Where to get distributor springs?

My marine parts supplier and local auto parts stores seem to look at me with a blank stare when I ask about new springs. Can the be bought seperately, or just springs and weights, and where?

Ignition timing, and especially the curve and limit, are extremely critical for a gasoline marine engine.
Unless you know exactly how to set one up, and exactly how to check the curve while installed in the engine (or if you own your own distributor machine), etc...... you'd best leave this to a pro!
Several degrees of Error, and at the Wrong RPM, and you will risk piston damage in the form of Detonation!

I would strongly encourage you to first see your OEM specs pertaining to this.
Follow the OEM curve and limit!
Secondly, have your distributor set up on a distributor machine, and by a qualified operator. They will play with springs and weights, and get it dialed in for you.

Be that as it may...., it can be done "On-Engine" if your balancer is marked off accurately, and if you know the procedure.

Not so critical for automotive..... but for Marine it is!

http://www.mr-gasket.com/ProductsListByMinID.aspx?minID=5282&majID=525&selection=17&minselection=3


Sounds like by the time you get a pro to tune your the new springs installed in an old distributor by a pro you could buy a new mallory distributor and install it.

Amen to that!
Mallory makes an excellent Marine ignition system...... and you get to begin fresh with all new internal components right on up to cap/rotor!

One other important note-worthy comment;
Most often these kits are for automotive use, where curves and limits are quite different than what best suits Marine Engine loads/rpm.
Again, Detonation being the potential Killer here!
The automotive engine will pass through this potentially destructive Detonation RPM range rather quickly, whereas a Marine engine may maintain a cruise RPM for long durations.

Read up on Marine Engine ignition timing and related "detonation" (not pre-ignition)....., and it will hopefully scare the heck out of you.

Thanks guys, on a regular basis I replace distributors with new or reman. units at work, however I am helping a friend with his '69 Chris Craft 350 commander with twin 350 drives. The mallory distributors have mechanical tach drives on them, and I have not been able to find a replacement unit. Only one spring on each distributor is broken, and I thought I could match the spring out of a kit. I would also like to be able to keep replacement springs on board my boat for my twin 318's. Is it not possible to match the broken spring with an identical one without having to do a complete set-up on a distributor machine?

Chris, again, if it weren't so critical, I'd say go for it! But that isn't the case!

You'd have to find a means of precisionally measuring not only the tension of the OEM spring, but also the length throughout the spring's range of expansion.
Even a rusty spring has lost some of it's value to a certain degree!
When the tension deminishes (or is below what it should be), the advance may come on too soon! Now we have the potential for Detonation!

Why don't you encourage him to look up his OEM advance curve data?
Then send this data, along with both distributors, out to a shop that over-hauls these.
Be sure that the shop knows that this is a Marine application, and to follow the curve provided!
(No automotive curve....... period!)

They can re-bush them, re-set the curve, check them dynamically on their machine, and so on!
It is the most accurate means of getting them dead on!

If one engine is RH rotation, the driven gear is different.
Both distributors still rotate CW.
But the RH rotation engine distributor has a "down-load" thrust bearing that must also be looked at, and/or replaced.

When he gets them back, he'll have a print-out of the curve, and like new distributors!

BTW, Mallory does offer a tach drive distributor for the SBC Marine engine.

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Thanks again, I will look for a local shop that can overhaul these for him. You answered my other question I had with regards to worn springs. I see them on a regular basis and assumed that it must affect the advance curve, I just was not sure to what degree. I would think it may be wise when getting an overhaul to request an extra set of springs to be sent for future use.

Even if you were to install these "Extra" springs in the future, the issue may still exist, IMO. Unless these were set-up, and then removed and bagged! Even so, I'd not recommend doing this without checking the curve once again!

Let me explain this in another way..... and please take no offense to the redundancy. You are not alone in not understanding this. I've witnessed so called "marine mechanics" set BASE advance ONLY....., and then walk away, thinking that they are done!

Any slight deviation in spring tension, changes the effect that the spring has against the centrifugal cam weights. These cams/weights control the amount and curve of the progressive ignition advancement. This curve has been pre-determined by the OEM, as to produce power during a certain RPM range, yet keeping "in check", the risk of Detonation.
This can be a very fine balance, even more so for our gasoline marine engines!
(the system in question, is fully mechanical.... no EST using ECU's or ECM's, knock sensors, etc.)

One (1) degree of change to the advancing mechanism, equals two (2) degrees at the crankshaft. Two degrees of change to the advancing......... well, you get my point!

Two or four degrees too much TA at the crank, and particularly too soon, may...... I say "MAY" contribute to ignition caused Detonation.
(again, not to be confused with "pre-ignition")
Detonation can be extremely destructive under our sustained Marine Engine loads.

If these springs are rusting, he may have another issue. He may have an engine hatch that is leaking water onto the engine, and into the distributor. These should not be rusting prematurely, IMO.


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Thanks again for the help, I am able to check the advance at any RPM against the OEM specs with a degree wheel and/or advance timing light, however, these distributors are 40 years old and have been in the salt chuck. I am not surprised at all to find broken springs and internal rust. I am surprised they have lasted this long. If I can find and identical replacement with the tach drive, I will relace them. It is a beatiful old boat and at least it deserves that.

Chris,
There are automotive springs available. Don't know if these are suitable for the curve needed in marine applications.

http://www.jegs.com/i/Mopar-Performance/312/P5153446/10002/-1?parentProductId=747036

http://chucker54.stores.yahoo.net/disadweigspr.html

I'm just tossing this in the mix here for conversation sake.
Do as you wish!

But if curious:
Look at a curve for an automotive XXX engine.
Now look at the curve for this same XXX engine in a Marine version.
You'll see that these are not the same.
Why aren't they the same?

Again, I can't emphasize enough as to the importance of using Marine Ignition parts and specs, etc, for our marine engines.

If you care to, Visit this page!
Look at some of these images showing damage from Detonation.
These are an array of pistons, not necessarily all Marine Engine pistons, and not all damage is from detonation.
(do a "mouse-over" and read the text)
Be sure that you do not confuse Pre-Ignition with Detonation.
You'll need to understand Ignition Timing produced Detonation, for this to have a full impact on you.

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