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Chrysler 318 Advance Curves (Mallory)

JJDebeers

Regular Contributor
This weekend I installed a new Mallory YLM579AV distributor on my Port engine. My Stbd engine already had the same distributor installed about 2 years ago. I plotted the timing up to 3000 rpm.

My Stbd distributor is giving me a few more degrees of advance, but considering that it's older and the springs are broken in, this is expected. Overall I think the curves look good.

-JJ

Port Timing.jpgStbd Timing.png
 
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i have prestolite dist and cant seem to locate the correct springs for my dist or even determine if the should be different or the same..... tne ones there prev were completly shot but also different
 
i have prestolite dist and cant seem to locate the correct springs for my dist or even determine if the should be different or the same..... tne ones there prev were completly shot but also different
If you'll read through a bunch of these recent Chrysler Igntion Advance threads, you'll see that we have not been able to find any OEM specs for the advance curve.
We can find BASE advance specs all day long.... and the limit is generally built into the advancing system.
But without the curves specs, it makes it tough to do anything with regard to replacing these flyweight return springs.

If you do anything, keep the curve linear, and hold back your "Full In" or "TA" until approximately 3k rpm, and you should be safe.
 
JJ where did you pick you distributor up at? Or can someone send me a link or model number to the one I would want on my 73 318 LM. Thanks
 
was hoping someone with same dist and motor had figured it out... not everyone wants to revamp system... me included may have to
 
You still might use the same distributor. Check marinepartssource.com and use the online catalog to cross reference the part #.

-JJ
 
I may not be following some of this. Are some of you having trouble with what distributor to use for a replacement????

Here's the Pertronix D241800 318, 340, 360 complete replacement distributor.
This one uses Hall Effect triggering.

$(KGrHqMOKn!E2eoyqyCbBNyYROeJNQ~~_35.JPG


Here's Mallory's YLM579AV (#MAL9-26305) 318, 340, 360 complete replacement distributor.
The YLM uses VR (variable reluctor) triggering. VR was pioneered by Chrysler Motor Corp.
If available, the YLU would be photo-eye.
18-5497-1_big.jpg




FYI, and at the risk of redundancy here:
When talking about distributor mechanical/centrifugal advance, keep in mind that BASE or Initial advance is not included.
This is the progressive advance only.

The first stage of mechanical/centrifugal advance will be determined via the lighter spring value, and the corresponding flyweight cam profile.
The second stage of mechanical/centrifugal advance will be determined via the greater spring value, and the corresponding flyweight cam profile.

We may perhaps see a light ramp-up initially, we should expect to see a nice smooth blend where each stage leaves/joins one another, and then a fairly linear curve from that point on out.


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They both look fine for a normal rotation engine. Not sure if the units are designed for the reverse rtation motors with their upward thrust loads.

Jeff
 
Rick
is the Mallory the correct one for a 1973 318 though?

Did you check marinepartssource.com for yourself? Or do you want spoon fed answers?

It's nice to be spoon fed, but you're better off confirming for yourself. Who's going to take responsibility if someone gives you the wrong answer? Not any of the guys here. I can promise you that.

-JJ
 
Did you check marinepartssource.com for yourself? Or do you want spoon fed answers?

It's nice to be spoon fed, but you're better off confirming for yourself. Who's going to take responsibility if someone gives you the wrong answer? Not any of the guys here. I can promise you that.

-JJ
Damn right

standard rotation will take that mallory .....but you better check...reverse... the shaft isnt long enuff
 
Did you check marinepartssource.com for yourself? Or do you want spoon fed answers?

It's nice to be spoon fed, but you're better off confirming for yourself. Who's going to take responsibility if someone gives you the wrong answer? Not any of the guys here. I can promise you that.

-JJ

LOL....you crack me up. I did check, but it was on my phone and everything I seen was 1971 or 1975 or later. Thanks for caring ......lol.
 
Anyone have some thoughts on this dist. Check out this item I found on eBay: http://pages.ebay.com/link/?nav=item.view&id=170877169036
That ignition distributor on e-Bay is accompanied with this title:

CHRYSLER SMALL 318 340 360 BILLET PERFORMANCE RACING DISTRIBUTOR READY TO RUN
(note the key word that I have underscored)

It's more than just the USCG approval re; fuel vapor ignition source prevention.
Auto units (particularily Racing) will generally throw more TA into the system, of which will very likely cause Marine Load detonation.
Although the description does state that the advance is adjustable, it's the advance curve and limit that also set the Automotive units apart from the Marine units.

IMO, this unit has several things going against it for Marine usage;
1.... it's not approved for Marine use in an enclosed engine bay.
2.... out of the box, the advance curve will be incorrect for Marine use.
3.... I'll bet you a nickel to a doughnut, it's using Hall Effect triggering.


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Chinese food?:(
I thought this thread was about distrbutors and curves.

By the way, has anyone seen an orange and black cat?:eek: Meeeeyowwwwwwwwww
 
Dave, you may be onto something.
The last time I saw this cat, he was chewing up a document.
I wonder if that was the only remaining copy of the Chrysler OEM ignition timing curve specs????

mystra_cat_white_orange_black.jpg
 
under v8 billet dist you will see the marine.dist I bought. so far works very well but im. having trouble figuring what advance curve to is on my 318' I tried to.copy image to post but it isnt working. so far now I have a copper and silver spring at wot im at avg 3800 rpm I assume I should be Atleast 4200 still better then last year I barely broke 3100rpm with old dist.
 
I would not suggest changing flyweight springs without A: knowing the OEM Marine Curve....... and B: without knowinging precisely what you're doing and/or how to test the progressive curve/limit!


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