What have I done! (R4 GTL)

[JonathanT]

The "blackness" might not be fuel related. It could be oil that is being burnt in the combustion process finding its way past the valve guides if they are worn and making the exhaust appear black. When you say the car drinks too much how much more thirsty is it than you expected it to be?

As to the choke butterfly valve, the valve should be vertical (i.e., not causing any obstruction at all) when the choke is pushed fully in (that's the choke in the "off" position)

One other thing I've JUST though of: maybe the float is damaged in the float chamber, allowing too much fuel too flow, a bit like when your ball-cock in your toilet cistern stops floating properly and allows water to run away into the toilet, except in your car it's petrol that's being flushed away! I think I read earlier in this thread that the carb body had a leak down the side of it. Maybe this is worth a look.

I'm a great believer in following a logical path but rely heavily on 'feel' for the fine tuning.
I had a big problem with the float valve that could have caused a fire when first on the road after restore. With fuel dripping onto s hot manifold.
One thing I would add to this discussion is feeling for any play in the butterfly spindle. If it's worn it will cause uneven running and be near impossible to fine tune. It can also cause fuel to leak onto the outside of the carb body.
Play is most likely on the bulkhead end of the spindle

 

[petak]

Thank you guys for really constructive suggestions how to solve problem.

uaz04.....I am aware that eco number on MOT are not that relevant for driving. And often drivers of R4 tell that setting for MOT is not good for driving.
I must remember position of mixture screw so i can adjust it before next year MOT

Malcolm......yes my car is reving up slightly on his own when working on idle. Will check if fuel is dropping. How can i check float valve is working correctly? I must open carb to do check but how can i tell if it is not working alright.
All this time i am talking with local mechanics that are helping me maintain my car(s) and they (two of them - twins) are thinking that jets are worn out from years of use and that there is not much you can do about it.

Mojobaby.....glad i can help.... i am using this pdf sheet to set my carb....there are also many other carbs for many other cars in this manual......if you would like to have it whole let me know and i can put it somewhere to download.

Harbourseal...... So you think that CO should not be that low? I really have been surprised when i saw numbers. Did not believe it CO can go that low.

So one hole turn is 360°, and choke butterfly should be completely vertical when lever in cabin is pushed in. Remembered. Thank you all.

Andrew... i do not think my black exhaust is result of engine oil....car does not consume oil.....check oil level in engine regular and it spend form full to 1/2 on oil stick lever in 5000km. And valve clearance was checked not that long ago.
How can i tell if my float is damaged?


JonathanT....i heard before about butterfly spindle play but do not know how much (if any) is allowed....Can you tell?

I am aware that "feel" is main fine tune tool for R4 carb but unfortunately i do not have that "feel" in my ear....so I am trying to get it thru all sort of "silly" questions that i am throwing at all of you


To thank you all for all this discussion i am sending you another picture. Zenith 28IF exploded view

 

[Jurjenz]

Thanks all for sharing your thoughts, interesting to read and helpful. I hope you get your problem solved quickly Petak!

Just curious, do you also have a manual or drawings on the zenith 32IF7?

 

[JonathanT]

Petak if you can wiggle the end of the butterfly shaft in the bearing and feel a little slop then it's likely worn. I do have a suspicion Malcom is onto something here and it's to do with the needle valve and or float

 

[petak]

JurjenZ.... i have manual for 32IF7....will attach pdf manual for it in this massage
Unfortunately manual for all Renault carburetors is to larg so i can not attach it in post.
I can send it to your email if you give me one!
Also will attach explode view for Zenith 32IF7


It would be nice if Malcolm could collect all manuals in one topic so newcomers can find it easily.


JonathanT...thank you for clearing....so no play is allowed. My thought are going in the same way as Malcolm's and your's as i believe i have checked and rechecked all parts of carb that can be adjust from outside....only thing left is to open it.

But do not know how can i tell if my needle valve or float is faulty.

 

[mojobaby]

Hello Petak, here is the correct measurement for the needle valve height.
It is taken from the flat surface of the carb body (without the gasket in place) to the tip of the needle. The needle must be extended and not pushed in, in other words hanging downwards. It is 8.9mm +/- 0,05 on the GTL. (Edited!!! see new post below)
If the measurement is too big, screw the valve tighter and compress the washer, if the measurement is too small, replace the washer and screw it down to the correct measurement.
It's difficult to take this measurement, because of the position of the valve, so you'll have to work out your own method

Have a look at the top of the float where it touches the valve needle. The area of contact can be a little worn sometimes and affect the measurement.

 

[Johnny]

[QUOTE="petak, post: 54294, member: 2


To thank you all for all this discussion i am sending you another picture. Zenith 28IF exploded view


Thank you for the exploded view of the Zenith 28IF carb Petak. Are you able to re-send it in a different format please? I seem unable to magnify it and get a clear, readable picture?

Thanks,

Johnny

 

[petak]

TX mojobaby......once i have opened carb and have all those measurements. It is really hard to measure that 8,9mm. Even post pdf somewhere here on forum. But it is in Croatia so not much of help to read...but pictures are nice and detail.

Johnny......
Try open it in new window. arrow in upper right corner. And then save as jpg to your comp.
You should have really nice picture.

If does not work then send me email and will get back with original picture and pdf file.
This is best quality i have

 

[JonathanT]

Hi Petak my overflowing carb was easy to spot. Two things happened. When I switched off the engine the carb would suddenly overflow spilling fuel. This was obvious because of the smell initially and alarming to watch when I stopped the engine and watched. Opening the top it was easy to see the petrol right to the top of the bowl. Putting the original needle valve back in solved the problem though I couldn't see a fault with the replacement that came in a kit. I've not actually measured the needle as Mojo suggests but assume all ok as its running well

 

[uaz04]

Jonathan T's experience was just like mine - obvious overflow on shutoff. Fixed once with new needle, and once by rigging up a makeshift float hinge from stiff wire because we were traveling (thanks to supernice guys at Renault4Serbia!).

 

[mojobaby]

Petak, I apologize, I think that the measurement of 8,9mm must be taken with the needle pushed in. I have taken off my carb to clean and check measurements so will put up photos later tonight. I have to work out a way to check that measurement.

Thanks Petak, I've opened a new thread to solve my carb problem. Good luck with yours
http://www.renault4.co.uk/forum/threads/zenith-28if-problem-solving.8248/

 

[petak]

After some time absent from forum i am back to give you report.

For start i have removed carb to check clearances....everything is according to carb manual. more than that i do not know

Then connect my instrument to check dwell angel and strob light to see timing.

Everything was same as shown on pictures few pages back. dwell 54, rpms 750-780, timing 6-7°

All pipes are tight, restrictions are there.

Only thing i have done is open mixture screw as you have suggested.
So instead of 1,5 full turn out (as according to manual) i have unscrew mixture screw 3 full turns (3x360°).

Then i went for businesses trip to Split (180km both ways) with hard uphill when going back from Split.
It is significantly better situation. it feels like i have power again. Aldo still feeling that it should do better accelerating from 80 to 100km/h.
But i felt some more pinking on my uphill part of journey. Deliberately drive it at low rpms at uphill. So i have retarded ignition just little bit more.

Still sometimes i can fill slight juddering when i am in 4th gear at 55-60 km/h and road goes little bit uphill. But it seems that it is really to low speed for engine.
Wont drive it like that, this was just test faze!

Now i need do that adjustment you guy describe, playing with idle and mixture screw to get it right.

There is left to see real consumption after all this fiddling.

Before, consumption was at 6,5l/100km that would be 43,5MPG

I believe that it can go down for whole liter closer to 5,5l/100kmh or closer to 52MPG

What is your consumption on R4 GTL?

 

[petak]

Yesterday made small service. Oil change, filter and spark plugs.

Here are 2 pictures of old plugs. EQUIEM N43. Sorry for bad/dark pictures

Three have gray color and one is going more to brownish, but i would say that they are looking alright, and engine is working fine.



Have put new one CHAMPION L87YC

Will see how they will work, for now (some 30km done) i do not see any difference

 

[uaz04]

Why not Super Bosna? They work great for me, and I like the name

 

[petak]

SUPER BOSNA are harder to find....Champion were available right away

 

[JonathanT]

According to Haynes - A brown tan or grey firing indicates that the engine is in good condition and that the plug type is correct

 

[Azazello]

According to Haynes - A brown tan or grey firing indicates that the engine is in good condition and that the plug type is correct

My Haynes manual is b/w!

 

[JonathanT]

My Haynes manual is b/w!

That's helpful (not )

 

[jjad]

[I think they all are black and white, except for the inside front and rear covers of some of them. And the quality of the photos in the R4 'classic reprint' (that doesn't even have a proper hardback cover) is quite poor.]

 

[petak]

Mine haynes manuals (Super 5, Laguna II) are also bw. Except few first and last pages of the book.