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View Full Version : school me on points and dwell on the ford 351W


pbgbottle
07-07-2012, 06:09 PM
how do you adjust the dwell on these dissy's ,or is setting the gap all we can do ?
school me on these old ford distributors.

JimN
07-07-2012, 06:33 PM
how do you adjust the dwell on these dissy's ,or is setting the gap all we can do ?
school me on these old ford distributors.

If you look online, some sellers will have a dwell meter. I know AutoZone and other parts stores loan tools, but I don't know if that still includes this. It's worth a shot. I have a multi-meter that does RPM and dwell. which I got from MCM- I think it was about $25. If you plan to keep the boat the way it is, it would be worth getting one of these. If nothing else, you'll have a decent multi-meter to use on other jobs.

Here's one from Harbor Freight- I have one of their meters that was $3 on sale- Sears has exactly the same one for $27.99. Too bad I didn't know about this one at the time- I would have bought it for the capacitor check.

http://www.harborfreight.com/lcd-automotive-multimeter-with-tachometer-kit-95670.html

pbgbottle
07-07-2012, 07:19 PM
i have an old multi meter with dwell on it ,im just not sure how to adjust it . i can read it but that is it . i just had a 3 month old ignitor 2 die .went back to points until i get a new one .
but i am interested in learning about the setup of the timing ,points ,and dwell, i can setup the points gap and check the timing and adjust it but I dont no what to do with the dwell. my dwell is at 25 stock is suppose to be around 30 how do i get it there ,what do i adjust. ?

the ford is different than an old chevy .the chevy had a window
in the cap and you could stick a screw driver in there and adjust the dwell
the ford does not have this option


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JimN
07-07-2012, 08:00 PM
i have an old multi meter with dwell on it ,im just not sure how to adjust it . i can read it but that is it . i just had a 3 month old ignitor 2 die .went back to points until i get a new one .
but i am interested in learning about the setup of the timing ,points ,and dwell, i can setup the points gap and check the timing and adjust it but I dont no what to do with the dwell. my dwell is at 25 stock is suppose to be around 30 how do i get it there ,what do i adjust. ?

the ford is different than an old chevy .the chevy had a window
in the cap and you could stick a screw driver in there and adjust the dwell
the ford does not have this option


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Ballpark the gap and measure the dwell. Worry about the dwell more than the gap, but if you can't get one without the other being really whacked out, you may have a problem somewhere else. If it comes in at normal dwell, it would be in the 24-34 range but I would verify the correct number with a manual, MC or Indmar. If the engine still has a readable sticker on the valve cover, use that.

BTW- you don't need to run the engine to adjust/set the dwell or gap. Leave the cap off and connect it normally. You don't need the coil wire, cap or plugs to do this- it's the points opening and closing that you're working with.

WRT raising it from 25 to 30, think about what 'dwell' means. You would need to open the gap to increase the dwell. Increase the gap in small increments, about .001 at a time.

From Dictionary.com, it means (of a moving tool or machine part) to be motionless for a certain interval during operation.

Re: Machinery .
a.a flat or cylindrical area on a cam for maintaining a follower in a certain position during part of a cycle.
b. a period in a cycle in the operation of a machine or engine during which a given part remains motionless.

Philscbx
07-07-2012, 08:38 PM
Set a matchbook cover between points at slight drag is best starting point.
Moving cam touching the rubbing block of points at it's highest point.
Make sure to dab teflon grease on the rubbing block on back side.

Make sure condenser and points have a clean surface.
One can fog LPS3 over entire zone to protect everything under the cap.
Just keep it off the points contacts.
LPS3 with keep it looking new for 3-4 years easy.

High grade silicone for everything else - inside/outside the cap - rotor - plug wires ends/boots -
and the coil too.

Dwell is simply the time the points are closed charging the coil. Setting the gap is setting the dwell.
Keep a small can on board when you're bored to coat other items - relays, hoses, etc.

JimN
07-07-2012, 08:45 PM
A new matchbook cover, or an old one that has become swollen and limp? Don't like the precision that comes with using a meter or feeler gauge?

Philscbx
07-07-2012, 08:50 PM
Points always end up pitted - and so many tests - steel gauge actually makes a wider gap - buts it's not that big a deal really.
If timing light is on - moving the gap slightly won't see much difference on the timing marks.

It just might be more likely a matchbook is on board than the meter.
Dial caliper will probably show cover at .017

JDC
07-07-2012, 09:31 PM
how do you adjust the dwell on these dissy's ,or is setting the gap all we can do ?
school me on these old ford distributors.With the cap and rotor off, hook up the dwell meter and have someone crank the engine while you adjust the points. Use two screwdrivers, one to loosen slightly the points retaining screw, the other to fit in the slot provided to move the points. When you get it where you want it on the meter, tighten the screw.

You'll probably find that dwell during cranking will be a bit higher than when it's running. If you don't like what you see after it's running, do it again but adjust for that difference. It shouldn't be much.

JimN
07-07-2012, 10:41 PM
Points always end up pitted - and so many tests - steel gauge actually makes a wider gap - buts it's not that big a deal really.
If timing light is on - moving the gap slightly won't see much difference on the timing marks.

It just might be more likely a matchbook is on board than the meter.
Dial caliper will probably show cover at .017

I didn't know the points were for determining the spark advance. The dwell is what's important at the points- if that's too short, the spark won't be intense enough and if the wedge that rides on the cam is worn or distorted, the gap could be dead on with improper dwell.

I did like the Chevys with the door for adjusting it, though. That was pretty handy.

pbgbottle
07-08-2012, 12:56 AM
thanks for all the info .JimN i just finished readying everything . tonight i also changed the cap,rotor,new points,condenser. used a .018 feeler guage . fired it up and dwell showed 20 even lower with the new points .i did run out of light tonight and i didnt have enough hands when tightening the points. they kept moving .i will recheck everything tommorrow .and get it dialed in. thanks for all the info . i hope my old dwell meter is accurate.

what about spark plug gap does this come into play?


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pbgbottle
07-08-2012, 01:00 AM
philscbx where do you find LPS3 ?

thanks to all for the reply's

Philscbx
07-08-2012, 01:45 AM
The dwell is what's important at the points-Once the Meter used shows the Dwell desired - measure the Gap - it will be .017.

Philscbx
07-08-2012, 01:58 AM
philscbx where do you find LPS3 ?

thanks to all for the reply'sI've seen it from Hardware stores to Industrial supply.
Maybe a local google search shows auto supply near you.
Then again - I wouldn't doubt Amazon has it. (http://www.amazon.com/Laboratories-00316-LPS-Heavy-Duty-Inhibitor/dp/B000GKXU7O/ref=sr_1_1?s=automotive&ie=UTF8&qid=1341728117&sr=1-1&keywords=LPS3)
For some reason lately - they upped the price on this stuff as if it's illegal. http://www.jdindustrialsupply.com/lps.html

I've done extensive tests with it on farm machinery to aircraft restorations sitting out for years.
No amount of snow rain sun wrecks what I coated it on.
Live electrical controls still look like new. Fogged entire fuse panel.

Friend just called today with his AC that went out - sure enough - condenser/capacitor for fan motor- all connections corroded - from all winter slop wet getting into controls.
Sometimes there's just too much on the list to get to.

JimN
07-08-2012, 05:22 AM
thanks for all the info .JimN i just finished readying everything . tonight i also changed the cap,rotor,new points,condenser. used a .018 feeler guage . fired it up and dwell showed 20 even lower with the new points .i did run out of light tonight and i didnt have enough hands when tightening the points. they kept moving .i will recheck everything tommorrow .and get it dialed in. thanks for all the info . i hope my old dwell meter is accurate.

what about spark plug gap does this come into play?


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The points usually creep as you tighten them- I used to start with the gap a bit more than needed and snug the screw, measure, tighten, re-measure and tweak as it got tighter. As I posted, get the dwell right- if it's not enough, the spark intensity won't be where you need it to be, especially at higher RPM.

The plug gap needs to be correct for spark intensity. If you couple low dwell with excessive plug gap, the spark won't be sufficient to burn the fuel completely. If the plug gap is too tight, the electrodes can burn. Check the plug tips after you run it hard and don't idle for long before shutting it down- you want it to be tan, like coffee & cream.

pbgbottle
07-08-2012, 09:54 AM
ok i will check everything today. i will have to regap my plugs .pretty sure they are at .40 i had an ignitor 2 in there. died
question maybe i am connecting my dwell meter up wrong . how do you connect the dwell meter?

JimN
07-08-2012, 01:53 PM
ok i will check everything today. i will have to regap my plugs .pretty sure they are at .40 i had an ignitor 2 in there. died
question maybe i am connecting my dwell meter up wrong . how do you connect the dwell meter?

Connect one wire to the coil + and put the other on the wire to the points. Your meter may be different.

pbgbottle
07-08-2012, 04:22 PM
thanks i just found out my dwell meter is not accurate . i am going to wait for my mechanic buddy to bring home his fluke meter i think he called it and i can dial it in then .
as it is now it is actually set at points gap of .17 he just checked it for me .to make sure i had it on the lobe right . it runs fine on the garden hose. now to get it on the water .

thanks for all the info . ill post up what my dwell is once i figure out what it is . :D
he also mentioned my cam lobe looks OK. the ignitor II sure was alot easier.

how do the points compare to the electronic ?

cheers




Connect one wire to the coil + and put the other on the wire to the points. Your meter may be different.

JimN
07-08-2012, 04:35 PM
thanks i just found out my dwell meter is not accurate . i am going to wait for my mechanic buddy to bring home his fluke meter i think he called it and i can dial it in then .
as it is now it is actually set at points gap of .17 he just checked it for me .to make sure i had it on the lobe right . it runs fine on the garden hose. now to get it on the water .

thanks for all the info . ill post up what my dwell is once i figure out what it is . :D
he also mentioned my cam lobe looks OK. the ignitor II sure was alot easier.

how do the points compare to the electronic ?

cheers

Points wear, electronic doesn't.

pbgbottle
07-10-2012, 07:02 PM
thanks again for all the help .
my buddy came over and spent the afternoon explaining to me how the points and dwell and stuff work i get it all now .
he hooked up his dwell meter to see how close he had set the points the previous day with the feeler guage and the dwell came in at 29-30 ish , it fluctuated from 28-31 he said the lobes may be worn funny or the distributor shaft could be wobbling ,something like that i cant remember the exact words he used.

he himself told me that the match book would be fine ,i'll use the feeler guage
he said set the points with matchbook and who cares about the dwell. the dwell should be fine if you no how to set the points gap up properly ,and as long as you set it on the right side of the lobe or something like that, just as it starts to crest over the top i think .

me myself i will always check the dwell , i will be on the lookout for a new meter.

i also found out that my tach is not accurate .its the original tach from 1988 ,
his guage showed the idle at 625 RPM and my tach said 500 RPM




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