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Alpine 1968 Renault R8

  • Thread starter Thread starter Adey
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Cheers @Steve Swan I have the original cantilever setup from the 8 and from the r5 so can hopefully cobble something up from that. If not ill be cutting up lever arms and making something (y)
 
a little better



hooked up a diy throttle and it needs a change in throw. even with the r8 part in place it isnt enough for the carb.
 
Playing with the linkage arm start and finish points may help, the carb lever looks to be at 12 o'clock start point, making it 5 past 12 as a start point would help. The rule of thumb is that all mechanisms should be tangential at half travel, all levers at 45 degrees to each other. It's a bit of a game. Sounds loads better today
 
Defo seems to be. I've got the lever mounting point roughed out, just need to work out the lengths of each arm to work with this carb.

The carb pickup is set to about 5 past from factory, must be the angle of the camera.

Currently full throttle at the pedal is giving half at the carb, thats with the original r8 lever.... so I think I need to move the pivot further out on the "carb side" arm to give it more travel?

Strangely the original 5 lever gave what looks like a 1-1 throw, I guess it had more travel at the pedal itself?

I will rough out everything and hopefully tidy all the brackets and arms up once I've cobbled a working item up.
 
Haven't managed to get the throttle throw properly working as of yet.

Checking out the carbs, the new one has twice the degrees of turn to go fully open than my old one, hence the 50 percent throttle using the original r8 throttle lever arrangement.

So... please do correct me if I am wrong, I could just double the length of the output side of the intermediate lever to increase the throw on the carb? effectively changing the fulcrum point? (@Turbell @Steve Swan @BobG ) looking in your direction as you may have been here before.
 
That's probably easier to achieve than reducing the size of the carb lever, although a bit of both, could be the answer. Check the pedal is free at it's own end it may be possible to find a bit more travel at that end.
Make sure that the fan belt is tight and keep checking it. You can put the crankshaft pulley mod on the list of things to do. This motor will be free revving compared to the original, which puts the windmill mechanism under increasing stress. Dropping the crank pulley size is the Demon tweek here to those who know.
 
Cheers Steve (y) There's not much material left to play with and adding material is easier. Ill rough out an arm and move where I have mounted the spring unit to compensate a little too.

Smaller crank pulley is something I/we did on the R5 c1j turbo, helped with throwing belts at high revs/vibration. I haven't looked if the one off the old engine is smaller and if it could go on my new one...
 
I suggest making at least three new linkage set ups , before kicking the shit out of an inanimate object when it's worse......

I'd measure degree of both original set ups , compare first, check Weber hasn't any progressive linkages etc on the carb itself.
Depending on what set up you're currently using, have you got the same amount of travel after it's turned 90 degrees?
Measure travel on the cable to WOT , that'll dictate where the cable needs to be attached on the first lever, as above, and that is then sufficiently opening the throttle, wrong ratio and you'll be going through a wall with an inch press on the loud pedal, wish I'd paid more attention on physics/maths instead of dreaming of Linda Lusardi.....good luck!
Thinking about 5 pedal, cable is quite a long way from pivot, R8 ( imagining it's similar to Daup/4cv ) it's fairly close to pivot, as it sits below ??? As in cable is under slung on 8 ,going to the back of the car, over slung on 5 going through bulkhead.....I might be talking bollocks, but that's what's in my head
 
Yeah I think the whole lot needs looking at if im to keep this carb setup.

I extended the arm this evening and it just increased the stress on the pivot and started twisting everything. Angle of the cable isn't helping either.

Its starting to piss me off now tbh... sounds like such an easy thing to sort but I really cba rolling around under the car to sort it. Think im just being grumpy after spending a few hours bodge welding bits together to get no where, and a bit of weld jumped in my shoe, and my foot now hurts... grrr
 
Straight on pics of the carb lever in the closed and open position, the intermediate lever that the cable from the pedal attaches to, in the throttle off position. If you can get some good overall shots that would be good too. R8 Throttles are a law unto themselves. Double check the pedal itself sometimes its possible to get a bit more if it is all free and lubricated, make sure there is no free play at the pedals end.
 
Had this with mine years ago then came up with the cable option that i now run , only problem you might have is finding a renault extra diesel cable end but there are ways over that . Basically run a cable from whats there to the carb linkage .
 
Had this with mine years ago then came up with the cable option that i now run , only problem you might have is finding a renault extra diesel cable end but there are ways over that . Basically run a cable from whats there to the carb linkage .

Don't suppose you have any pictures of the setup do you?
 
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