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845cc R6

DFigueira

Enthusiast
Messages
26
Location
Portugal
#1
Hey guy's,

I've recovered a fully restored 845cc engine from a R6 that was in a junkyard (couldn't bring the car but it was fully restored... don't know why would someone do that).
I've heard that these engines are peppy compared to other R4 engines and the R4/R5 845cc and considering that my original 852cc engine on my R4 is completly dead I'm going to put this on it.
My question is - since this is the sturdiest engine on the ventoux family, can it take a little more power/abuse? Are there bolt ons that I could put without hurting it? I'm going to do some work on the car to take some of its weight out to help too.
I've considered a double barrel carb with a larger admission (R5?) and probably some kind of air filter (if there is any?) and custom headers and exhaust with a resonator.

This is for a Barn Find 73 R4 to drive daily.
 

harbourseal

Renault R4 Lunatic
Messages
752
Location
Breda The Netherlands
#2
You can put an oversized carb on the small engine, but if you don't do something with inlet valves it won't do any good.

A 32mm carb will give you some more power without having to do something about camshaft and valves.

The 845cc engine is a long stroke engine with good torque at low revs. It’s not a powerhouse.

I don’t think that you will be able to find an manifold that fits a 845 engine with the inlets for a double barrel carb.

But maybe someone has made one.

Good luck with the modifications.

Robert
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#3
You can put an oversized carb on the small engine, but if you don't do something with inlet valves it won't do any good.

A 32mm carb will give you some more power without having to do something about camshaft and valves.

The 845cc engine is a long stroke engine with good torque at low revs. It’s not a powerhouse.

I don’t think that you will be able to find an manifold that fits a 845 engine with the inlets for a double barrel carb.

But maybe someone has made one.

Good luck with the modifications.

Robert
I feared that. Double carbs were just an idea since I saw a couple of them being sold so cheap but I feared that they would just sent more gas for nothing.

So the best thing would be a 32mm carb. If the engine comes with a Solex, should it be a Solex 32? The 852cc had a Zenith 28iF so I'm deducting those changes... and would I need a different manifold?

This is mostly as a daily project. I know its no powerhouse but I kinda like to go fast in a slow car and it will carry a few things to camp around the country so it needs to climb :D

Btw, 845cc engine would have a 'redline' of what? 5.5/6k? Maximum power is rated at 5k but I will be setting a limiter to be at its 'redline' in order to not go over and damage any internals.

Thanks!
 

harbourseal

Renault R4 Lunatic
Messages
752
Location
Breda The Netherlands
#4
If the Engine is from a R6 it probably has a Solex 32 carburetor with a matching manifold.
You can ad some power though. I raised the compression a bit by shaving a little off the cilinderhead.
I also shaved about 900 grams of the flywheel and had it balanced to the crankshaft.
By putting on a spaghetti manifold en polishing the outlet ports you'll be able to coax some more power out of the engine.
 

mr-reno-139

AKA Paul Cunningham
Messages
1,925
Location
lancing west sussex england
#5
Don't forget this engine was designed in 1950 with a 3 bearing crankshaft when pottering along was the aim of the game although the Dauphine Gordini modifications did improve matters by the time the 70s arrived the Renault 6 version was probably the most reliable version people have put superchargers on these if you're feeling really adventurous but it may not last long
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#6
Things are rare around here, so my idea was only to have bolt ons and when the engine decided to die on me for any reason, I would swap for a stronger version.

How much agressive is the gordini engine on the dauphine compared to the R6 if they have +/- the same hp?
 

mr-reno-139

AKA Paul Cunningham
Messages
1,925
Location
lancing west sussex england
#7
Although the Dauphine engine is very similar it runs in the opposite direction so camshaft etc can't be used I'm definitely not an expert on this as I would always have converted to the 5 bearing crank engine used in the later 1100 which gives you options to then change to Gordini if you're feeling really silly
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#8
Although the Dauphine engine is very similar it runs in the opposite direction so camshaft etc can't be used I'm definitely not an expert on this as I would always have converted to the 5 bearing crank engine used in the later 1100 which gives you options to then change to Gordini if you're feeling really silly
Ill stay with the one I have for now :P

As long it sounds fast, it will be fun :drunk:
 

angel

Enthusiast
Messages
1,861
Location
Athens, Greece
#11
In the '60 there were some interesting development projects on the Dauphine engine, for racing use, that can be applied to our cars, at least in theory because finding the parts would be very hard. There was the famous 904cc liner/piston kit (60mm diameter), which, when used with a special camshaft and double barrel 32mm carburettor boosted power to around 60HP.
There was one French engine builder that ground a special camshaft so that the exhaust valves and ports were used as inlet, and vice versa, in order to allow fitment of twin horizontal carburettors. I doubt this solution worked as it should...
There was even a marvellous twin cam head built in France in the '60s for the Ventoux engine, reported power output in conjunction with the 904cc block was 80HP.
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#12
In the '60 there were some interesting development projects on the Dauphine engine, for racing use, that can be applied to our cars, at least in theory because finding the parts would be very hard. There was the famous 904cc liner/piston kit (60mm diameter), which, when used with a special camshaft and double barrel 32mm carburettor boosted power to around 60HP.
There was one French engine builder that ground a special camshaft so that the exhaust valves and ports were used as inlet, and vice versa, in order to allow fitment of twin horizontal carburettors. I doubt this solution worked as it should...
There was even a marvellous twin cam head built in France in the '60s for the Ventoux engine, reported power output in conjunction with the 904cc block was 80HP.
I'm assuming that if any of those ideas gone foward, the engine didn't lasted much? :P
 

angel

Enthusiast
Messages
1,861
Location
Athens, Greece
#13
I don't think these engines would need an overhaul for each racing season, but I don't think they would last 300.000+kms either, as the standard 34HP engine does.
For people needing the ultimate in throttle response and rev-happiness from the Ventoux engine, and didn't mind more frequent overhaul intervals, aluminium connecting rods were available, too! ;)
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#14
I don't think these engines would need an overhaul for each racing season, but I don't think they would last 300.000+kms either, as the standard 34HP engine does.
For people needing the ultimate in throttle response and rev-happiness from the Ventoux engine, and didn't mind more frequent overhaul intervals, aluminium connecting rods were available, too! ;)
So overall, other than a carband maybe an air filter, reallistically I don't have any options at all.
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#15
If the Engine is from a R6 it probably has a Solex 32 carburetor with a matching manifold.
You can ad some power though. I raised the compression a bit by shaving a little off the cilinderhead.
I also shaved about 900 grams of the flywheel and had it balanced to the crankshaft.
By putting on a spaghetti manifold en polishing the outlet ports you'll be able to coax some more power out of the engine.
Btw, did you noticed a big difference with this?
 

harbourseal

Renault R4 Lunatic
Messages
752
Location
Breda The Netherlands
#16
It did something.
It runs quite smooth. Pulling power in low regions is better then my F6
Speed wise I didn’t gain anything because of the Sinpar gearbox.
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#17
It did something.
It runs quite smooth. Pulling power in low regions is better then my F6
Speed wise I didn’t gain anything because of the Sinpar gearbox.
Ah Sinpar... had the opportunity of buying one for 500€ but I didn't had the license and I thought it would be just another 4L.

Now I want one :(

But thanks for the input!
 

DFigueira

Enthusiast
Messages
26
Location
Portugal
#18
Btw, are there any gearboxes available for the 845cc? I'm wondering if there are shorter ones and even a way to fit a 5 speed on one. Crazy idea but I don't to what extent this gearboxes can be modified.
 
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