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Revisit Chrysler 318 timing suggestions

J

jp253

Member
Plenty of people have 318 chryslers id like to see what everyone else runs not assumptions based on other engines. There are so many posts but most are all assumed. There are so many thoughts based on the facts id like to see an easier thread were someone can get a good answer and not go thru a thousand posts and still be scratching there head.

is what I know

most specs show 5 degrees btdc
★ what im running at
petronix marine distributer link to specs on it http://www.pertronix.com/support/manuals/default.aspx
based on that guide im running. 1 copper spring with blue stop and 1 silver spring.
im running at 14\16 knots @3300/3500 rpm wot

missing about 600 rpm and about 5/7 knots from previous runs

it is a big mystery the actual specs but surely somone must have some good educated thoughts on how I can proceed to fine tune.

think jjbeers had a nice image of his 318 timing curve which has helped I just cant determine how to translate that as a starting point for me.

Thanks in advance. ..lol.
 
Stock, the initial advance was 5 degrees, with a total of around 26 degrees coming in at 3,200 rpms (or so).

You might look into borrowing (Auto Zone) an advancing timing light so you can see how much advance you're ACTUALLY making, and at what rpm. I suspect it's no where near enough.

Jeff
 
fastjeff said:
Stock, the initial advance was 5 degrees, with a total of around 26 degrees coming in at 3,200 rpms (or so).

You might look into borrowing (Auto Zone) an advancing timing light so you can see how much advance you're ACTUALLY making, and at what rpm. I suspect it's no where near enough.

Jeff
Click to expand...

That's how I plotted my total advance curves. If I remember correctly the digital light was like $120 at Auto Zone. I don't think they had them available for loan.

Thanks,
JJ

Port Timing.jpgStbd Timing.png
 
JJDebeers said:
Your carb shouldn't have anything to do with your timing.

-JJ
Click to expand...

I did correct my self guess forgot to submit.

ok so I called petronix for some help and they think at least 30 or so full advance is needed.

So I made some spring adjustments as they said and saw instant improvement now im at 3750rpm at wot and they said if need more add 2 1/2 more degrees to btdc.
 
jp253 said:
I did correct my self guess forgot to submit.

ok so I called petronix for some help and they think at least 30 or so full advance is needed.

So I made some spring adjustments as they said and saw instant improvement now im at 3750rpm at wot and they said if need more add 2 1/2 more degrees to btdc.
Click to expand...

With this it was running good but out yesterday move windy and rough and she barely got out if her way. Ramped at full throttle to 3300 rpm ans struggled to go higher then slowly fell down to 3000k at wot and ran same when I eased back on throttle and couldn't get it to go higher.

The carborater that is on there is a 4 barrel all same size carb could that have any play in this?
 
jp253 said:
With this it was running good but out yesterday move windy and rough and she barely got out if her way. Ramped at full throttle to 3300 rpm ans struggled to go higher then slowly fell down to 3000k at wot and ran same when I eased back on throttle and couldn't get it to go higher.

The carborater that is on there is a 4 barrel all same size carb could that have any play in this?
Click to expand...

Check your fuel delivery system. Everyone is having problems with ethanol. It generates gunk that's clogging up lines, filters, dip tubes, carbs, etc...

Thanks,
JJ
 
What you actually need, is the OEM specs for more than just BASE or Initial advance. You need the progressive advance, and the total advance/RPM.
To date, no one has been able to find what Chrysler Marine Corp recommends for this engine.
The Automotive specs are pretty worthless for us.

You said that you'd like to see what everyone else runs not assumptions based on other engines.
That's all fine and dandy, but what other choice is there when Chrysler Marine doesn't offer this important information?

In another thread, I did make a comparison to the SBC Marine version, in that both engines incorporate a wedge style combustion chamber.
The shape of the combustion will influence a Marine Engine's Progressive advance and TA.
The 350 GM and the 360 Chrysler are fairly close in bore/stroke.

Your phone call to Pertronix where they said; "at least 30 or so full advance is needed" is bogus without an associated RPM.
So here we are again.... with basically no data from Chrysler Marine, other than BASE advance.
Believe me... I'd love to see these specs.


JJ's curves are fairly conservative and safe if his curve graph includes BASE advance (just based on what I'm seeing).
(most Marine curves that I've seen are minus BASE advance in the vertical scale)


I don't quite trust the digitally advancing timing lights. A bit too much to leave to electronics and algorithms for me, since this is much more critical for the Marine Gasser than it is for it's cousin the Auto Engine.
I much prefer to mark off the harmonic balancer, or the flywheel, and strobe my timing marks with a standard light, and see the results in Real Time/Real Degrees........ but that's just me.


The reason why this is so critical.... IMO, is because we can find ourselves undergoing ignition induced detonation very quickly with the Marine engine.
It's always a fine line that we walk..... just enough TA to make good Toruqe and Power...... but not quite enough to cause Detonation.


I appologize.... I didn't mean to take center stage here.
It's just that I get pretty passionate when it comes to the Marine Gasser ignition timing. :D



.
 
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You should also make sure that your props and shafts etc. are all barnacle free. You would be surprised how much drag is created by a few barnacles. Our marina is charging only $5 per foot to haul,clean and put the boat back in the water.

If you are judging engine performance by speed on the water, you may have it running better than you thought after a good cleaning. My chrysler 440's will usually turn 4000 R.P.M. and are down to 3500 R.P.M. already. I guess that I should have mine cleaned also.
 
I just stumbled on this spec sheet... Would never have thought the 318 and 360 would have different BTC spec...???

Chrysler marine small block specs.jpg
 
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