EFI/Individual throttle bodies on old renaults

I see. That Hurco looks like it could do the job nicely though.

If you look up This Old Tony's channel on youtube, you will find a brother in arms. I think he is now trying to do the same CNC conversion on a Maho mill (which was sort of CNC back in the seventies).

Would be a hell of a project though to make a four throat manifold on a CNC, even an industrial one, let alone a home brewed machine. But hey, if it works, it would be worth its weight in gold.
 
 
They really look perfect. That spacing is great.

Looking forward to how these end up for you :)
 
@Bowie: What is the port spacing on your engine? These bodies have 47mm SS while my C2J have 45mm SS. The core prints on my model can easily be alterred a few mm. The model is now nearly finished for a new test. 6mm narrower and about 7mm shorter.
 
Realy tight.

3bGLgXU.jpg


Here you can see one port on the way with the other left. You can also see the scratch marks out the outside that would match the standard DGV weber manifold, but with the standard valve in it, there isn't much point in making the inlet port bigger then the valve (if I understand my books correctly)

The port spacing on these heads is crap next to your C1J's (which we didn't get).

I'm going to end up with ~30mm inlet ports and maybe a ~1mm wall between them... I figured I would use a shared wall between the two runners when making the V manifold. Thankfully, because the angle is relatively steep out to the bike carbs I'm using, it should work ok. I was planning on using 30mm dai steel pipe with a wall thickness of 1.2mm and then slice up the ends and flare it out to accept these ~38mm throttles. Alla, something like this;

a5wAqjG.jpg


Yes the carbs are huge, probably to big, but they where cheap to experiment with, and the kawasacki spacing doesn't really change much, and they flow similar to 45 DCOE's or said this chap I found who measured them. If i's crap a set of 600cc carbs will be fine. A success will be if it only makes power between 5k-7k by the time I get silly cam in it. So not to precious about it.
 
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Those Vulcan carbs however.. perhaps that is my plan B.
 
Looks like a challenge making a good four port inlet for that head. The flange will have to fit perfect with no play. I guess a few dowels would be an idea. Also you might also have to glue the manifold on to ensure no leak between 1-2 and 3-4.

I guess those carbs are a bit on the big side. Size are more critical on carbs than on throttle bodies as they require better fliw to work properly.
 
yeah... sealing is going to suck.

But enough about my mess, sitting tight for more news about your craftsmanship!
 
G'day,

Reidar said:
.......I guess those carbs are a bit on the big side. Size are more critical on carbs than on throttle bodies as they require better fliw to work properly.
Click to expand...

but don't be afraid to experiment with bigger.... :)

In an earlier life I had a Standard 10 [about 1 liter, 4cyl for the newer generation] that had a tiny Solex, this was initially replaced from the junk pile by a dual barrel unit from side valve Ford V8 - dumping both barrels at once. No problems at all, bit more go of course, and better economy !!

This motor ended up with dual 1.5" SU carbs on a factory manifold produced for the Triumph Spitfire - part of a transformation exercise with the bores ending up 3/16" or so apart, compression around 11.5 and a big overlap cam. It went rather well.... :tongue:

cheers,
Bob
 
Renault R12G, R1063 etc. Always had massive carbies for the capacity of the engine. Weber recommend maximum of 2 X 40 mm DCOEs (4 barrels) for 1600 cc. Where as Renault fitted two by 45 mm DCOE carbs. The difficulty is getting the correct sizes for the various bits that can be changed.
 
As I understand the old webers were fitted with venturis a bit smaller than the butterflies. Dont think the motorcycle carbs have those.
 
Correct!

These are Keihin (CV40's) CVK40's (Kawasaki added the K), a nice constant velocity side draft more or less. Like a baby SU.. only more cultured. :p At WOT, the max venturi size is 38.5mm.

Care & Feeding Of The Keihin Carb

And like mentioned prior, I'm happy to forgo the entire button part of the rev range, and they where cheap :p We'll see.
 
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Constant velocity sounds good. So instead of a set venturi the venturi is actually alterred according to the conditions? No worries then.

i know a guy who runs a similar setup on his 205 rallycar. Not sure if its a 1,6 or 1,9 but it goes. And his father also uses similar ones on his Ford RS2000 Escort rallycar. Changed from Weber IDFs after seeing how they worked on his sons Peugeot.
 
Yep, that's the plan / hope / science experiment.

We'll see.
 
G'day,

bowie said:
..... Like a baby SU.. only more cultured........
Click to expand...

or, Stromberg CD.

The SU & CD rely on that skinny needle [and the oil in the dashpot above it] for correct mixture . The needle had a number of measuring points, 12 or more I think, along them which were altered to suit the requirements of the engine builder - this produced a list of hundreds and hundreds of different needles, selecting the correct one for a modified engine was a nightmare.

Generally, one could bolt on a carb built for another engine and it would run. Just maybe not as efficiently as it could if the correct needle was fitted.

cheers,
Bob
 
I had another casting session today. The model is now 6mm narrower and 40mm shorter. Also the coreprints are 46mm apart witch scrinks to 45mm to match ports.
I ended up with one nice, one usable and one disaster.

The previous design vs the new:
209C9933-8CCB-495C-886E-E7079C306824.jpeg

Disaster. A so called «Cold shut» caused by to cold metal.
0DE0AA10-A89A-440D-9F1E-4EBCE9466122.jpeg

I’ve still got some things to learn...
 
Thanks sclitzaugen. The sand I use is premade of high quality. The first layer of sand is siffed to be easier to ram into the details. I’m strugling to find the optimal pouring temperature. The casting that looks best was poured at about 730C but ironicly the disaster pouredat 660C har a smoother better finish. The usable one was poured at 680C is also quite smooth some places but was not rammed good enough so some sand fell out.
 
Have a look on youtube at oldfoundryman channel. He's an old guy and is casting all sorts of really intricated stuff quite beautifully. It may help. He does give some technical detail and you might even be able to ask for advice.

Do you use any fluxes? These can have a dramatic effect on the relation between temperature and flow.

Another aspect I have seen oldfoundry man comment on was how moist the sand is and something else I can't remember that impacts the gas expelled (Hydrogen?) when pouring, plus all sorts of other details I can't relate to problems because I simply don't know enough about this stuff, but he does.
 
Oldfoundryman is my favourite. I,ve spent quite a few hours watching his videos. And there is lots of little details to pick up. I plan to stay clear of both fluxes and degassers etc for now. Keep it simple. This time I got closer to getting the gating right(copying olfoundryman) while the temperatures were all over the place. I use a electric kiln that is dead slow and a 100m cord does not help.
 
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