Thread: Vacuum Advance

I used a cut down open ended spanner and welded a socket extention bar on at right angle to it.
That way I could reach it from above , put the spanner onto the nut and used the socket rachet to undo it. ( sort of like a crows foot )

That's thinking outside the box/lateral thinking, or something.

[Blushing smilie]

yeh, had a look last night looks easy.... but in the past have had problems getting the rotor button off, even my local LR mechanic had problems too, will go and get another one, just in case

Rotor button's - Ritter didn't have any stock as they said the Lucas ones are crap at the moment and said you have to use the geniune LR part ones but they don't have them as there is a shortage !!

So MLR/ULR have them, but they are $69.50

Will try getting it off without breaking first I think

Hasn't Glen in Boronia got one in you could 'sovenier' from him ?

............& if you do, I bet me nuts at that price. you'll be applying some releasing agent before refitting it.

Oh well all done, took all of 15 mins !!

Hardest part in the end was putting the little screws in that hold the vac advance, there little star head ones.

The rotor button came off with very little force.

Now that I have it all in is there anyway of telling if it is working properly, or just watching the fuel mileage the only way ?

Thanks guys...

Matt.

Matt, this article gives a good explanation of the whys & wherefores so it would appear as though it's all positive.
My V8i one leaks when the tube is sucked so it would appear as though I'll be going down this path as well. I have swapped the tube but it still leaks. Ho hum.

http://www.stoveboltengineco.com/howto/vac.htm

Thanks 4bee, that gives a good explanation on vacuum advance. I notice when I started the car after putting the new vacuum advance on that the idle was a bit better.

Highly recommend the guy I got the part from, very good, fast service, don't see much of that these days !!

taken from : http://www.stoveboltengineco.com/howto/vac.htm


VACUUM ADVANCE AND WHY YOU WANT IT FOR YOUR CAR

An often-asked question from many callers relates to whether they really need a vacuum advance mechanism on their distributor. I think this question stems from their observation that many "high performance" distributors do not incorporate vacuum advance and the resulting implication is that it is not desirable or necessary for a "good" ignition. There are a handful of applications where vacuum advance is not of significant benefit:
1) Pure racing engines
2) Severe duty very large trucks
3) Constant speed and load applications (airplanes, generators, pumps)

Other than the above, for normal automotive applications the vacuum advance will benefit the engine as follows.
1) Improved idle cooling
2) Improved idle quality
3) Improved fuel economy
4) Improved throttle response
5) Improved drivability
6) Enables improved spark knock control under full throttle accelerations
7) Enables leaner fuel jetting at light load to further improve fuel economy.

The basic reason for all these improvements is that the vacuum advance mechanism allows the distributor to supply a more optimum spark timing proportional to the load and speed output. Without the vacuum advance the distributor can only vary spark timing in proportion to speed and ignores its need for approximately 20 additional degrees of spark timing ("advance") at light loads: (idle and cruise conditions)

The basic reason for the change in optimum timing at light loads is that when operating at light loads, the mixture is leaner for fuel economy and less dense because of light load. These conditions cause the charge to burn slower, and thus, to reach peak pressure at optimum point in the cycle, the spark must be initiated earlier. Failure to do this will result in "retarded" spark timing and all the aforementioned losses.

All engines are different, and have different spark timing requirements, but they are all the same in that as load is decreased, additional spark timing is required for optimum combustion.

Do yourself a favor - 1) make sure your distributor has a vacuum spark system and 2) experiment to find out what your engine "likes" for timing at idle, light load, and heavy load. Then change the vacuum can to achieve a result closer to the optimum.