Information request; Differences in chassis construction & engine characteristics R4

[sideslip]

Hello. Long message alert!

I am trying to find more information about various Renault 4 differences. Was wondering and hoping that some of you may know /have opinions on different engine traits, and also chassis dimension specifics. I would be so grateful for any information/opinions from people that are in a position to give it
Questions are below; but my background:-

In the past I have some trans-global trips in Citroens , the 2CV, the (original) DS etc. From behind what was the iron curtain a few years after the wall came down; to Asia; New Zealand; and African countries. One of my potential future journies maybe in a Renault 4 /F6; and I am considering getting an R4 anyway; trip or no trip.


(1) The four wheel drive system & chassis lengths. Did Sinpar & the other 4WD makers make 4WD options on the long chassis as well as the 'normal' chassis? IE is there a long chassis 4WD system too; in addition to the regular chassis 4WD system?

I have heard today that 4WD R4's were also made in Scotland for utility service businesses. I naturally assumed that this meant "vans"; but I don't know. Does anyone? And if so were they long or short chassis/wheelbase vans? It is possible that " normal cars" were converted too; to ferry staff around. (Just like the Citroen 2CV Sahara was made for--four wheel drive and two engines).

The extra length in the "Long" chassis for the F6; which I have documented as being 120 mm longer than the standard chassis; is shown in my diagram as being in the section towards the rear of the floorpan. Ie in front of the rear axle. (This is in addition to the extra length added on the back)

Also thewheel base is listed as being longer.

This therefore means that the propshaft would have to be longer; and there therefore must be two different lengths of propshaft for the 4wd system(s). Does anyone know definitely please; how many 4WD system and lengths there are?

That leads me on to the next question. If people have adapted the 4WD system from a short to long chassis; have they "just" lengthened the propshaft; or has anyone moved the whole rear axle/components forward?

(2) Engines
I read the 1108cc engine has a lower rpm for both power and torque compared to the smaller engines. Does this mean the smaller sized engines are much more freely revving; and therefore perhaps better suited and balanced to harsh use?

I am aware the 956cc unit is derived from the 1108 and presumably has the same characteristics. As my background in cars is a Citroen background; this flexibility and "revability" to me seems a useful trait.

(3) I have heard that these engines had problems accepting four star fuel at the time; and have problems with unleaded. Mostly the 1108cc engine I thought; but today I was told that all R4 engines did not get on well with unleaded. What are peoples findings? Again coming from Citroens where there is no problem at all with unleaded fuel; this was a surprise and a shock to me. I assumed Renault, being a French car maker too would be similar.

(4) I was intending to run the original size engine. The theory being light weight and relatively understressed; and so therefore hopefully reliable. I know some people put bigger R5 engines into R4's. Are these are more reliable with fuel unleaded etc etc?.
I have had Citroen mechanics that have been fine. However in the 1990's when I had a 1299cc 65bhp Citroen GSA engine running through the "1015cc" Citroen Ami Super gearbox ; that was designed for 50bhp; it broke a planet wheel in the differential. Is this a problem with the R4 too? or do people slot the R5 gearbox in too/does that physically fit in the R4?

(5) The Fourwheel drive system.
I assumed that it may have been a system similar to the original Fiat Panda 4x4 system; whereby once 4WD is engaged it is locked centrally. So at least one rear wheel rotates with at last one front wheel.
However I saw a photograph showing two floor mounted levers. So does it have a rear diff lock? (like the contemporary Citroen Mehari 4x4?; or is it one lever to pop it in; and another to pop it out?

(6) Is there an extra low ratio gear on the 4WD gearbox? Or do they have a lower final drive ratio; or are the gear ratios "standard"?


Why the R4 for a trip? I probably don't need to mention this to any of you....

• Soft suspension to exploit off road traction
• Light weight to push car out alone (as I have done on 2CV's)
• Fuel economy
• Longitudonal engine (easier to work on; I have removed single handed with no lifting device engines/drivetrains from Citroen 2CV's; GS's)

Of course if I never do the trip; I am thinking of getting an R4 anyway!

Whilst I have considerable experience on Citroens; I have never had a Renault ; so any experiences or particular problems that you can raise will be most useful; and I can think about.



Thanks for any information or advice in advance. I will dip into this site every once in a while; so apologies if I cant get back and thank you right away.
Cheers
Mike

 

[malcolm]

For the long wheelbase 4WD you would need to find a Simpar F6 van:
http://www.4lmag.fr/2015/01/renault-4-f6-sinpar/

I don't know how robust the Simpar tramsmission is, but it is very rare and more complex than the 2WD. Chances of finding parts in the middle of nowhere would be quite slim.

The later gearboxes (post 1975 ish) are quite robust and the same box was used in Renault 5s up to the 64bhp 1400cc. Renault themselves fitted a different gearbox to the 93bhp Gordini so they might be marginal if abused. I avoid wheel spinning starts where practical in my Gordini.

The 850 engines were low geared and rev higher than the 1100. The 950 just has smaller liners than the 1100 but is geared like the 850.

For unleaded fuel it depends who you ask. It is only those who blast along for hours at full power that have reported valve seat recession. Pottering around more sensibly seems fine. Same can be said for the R5 engines.

Don't know anything about Simpars so can't comment on the transmission.

 

[angel]

1) If you can't find a (very rare) F6 Sinpar, it's just a matter of lengthening the rear part of the propshaft and the rear diff engagement cable, to fit Sinpar parts on a FWD F6.
2) The 845cc engine may be more free-revving as it has very light moving parts, but has a lot of shortcomings compared to the later 956 and 1108 engines (three main bearings, poor breathing, small bore to stroke ratio) that don't suit you that well. Don't compare these engines with Citroens, they have a completely different phulosophy.
3) No problem with unleaded if exhaust valve clearances are beibg checked regularly - just like Citroens.
4) Apart from the R5 Gordini engines, even the TX ones (1400cc-65 HP) are not stressed. That's what I was meaning above by comparing them with Citroen engines. All Renault engines are more "torquey" and "flexible" than "rev-happy".
5) The second transfer lever is there to engage / disengage the rear differential, so that, in 2WD mode the propshaft does not rotate. I don't know whether it's useful or not, as the rear final drive that is the main source of frictional losses remains engaged to the rear wheels.
6) There is no low range in the transfer box. Final drive ratio is as on the standard Fourgonettes (4,125:1). There was an option of a very low 1st gear, I don't know how many of these gearboxes are still in existance.

 

[Lobster]

Not a great deal to add other than the 1108 is fine on unleaded. I've had no issues with local stuff and for long distance / motorway / high speed stuff then I add a bit of additive.

 

[sideslip]

Thank-you very much for your detailed replies. Very much appreciated. I have been away hence the reply delay.

Thankyou, so you have confirmed there was an Sinpar version of the F6 as well as the standard car version; and the wheelbase/propshaft is different.
So its a relatively simple conversion of "just" the propshaft and cable. (Intitally I was not sure if the Sinpar wheelbase on the F6 would have been kept the same as the cars)

You mention the rear differential can be engaged/disengaged (from the road wheels I understand that as (?).........but can it be locked? (like the Citroen Mehari 4x4).
As I am sure you all know on front engined cars on adverse terrain it is usually always the rear wheel that is left hanging in the air.

I take on board the 3 or 5 main bearings of the different engines. But is the implication that the three bearing engines suffer due to this or are unreliable because of only having three bearings?
My Citroen DS happened to be the later 5 bearing engine. Ten years of ownership and travelling in many continents and it still ran balanced and free after 43 years.

Interesting; there appears to be a difference of opinion about the unleaded fuel situation. The local garage here; that used to be an official Renault garage (and used a Renault 4 van for the garage business) said the Renault 4's can not cope with unleaded fuel; and need all the additives.

The mechanic also said that at full throttle there was too much air going into the carburettor, and so maximum power was actually achieved just back from full throttle. Is that what people find too?

Thank-you for the information.

 

[sideslip]

Are all the different Renault 4 gearboxes "interchangeable" with the different Renault 4 engines? (Or even Renault 5 engines come to think of it?) So would for example a gearbox from an 847cc engine, fit onto say an 1108cc engine?

(Some of the Citroens across the aircooled range 2CV/Visa/GS/GSA were; some required a certain flywheel in between etc).

I was wondering because on the Citroens some people have also mixed/matched gear ratios for the four wheel drives, and indeed two wheel drive cars.However they have to be done in particular set arrangements.

On the Citroens for the forward gears 1st gear is on one shaft, 2nd and 3rd gear share another middle shaft; and 4th is on another.
So a changing a ratio on 2nd gear for instance also affects 3rd.
So some people played with the ratios to get what they wanted, or the best compromise.

In this way one can "mix"different ratios from the 435cc Citroen 2CV engine/box with the 602cc engine/box. The Citroen Dyane/Ami have different ratios also; then of course there is the final drive to consider and so on.......

So there are a few variations and tweaking that one can do; using standard Citroen gear parts from different models. For example maybe a lower first gear for crawling off-road; and maybe a higher 4th gear (or even 5th gear) for the motorway tarmac. I was wondering if these cross over options existed for the Renault's. R4; R5, R6/16? etc

On the Fiat Panda 4x4 they got around the low first gear issue by making it 5 speed. But the "new first gear" was now a crawler gear; and all the other gears were the same original ratio...but a nominated higher gear on the gear stick.

Ie what was the original 1st gear ratio was now 2nd gear on the gearstick; and second gear was now called third, and so on.
So on the tarmac road people normally just pull off in second gear; and bypass the "First crawler gear" altogether..

However Citroen has also been brilliant at getting the gear ratios "just right" for the cars/engine combination they made. I suppose one would expect that as they were a gear manufacturing company at first...but do people think that Renault too have got the gear ratios "spot on" for the 4?

I was intending to keep things original in the engine/box department; but am keeping all options open. Best to do the thinking first; rather than at the side of the road on a trip! On motorcycles I have improved gear ratios for particular riding use/journey type. But of course it is always a trade off balance.

 

[angel]

Rear differential is not disengaged from driveshafts, but rather from the propshaft. That is, the final drive is being "driven" from the wheels, but not the propshaft.
The differential itself is open, no limited slip or locking differentials were ever made.
The three bearing engines are by no means unreliable, and crankshaft failures are unheard of. I was meaning they are not suitable to soup-up, because of their design philosophy.
Gearboxes are physically interchangeable, but there is one "minor" detail: 3 bearing engines rotate counterclockwise (a la DS) while 5-bearing ones clockwise, so if you don't intend to have 4 reverse gears, it's better to keep each gearbox with the engine of the same "family".
I have always found the gear ratios on any 4-speed R4 gearbox to be "more right" than on 2CVs, maybe because engines are torquey.

 

[Niels Svane]

Hi there
My 850 runs fine on unleaded and have no issues in that department. Its fairly economic and nice running with 15-19 km/l and half a liter oil use after 6000km.
I really like the smaller engine, and I dont think it has any particular shortcomings. It tugs along nicely (sometimes I accidently start in 2. gear, which is no problem), and is fun on bad roads. I dont know if my 83' 850 is any different to what angel mentioned, but as it is a late model, it has a different carburettor, and different other improvements from the gordini engine i think. 70-80 km/h is a pleasant speed, but 90-95 is not stressful either. Above that, it becomes a bit noisy. I am also fond of its ability to bimble along at 55 in 4th. The brakes are adequate and the lights on mine is really strong.

Choosing the old engine is maybe also due to its history, thus having a car with roots back in the 40's/50's.

It has a lot of space, and I have travelled with both 4 persons and gear (app. 360kg), and later 12 bags of 80L dirt, which is the only time ive seen the back suspension give up a bit