I thought I had better start a new thread on this - it is not related to my other question about the 105 you see.

Looking through the 1991 isue Estelle/Rapid parts book and workshop manual, there are two different distributors listed - one for the 105 range and one for the 123/130/136 range. The only difference between them is the advance curves - as stated by the workshop manual.

Nowadays, only one distriburor is available for all cars. My queston is how were two distributors amalgamated to one type? Is the curve in the new type partway between the original two?

Can anyone elaborate on the two curves and let me know how they affect the running properties of the car. Will having the wrong curve give a problem?

Thank you,

Ian

I'd think that the advance curve on the "new" dissie must be different. I don't know how though, because different rate springs will change the mechanical advance rate, and a different vacumn unit will change the vacumn advance.

As for how the change will affect the running of the car, I don't know. You'd need someone with experience (ideally including engine dyno time) of both to answer that properly.

See skudman on the skoda-forum, he will know

Thank you. Do you have any contact details for Skudman? I am only on this one Skoda forum you see, and although I could join another, I would like to stay loyal to just one as I will not be able to contribute very well to two forums (if I was a member of both).

Cheers, Ian

:)The advance curve is different for the 105 distributor. It used to be quite common for 105 distributors to be fitted to 120/130 models as apparantly it makes them go better. To be honest I doubt very much if it would make much difference in the real world, and it appears the distributor manufacturers agree. You can vary the amount of vacuum advance by undoing the 19mm bolt on the end of the vacuum unit and adding/removing washers as required. The official Skoda method of curing early Favorit 136's pinking problem was to add an extra washer to reduce the amount of vacuum advance.

Worth remembering that the ignition timing will never be spot on if there is excessive slack in the timing chain.

Also worth remembering that on old cars such as these setting the timing "by the book" doesn't necessarily mean the engine is set for optimum efficiency. It's often better to use good old fashioned "earsight" and a few roadtests!

Thanks Dave - that is much appreciated info:thumbup:.

Well, I went a test run today to get some fresh LRP, and with the timing at 3 degrees before TDC with the Luminition fitted I am getting pinking on acceleration and also a roughish tickover - not able to smooth it out by tinkering with the mixture screws. Also when starting from cold it sounds like the engine is 'working against itself' and almost stalling the starter motor out for a few turns (then it fires).

I will try some road tests and vary the position of the distributor a little at a time (retard) and see where that leads me.

Thank you once again,

Ian

Pinking suggests too much advance. What I used to do back in the day was set up plugs, points gap etc, get the engine hot, then set the timing by ear to the fastest idle speed I could get, then slow the idle back down with the throttle stop screw.

Thanks Dave - that is much appreciated info:thumbup:.

Well, I went a test run today to get some fresh LRP, and with the timing at 3 degrees before TDC with the Luminition fitted I am getting pinking on acceleration and also a roughish tickover - not able to smooth it out by tinkering with the mixture screws. Also when starting from cold it sounds like the engine is 'working against itself' and almost stalling the starter motor out for a few turns (then it fires).

I will try some road tests and vary the position of the distributor a little at a time (retard) and see where that leads me.

Thank you once again,

Ian

I removed the cylinder head from this car today. Looking at the state of the head gasket I'm not surprised it pinked!

I removed the cylinder head from this car today. Looking at the state of the head gasket I'm not surprised it pinked!

Well and truly cream-crackered?