Packard Forum Index » V-8 (1955-56)

Most often when the centrifugal advance isn't working, it's just neglect of lubrication which is easily fixed with a little cleaning and oiling. Another possibility is broken springs. Why not just take it apart and determine what's needed and go from there?

Perhaps I should rephrase the question.

From my perspective, parts are an issue if needed. The mechanic may do the work, but my part of the deal is that I do the research and come up with the parts.

Are suitable weights and springs easy to get/find? They don't seem to be listed anywhere.... Or is that something that everyone has stashed in a box??????

Having done a bunch of these, 9 of 10 are just gummed up. It's possible you may need parts, but used distributors are pretty easy to find. A WTB here would get several offers. You do need to be specific if you have an Autolite or Delco.

jack vines.

You guys are making way too big of a deal about this.

Clean up the weights and make sure they are free. Make sure the vacuum advance works and set the points. From there, mark your harmonic balancer at 35 degrees and time the engine to that mark at 2000 rpm. Listen for any knocking or pinging during full acceleration. If you hear it, back off 5 degrees.

It is what it is, don't worry about it.

They were having detonation issues and started issuing distributor advance kits for customer complaints.

I wouldn't run anything except premium in those motors because they have high compression and a quench area that collects carbon.

The advance curves on those distributors really need to be checked on a machine because who knows what springs are in them.

When I was down in DC my modern car failed the stupid emissions test. It was slightly over NOX due to the cheap cat converter I put on it. The manual said running premium would improve performance. So I tried it and was surprised that the car really did run better.

I'm not interested at all in timing by ear. However, there are instances when it can't be avoided. In that case start with a good smooth motor speed and advance to the highest vacuum on a gauge, then back off 2 inhg mercury.

Otherwise put the thing on a dyno and hook a knock sensor up to a scope. You can also use the knock sensor and scope to set the timing on the road, but those old distributors really need to be checked.

I hate seeing those old motors being stressed by such problems.

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We'd better clarify this procedure. Most distributors gain another 8-10 degrees of centrifugal advance between 2,000 and 4,000. Wouldn't that mean a total of 45 degrees advance at 4,000 WOT?

jack vines

It should be 35 degrees total. IF it isn't fully advanced by 2000, run it up to see where it is all in. I wouldn't think it will be much faster than that.

The biggest thing about the initial advance is too much works against the starter. WOT needs less and that's why there is a vacuum advance. More RPM can take more advance because of the speed of flame travel, hence the mechanical advance.

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Let's don't think; let's read the Shop Manual. From 2,000 to 4,000 RPMs, where it tops out, depending on the model, there will be another 10* of centrifugal advance.

Given that, one might want to see 25* total advance at 2,000, but certainly not 35*. Naturally, that's without any vacuum advance.

At a 2,000 RPM cruise, the vacuum advance will be providing from 16* to 22* of vacuum advance. So 25* initial and centrifugal, plus say 20* vacuum will be 42* total. This is only tolerable under a light load. When the throttle is opened for acceleration or hill climbing, vacuum drops and centrifugal kicks in, giving 35* total at 4,000 RPM WOT.

jack vines

You have a valid point, Jack, except when you say:

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Now, I'm never reluctant to tell anyone to RTFM, but in this particular case, you might wanna consider a concurrent thread from the same owner WRT to a purported Error in 55-6 shop manual! (though it's not actually in error, at all).

While the owner hasn't told us the model number of the distributor he's working on, I suspect he has either a later production car or factory-issued conversion installed (per STB 56T-14). That is Delco #1110880, which has a substantially different advance curve than what is shown in the shop manual for #1110865 - will affect the additional degrees of advance that you're talking about.

For a simple problem this is certainly complex...or is it the other way?

I do have the later distributor and I think I have all the pertinent service letters/bulletins.

We had figured to set this according to the service letter material, aided by meters and ears.

To clarify, I always use 93 octane gas plus artificial lead from gunk.

The reason I am fussing about this is precisely because I do not want to abuse the motor.

The other problem I am having is differing advice overload syndrome. It scares me when you all disagree just enough to seem really different. One local tech expert wants me to run only 87 octane "because it runs cooler". (Remember, this began as an overheating issue,)

Every third person has either a highly preferred gas and/or oil that is the only product any living person should use.

I really appreciate that all of you are trying to help. Leaving your own advice out, who makes the best sense here?
Hopefully I can reach a comfortable consensus....