When Centrifugal Advance Springs Get Old

[KM7]

When centrifugal advance springs get old, do they get stiff and therefor not advance the timing as much as they should or get soft and advance too early (at a lower rpm).

My guess is they get stiff.

This is on a Ford 5.8 L the timing should be 10 Deg BTDC at Idle up to 1000 rpm then increase up to 30 deg total advance at 5000 rpm. It should be about 19 deg total at 2000 rpm.

I was getting much less that that at 2000 rpm.

Old stiff springs?

 

[Grub54891]

They can get stiff, or so loose they won't work properly. The only way to tell is to look. There are repair kits out there for them.

 

[Lou C]

It’s more likely that the weights are binding on rusty crud and not able to move properly. You might have to remove the base plate and clean all around the witches and then lube them with motor oil.

 

[KM7]

I did open it up and they seem to move freely, Could be just old and stiff.

 

[Lou C]

try looking on OMC parts sites, I was able to find a set of new OE ones for my '88 4.3, springs and points plate.

 

[KM7]

Here is what they look like

 

[Lou C]

They don’t look bad, I’d clean out any dirt/debris with carb cleaner then use some compressed air (wear goggles) and the lube the pivot points with motor oil.

 

[KM7]

By repair kit, do you mean just replace them? In the picture you can see that the 2 springs are not the same. is that unusual? Did the prior owner do something strange?

 

[Lou C]

No it’s not unusual for the 2 springs to be different. You have to be careful about changing springs because they will affect the amount of advance.

 

[KM7]

I removed the felt piece and got out the clip under it. (not easy). Then I was able remove the complete mechanism, clean it up and lube it. I am getting a little more centrifugal advance now:

10 deg at 0 - 1000 rpm

18 deg at 2000 rpm (matches the manual)

24 deg at maybe 3000 rpm (my dwell tach does not go that high, but that would match the book)

I was not seeing much advance beyond that but I was not comfortable running much higher on the muffs. Thoughts?

I may look for a tach that goes higher, but it's not that critical

 

[Lou C]

I don’t have the specs on your engine because they weren’t using it yet when our manuals were published but that doesn’t sound out of line to me. Most of the advance curves in manual peak at around 3000-3500 rpm.