Vacuum advance

[reidalpine]

He-he..thought you just Had to check it out!

Got a question for the more techically advanced out there..
as opposed to us techically challenged I mean.

-Seeing my vacumclock isn't holding vacum and so is leaking..Am I totally off in thinking it was an old-school trick to get rid of it alltogether spotveld the bob-weight (sentrifugal weights)in distributor
and set ignition-timing somewhat more advanced ? -In addition this would give a little extra oumph as well as ignition could be set more correct ?
as the vacumadvance by means of weights and vacum is just so-so accurate.
-Think I remember something about this from way back when R8Gorde's were the icing on the cake in rallying etc.

re.the Animal-hunt is ON.. well as I'm looking into finding what Horsepower lies dormant in there...... -R.

 

[malcolm]

You'd be almost completely incorrect in thinking any of that. Hit your brain with a stick!

I ran a car with fixed timing once. Poor Florence came to a grinding halt on her way back from the former Czechoslovakia after a circlip fell off the advance mechanism. In the pouring rain near Koln we modified the distributer to completely fixed timing. Difficult to start, and poor at low speed and high speed (OK in the middle) and cracked the exhaust manifold by the time we got home.

It's possible to buy a new Ducellier advance mechanism. Try your friendly local motor factor. Car will be set up for the intended ignition characteristics, so you might have to mess with the carb if you change the ignition curve or remove the vac advance, and the car will likely behave in a less friendly manner, be slower, and consume more fuel. They take a bit of time to design so don't assume modifications will improve things.

Good luck finding the animals. Frederick the frog has gone into hiding.

 

[reidalpine]

Bang bang-bang..Darn Malcolm! -I was looking for a Much more encouraging reply!!
Ok-I will take your word of expertize on this one.
-I have checked here,but dealers only sells points/condencer etc
No vacumclock -Haven't seen any in my Pink-parts catalog either.
can live with it for now,but will try to use another clock from different distr.to see what happens..

Frederick the frog is on my goodwill list so you can tell him he's safe so can join you for a cupper now!

 

[angel]

Fixed ignition timing works acceptable only on two stroke engines (are we going to see Roffen puffing blue smoke maybe?!)

You may be confused with an old trick well known in racing circles, that is, locking the vacuum advance. That is being done 1) because with such wild camshafts, big carbs, large inlet valves the engine does not have a steady and high inlet vacuum, 2) because there is always the possibility of something going wrong with the vacuum advance mechanism that can cause the timing to become over-advanced. What follows is pre-ignition, and goodbye engine! (and we are talking in thousands pounds/euros here...) 3) because vacuum advance is not really needed on an engine that is almost all the time run at full load (=very low/zero intake vacuum).

Just as we started this topic, there is our eternal rival, VW Beetle, most of them have a distributor with vacuum advance only (no centrifugal weights) as its useful rpm band stops to 3600 rpm...

 

[reidalpine]

Hi again angel! - between you and Malcolm you have settled this one for me.
You're probably right re.locking the vacum advance and this only really working on a race-prepped engine at full blast..
getting older my memory isn't what it used to,so it's nice to be able to use you guys as ping-pong partners Throw out a question and see what returns.
No plans of going 2-stroke even if I love the smell of burnt 2-stroke
oil! Remember Redline had a real nice one I used on my Suzuki T500 Titan back then..
Need to find a fix for a curious problem.the smallest pulley on the waterpump has what seems to be a odd shape to it-The V-shape is very tight and So deep it pinches the belt when I adjust it to get rid of squeeking noise until belt disintegrates inthere... -I have a slack of 0.5/0.6cm in the middle.Pulleys are not bent or dented and seem free of burrs etc and they are all in line,so think it must be this pulley that causes this...Will take off all pulleys tomorrow give them a going-over and polish the wedges inside.. -R.