flap on one of the left ports, assuming it was the auto choke ?

or is it just me looking for excuses to blame it on the high fuel price :D

im using both LRP and unleaded from shell, i first run the car empty then put in another grade, or should i mix it ?


recently changed oil castrol gtx 20w50 multi grade
changed spark plugs
fanbelt

currently if i work it out 9.2 litres per 100km
Click to expand...

Is it actually possible to safely bore it that much?
 
KingMikel said:
Is it actually possible to safely bore it that much?
Click to expand...

yup , not to sure about the specifics as the guy who did the boring passed away so i do not have precise measurements etc.

been driving city and lots of gravel for 2 years now and no problems, only things i had to is servicing :)

this thing is reliable as hell and a beast at taking a beating ! going to respray it soon (lots of little gravel chips) and still no rust
 
catman37 said:
Have you checked the float level?
Click to expand...

hmm, interesting. so if it is too high the car will use more fuel i suppose ? ill scratch around for the haynes manual and check it. when i first got her she had a small hole in the float which made it die obviously ^^ very rare that it happens.
 
So when you say that the top end was left stock 1.3 Cub, there was nothing done to aid the obviously greater airflow requirements?
 
I might have this the wrong way round. ( I am also not sure if its the same Carb as I had on my VERY OLD 1982 Opel Kadett 1.6) But if it's too low then it will let fuel into the float chamber as the needle won't seat properly when it is supposed to. So it will let more fuel into the chamber.
 
KingMikel said:
Is it actually possible to safely bore it that much?
Click to expand...

9.2L /100kms

That's not bad for a 1.6.

I've been driving my sisters 120i and on highways it does roughly 9.6L/100kms.

I'm assuming traveling on a dirt road a lot, there is more resistance on the tyres, as its bumpy and you are constantly changing gears, and the lack of momentum being built up would also add to higher fuel consumption.

Don't see anything wrong with that consumption hey.

But I'm not very clued up on mechanics...
 
Dude, 2 things:

a) Do NOT use CASTROL GTX in your engine especially if you just overhauled the motor. I recommend you use Shell Helix 15w40. It's about R170 at Midas. Also make sure you use the proper GUD oil filter. You may have to use a 1.6 spec oil filter. This will keep your engine running healthy for years to come as the Castrol GTX has been found to build up sludge in the sump thus wearing the piston rings out and the higher viscosity will cause strain on the bearings.

b) I had a similar issue with my carb and no matter how much mechanics adjusted the air screw, it still had the stench off fuel. The only solution I found was to get Carburetor Doctor in town to diagnose the problem. Turned out that their was multiple issues with the card but for R450 it was sorted and that included a tune up. Car felt like new ever since.
 
Maverick Jester said:
So when you say that the top end was left stock 1.3 Cub, there was nothing done to aid the obviously greater airflow requirements?
Click to expand...

from what i have seen is that some pipes have been changed, like the pipe next to the air/fuel mix pipe has been blocked off on the carb, you mean i should replace the airfilter with a KNN ? or a smaller pancake version ?

Im not 100% schooled in building engines so forgive me if some details are missing or fague but i can do servicing myself and know which parts to order :D
 
I had my float in my old 1.6 actually get petrol inside the float, to this day it still has petrol in it, sitting in a draw somewhere.
 
Fox1 said:
Dude, 2 things:

a) Do NOT use CASTROL GTX in your engine especially if you just overhauled the motor. I recommend you use Shell Helix 15w40. It's about R170 at Midas. Also make sure you use the proper GUD oil filter. You may have to use a 1.6 spec oil filter. This will keep your engine running healthy for years to come as the Castrol GTX has been found to build up sludge in the sump thus wearing the piston rings out and the higher viscosity will cause strain on the bearings.

b) I had a similar issue with my carb and no matter how much mechanics adjusted the air screw, it still had the stench off fuel. The only solution I found was to get Carburetor Doctor in town to diagnose the problem. Turned out that their was multiple issues with the card but for R450 it was sorted and that included a tune up. Car felt like new ever since.
Click to expand...


A reply : should i change oil in the next interval or change it immediately to avoid damage ? otherwise this weekend ill do it. So if i need a filter i should ask for the 1.6 cub filter? the bottom end of the engine has only been modified on the inside so im not sure if the filter would screw in or if it does screw in it wont be properly and it will leak


B reply :The fuel stench and leaks have gone after tightening screws around the carbs body to spec, its now only sputtering a bit black residue in the mornings (carbon) after that she is purring and no smoke , healthy (but oddly thirsty beast)
IT might be something as simple as the float as someone else mentioned or the mix screw has gone off a bit with all the bumping on the road. I know the carb doctor :D:p
 
Draconia2 said:
A reply : should i change oil in the next interval or change it immediately to avoid damage ? otherwise this weekend ill do it. So if i need a filter i should ask for the 1.6 cub filter? the bottom end of the engine has only been modified on the inside so im not sure if the filter would screw in or if it does screw in it wont be properly and it will leak


B reply :The fuel stench and leaks have gone after tightening screws around the carbs body to spec, its now only sputtering a bit black residue in the mornings (carbon) after that she is purring and no smoke , healthy (but oddly thirsty beast)
IT might be something as simple as the float as someone else mentioned or the mix screw has gone off a bit with all the bumping on the road. I know the carb doctor :D:p
Click to expand...

Change the oil if you have already passed the 1000km mark if not wait until then. Yeah, I don't think the 1.6 oil filter will be as interchangeable as the Corolla 1.3 and 1.6 so best stay with what you got.

Sounds like a healthy engine to me. The Carb Doc is your guy to sort out the air/fuel mix and the float. Best let the experts handle it and not the average mechanic ;)

Just out of curiosity, are you using anti-freeze in your engine?
 
Fox1 said:
Change the oil if you have already passed the 1000km mark if not wait until then. Yeah, I don't think the 1.6 oil filter will be as interchangeable as the Corolla 1.3 and 1.6 so best stay with what you got.

Sounds like a healthy engine to me. The Carb Doc is your guy to sort out the air/fuel mix and the float. Best let the experts handle it and not the average mechanic ;)

Just out of curiosity, are you using anti-freeze in your engine?
Click to expand...

yup i mix it with water, castrol anti freeze. rad is slightly rusty from age but ive seen worse like worse in when you touch the rad, rust falls off hmmmmm needs to get replaced around 2 years from now at least.

yeah i got my mechanic ( not a sunday one lol ) he does performance cars and mostly opel.

he is going to check the timing saturday morning and i need to go do the CO's tomorrow just before my work starts. im pretty sure it will bring the litre per 100km alot down, i know its not going to be as good as a chev spark, but i use to get roughly the same fuel usage as my 1.1 uno before it got stolen which im glad it happened lol that thing was one of those end of the month cars.



anything is better than those other heavies out there ! been to the kruger and back TWICE
 
before i took to the road to waste money i found this out upon my own investigation:

so the guy who passed away WHO I ASKED TO CLEAN THE CARB while the engine was out ......



never cleaned it ! :mad:



Instead he took some putty and colored it the same color as the carbs body, and stuck the idling screw thats ontop on a certain level , keeping the car idle steady. Some parts where put upside down as well when i took the carb apart i noticed some **** unfolding like never before....


upon removing the putty the car instantly died when i placed the screw back in and started her up which means the port was FILTHY, one good clean with the air hose and fired her up the idle was quieter than a merc !

went around the block the car stalled again, opened the top and gave it a good clean again with carb and air hose cleaner, The breather pipe was disconnected to the air filter at the time.


Car seemed fine but cut out again .... so i connected the breather pipe to the carbs air filter and raced it a bit without stalling once, seemed good and could go to work and back without problems (stop and go included) then now last night while going around 40kmph over the robot the car just randomly stalled , luckily no traffic !

Without hesitating started up again while moving and the car started instantly no hesitation ( it has happened before going uphill which i think the filter could not process the fuel fast enough as it was REALLY steep, almost 4x4 level steep)



I do not see any vacuum leaks , all hoses are fairly new, it is a mechanical fuel pump i have not had enough time to change it to a more modern electric one which i see is the norm on kadettes nowadays.

Timing is good now after the carb cleanup so i did not do the timing saturday.


Why would the car just randomly cut out at such a slow speed ? the old fuel pump ? racing it at 120kmph doesnt seem to be a problem and slowing down also no problems, it was just once lol so im a bit stumped.:confused:

Fuel filter is good
Idling is at 900rpm which is good ?
oil is good , filter is good no leaks
 
Why are you even trying Unleaded?

There's no point and you should be running LRP only.
 
genetic said:
I rebored my 1.3 Fox to a 1.6 with no issues.
Click to expand...

It is possible, but you need to be sharp !


Good news is the car is sorted, what seemed to be a chain reaction due to the badly gummed carb.

The timing was off and the idle was low. Its now been set and im ready for my next long distance trip :D

I mix the fuels as it lubes . Keeps the engine healthy and makes no difference really, for me it feels the LRP burns bit faster idk

also 200% fuel economy increase :D
 
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"Reboring" a 1.3 to a 1.6 usually won't require any actual reboring. Most manufacturers use the same bore for their 1.3 and 1.6 engines, and just use a longer stroke, so by swapping the con rods and crankshaft out, you can turn a 1.3 into a 1.6 without even putting new pistons in. Granted, if the 1.3 was poked, then it will need a standard 50 thou rebore and new pistons and rings too, but if there's nothing wrong with the engine, it's pretty easy to change it. The harder part is getting it to run smoothly and economically.
 
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