Carb setup

[F6frogie]

Steve you don't happen to know the thread size of the main jet do you - M5 X 0.75 by anychance ?

I changed the inlet manifold gasket today and noticed that the exhaust oil vapour connection on the exhaust manifold was all blocked with soot ! so cleaned this out too before re fitting.

When I re fitted the carb and started it up it ran very weird - very high revs with choke on and died with choke off - I had to leave it though for today a I didn't have time to finish the job - I read in the haynes manual that the exaust side of the re circulating pipe should be 1.5mm dia and mine is more like 5 or 6mm ! is there meant to be some sort of restictor in the tube ?

Regards

 

[angel]

Apparently it sucked air through the oil recirculation pipes. Yes there should be a restriction-either on the manifold or in a pipe, there was a topic on this some time ago.

 

[Steve Hennessey]

Matt, sorry I don't know the thread size of the jet. Hope you have sorted out the fast idle. I remember that my pipe had totally perished so I managed to get a new one from Renault but I can't remember if the restrictor was built in or came as a separate part. As this is part of the emission system you could temporarily block off the pipe from the inlet manifold to keep the car running whilst waiting for the correct parts to turn up.

 

[F6frogie]

Hi, Yes I sorted that out - I slept on it and thought it must be the exhaust re-intake system pipe. The car was running alright before without the restrictor as the manifold exit was totally blocked ! I did change this pipe before as it was perished but for an identical size one - I installed a small rawlplug (Yes, I know) into the pipe which has around a 1.5mm hole straight through it and was a snug fit - I then tried the car and it was back to normal

Yesterday I adjusted the carb as per the haynes manual - the float jet measurement was about 1mm to high, so installed the original washer which was thinner (couldn't crush the new one enough). I adjusted the initial throttle opening, the pump travel and the defuming valve which was also out a little.

I tested the car this morning and it's a little better but still needs quite a bit of choke - at aroung 90km while still accelerating if I back the choke off completely the revs pick up then a lot better and it keeps accelerating

I know I should adjust the carb last but had the time yesterday and still had not received the compression test kit until this morning - I can probably get this done today if I get the time.


Do you still think that the main jet will need enlarging a little ?

I have purchased two jets (115 and 117 - Mine is a 110) to play around with (if I cock it up too) but am only 90% sure they are the correct ones - they are M5 0.75mm thread which look like the one I have and are from ebay for solex, pierburg and some zenith carbs so fingers crossed.

Cheers

 

[Steve Hennessey]

Yes, if the threads are the same put the 115 in first. If not then get the micro drills out or try the Carb Exchange - but not until you've checked compressions/tappets etc.

 

[merlody]

hey guys, sorry but i have a question,
i have the same carb. in my r5 engine, i don't understand where's the mix screw? the one that controls the air quantity i mean. plz if u could reply with a detailed pic showing it's place i'd b so glad
thnx

 

[F6frogie]

Hi steve, sorry for the long delay in updating this post - Have been really busy.

I got the jets as I said but they were the wrong thread - so checked the points gap and timing again then the compression which were all fine and so decided to drill my main jet out to a 115 - Et Voila, problem solved! - before the last 1/4 of the accelerater pedal travel seemed to brake the car and now it continues to accelerate - it would probably be a little better if I go a little larger (117/118) but this will probably effect fuel economy? and as it's 1.66 euro a litre here - probably not wise.

It is a little hard to start when warm though (maybe due to the hot weather too - not sure)?

All I have still left to do is my wheel bearings and try to cure the anoying lean on the drivers side rear (2cm lower than opposite side !!).

You dont' know by any chance how the flexible steering disc is removed do you which links the steering colum to the rack ? - there is X4 fixings, 2 bolts to the colum and 2 weird looking fixigs whick look likr the need to be ground off and replaced with new bolts?

PS, for MERLODY - take a look at the photo below to see the mixture scews exact position.



Cheers, Matt

 

[Steve Hennessey]

Matt, I don't think that drilling the jet out to 117 will use any significant amount of fuel extra. It's just that as you've got more poke in the engine then you'll tend to use it!!
What do you mean about hot weather - it's peeing down here and I've got a sweatshirt on as it's a little nippy!! Have you tried different techniques in starting when hot?
I've never had to replace a flexible coupling. Can you buy new ones? If so, then high tensile bolts with locknuts would do. Not sure how you can grind the fixings off whilst the rack is still in the car.
Is the driver's side front low as well? if so, which torsion bar is the one that needs attention? I've never had the pleasure of adjusting suspension yet.

 

[angel]

You must grind the two rivets and use 8.8 or higher bolts on reassembly. It is not practical to do this on the car. It is possible to remove the rack pinion to do this with the rack still on the car, I have done it once.

 

[F6frogie]

Matt, I don't think that drilling the jet out to 117 will use any significant amount of fuel extra. It's just that as you've got more poke in the engine then you'll tend to use it!!
What do you mean about hot weather - it's peeing down here and I've got a sweatshirt on as it's a little nippy!! Have you tried different techniques in starting when hot?
I've never had to replace a flexible coupling. Can you buy new ones? If so, then high tensile bolts with locknuts would do. Not sure how you can grind the fixings off whilst the rack is still in the car.
Is the driver's side front low as well? if so, which torsion bar is the one that needs attention? I've never had the pleasure of adjusting suspension yet.

Hi Steve, No really it's hot here - 30 deg C + ! It seems the best way to start the car when it's hot (dosen't seem to be a problem when the engine is hot but the weather cool?) is to just turn it over (turns over fast/normal) with the accelerater depressed to the floor and when it starts, sometimes 5 seconds (1 when cold).

So you think it would be best to drill out to a 1.17 ?

Another thing when I let off the accelerator at high revs the exhaust can be heard popping (like un burnt fuel) - could this be a pin hole somewhere in the exhaust?

Yes you can buy the flexible coupling disc as I did a while back from the Franzose site when ordering other bits (6 euros I think).

The rear drivers (L/H side) is down about 2cm and the front drivers nearly 1cm compared to their oposite sides, which means to me that its the rear drivers which has the fault and this is obviously causing the front to be brought down a little too - All the shock absorbers are new.

Thanks for your advice Angel

 

[Steve Hennessey]

Matt, regarding drilling out the jet even more, if you are happy with the performance then leave alone - if not then drill it out some more. You can remove more metal but you can't replace it!!! Saying that, if you did drill it out too much then you could fill the hole up with solder and start again!!

Exhaust popping is usually a sign of an air leak. It could also occur if your tickover is set too high.

When you get the time then see if you can raise the rear suspension. There's a bit in the Haynes manual about setting it up but I would imagine the torsion bar could be a tad difficult to remove due to rust. Something to play with for when you get bored!
The shock absorbers won't make any diffence to the height settings.

 

[F6frogie]

Steve, yes I think the performance is OK now and am happy but would like to see the difference a 117 jet makes - I'll have to find one I can buy although that is a good idea with the solder!

Do you think I could have an air leak if the performance is so good? - as I said it only does this at really high revs when I let off the pedal (remove foot completely) - the tick over is actually really low.
I have still to find a nice fitting o ring for the mix screw -it can't really be that though if the tick over is good.

Yes, I was leaving the rear torsion bar until a rainy day and when all the other things are done but and can feel it upset the handling when there is weight in the back at speed.
Yes I know there is a small section on this in the haynes manual and think they work on cams and can be fine tuned - I don't think it will have to be removed, just have all the weight took off it and then it can be adjusted.

Cheers, Matt

 

[angel]

There has been a lot of discussion here about torsion bars. When you get bored (but before you start playing with them on the car!) try to read what has already been said. Unfortunately, the later R4s as yours do not have the adjusting cams and you should remove and reposition the bars-ouch!
How do you measure the height?

 

[F6frogie]

Hi Angel, I have already read quite a bit on the torsion bars (would never start anything like that without firstly doing so) but I did not know that my car had ones which were not adjustable?

I have lowered/raised many french cars by means of removing and re-inserting the torsion bars and am sure the R4 won't be really that different?

If I stand about 5 meters or so from the rear I can see that the L/H side is considerably lower than the R/H side. Even looking at one wheel and the space above it then going to the other side the difference can be seen.

It does also look like the body (not chassis) is lower on the L/H side as the chassis runs out towards the rear wheel ?? but not sure how this could of happened? I will try to get some photos together.

to get the measure ment of 2cm difference I measured from the floor (on a solid level surface) through the center line of the wheel to the arch lip to measure but I do know that this is not an acurate way and from the floor the chassis is better but anyway as I said you can see it.

 

[angel]

I have lowered/raised many french cars by means of removing and re-inserting the torsion bars and am sure the R4 won't be really that different?

No, the principle is the same, but on the R4 (opposed to modern Peugeots, Citroens) the torsion bars are under tension even when you remove the shock absorbers so it's a step more to release them and then adjust their position.