Which Spring is Sprung?, Not sure we have the answer here at 914 World ? Options

[ctc911ctc]

1970 916-6 all original

I rebuilt the Marelli distro, it was caked in grease and the shaft was sticking because of the shaft grease had turned into glue,,,,,,,typical stuff.

Purchased the rebuild kit from one of our best vendors, and when I went to replace the springs I noticed that one was very different from within the kit. Sooooo, either the kit is wrong or the previous owner/mechanic/factory used a different spring formula.



The ones on the left are the same, each are in good shape, the ones on the right are VERY different. My guess is that the advance curve is designed to be smoother through the arc of the engine RPMs, where one side of the two weights advances first and then the other. My concern is that the stiffer spring is really stiff, even on a log scale there is a long way between these two.

Any ideas as to which is the correct one? (Yes I did triple check that I had ordered the correct kit.)

[ClayPerrine]

It is the bigger spring on the right. Marelli distributors use two different springs. If they are the same, it alters the advance curve and will cause detonation due to too much advance at low rpms.

Make sure you check the top of the shaft where the advance weights push against the square plate. The plate gets worn, and a ridge will form that keeps the advance weights from returning fully to the closed position. That will give you an issue where the engine won't come back to idle until you drag the motor down with the clutch.

I fought this for months before replacing the distributor with another that had no wear on the plate.

[ctc911ctc]

It is the bigger spring on the right. Marelli distributors use two different springs. If they are the same, it alters the advance curve and will cause detonation due to too much advance at low rpms.

Make sure you check the top of the shaft where the advance weights push against the square plate. The plate gets worn, and a ridge will form that keeps the advance weights from returning fully to the closed position. That will give you an issue where the engine won't come back to idle until you drag the motor down with the clutch.

I fought this for months before replacing the distributor with another that had no wear on the plate.

Hi Clay

On the left are 2 springs, one from distro the other from kit - both look the same

On the right are also two springs the less beefy ( on the left) is from the distro, the right most being from the kit

Question: does the disto need this heavy spring?I AM NOT SURE WHAT IS GOING ON HERE?

(IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

[porschetub]

1970 916-6 all original

I rebuilt the Marelli distro, it was caked in grease and the shaft was sticking because of the shaft grease had turned into glue,,,,,,,typical stuff.

Purchased the rebuild kit from one of our best vendors, and when I went to replace the springs I noticed that one was very different from within the kit. Sooooo, either the kit is wrong or the previous owner/mechanic/factory used a different spring formula.



The ones on the left are the same, each are in good shape, the ones on the right are VERY different. My guess is that the advance curve is designed to be smoother through the arc of the engine RPMs, where one side of the two weights advances first and then the other. My concern is that the stiffer spring is really stiff, even on a log scale there is a long way between these two.

Any ideas as to which is the correct one? (Yes I did triple check that I had ordered the correct kit.)

Did you buy the BX or AX kit ? , yours will be an AX dizzy if correct fitment ?
The kit you have could be a BX type which from memory is for the 2.4T dizzy and has a different advance requirement hence the heavy springs.
IMO fit the springs for your old unit if correct as you mentioned the engine ran fine previously ,can't see an issue here ,cheers.

[ClayPerrine]

I have 3 marelli distributors for the 914-6. All of them had one small spring and one big spring in them. You need the big spring to keep it from pinging sue to too much initial advance.

[ctc911ctc]

I have 3 marelli distributors for the 914-6. All of them had one small spring and one big spring in them. You need the big spring to keep it from pinging sue to too much initial advance.

One more question Clay - when you say big, both the ones on the right are big. Are you saying the thicker one on the extreme right is the correct one? The spring made with the thicker wire.........

Thank you Clay

[ClayPerrine]

You need one big one, and one small one to get the correct advance curve.

[ClayPerrine]

I have 3 marelli distributors for the 914-6. All of them had one small spring and one big spring in them. You need the big spring to keep it from pinging sue to too much initial advance.

One more question Clay - when you say big, both the ones on the right are big. Are you saying the thicker one on the extreme right is the correct one? The spring made with the thicker wire.........

Thank you Clay

Yes, the thicker one.