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LeisurLee
08-05-2010, 02:03 PM
Does anyone know where I can the advance flyweight springs for a 89 454 with a Prestolite distributor.

makomark
08-05-2010, 09:55 PM
The current corporate Prestolite doesn't support those distributors anymore. check with your local hot rod shop. they should have a kit or two that will have some springs that will fit or fit with a little effort with some pliers.

just make sure the advance curve is close to the factory curve; marine engines see a lot more load than a road engine and won't tolerate excessive advance.

bryandavis
08-21-2011, 06:58 PM
I would like to know more about the springs in the prestolite distributor also. I have a IBM 7007-S. I found the springs are mismatched. One spring has no real spring or tension and is much bigger than the other. See pics of how I found it and the two springs side by side for comparison.
30443045
I have replaced the bigger with one that may be a little stronger than the other small spring. But now the boat runs for crap. (That's really not new though. Does anyone have a good picture of the springs & weights in the prestolite? Also, how can the advance curve be checked? Does this require a specialty machine?

makomark
08-21-2011, 10:31 PM
Welcome aboard!

If the springs are shot, best bet is to remove the entire distributor and take it to a 'hot rod' shop. Explain to them the application and make sure you are confident that they understand this is a marine application. They can 'dial in' the advance curve based on both the springs and the weights, yes, using a specialty machine. Another approach to determining the curve in the distributor is to get a timing tape and a timing light and measure it. With the engine "not running well", the measurement method may be suspect.

FWIW, a bad spet of springs or sticking weights will mess up the advance curve and generate poor ot very poor performance.

RicardoMarine
08-22-2011, 08:56 AM
................ just make sure the advance curve is close to the factory curve; marine engines see a lot more load than a road engine and won't tolerate excessive advance. Ditto Mark on that!
This is extremely important for our Marine gassers!


.......... I have a IBM 7007-S. I found the springs are mismatched. One spring has no real spring or tension and is much bigger than the other. See pics of how I found it and the two springs side by side for comparison.
30443045
I have replaced the bigger with one that may be a little stronger than the other small spring. But now the boat runs for crap. (That's really not new though. Does anyone have a good picture of the springs & weights in the prestolite? Also, how can the advance curve be checked? Does this require a specialty machine? These two return spring values are never the same......... it's part of the design.


................... If the springs are shot, best bet is to remove the entire distributor and take it to a 'hot rod' shop. Explain to them the application and make sure you are confident that they understand this is a marine application. They can 'dial in' the advance curve based on both the springs and the weights, yes, using a specialty machine. Another approach to determining the curve in the distributor is to get a timing tape and a timing light and measure it. With the engine "not running well", the measurement method may be suspect.

FWIW, a bad spet of springs or sticking weights will mess up the advance curve and generate poor ot very poor performance. Ditto again!

Conversely, a weaker set of return springs will allow the advance to come on too early, putting your engine at risk of Ignition induced Detonation damage! Not Good! :mad:

Like Mark suggests, find a Hot Rod shop who has an old school Distributor Machine, and one who knows how to operate it.
Supply your own OEM Advance Curve specs because they will know what the correct curve/limit and/or limit RPM will be for your Marine Engine.

http://t3.gstatic.com/images?q=tbn:ANd9GcRrP5Zw39Nk2m-GIR-tl2BwRP-NIQGQOeF542CJDRPv5LdKQAVU http://t0.gstatic.com/images?q=tbn:ANd9GcTwsOlYlbAojczN8BZ5xAow9o4MVcGn6 8QufBYplUGwQe8UFvTs

Very important to not confuse Hot Rod street use spark advance with Marine Cruiser use spark advance.
Apples/Oranges.......... actually, Apples/Artichokes! :)

*********************************

These springs control when the advance begins..... the rate of advance..... and the RPM at which the advance limits out!
Bringing this advance on too early is the more dangerous apsect!

1 to 1-1/2 degrees of error at the Distributor, is 2 to 3 degrees of error at the crankshaft.... which may not sound like much!


IMO, None of us should be hap-hazardly replacing advance cam weight return springs without the aid of a Distributor Machine...... even when replacing springs with the exact specified springs. Not all springs are exactly the same..... and we cannot account for wear.
The Distributor Machine is a much better way to go.

But as Mark suggests, we can use our engine, a marked off balancer, a Std Strobe Light, and perform a test from 1k rpm through the OEM advance rpm range.
The engine does not need to be loaded for this!

Plot this out on graph paper, and compare to the OEM curve!



.

jp253
08-04-2012, 08:53 PM
bryan, how did you make out i have the same dist and same issue

RicardoMarine
08-05-2012, 11:03 AM
Wow, this thread is from a year ago.

OK, since this topic has come up so often lately, I'm going to be bold here, and make a bold suggestion to you guys who are messing around with old and possibly worn distributors, and who want to play with flyweights and flyweight return springs, of which more often than not, are automotive spring kits.

I'd suggest that you cut your losses right now.
Get the idea out of your head that you are going to correct your progressive advance curve by doing this yourself, and on your own work bench and without the aid of a distributor machine.

Take the otherwise spent money, and apply it towards a new ignition system.
You can go with Photo-eye, VR, and even Hall Effect, although that would be my choice.
You can go with mechanical advance, or go with EST..... including HEI if you want to.
Choice is yours.

You'll get all new everything; housing, lower gear, shaft bushings, advance system that functions as it should, cap/rotor, etc.
Done! No more fooling around!

Just a thought! No offense.


.

hystat
08-09-2012, 10:30 PM
except the guys with the 229 V6's (Crusader, OMC, Mercruiser or VP)
no one has ever produced a replacement for the IBM7014 unfortunately - we are stuck with points and springs.

so many 229's went in boats too... maybe I should pick up a 4.3 Delco Voyager and see what can be modded in it to make the semi-even pattern

upjumpin
05-05-2016, 11:53 PM
I would like to know more about the springs in the prestolite distributor also. I have a IBM 7007-S. I found the springs are mismatched. One spring has no real spring or tension and is much bigger than the other. See pics of how I found it and the two springs side by side for comparison.
30443045
I have replaced the bigger with one that may be a little stronger than the other small spring. But now the boat runs for crap. (That's really not new though. Does anyone have a good picture of the springs & weights in the prestolite? Also, how can the advance curve be checked? Does this require a specialty machine?

This is an old thread but in case someone finds it as I did, here's my story and what I learned.
I have a 77 Sea Ray with a Mercruiser - Ford 351W and Prestolite mechanical distributor like the one being discussed. I purchased a Pert Ron in electronic ignition setup. When I removed the cap, one of the springs was broken and laying in the distributor. The other spring was heavier and okay but, at first, I thought it was stretched or something. Turns out, that is the design. It doesn't come into play until at the very top end of the RPM band. Now, back to the small spring... I learned online that Mr. Gasket makes a kit for another application - 929G. I used the mid sized spring... installed the EI and it runs like never before.
I took the time to write this because of all the help I got here and elsewhere. Thank all of you who share your knowledge. It helped me immeasurably.

RicardoMarine
05-06-2016, 10:47 AM
Please, please, please....... do not haphazardly change flyweight return springs without at least plotting out your NOW Progressive Advance curve along with your TA.
Plot this out in graph form and on paper..... and compare it to your OEM advance curve!

Weak and/or rust compromised return springs, or an incorrect value replacement spring may cause an early and aggressive ignition advance.
Such a scenario will definitely lead to detonation !!!!


.

upjumpin
05-06-2016, 07:49 PM
Please, please, please....... do not haphazardly change flyweight return springs without at least plotting out your NOW Progressive Advance curve along with your TA.
Plot this out in graph form and on paper..... and compare it to your OEM advance curve!

Weak and/or rust compromised return springs, or an incorrect value replacement spring may cause an early and aggressive ignition advance.
Such a scenario will definitely lead to detonation !!!!


.

I would happily do that if I had the OEM curve. Thanks for your input, Rick.