Here it is, my R4 :)

[Nikswe]

Lets start from begining of story about this car, 10 years ago i was driving daily R4 and of course like most of us i was dreaming about putting R5 alpine engine in it.Few years later i have change car for another one or third one and time was passing pretty fast.Some changes came to my life and one day in 2018 i saw accidently R5 alpine atmo engine on ebay, for a good price.I was thinking lets buy it, its a rare engine, it is not so much money and i can keep it just in case if i decide to make R4 alpine one day.So I brought it and started thinking about what should i do with it.

 

[Nikswe]

....few days later, before even engine came to my adress.

Hmmmm, one day? Hahah, that plan didnt last so long, but i had another problem.My old Renault 4 is in very bad condition, i stop using it 7 or 8 years ago and if i will use this engine i need to rebuild it.Rebuilded gordini engine deserves decent body/chasis without rust, and i didnt had time,energy and motivation to do restoration on car, so this game just came to another level.Plan was to fix engine and start searching for best R4 i can find in my country, and that was not easy task to do.

 

[Nikswe]

Soon as i open engine i was very dissapointed, because engine was sitting only with water inside and of course cylinder head and engine block has been frozen with ice inside and make cracks on it.

 

[Nikswe]

Soon i have found another cylinder head, engine block and started to order necessary parts for rebuild.

 

[AdamWilkes]

Well done Nik - you seem to be using several rooms in your house to rebuild your engine Best of luck, that was unfortunate with the cracks in your first Alpine engine

 

[JdeW]

Good job finding a rare engine and keep it up on restoring.
Just a small thing, I always thought the cylinder heads of the alpines atmo and turbo where different in casting, hight of valve stem guides, diameters of valve push rod holes, diameters of cooling channels and they've different camshafts....

It looks to me you've got a AT cylinder head on an atmo, but maybe the differences are within tolerance, though the camshaft looks as it has been beaten...

 

[AdamWilkes]

Nicely compared !

 

[Nikswe]

Hmmmm, i knew that my second cylinder head is from alpine turbo, and that heads are not exactly the same, but i was believing that they fit without any problems/consequences .Now i wonder do i have problem or not?I had problem with adjusting valves, but i didnt understand why is so big difference in height beetwen old settings and after assembling of engine.Now i know for different height of cylinder heads.

Camshaft is not great, but anyway soon i will put catcams camshaft with adjustible chain sprocket and complete different intake/ exhaust setup and some stuff more.

Does anyone know is it same volume of combustion chamber on cylinder heads?I believed that difference in compresion of turbo / atmo engine is only in pistons, now i am confused

 

[JdeW]

Here are the different types of engine mounted on R5 ALPINE and R5 ALPINE turbo:

R1223 (R5 Atmo):
840-7-25: compression ratio 10: 1

R122B (R5 Turbo):
840-C-7-26 / C6J-7-28 / C6J 7-50: compression ratio 8.6: 1

Here are the different characteristics of cylinder heads according to the engine types:

840-7-25:
Height: 79.30mm
Combustion chamber volume: 43cm3

C6J-7-50 1st model:
Height: 79.80mm
Chamber volume: 45.30cm3
Joint thickness: 1.4mm (there is a mark J on the cylinder head)

840-C-7-26 / C6J-7-28 / C6J-7-50 2nd model:
Height: 79.30mm
Chamber volume: 43cm3
Joint thickness: 1.9mm

Here are the different camshafts according to the engine types:

840-7-25 / C6J-7-28
Camshaft diagram: 30-72-72-30
Inlet open before TDC: 30
Inlet close after BDC: 72
Outlet open before BDC: 72
Outlet close after TDC: 30
With 0.3mm theoretical valve clearance

840-C-7-26 / C6J-7-28 / C6J-7-50
Camshaft diagram: 10-54-54-10
Inlet open before TDC: 10
Inlet close after BDC: 54
Outlet open before BDC: 54
Outlet close after TDC: 10
With 0.4mm theoretical valve clearance

Valve clearances (cold):
840-7-25;
Inlet 0,20mm
Outlet 0,25mm

840-C-7-26 / C6J-7-28 / C6J-7-50;
Inlet 0,25mm
Outlet 0,30mm

Respect the position of the valves in their seats:
All angles are 90 degrees.
valve seat length (mm) (X):
- Inlet 1.5 to 1.8
- Outlet 1.7 to 2

 

[JdeW]

The pistons are also different between the atmo and turbo, it looks you have turbo pistons.

At mecaparts http://www.mecaparts.com/Moteurs/page.php?lang=0&sortie=html&col=R5&page=1#ok you can order the correct parts needed for the specific type of engine

Left: R1223 (R5 Alpine atmo) Right: R122B (R5 Alpine turbo):

When you use the turbo pistons on an atmo you create a lower compression ratio so performance drops, because a turbo or compressor provides the extra power and higher compression ratio.
On the other hand don't use atmo pistons on a turbo to create a surplus compression ratio, good chance that pistons, push rods and more cracks as it ain't made of the wright materials and it isn't designed for mixing wrong parts!

My advice is to rebuild your engine as it was originally designed for, so everything works well.
Either you build an R1223 engine or you build a R122B engine.

 

[Nikswe]

Thanks everyone for all informations!

According to upper details combustion chamber is same beetwen 840 725 atmo and 840 726 turbo engine, which is good for me because i want to keep original compression ratio.

About difference i dont believe that this 0,5mm height difference can make some problem because most likely it is wider in middle of cylinder head because of bigger coolant channels or simmilar.Even intake and exhaust valve are same size on both heads, only i am not sure for ports but on turbo engine can only be bigger.

I still have old cylinder head and i have friend with dismounted turbo head, so soon i will compare nicely.

 

[Nikswe]

Here it is part no. 2 of my story


second engine block

 

[Nikswe]

carburetor...

 

[malcolm]

Your work looks very good. I'm looking forward to seeing the project.

 

[Nikswe]

some new parts including oil pump

 

[Nikswe]

Meanwhile i brought 5 speed gearbox HA1-01 from R5 mk1 already converted for R4 and aluminium rims

 

[Nikswe]

After painfull cleaning of engine block, time came for assembling.I have ordered crankshaft bearings by oem number, which means that i kept standard size.






Here you can see difference before/after cleaning pistons, i have avoided sandblasting pistons with purpose to keep as much as possible closest original measurements.More than three hours was needed to clean several times all four pistons with different chemicals and teeth brush.But even that was nothing comparing to cleaning camshaft tunel in engine block.That was not so funny job to do

 

[Nikswe]

During dissasembling of engine, i didnt had time to make tool for removing crankshaft chain sprocket so i have cut chain. Of course it was not possible to mount new chain without separating sprocket from cranskaft, and now was a moment to do it.

 

[Nikswe]

Next step is oil pump, and aftermarket one was not a option in my case.Finding new genuine was impossible so i did one trick.I did research on google which cars have similar oil pump with cleon engine block and i have started looking on ebay.Soon i found one with same main part number as alpine atmo, which means that oil gears are same diameter and length, but suction pipe was different.That was not a problem, i decide to use pipe from old one and combine what i need.I have remove sieve and cleaned together with pipe and mounted new rivets.

 

[AdamWilkes]

Very nice work - you have great patience