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Is this a prestolite distributor? upgrading to elec roller+flat cam compatible dizzy

Here is the parts page on this site for a prestolite distributor for your year engine.

http://www.marineengine.com/parts/m...-thru-4902304/distributor-assembly-prestolite



I would definitely get a new Cap and tune up kit (points, rotor and condenser) and possible a new wire set if needed.

Your coil should be a external resister coil due to the point ignition already used for your engine so you should be good there.


These point ignitions can be a bit tough to set so be patient. the cap has to be removed and then set gap, install cap and check with a dwell meter.
If not within spec you must remove the cap and reset gap and recheck. One dwell is set correctly you MUST next set base timing.


The picture are the tune up specs for that engine.
 
Once dwell is set correctly you MUST next set base timing.
Click to expand...

Yes, but take it further by also looking at the PA (progressive advance) and the TA (total advance).
Make sure that the TA is correct and is Full In at the correct RPM.
 
RicardoMarine said:
Yes, but take it further by also looking at the PA (progressive advance) and the TA (total advance).
Make sure that the TA is correct and is Full In at the correct RPM.
Click to expand...


With the exception of the mechanical advance sticking there should be NO concern for this considering the distributor he purchased is OEM New.
 
kghost said:
With the exception of the mechanical advance sticking there should be NO concern for this considering the distributor he purchased is OEM New.
Click to expand...

Jack, I must completely disagree with you! We should always check the PA and TA....... regardless of new or not!


.
 
Again

NO ISSUE HERE.

There is nothing he will be able to do to change any of it.

Pre set by the factory with weights and springs.

As far as I know there are no parts available to make any changes..........even if there are good luck finding them.
 
kghost said:
Again

NO ISSUE HERE.

There is nothing he will be able to do to change any of it.

Pre set by the factory with weights and springs.

As far as I know there are no parts available to make any changes..........even if there are good luck finding them.
Click to expand...

Again, not so!

Jack, you may or may not be familiar with the Sun, Allen or King machines. If you are, you'd know that most any mechanically advancing ignition distributor can be tested on these machines. If a change to the curve or TA needs to be made, most any good Tech will be able to make the changes bringing it back to within OEM specs.

If BASE only is set, and if you were to find that the TA is off by several degees, that error alone may cause a cylinder or two to undergo Marine Load Detonation. As I'm sure you know, detonation damage is not pretty, and it is always expensive to repair.

And by the way....... this is NOT theory....... this is truth in practicality!


Furthermore, I don't know why you would suggest that the OP NOT check this.... and again, whether NEW or NOT NEW!
If the OP should decide to check this, and if he was to find out that all is good...... there's nothing lost!
Conversely, should he find that it did indeed require an adjustment, it may have saved him $$$$$



People come to these forums for good and solid advice and suggestions.
Let's error on the side of being safe for these guys.
If they chose to not be on the safe, then the onus is on them!


Fair nuff?


.
 
RicardoMarine said:
Again, not so!

Jack, you may or may not be familiar with the Sun, Allen or King machines. If you are, you'd know that most any mechanically advancing ignition distributor can be tested on these machines. If a change to the curve or TA needs to be made, most any good Tech will be able to make the changes bringing it back to within OEM specs.

If BASE only is set, and if you were to find that the TA is off by several degees, that error alone may cause a cylinder or two to undergo Marine Load Detonation. As I'm sure you know, detonation damage is not pretty, and it is always expensive to repair.

And by the way....... this is NOT theory....... this is truth in practicality!


Furthermore, I don't know why you would suggest that the OP NOT check this.... and again, whether NEW or NOT NEW!
If the OP should decide to check this, and if he was to find out that all is good...... there's nothing lost!
Conversely, should he find that it did indeed require an adjustment, it may have saved him $$$$$



People come to these forums for good and solid advice and suggestions.
Let's error on the side of being safe for these guys.
If they chose to not be on the safe, then the onus is on them!


Fair nuff?


.
Click to expand...

Dude,

Don't suggest I am or am not familiar with anything.

If you think for one minute he is going to waste his time finding a shop that has this equipment to precision tune a factory OEM distributor for an over 30 year old boat engine you are in LA LA land. No one should ever waste that kind of time or expense. This would only be done for a new precision build when max performance is desired and when tune on a DYNO!!!!!!!!

With the millions of factory boats out there with point ignitions being used every day and not one of them has ever had a distributor precision "tuned"..............

I would think, in fact I know he will be just fine with what he has and the way it works right out of the box.

This is a slug engine in a slug boat. It will likely not even go over 45 mph on its best day.


He should get the distributor, remove the points base plate, make sure the weights and springs are functioning properly, clean any residual lube off them that may have hardened over the years if any is there at all, reinstall base plate then install the distributor, put new points, rotor and condenser in it (coat the 8 point distributor cam with some grease if the "sponge" material is not present to hold said grease) (do not run the engine with the 8 point cam dry or the plastic tip on the points themselves will wear away very quickly). Set point gap with FEELER GAGE to mid way of spec (.019" a match book cover), set base timing to spec 10* BTDC and forget about anything else.

Simple. enough said!

As usual you fill these posts with unnecessary garbage. Not one thing to be gained here by any of this non value added information on progressive timing ect. other than you repeating the same old, very same old posts which you post every chance you get!
 
RicardoMarine said:


People come to these forums for good and solid advice and suggestions.
Let's error on the side of being safe for these guys.
If they chose to not be on the safe, then the onus is on them!


Fair nuff?


.
Click to expand...

Yes people come for advice. Simple advice, simple remedies, simple answers.

I am not sure what you are giving is advice. Over complicated and confusing to most.

The average boat owner, back yard repair mechanic could give a SH!T less about tuning a distributor to accomplish what? That the engine starts and runs and when under power it reaches wide open throttle specifications...............

Why would anyone be concerned how it does this?

In fact I am not concerned myself and I fully understand all of it and have done all of it.

The engineers who designed this stuff already did this work. No need to take it any further.

This is not an issue of being safe here. He is not building a new custom built engine that would require any of this.

Over advice, complex answers, going down rat holes no one needs to go down.

KISS, KEEP IT SIMPLE STUPID
 
Yes I will index the crank marker and measure the degrees and check it - the Mr Gasket Chevy spring kit works for these actually. Read up about some chaps that had great results using the springs for this distributor..

Im more concerned that an elec upgrade wd suck on this since its a prestolite.. id rather go and spend money on a HEI unit which is probably more "marinized". Ultimately I wanted elec ignition from this! Anyway the boat wont be seeing tons of hours.. its a pleasure fishing cruiser we are going to use to goto the catalina islands down here -

yes I doubt ill be super tuning it on a ind machine lol - but tx anyway.. sure they came out just fine from the factory..

So this "hall" effect sux then?
 
FstaRockr Burns said:
So this "hall effect" sux then?
Click to expand...

Hall Effect itself is great.
Typically Hall Effect triggering wheels are of a larger diameter, which increases the accuracy.
Hall Effect sensing is used for some of the later model engine ignition triggering, ABS braking systems, etc, but these incorporate a larger diameter wheel.

As for Pertronix, look closely at the triggering wheel.
These are small diameter die cast plastic rings that incorporate embeded triggering magnets within the plastic ring (wheel).

Pertronix themselves have reported errors of up to 1.5 degrees.
A 1.5 degree error at the distributor (1/2 rpm of cranksaft) equals a 3 degree spark event error.

If you are OK with this...... then go for it!

Photo-Eye or VR offers a much better and accurate triggering system.


But as the "expert" says ....... why would anyone be concerned how it does this? Don't waste your time on a 30 year old engine. Keep it simple, no complex or complicated answers, no unnecessary garbage, yada yada yada, and keep it easy for the back-yard guys to understand, because none of this really matters for your 30 year old marine engine.
And on top of it all, you get to be called "Dude". :rolleyes:


.

 
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Again over advice.
For a basic point to electronic conversion and considering there are few choices.

Nothing wrong with the pertronixs kit if they have it for that distributor.

Used many and all work and continue to work fine.

When using these kits the one thing that has to be done is to reset the base timing.
The "dwell" if you will gets changed requiring retiming and becomes fixed as it does not change like with points.
Once done you will never need to adjust timing or points again. Only periodic cap amd rotor replacement.

Best alturnative to spending hundreds more for a full electronic.

AGAIN WHO GIVES A SH!T ABOUT SOME TIMING ERORS OF SUCH A SMALL DEGREE.
Ya think the factory points sysyem was even that accurate? OMFG!!
 
Last edited:
FstaRockr Burns said:
Yes I will index the crank marker and measure the degrees and check it - the Mr Gasket Chevy spring kit works for these actually. Read up about some chaps that had great results using the springs for this distributor..

Im more concerned that an elec upgrade wd suck on this since its a prestolite.. id rather go and spend money on a HEI unit which is probably more "marinized". Ultimately I wanted elec ignition from this! Anyway the boat wont be seeing tons of hours.. its a pleasure fishing cruiser we are going to use to goto the catalina islands down here -

yes I doubt ill be super tuning it on a ind machine lol - but tx anyway.. sure they came out just fine from the factory..

So this "hall" effect sux then?
Click to expand...


I would be cautious playing with the factory advance curve by changing the springs. If this was an aftermarket points distributor or one with an unknown past then maybe.

By the way, 10 BTDC may be too much with todays fuels. You may need to back it down 6-8 BTDC. back in the late '80's and early '90 merc issues bulletins for this due to changes in octane and lack of lead in the fuel. you will need to determine what works best.


If it is even necessary????????? You should be at 16 to 20 BTDC (26 to 30 total advance) at 2400 rpms and full 22 to 25 BTDC (32 to 35 total advance) at 3800 with a base of 10 BTDC
here is the factory timing spec in chart form.
 
Last edited:
kghost said:
I would be cautious playing with the factory advance curve by changing the springs. If this was an aftermarket points distributor or one with an unknown past then maybe.

By the way, 10 BTDC may be too much with todays fuels. You may need to back it down 6-8 BTDC. back in the late '80's and early '90 merc issues bulletins for this due to changes in octane and lack of lead in the fuel. you will need to determine what works best.


If it is even necessary????????? You should be at 16 to 20 BTDC (26 to 30 total advance) at 2400 rpms and full 22 to 25 BTDC (32 to 35 total advance) at 3800 with a base of 10 BTDC
here is the factory timing spec in chart form.
Click to expand...


sweet info, yes I always back the timing down a notch as a safety precaution, esp on a boat motor. tx for the specs.. When the dizzy eturns (and the stupid boat yard were renting at reconnects the water) ill pop her in and set it up - at least I can repaint the timing pulley and index the pointer in the meantime -

:)
 
FstaRockr Burns, as said I wish you the best of luck!
You have a few different takes on this, and I do hope that you make a good decision as to which way you go.


Observations:

With regard to post #42, some of us just don't care how accurate things are. I am NOT one of those!
Pertronix (as they use Hall Effect) is a less than good system.... plain and simple!


Please note: The curve graph shown in post #43 is for the GM engines. I would NOT use it for your Ford 5.8LW Marine Engine.

Even while the graph is for the GM engine, the important TA RPM area is right around 3,200 RPM and above. The curve will be rather linear.

And by the way........ 30* @ 2.4k rpm may be a recipe for Detonation. Your call on that!

Also, look at the curve graph. BASE advance values have been ommited from the vertical line graph. It is even noted off the left side.
It is very common to see the BASE values NOT inluded.
The BASE value must be added to the RPM/Degree value in order to verify the dynamic advance reading.
That being said, when we strobe our timing marks dynamically, we can't help but to see BASE being included.


And with regard to "back it down 6-8 BTDC", any change to BASE advance is an equal change to the TA. Keep that in mind.



And Jack, the abreviation RPM = Revolutions Per Minute.
Revolutions is plural and Minute is singular.
The use of RPMs (with the S) is an incorrect abreviation. Most any good, well seasoned mechanic will know this! :rolleyes:


.
 
Last edited:
You are correct.

My mistake!!


The correct graph is here.....

my copy from the pdf left out this half of the image. I was trying to show all V8's and the differences.

(Corrected for ford engines) You should be at 18 to 20 BTDC (28 to 30 total advance) between 1600 and 1900 rpm and full 23 to 26 BTDC (33 to 36 total advance) at 4000 rpm with a base of 10 BTDC
 
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gr8 thanks for the info! Well this is a Prestolite distributor, brand spanking new in the box so I read they are SUPER reliable units. As for the elec route - I found hot spark and they recommend a kit for 65 bucks - if it turns out to be junk ill have a backup of parts on the boat in any case..

Boat yard disconnected the water cos of a leak this week so will have to wait till they sort it out!
 
That will work for me from now on. I guess i am not seasoned enough either. BTW. abbreviation was spelled wrong in thread 47 which i think is ironic after all of that verbiage.2 b's
 
FstaRockr Burns said:
gr8 thanks for the info! Well this is a Prestolite distributor, brand spanking new in the box so I read they are SUPER reliable units. As for the elec route - I found hot spark and they recommend a kit for 65 bucks - if it turns out to be junk ill have a backup of parts on the boat in any case..

Boat yard disconnected the water cos of a leak this week so will have to wait till they sort it out!
Click to expand...


Good plan

I think you will be very happy with the conversion kit.
Install, set gap if needed, set timing and that should be the last time you will need to deal with it.

I read the instructions sheet from the link you posted for this.

Mercruiser used a resistance wire in the wire harness. This would be the "12 volt" input to COIL +.
This wire is approx, 3 feet long and is not standard copper wire. It is connected deep within the engine wire harness. It is typically ~ 2 ohms as suggested in their instructions.

So if you see the coil getting very hot this may be the issue. The wire is bad, damaged or may have been removed. If this occurs the a simple ballast resister replacement can be had at almost any automotive store.
 
yup I have a resistor in there now - Ill take some voltage measurements at higher rpms and see what happens. Been driving coil cars for years - very well aware of all the issues, always a spare set of points and 2 condensers in the spares box! plug wires - heck I even carry a spare prop in the boat! Im one of those you never know guys... always ready - mostly :p
 
....a spare prop AND spare "attachment" hardware. :)

BTW, last time I used a SUN "Disti" machine was when I checked the advance curve on a replacement disti for my Granatelli (Paxton) built R3 Avanti engine... a 304.5 CID 365HP Supercharged engine w/ mechanical lifters and a 7500RPM redline.... Boy, do I miss that beast... :-(
 
FstaRockr Burns said:
yup I have a resistor in there now - Ill take some voltage measurements at higher rpms and see what happens. Been driving coil cars for years - very well aware of all the issues, always a spare set of points and 2 condensers in the spares box! plug wires - heck I even carry a spare prop in the boat! Im one of those you never know guys... always ready - mostly :p
Click to expand...

You say you have a resistor in there now???

Does this mean the resistor wire was gone/not used or missing? If so do you know where the + 12 to coil + is coming from?

Are you using a (non EOM) ballast resistor similar to what I suggested earlier??
 
kghost said:
You say you have a resistor in there now???

Does this mean the resistor wire was gone/not used or missing? If so do you know where the + 12 to coil + is coming from?

Are you using a (non EOM) ballast resistor similar to what I suggested earlier??
Click to expand...


I havent put the new dizzy in, the old one got hot right after running, there was a resistor lying around which I plumbed in to the + side of the coil inline - I guess the chaps couldnt figure out the "miss".. hooked it up and runs perfectly and coil stays cool. Evidently the coil says xplicitly to run with an external resistor..

Waiting for dizzy cap to arrive - not sure but the coil is blue, anyway it works fine as is with current distributor - starts easy and idles super smooth.. But ill put the marine one in this week on existing coil and see how she runs..

just a reminder I bought this thing 3-4 weeks ago and spent alot of time on the deck / stern drive etc - incl a leaky carb thats now sorted with a new needle/seat..

Will report back when prestolite is installed. Repainting the motor too so will scribe timing marks so I can watch the advance..
 
careful

don't start with the advance stuff again......................

it will be what it will be and I would say everything will be alright!!
 
If you are running with points still be sure and check adjust the dwell angle according to spec. Dwell is set by point gap and then adjust base timing after confirming dwell is correct. If you are going to install the electronic dist keep the ballast resistor to the coil but connect ignition hot to the distributor before the ballast resistor. The ignition module requires battery voltage not ballast voltage.
 
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