Advance spring

[Snake]

SO my new factory distributor had stock springs, I got the Mr Gasket spring kit.pulled 1 heavey spring and put 1 lighter spring in. Awesome throttle response,but it pings at part throttle but not at wot.360 30 over 9 2 1 compression.18 at idle and 34 , full advanced i have put my old dizzy back in with the factory heavey spring no ping but not so good throttle response. Is there a better spring kit that is out there.thanks again.

 

[Projectile Dart]

 

[Rat Bastid]

You need to control the curve, not just bring it in quicker.


@halifaxhops can hook you up.

 

[TrailBeast]

SO my new factory distributor had stock springs, I got the Mr Gasket spring kit.pulled 1 heavey spring and put 1 lighter spring in. Awesome throttle response,but it pings at part throttle but not at wot.360 30 over 9 2 1 compression.18 at idle and 34 , full advanced i have put my old dizzy back in with the factory heavey spring no ping but not so good throttle response. Is there a better spring kit that is out there.thanks again.

Pinging at part throttle can normally be solved by backing down on the vacuum advance.
At part throttle the manifold vacuum is higher and pulls the advance higher.
(That is if you are running vacuum advance)

 

[Murray]

This simply means that you have too much advance for your engine combo. There are other factors that also be adjusted. Is your vacuum advance adjustable? Is it working? What grade of gas are you using?

 

[QuickDart360]

Fbo has a spring kit with different rate of stiffness. Might be a choice to consider.

 

[Snake]

Pinging at part throttle can normally be solved by backing down on the vacuum advance.
At part throttle the manifold vacuum is higher and pulls the advance higher.
(That is if you are running vacuum advance)

Yes vacuumed advance is hook up

 

[Snake]

This simply means that you have too much advance for your engine combo. There are other factors that also be adjusted. Is your vacuum advance adjustable? Is it working? What grade of gas are you using?

Vacuume advance is not adjustable gas 87 when I can afford it 91

 

[Mattax]

SO my new factory distributor had stock springs, I got the Mr Gasket spring kit.pulled 1 heavey spring and put 1 lighter spring in. Awesome throttle response,but it pings at part throttle but not at wot.360 30 over 9 2 1 compression.

Yup Exactly as would be expected.

Is there a better spring kit that is out there.thanks again.

Nope

Vacuume advance is not adjustable gas 87 when I can afford it 91

H'm. New factory? What exactly did you buy? NOS - what's the part number? Or something from a parts store? or ?

 

[abodyjoe]

read through these articles..

 

[Mattax]

Sorry Joe. Some of that is good, some of that is wrong, but regardless, it all unreadable!

The answer to his problem is pretty straight forward. @Murray already posted it.
With the two light springs, timing was too advanced in the mid rpms to work with vacuum advance.

 

[TT5.9mag]

Not only do you need to understand the amount of timing you’re bringing in, but also the rate at which that timing comes in. @Rat Bastid nailed it early on. You need to tailor the curve to your engine.

 

[Mattax]

Concept:
Its best to let the mechanical advance compensate for changes in combustion that change with rpm.
Then use vacuum advance for changes in fuel density.
The reason for vacuum advance is to compensate for slower burning conditions. In particular leaner, less dense mixtures above idle rpm. Lean conditions are prefered for maximum efficiency and power during light and mid-throttle. Chrysler illustrated that - see this


In practice:
An LA with 4 bbl will work well with mechanical timing that looks similar to this

A 360-2bbl timing probably looks roughly like this. Without knowing the distributor number and having the shop manual, really don't know what the distributor has in it.

Alot of unknowns with the new distributor and two light springs, but even a very fast advance can be OK at WOT. Especially on a cold engine.
In fact for drag racing it is often preferable.
But it will ping at part throttle when used with vacuum advance.
it will also ping at very light throttle when the engine is fully warmed up.

Using a heavy spring with long loops is the secret to shaping the curve to avoild part throttle ping.
It also helps power at very high rpms but thats another story.
A timing curve shaped as shown in violet illustrates the effect of one light spring and one long looped spring.

.

 

[RustyRatRod]

Pinging at part throttle can normally be solved by backing down on the vacuum advance.
At part throttle the manifold vacuum is higher and pulls the advance higher.
(That is if you are running vacuum advance)

This ^^^^^^

 

[Snake]

Well would I better of buying a new dizzy, say Firecore

 

[Rat Bastid]

Well would I better of buying a new dizzy, say Firecore

No. Because the curve won’t be correct in that one either.

 

[RustyRatRod]

Well would I better of buying a new dizzy, say Firecore

I much prefer fixing what I have and curving it to my engine than just throwing parts at it. It's cheaper and you usually have better results.

 

[Projectile Dart]

I think what the OP is asking is if there are any spring "kits" that anyone recommends. I have a stock dizzy as well that I feel is too sluggish which would make sense because it came out of a motorhome. Similar to what the OP said, I got a 2nd dizzy I had lying around and took out the heavy spring with long loop and put in 2 light springs and swapped it back out after about 2 miles of driving because it felt like it would just flop to full advance at any rpm above idle. I tried looking around and I was recommended NOS springs because everything else is crap nowadays but I can't bring myself to paying ebay prices for just a couple springs and still not be sure if they will be any better. I figured a "slow" curve is better than too "fast" of a curve so I'm back to where I started. If I hear of a good kit with multiple springs of good quality then I might... spring for that deal.
Personally, I am really trying to avoid having to go with an aftermarket distributor for the sole purpose of being able to find tuning parts for it.

 

[H22A4]

To put it a different way, it sounds like you’ve walked into the pharmacist at Shoppers Drug Mart and have made a statement along the lines of “I’m experiencing some pain. Can you give me a pill?”

The pharmacist needs more information to give you the correct pill (assuming it doesn’t require a prescription). Walking out and heading into talk to the pharmacist at Rexall isn’t going to lead to anything different either.

You need to describe when and where the pain is for the pharmacist to give you something to help with it.

You need to know more about your engine instead of just tossing different distributors in it.

 

[Mattax]

There are no spring kits with a variety of primary and secondary springs for Chrysler made distributors
There were spring kits for distributors with Mallory YH and YT advances. That's a total side track and will not go there.

It is not really a question of an entirely unknown engine. We know a little bit about it and it responded to the changes in a predictable way.

We don't know much about the distributors.
That is the big unknown or both distributors.

The original distributor, that seemed sluggish. IF it still has its ID plate on it, its probably unmessed with. We can use that part number and the shop manual for that year to know what the curves looked like. If the ID plate is missing, then we can still turn to the shop manual, but will need to verify the advance with a timing light and tach.

The new distributor, with its original springs, or its replacement springs - the only way to know the curves is to measure timing vs. rpm from as slow as it will run to as high an rpm as one feels comfortable.
^^^^^^^^^^^^^This the starting point. ^^^^^^^^^^^^^^^^^^
Knowing this info, the curve can be altered.
If you do both sets of springs, and the old distributor, then you'll really have some baselines to work from.
When changing springs, write down the distributor degree info stamped on the governor, and note if the slots are parallel or slanted.

The changes may or may not involve replacing springs.
Been through this a few times. A search should turn up several posts explaining how to do it.

Yes it can be a lot of work just to measure the timing curves, and then more to make the adjustments.
That's where distributor machines come in. Yes that involves buying one or paying someone who bought one.
Alternatively one can buy a distributor that will be pretty close to begin with. Rick E claims to sell an exact copy of the Chrysler built MP distributors.
Halifaxhops sometimes has original Chrysler built MP distributors or, if you can wait, he can customize a distributor for your engine.

 

[Mattax]

A search should turn up several posts explaining how to do it.

Here's one for those interested

Distributor curve help needed

I just checked the curve of my stock distributor (ported vacuum blocked) and need some help to optimize. Car is a 70 Duster with a stock 360, stock converter, 3.23 gears, 28" tires. Distributor currently has FBO black & gold springs with no limiter plate. 500-24* 1000-24* 1500-25* 2000-27*...

www.forabodiesonly.com

 

[RustyRatRod]

Why not send your distributor to @halifaxhops and tell him what you want? He will fix you up.

 

[AJ/FormS]

When you don't have a spring selection, then you need a selection of weights.
Your engine can be used as a distributor machine.
Just defeat the V-can, then take timing readings every 400 rpm, until it stops advancing, then plot the results on graph paper, then connect the dots with straight lines. Where/when the 400 rpm window is vague, you go back and get a couple of 200 rpm increments.
Now you know the Power-Timing curve that is in your distributor. and
now you get to road test it at WOT, making note of at what rpm it detonates, marking it on the graph.
I use Second gear for two reasons;
1) this is the gear that I am in almost all the time, and
2) this puts a reasonable load on the engine to excite detonation.
I use 87E10 because my engine will not ping on it.
After you get that done, you get to decide what to do about the ping..... which has to be avoided.
It's a bit of work, and costs you a couple of gallons of gas, but before too long, you will have her in the ballpark. Then comes weeks of fine-tuning. After which you get to reconnect the Vcan, and start over.

 

[Bewy]

Maybe I missed it.....
The starting point would be to compare these two PARAMETERS:
- does the new dist have the same total amount of centri adv as the old dist
- is the TOTAL vac adv added by the new dist the same as the old dist

The new dist should add the same timing, not more, & if it is adding more then that needs to be fixed before playing with springs & weights.

 

[halifaxhops]

Well would I better of buying a new dizzy, say Firecore

No matter if you buy a 100 or $2000 distributor if the curve is not right for your engine it will never run optimal. Like matt Graphed the MP or Mr. G springs are seriously light and advances all in fast. There are dozens of different springs that mopar made. All sorts of combinations but you also have to know what your advance plate is. Say it is 11, and you need 15 dist degrees, you either have to change it or get the slot milled longer. There were a good set of springs I found a yeear or so ago they were Blue Dot. Pretty much a decent curve in most not to light and not to heavy. As of different weights no selection I know of out there they are all 69G.