Timing specs 318 chrysler

[mattv]

Does anyone know the timing specs for a LM318 chrsyler?

Thanks,

Matt

 

[fastjeff]

5 degrees BTDC.

Jeff

 

[RicardoMarine]

Matt and Jeff, 5* BTDC is BASE advance. We fire and idle on BASE only.
I just looked at the Chrysler service manual, and it does not show any progressive advance or TA (total advance) in the specs, only BASE.

(See page 83)
http://www.chrysler-marine.com/inboard/startup-facts.pdf

Matt, just a friendly FYI for you;
Our Marine gassers require a progressive spark lead as RPM increase. This is part of what produces horse power and torque.
There is a fine line to this..... it must meet the OEM's intended ignition curve, and remain very close to this!
Too late and/or not enough......... and we leave performance on the table.
Too early and/or too much....... and we risk Detonation damage.


Assuming that this is a mechanically advancing type ignition distributor, you may want to check your advance curve dynamically to make certain that your advaning system is working correctly.
Worn or weak springs can and will lead to early spark advance.... and this is where Detonation can become an issue.
Short of no oil pressure and/or over-heating, Detonation is one of the Marine gasser's worst enemies!

Point being...., if someone can lead to you a LM 318 advance curve/graph......, it would allow you to at least check this.
Otherwise, you're at the mercy of the condition of your old advancing system.



For Chrysler to list BASE advance only, would seem to imply that their ignition advaning system would remain stable for years and years.
Real world experience tells us that this is not so!

Somewhere out there..... there's got to be some info on this!!!!!

When/if you find it, it should look similar to this SBC ignition advance curve graph.
This is the GM curve, and is an example ONLY!

Again.... BASE is BASE all day long, and is rather meaningless withyout seeing what the progressive advance is doing, and without seeing what RPM the Full-In advance occurs, etc.
Hopefully one of the Chrysler guys knows where this can be found, and will post it for us.
Perhaps member "Greasemonkey" will post it for us!

Edit:
Matt, if you have any concerns, a Tech who has access to an old school Distributor Machine can test and re-calibrate your distributor for you.
He'll need the Marine curve provided......... DO NOT use the automotive curve!

.