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Renault 18 engine conversion to fit a Renault 4

mr-reno-139

AKA Paul Cunningham
Messages
2,213
Location
lancing west sussex england
I forgot to mention that this is actually a 1397cc engine before you start ordering parts as it has got rubber liner seals not paper
 

harbourseal

Renault R4 Lunatic
Messages
1,021
Location
Breda The Netherlands
Crunching numbers and crunching on.
Torqued all the bolts that needed to be torqued.

Looked up the motor numbers and found out that it is indeed a R18 engine
The motor number is 847/ 20.
And the leaflet that came with the head gasket says that is for a R18
A750AFBE-4B51-4AB1-A6FF-C9EE000E454C.jpeg

So I have to change the header on this topic.
But according to the leaflet the R12 had a 1397cc engine as well.

I put in the oil pump and put on the sump and some auxiliary parts.
Finally it looks like an engine again.

I also found the formula to calculate the compression ratio.

So I crunched some numbers.

The formula is:

Stroke volume + combustion chamber volume / combustion chamber volume.

The stroke volume is the easy part.
1397/ 4 = 349ml

The combustion chamber volume is a bit more difficult.
So I took another 1108cc head that was laying around. Put it on a horizontal place with the chambers to the top. And filled one of them with water. This head still had the head gasket attached to it. With the same thickness as the new gasket on my engine.
It took 42ml from a syringe until it overflowed.
So I estimate the chamber volume on my engine as 45ml.

In the calculation it gives.
349 + 45 / 45 = 8,8:1

Well within save margin for a petrol engine I think.

And this is the result for today.
37A15840-7563-4C4F-980E-AB7651575B23.jpeg
 

mr-reno-139

AKA Paul Cunningham
Messages
2,213
Location
lancing west sussex england
The Renault 12 in Australia definitely had the 1397 engine
what your ending up with will be very similar to a 5TS Mark 1 1981 onwards engine except that it has the combustion Chambers the same shape as c1j engine from the transverse version
If you do further research you will find that the cam lift duration and overlap varies on these engines you could have used a 3 Series Volvo 1.4 engine as well
I have converted 2 to 1300 Renault 12 cars recently this is obviously a straightforward conversion as everything is at the right end :-)
 

harbourseal

Renault R4 Lunatic
Messages
1,021
Location
Breda The Netherlands
Have not been doing very much these few weeks.
A bit of tidying up the workshop and I took the engine off the stand an put it on a small trolley.
I put on the flywheel from a Renault 4GTL witch is quite a bit lighter than the original Renault 18 flywheel.

In theory that also gives me some more power than a thick heavy flywheel.
0B5BCDF2-66A9-4167-9162-0AF965CB4563.jpeg
 

AdamWilkes

Enthusiast
Messages
386
Location
Poole
Just from interest, does not the 1397cc include the combustion chamber volume, - the 1397cc is not just the swept cylinder volume?
 

harbourseal

Renault R4 Lunatic
Messages
1,021
Location
Breda The Netherlands
You might be right
I have just done the math.
Diameter = 76mm
Stroke = 77mm

That makes
38x38x3,14x77 =349ml
So my calculation seems to be correct on the cilinder volume.
It is without the combustion chamber.
 
Last edited:

mr-reno-139

AKA Paul Cunningham
Messages
2,213
Location
lancing west sussex england
I always,use r4 1108 flywheel on the Gordini 5 engines too as it's definitely lighter with out problems
 

harbourseal

Renault R4 Lunatic
Messages
1,021
Location
Breda The Netherlands
Today I fitted a very important part on my engine.
In the front of the crankshaft ther is a hole to center the price axle from the gearbox.
If you put the R4 price axle in it floppes around. it is a bad fit.
CEE026B1-300B-4FF3-B7D4-8414F6984928.jpeg
Renault made a bronze bushing to make a tight fit.
This week I got hold of the elusive part. A85B5E9A-C454-478A-B73E-ED16CA37216A.jpeg
The part number is. 7700553174
It is a tight fit but with some gentle persuasion with a copper mallet it sits nicely in its place.
D67268E5-AC31-4099-9D45-D0BD48594D77.jpeg
Now I could finally fit the clutchplate and pressure group.
34A1755A-586F-4F8D-B47D-3A8C41EE74CC.jpeg
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E68779E8-73AD-4645-AF4A-0AB4F3FE7C77.jpeg
94EEBD70-D1A9-47FD-89AC-BD3A1810821A.jpeg
 

petak

Enthusiast
Messages
1,728
Location
Vodice, Croatia
Is that engine similar to one that was in R5 (1984-1996)?
 

petak

Enthusiast
Messages
1,728
Location
Vodice, Croatia
Good to know.
Once you have send me a link to a guy from Netherland who made such a conversion but I didn't study it properly
 

harbourseal

Renault R4 Lunatic
Messages
1,021
Location
Breda The Netherlands
Right. That was Jeffrey’s monopoint conversion. he left the engine as it was. With the auxiliaries against the firewall.
He took a chunk out of the firewall to make it fit.
With this conversion it isn’t necessary to do that.
 

petak

Enthusiast
Messages
1,728
Location
Vodice, Croatia
Yes, that is why your conversarions is more interested to me.
Engine looks more like original 1108 engine.
It would be nice to keep original look but with more power
 

mr-reno-139

AKA Paul Cunningham
Messages
2,213
Location
lancing west sussex england
I bought the crank bush on eBay as Renault told me none available
Put dimensions in and searched oilite bush
Mk2 super Cinque has different head port spacing and head would need pump end modding to let water flow
This would produce more power but more work
 

harbourseal

Renault R4 Lunatic
Messages
1,021
Location
Breda The Netherlands
We are doing the Supercinq conversion with a R4 GTL head. No trouble with port spacing and flow conversion.
 

harbourseal

Renault R4 Lunatic
Messages
1,021
Location
Breda The Netherlands
After attaching some of the outer parts from the R4 and the new engine supports I put the engine on to the chassis.
It turned out that I do have to take some bits off with the angle grinder.
F5478831-A6A8-4DEF-AE8F-5EC36C94BD86.jpeg
On the other side there is a similar piece sticking out.
E7F2553E-65E5-4026-8A27-4776A18E36F7.jpeg
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Now the engine sits nicely with in the engine bay.
I also put on the radiator and the manifolds
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