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m440x timing

fastjeff said:
Well! We've sure beat this subject to death!

Exhausted Jeff
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Oh come on, Jeff.... join in! :D



Woodie, if nothing else, this thread is a good brain exercise for us! LOL :D Well, for me anyway!

WoodieMan said:
1... The more I read up on this the more it makes sense and believe these figures are right. What I do know is that "Distributor Degrees at Distributor RPM" is old school; best way to check distributor operation on a distributor machine independent of any performance issues that may be present at the engine thus affecting the ability to get accurate advance diagnostics as well as setting up and repairing the distributor of course (wish I had one). With this advance menthodoligy/numbers you are supposed to double RPM AND DEGREES at the crank.


2.... The only issue I'm having is with the last set; 19-21* @ 2200 which would translate to 38-42* @ 4400 plus base. Seems high to me however not unusual for higher performance specs as I understand, and given the higher advance I would expect to see the lower base of 5* and in some Chrysler apps 2* as is the case.


3.... Of course the app makes a big difference, in general, Chrysler was all over the place on base timing with anything from 0 - 10* which will affect advance curves but this is the only 440 one I have.

4... Rick, I see a different curve than you. Given the above info, it`s pretty much linear to 1400 rpm then off on a different slope to 4400 so not quite a singular linear advance line as customary with your Merc example but I`m ok with that. I need some clarification on where you`re getting 6000 rpm. I`ll pass on anything else I find.

5... PS; checked a couple of old Chrysler automotive manuals and found the same reference to Distributor degrees and RPM for advance info
Click to expand...

1... Woodie, I too wish that I owned one of the old school machines, in fact, wish I'd had owned one twenty + year ago, more so than today. I've always farmed this out to a company here in town who also fabricated new bronze bushings for them.... sort of breathing new life into an old one!

As for the distributor degrees and RPM needing to be doubled for crankshaft degrees and RPM, yes.... I agree. This would be true for any 4 cycle gasoline engine that uses a 2:1 driven mechanically advancing distributor.

NOTE: perhaps the phrase "Distributor advance only" could be open to misinterpretation.
"Distributor advance only" does not mean "Distributor Degrees only!"....( as in 1/2 or 50% of crankshaft angle! )
What this means, is that it is minus BASE advance!
IOW, BASE must be added ..... ( not when strobing ) ... but when viewing the graph and doing the math in order to calculate TA.
Strobing the timing marks will inherently include BASE......, it can't help but to include BASE..... even if we were to include a ZERO or Negative BASE advance.
IOW, what we see via the timing light, is what the crankshaft and pistons see!

(sorry for such an elementary explanation.... but perhaps better said than not said!)



2 & 3..... Yes.... too high to me also!
Add to the equation that this is a Marine application, and it further puzzles me.

As for BASE advance, BASE will influence the curve, but it is generally factored into this by the OEM.
I pay less attention to BASE (as long as the engine will fire and idle OK) than I do to the curve and TA.
The curve and TA are much more important to me as to gain performance, yet control detonation potential.


4... Well, it climgs up the vertical scale from 275 to 425 rpm, then at 700 rpm it begins a ramp curve up to 2,200 rpm.
That is odd to me!
Why the huge jump shown in the specs from 700 to 2,200 rpm?
Where are the intermediate numbers????


5... Woodie, I think we can get ourselves into trouble when comparing to an automotive curve. The two should be quite different from one another given the Marine engine loads.

********************************
Back to #1 for a minute:
Perhaps where we disagree, is in the Marine specs whereby my experience has always been that the curve graphs always reflect crankshaft angle (not distributor angle), and in both the vertical (*) and horizontal (rpm) scales.
True........, this would 1/2 of the crankshaft angle value while on the machine........, but when we do "On Engine" testing/timing, those numbers would be meaningless!
During "On Engine" testing/setting timing, we strobe using the numbers on the crankshaft harmonic balancer, not any numbers on the distributor!
So this would involve crankshaft angle ONLY.... thus the OEM curves reflects this! Yes/No?

But even so, the way that I have roughly translated this as to accommodate for the 1/2 RPM......, the curve still does not make sense to me from what I'm used to seeing.
Even if I were to reverse engineer a known-to-be-good BBF, BBC or SBC curve, I do not believe that it would resemble what I came up with on the 440 data.

The question for me becomes: if your data is accurate, what is so different about the 440 crankshaft/pistons/valves that would require such a different ignition advance curve?????
I understand some differences....... but these are vastly different.... especially the initial ramp-up at the lower RPM! (blue line/red dots)

***************************
Using the higher of the numbers that Woodie found.

Distributor advance only... no BASE shown
0 deg @ 275 - 425 rpm
7.5 deg @ 425 rpm
14.5 deg @ 700 rpm
21 deg @ 2200 rpm


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At least we're not talking about #1 cylinder or which way we should face to determine rotation!!

I like the brain teaser stuff....when it doesn't make sense it warrants investigation lest we miss something we should know.

Rick, in point five, I was reffering to the method of stating advance figures. The intention was to see if this method was used elsewhere and to confirm it's meaning. Apparently it's been around for a long time; I suspect probably longer than crank degree/rpm specs. I think most of us are used to seeing a linear advance curve such as what you get in typical Merc apps where both advance springs are of the same tention/strength and as such produce a linear curve. Better engine performance is achieved by using a weak spring on one advance weight and a strong spring on the other. This combination produces a non-linear curve and allows for customizing an advance for best performance given the vehicle's intended use. I've always considered a linear curve to be a compromize the OEM can use to market performance to a wider audience.

Here is a good graph to illustrate all we've been talking about for comparison; degrees advance and rpm at crank versus distributor, different curves based on spring strengths. the "X" would be the weaker spring and the "Y" the stronger spring. Though this is taken out of an automotive manual, it does well in illustrating the above.

scan0001.jpg
 
Yes... these brain teasers are OK by me. Much more fun than arguing over the location of # 1 cylinder. :mad:


Woodie, I must say that I'm still not on board with you regarding crank degrees -vs- distributor degrees.
While I was experimenting and learning (60's), we always used crankshaft angle for ignition data and/or for phasing in camshafts, etc.
Even diesel injector timing was based on crankshaft angle.
This is because everything must offer the desired dynamic LPCP (location of peak cylinder pressure) or PCP (peak cylinder pressure), of which is based on crankshaft angle/degrees.
With any reciprocating piston engine, PCP is limited to crankshaft sweep.... of which is 180*.
PCP must occur within this perimeter, or the dynamics are all wrong for any performance.

LPCP or PCP is generally around 12-14* ATDC..... Gas/Diesel, lawn mower engine, and/or any piston type engine...... it doesn't matter.
We get there via when combustion is initiated due to the burn delay. The lead is required in order to reach LPCP.

Gasoline Engine combustion is initiated BTDC (unlike the diesel engine that is ATDC) and occurs at an array of initiation (I.E., a variable advance relative to the piston's position within the cylinder at which the burn begins).
This is varied due to the way that the burn occurs (delay) at different RPM..... hence the Spark Ignition Advance Curve.
(I know.... this is nothing new to you.... understood!)

I also understand your comment on the non-linear curve.
However, this is all about Gasoline Marine Engine loads (not automotive) where ignition induced detonation is a great concern.
We don't have the advantage of running quickly through the more critical RPM range as does the High Performance Automotive engine.
Perhaps this is where the Apples/Oranges comes into play.

The Marine Industry provides an ignition curve that protects the engine from average "Dumb Joe" who doesn't have the sense to stay out of the high cylinder pressure RPM range that is dangerously close to the Detonation RPM range as well.
All it requires is several degrees too much advance, and at the wrong RPM and Marine load, and we can easily and quickly destroy Marine Gasser pistons, and possibly more.

An example would be sustaining 2k rpm while pushing a heavy hull at below planing speed and yet above hull speed for any length of time.
If the more aggressive Automotive curve was used, we may risk detonation and eventual piston damage, and again, perhaps more.

So it becomes much more than a performance issue, it becomes a safety measure against Marine Load Detonation as I see it.

I guess that another way of saying this might be to explain that if the dynamics of the Auto engine work load was to be changed to a Marine type load....., and with NO change to the Automotive ignition curve/limit......, it's doubtful that the engine would survive for any length of time.

It would appear to me that the LPCP plays an extreme role in this in that how we get there... and that is for the most part, via ignition spark lead (advance).
Granted.... piston selection, camshaft profile, etc, all play an important role also, but we're talking Ignition Advance today.

Hey, I enjoy this, and certainly don't mean to argue negatively.
I'm just throwing this out there for discussion, as I'm sure you are.
It's fun to read and respond to....., and I welcome yours or anyone's response.

Hey, I may be all wrong and be suffering from too much coffee this morning! :)
 
Yikes! And I thought that "Where is # 1 cylinder" posting was a bit lengthy! (Think "War and Peace".)

A modern, computerized-to-death auto engine has its spark advance at maximum EVERY moment it's possible to do so: cold start, warm up, idle, part and full throttle, and deceleration. This is possible thanks to O2, throttle position, rpm, and knock sensors that monitor every aspect of combustion and modify the advance as necessary. Why? Because lower emissions and maximized fuel mileage are paramount to getting an engine accepted by both the EPA and the buying public would want maximum gas mileage.

With old, stone aged motors such as this old 440 it's a pure guessing game as to how much advance the old horse will take before holing a piston, so the engineers deliberately keep the advance conservative. That means--if you monitor the situation carefully and constantly--you could slip in a few more degrees of advance. But keep in mind Fastjeff's Immutable Law of Timing: Too little timing burns gas; too much timing burns pistons!

It's your choice.

Jeff
 
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fastjeff said:
............ 1.... With old, stone aged motors such as this old 440 it's a pure guessing game as to how much advance the old horse will take before holing a piston, so the engineers deliberately keep the advance conservative.

2.... That means--if you monitor the situation carefully and constantly-- you could slip in a few more degrees of advance.

3.... But keep in mind Fastjeff's Immutable Law of Timing: Too little timing burns gas; too much timing burns pistons!
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1.... Yes, hence my earlier average "Dumb Joe" comment.

2... Very carefully!

3.... Bingo! That's a great law, Jeff! :cool:
 
So I question an ignition specialty shop on this subject and get this for an answer..................


"All those old curves go out the window when you fill up the tank with 2011 gas/ethanol mix."

Not very helpful I must say.
Did a lot of searching and came up empty on any mopar advance charts except for automotive.

Did find this spec which is similar to Woodie's (similar wording is in my '71 auto service manual).....................

440PointDist.jpg
A two stage mechanical advance curve may be representative of the use of two different load (one light, one heavy) springs for the weights.
Mallory refers to this as "Hop-Out Curve"
http://prestoliteperformance.com/Po...lory_Instructions_advance_curve_kit_29015.pdf

Fastjeff's Rule Is what I'd have to follow.



Below is for refference only. Use at you're own risk
Anyway, back in the day for AUTOMOTIVE racing, when gas was leaded, 100 octane, and $0.38.9 a gallon, 38° BTDC for big blocks and 35° BTDC for small blocks was the full advance normal. All occurring before 2000 RPM. Way too much and quick for marine especially with todays fuel!

Some setup proceedures on automotive curves may be useful in marine apps......
Mechanical Only Advance
http://static.summitracing.com/global/images/instructions/dcc-5249775(2)1.pdf
Mechanical and Vacuum Advance
http://static.summitracing.com/global/images/instructions/dcc-3690426.pdf

 
100 octane or 87 octane or E10 in any octane rated fuel........ it doesn't matter.
We should NOT be using an automotive Ignition Curve for a Marine Engine.... Period!

Dave, sorry for the red/bold text, I'm not particularily yelling at you or anyone, but rather empasizing just how very important this is to know.


In the first PDF file, the "Instructions for Mechanical Advance Curve Changes" explains what occurs in both the Auto and Marine ignition system.
No arguement there what-so-ever!

However, they leave out an extremely important part of the equation, and that is the RPM at which this occurs.
TA numbers are absolutely meaningless without an associated RPM.

To show this, let's bring in that Total Crankshaft Spark Advance of 34* @ 1,500 RPM.
What is going to happen to the Marine engine if this were to be used?????

I'll tell you what's going to happen......
The second part of Fastjeff's Immutable Law of Timing "too much timing burns pistons!" is going to happen! :mad: :mad:

There is no way to avoid this if those specs were to be used.

To ommit the RPM is like suggesting to; "go down the road and you will be at the right place", rather than saying; "go down the road 14 miles, and you will be at the right place".

For both the DIY'r and even the seasoned mechanic, this is a huge ommission..... and more so for the Marine Engine.

*************************

The second PDF file info at least addressed the issue of RPM.
I see that these also show no progressive mechanical advance until at/after 1k rpm. This is good!

Woodie, note that the graphs are calling out crankshaft degrees.



Do as you wish..... I'm just offering you a suggestion or two.
 
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Rick, I too am used to dealing with specs at the crank. Not disputing any of the logic re advance or where we check it or automotive versus marine. Any automotive examples given simply serve to show the method existed; nevermind the numbers. The advance spec at the distributor when I posted the numbers was a first for me too. Never saw that method before but it's clear that it was used for what ever reason at the time. I can see why they used this method though you'd need a distributor machine to make the best of it. Are the numbers right? Only compairing with another manual for the same engine would clarify. All I can say is that for me anyway, it warrants further investigation, unfortunately, there isn't much out there on this particular Chrysler Marine app. I can say that after looking at old Chrysler automotive manuals, the text is basically word for word exactly the same as a marine manual except for the numbers. This goes for all systems/harware mounted to the engine and tear down/reassembly. Were there a few errors in the translation? maybe.

It should also be noted that the numbers I supplied were for a "Chrysler 330" with distributors:
Chrysler PNs: 2875893, 3675323
Prestolite PNs: IBM4108C, IBM7004B
 
I am really learning something here guys but it looks like I created a monster. Before I get to confused I think I am going to settle on Jeff's figure of 25 degrees between 2500 and 3000 rpm. Thanks to all.
 
old hatt said:
I am really learning something here guys but it looks like I created a monster.
Before I get to confused I think I am going to settle on Jeff's figure of 25 degrees between 2500 and 3000 rpm.
Thanks to all.
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No monster at all. Good topic, and good discussion, IMO.
We all learn from this.... myself included!

Old Hatt, if you use those numbers, I'd be tempted to favor the 3k rpm....... and I think that you'll be on the consersitive side.
Remember Jeff's rule!

"Thanks to all!" Does that mean we're done? Sheesh, what am I going to do now? :rolleyes:

WoodieMan said:
1... Rick, I too am used to dealing with specs at the crank. Not disputing any of the logic re advance or where we check it or automotive versus marine.

2... Any automotive examples given simply serve to show the method existed; nevermind the numbers.

3... The advance spec at the distributor when I posted the numbers was a first for me too. Never saw that method before but it's clear that it was used for what ever reason at the time. I can see why they used this method though you'd need a distributor machine to make the best of it. Are the numbers right? Only compairing with another manual for the same engine would clarify.

4... All I can say is that for me anyway, it warrants further investigation, unfortunately, there isn't much out there on this particular Chrysler Marine app.

5... Were there a few errors in the translation? maybe.
Click to expand...
1... Woodie, I may have misunderstood you at first. Sorry!

2... OK, got ya! Makes sense also.

3... understood!

4... I'm still hoping that someone can find the Marine 440 OEM specs.

5... That is possible.

Woodie, Jeff, Dan, Dave, Old Hatt and others....., I sure hope that you know that I've not posted simply to argue with you, per 'se, as you certainly seem know your stuff.
As far as I'm concerned, this has been a good discussion.
Just wish that we had an OEM curve to look at!
 
Rick, I too would like to know the oem numbers and as far as I am concerned if there is more to discuss re: this topic have at it!
 
Sorry old hatt, we never mean to hijack a thread, we just get carried away as Rick will attest; he still has a crew investigating #1 cylinder placement, the investigation is on-going!! All kidding aside, we can't help but walk away with something new when everyone pitches in. That's what this forum is all about, and I like that.
 
old hatt said:
Rick, I too would like to know the oem numbers and as far as I am concerned if there is more to discuss re: this topic have at it!
Click to expand...
Be careful of what you ask for! I may go off on another tangent! ;)

WoodieMan said:
... All kidding aside, we can't help but walk away with something new when everyone pitches in. That's what this forum is all about, and I like that.
Click to expand...
Ditto!

BTW, I think that #1 has been located. Update at 11:00.
 
Please: no more on # 1!

The work a boat engine does has been compared to a car/ truck driving up an endless hill. For that reason boat engines need less spark advance--or else.

My good buddy--a well respected drag racer--was surprised at how little timing a SB Chevy (his favorite) used in a boat: about 26 degrees all in. He runs 35 to 40 on his drag car, but it works hard for only 8.75 seconds. Big difference.

Jeff
 
fastjeff said:
Please: no more on # 1!

1... The work a boat engine does has been compared to a car/ truck driving up an endless hill. For that reason boat engines need less spark advance--or else.

2... My good buddy--a well respected drag racer--was surprised at how little timing a SB Chevy (his favorite) used in a boat: about 26 degrees all in.

3... He runs 35 to 40 on his drag car, but it works hard for only 8.75 seconds. Big difference.

Jeff
Click to expand...
1... and don't forget that this is while pulling a trailer up that hill.
That my friends is where Jeff's Law comes into play.:)

2... Jeff, as a general rule, that is correct for the average SBC GM Marine build, and perhaps the average machine shop Marine build where the full dished piston is used. This is why the OEM limits this to 26* or so.
However, when we build a Q/E into the engine design, this can be increased some without further risk of detonation.
I'm running 31* @ 3.2k rpm on my Q/E built engines.
(the Chrysler 440 also incorporates a wedge that could take advantage of this... but I don't know if they do.)


3... Yep. That engine passes through this RPM range so quickly that there are usually no issues.
But connect up the trailer, and aim that baby at the hill, and she'll probably self destruct!
 
The M440 Chrysler marine manual says timing is 7 1/2 BTC. (idle of 500 r.p.m.)(Chrysler 300)

It also gives Advance (Centrifugal) Automatic (Distributor degrees at distributor R.P.M.) (all models)
0 @275 to 425
0 to 7.5 @ 425
12.5 to 14.5 @ 700
19 to 21 @ 2200

ignition system-Ditributor
model M440-up to serial number E 169354
chrysler part no. 2875893
Prestolite Part no. IBM4108C

model M440 -after serial number 169354
chrysler part no. 367 5323
Prestolite part no. IBM7004B

(Timing 5 BTC)(Chrysler 330 model M440)
 
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Ed, this is certainly one of those long winded threads, so I can understand skimming through it, and not reading all posts.
However, these specs were mentioned by Woodieman back in post #18, and we sort'a beat that one up a bit in the following posts.
I sort'a summarized it in post #32 showing how it would pencil out in graph form. And it doesn't pencil out very well even if while using distributor degrees or crankshaft degrees.

I think that a few us are comfortable in saying that there is an error in this data, and it is absolutely incomplete by omitting the TA RPM info.


Then you read the specs posted by Dave, and the 34* TA... and again, with NO Associated RPM! :mad:
Even with an associated RPM of 3.2K or so, that seems excessive to me.... even for a good Q/E built engine.

The Chrysler Marine information goes on to discuss RH/LH rotation distributors.
Does the 440 do this.... or does the distributor and oil pump drive remain OEM rotation regardless of Std LH Rotation or RH Reverse Rotation?
Sort of moot for this discussion, I suppose. A curve is a curve for either rotation engine.

We can toss the Automotive Vacuum Diaphragm Advance data out the window.

***********************

What Old Hat needs, is a TA spec with an associated RPM.....otherwise, we're back to square one.


Come on spring time...... I think that we're all getting cabin fever.
 
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old hatt said:
After seeing all the posts regarding the importance of total advance timing I thought I should check mine. Unfortunately my service manual does not tell me what it should be. Does anyone know what is recommended for a m440x engine. Thanks
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My timing was 32* all in on both motors. The starboard 440 was 11* base with 32 all in and the port was 5* base with 32* all in. my friend that helped me said that the 32* was most important. He said the 11* motor was a bit advanced, but the extra advance would make it idle smoothly. We decided not to set the starboard timing to 5* because we would lose the top of 32*. I don't know how to fiddle with distributors, so that is fine with me. I do have one new Mallory distributor for a standard left hand motor that gives 26* of advance and of course that is the motor that is already within spec. They both run very smoothly and get full 4000 rpm (with the old carbs). I will run her today and see how it does.
 
captain_ed said:
My timing was 32* all in on both motors. The starboard 440 was 11* base with 32 all in and the port was 5* base with 32* all in. my friend that helped me said that the 32* was most important. He said the 11* motor was a bit advanced, but the extra advance would make it idle smoothly. We decided not to set the starboard timing to 5* because we would lose the top of 32*. I don't know how to fiddle with distributors, so that is fine with me. I do have one new Mallory distributor for a standard left hand motor that gives 26* of advance and of course that is the motor that is already within spec. They both run very smoothly and get full 4000 rpm (with the old carbs). I will run her today and see how it does.
Click to expand...
Well, even though this is an old thread being resurected from the dead........, it's always good to see new info.

However..... and once again (at the risk of the Dead Horse and Horse Burgers)
TA numbers are absolutely meaningless without an assocciated RPM.

Point in case: is this TA of 32* "All IN" occuring at 2.5K rpm.... or is it occuring at 3.5K rpm?
This makes a tremendous difference in terms of both power and detonation potential!

The ultimate goal for a piston engine (whether gasoline or diesel) is an LPCP at/near 12*-14* ATDC.
Anything we do to the progressive and/or TA affects the LPCP.


As for the differences in BASE advance from one engine to the other....... we fire up on BASE, and we idle on BASE..... that's about it.
We may see a small difference in what takes place as we leave low speed fuel metering and head into the high speed fuel metering (for carbureter engines). But as long as your progessive curve and TA are very close to the same, you should have no issues once the system has left BASE advance, and is into the progressive.

To correct or change this, you'd have to get into the mechanical advancing mechanism, and make changes to the flyweight limits/stops, and this is best done when on a Distributor Machine.
Otherwise, any change to BASE advance (via a change to distributor housing position), is the same change to TA in both + or -.

.
 
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