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jeremy13
12-25-2013, 04:33 PM
We have 2 Chevy 2 Ĺ ton trucks that run on propane. Both of them seem to eat cap and rotors at least 3 times a year. Itís to the point that we keep extra caps and rotors on hand and when the truck starts back firing under load we grab a new one and change them out. We have called MSD and have up graded to their 8mm wires with the porcelain spark plug socks there blaster coil and there cap and rotor. And changed the spark gap to their recommendations and plugs. The latest throw a part at it was to change out the factory distributor to the MSD billet replacement. Anybody have a guess whatís going on??
http://i1224.photobucket.com/albums/ee374/Jeremy_Hanak/Mobile%20Uploads/18BA2A20-AE94-4B69-A9EF-0DD139316059_zps1gvprfnq.jpg (http://s1224.photobucket.com/user/Jeremy_Hanak/media/Mobile%20Uploads/18BA2A20-AE94-4B69-A9EF-0DD139316059_zps1gvprfnq.jpg.html)
http://i1224.photobucket.com/albums/ee374/Jeremy_Hanak/Mobile%20Uploads/B28BF9C1-E433-4F01-AFF3-11A33448AF0D_zpsmvlttqck.jpg (http://s1224.photobucket.com/user/Jeremy_Hanak/media/Mobile%20Uploads/B28BF9C1-E433-4F01-AFF3-11A33448AF0D_zpsmvlttqck.jpg.html)
http://i1224.photobucket.com/albums/ee374/Jeremy_Hanak/Mobile%20Uploads/910FCE7C-F2EF-49D0-AA8E-9BABB94E0FB4_zps0wtbvykk.jpg (http://s1224.photobucket.com/user/Jeremy_Hanak/media/Mobile%20Uploads/910FCE7C-F2EF-49D0-AA8E-9BABB94E0FB4_zps0wtbvykk.jpg.html)

The Artful Bodger
12-25-2013, 04:37 PM
I think those dizzy caps need ventilation.

lakeside53
12-25-2013, 04:56 PM
Something for sure is allowing voltage tracking to get established. Road salt? High humidity? Engine wash getting in the wrong place?

What's causing all that white corrosion on the mount plate?

The Artful Bodger
12-25-2013, 05:10 PM
Maybe the tracking is getting established because the cap is filled with ionised air.

Another thing, is that the underside of the rotor you show? Looks like it is arcing to the top of the spindle, shouldnt there be insulation in there?

sasquatch
12-25-2013, 05:18 PM
Contamination from something, but what?

darryl
12-25-2013, 05:33 PM
Looks to me like moisture is allowed to get into it from somewhere. Could even be coming from the crankcase. A heating and cooling could be allowing it to suck in through any possible vent.

I think there should be a vent, but perhaps it could be through a tube which goes into a dessicant chamber, which would itself be vented.

Another possibility is that there is too much voltage going on, yet another is too much resistance in the spark plug leads. When the plugs fire, the voltage would normally be clamped at some level depending on the strength of the fuel/air mixture, but resistance in the leads would allow the voltage at the terminals of the rotor to be even higher

Another possibility is poor material in the rotor cap. It would not surprise me at all to find that the material is so cheap that it breaks down more easily than it should. The possibility does exist that some other manufacturer of that part would have it deal with the high voltages a little better.

What else- is there a discrepancy between the timing of the spark and the relative positioning of the rotor itself? Maybe the positioning is off and the spark is not kept within the range where the rotor contact is close to one of the leadouts. Could be lots of misfiring in this case too.

sasquatch
12-25-2013, 06:14 PM
Interesting to read the responses to this,, i still think this is contamination of some sort, if not oil vapours, possibly contamination from an outside source , may sound dumb, but some pesticides/insecticdes are very corrosive, just not sure how it would get in the cap though.
Pesticide sprayer used to wash the engine down?

Guido
12-25-2013, 06:31 PM
Ionized air inside a stock dizzy cap needs vented. BTDT

Hard to judge by looking at the pic of your distributor, but the base plate appears corroded? The small circular vent on that plate is probably plugged off, needs cleaning.

I would step way back if some parts jocky starts to sell me a 'billet distributor', waaaaaaay back.

jlevie
12-25-2013, 06:34 PM
If the picture of the cap is representative, it would seem that the failure is "cylinder sensitive". And might mean that spark voltage is going excessively high for those three cylinders. Looking at the coil output with an ignition scope might be illuminating.

Cheap Jon
12-25-2013, 06:42 PM
If the polarity to the coil is reversed could that be the cause.

Jon

gvasale
12-25-2013, 07:10 PM
Looks like the cap has aluminum terminals. Try to find higher quality (copper-brass) parts if available. Don't forget MSD means multiple spark discharge. Venting may be a plus. Seems like I did that decades ago too.

Tracking looks like it's coming off the coil lead (carbon button) but I can't explain its choice of cylinders.

Willy
12-25-2013, 07:18 PM
Something for sure is allowing voltage tracking to get established. Road salt? High humidity? Engine wash getting in the wrong place?

What's causing all that white corrosion on the mount plate?

I quite agree.

I also have to ask what type of service conditions these trucks operate under.
The aluminum plate below the distributor that mounts the electronic trigger module tells a story. The very high corrosion deposits on that piece and the very rusty and corroded condition of the distributor itself tell me that these trucks do not lead a "normal" life.

Operated under clean environmental conditions I think the problems would disappear.

snowman
12-25-2013, 07:29 PM
Are these just stock chevy distributor caps? I ask because I doubt the ignition coil is stock, propane generally requires a hotter spark to ignite properly...so they might have upgraded the coil, and you are just burning through them with stock parts downstream.

Willy
12-25-2013, 07:41 PM
Are these just stock chevy distributor caps? I ask because I doubt the ignition coil is stock, propane generally requires a hotter spark to ignite properly...so they might have upgraded the coil, and you are just burning through them with stock parts downstream.

From the OP.


We have called MSD and have up graded to their 8mm wires with the porcelain spark plug socks there blaster coil and there cap and rotor. And changed the spark gap to their recommendations and plugs.

As a rule MSD ignition products are quality components when used as recomended.

snowman
12-25-2013, 07:47 PM
Yes, but the previous distributor was stock...he also said that. Which is why I asked if it was just run of the mill chevy, or if it was specifically engineered for the propane.

If he's running that hotter spark through stock components, it's going to burn them up.

A.K. Boomer
12-25-2013, 08:07 PM
Boy that's some of the worst carbon tracking iv seen in along time maybe ever,,,

I agree with Snowman that throwing higher voltage products at it is not going to help,
also agree with Willy and others that it could very well be some kind of surface condition or venting problemo,

it's so extreme it's making me wonder if the engine block is grounded correctly or something like that, if it wasn't then maybe a spark plug would "resist" being fired off --- it's either that or the path to the plug has to many other options for some reason,,, is there the equivalent of a condenser in electronic ignitions ? I know when the old style points type distributors condensers went bad they would consume points like crazy... maybe something freakish is happening on the electronic discharge side of it... ok - just thinkin out loud now...

Doozer
12-25-2013, 08:25 PM
It looks like an External Coil GM HEI.
With the carbon tracks on the one side...
Is the ignition coil perhaps mounted right next
to the cap and the coil magnetism might be
attracting sparks to that side?? Wild thought.

Too rule out ozone, try running a small vacuum
line off the intake manifold and run it through a
hole in the bottom of the dizzy. That would suck
any ozone out. Might be a good test or even a
permanent solution. My dad has a Chevy truck
that is hard on caps and rotors, but no carbon
arcing. I used an Accel cap with brass parts
instead of aluminum.

--Doozer

quadrod
12-25-2013, 08:33 PM
Just a thought, but check if there is an air gap from the button on the cap to the rotor. Should be no gap, button in cap should touch rotor. In the pic of the cap it looks like the button is burned away from arcing.

A.K. Boomer
12-25-2013, 08:36 PM
in what relationship is the major tracking in accordance to gravity?

I just went back and looked at the aluminum plate Willy was talking about, wondering what kind of gasses get omitted from all that corrosion --- this maybe a what came first the chicken or the egg type deal...

almost seems like it has to be the atmosphere inside there as everything is going through it...

Willy
12-25-2013, 08:47 PM
It may or may not be related, but the Delco electronic control module mounted to the aluminum plate is highly dependent on a clean conductive heat sink for it's mounting location. I believe this type talks to the ECM in order to convey spark advance curve signals to the distributor.
If nothing else it won't hurt to thoroughly clean this mounting area and apply some thermal paste at the interface between module and heat sink.
I seen several go south from heat induced damage that looked cleaner than this example.

jeremy13
12-25-2013, 09:12 PM
I will try to cover all the questions.
Chevy 2 Ĺ ton 1994 and 1997 model they are propane delivery trucks. I’m in south east Texas so no road salts just sand on the bridges for the day they have ice. The trucks run 8 to 5, 5 days a week. The only time the engine gets a wash down is when there’s a water pump or something major to work on. Then it’s only a steam cleaner and engine degreaser. The bright red connector on the pickup coil says it was replaced recently and you have to pull the distributor shaft to change and the crud was cleaned off the aluminum plate with a wire wheel and vents cleaned. My thinking for a complete change out is that there could be something coming up from the crank case. Or that is so badly worn that it is out of time and firing at the wrong time.
The floor of the mounting plate is vented with 3 screen vents.
Cheap plastic ??? This one is a top of the line MSD replacement the only better is a replacement distributor and upgrade to a racing one. All brass electrodes and center one is spring loaded carbon one. We have picked up the cheap mom/pop auto parts one they don’t last either. GM dose have 2 rotors listed that fit one standard and one HD (heavy duty). The HD has more of a fan shape to the skirt around the electrode.
This is not a new problem just a let me run it buy the board of mechanical knowledge. The trucks started life as a gas truck from the factory and converted to propane with 50 miles on them. The up grades started about 3 years ago when we just got tired of changing parts. And started asking questions of how do we stop this from happening?
The carbon tracking is new and that’s what made me post the question hear.
This is an external coil type system
We used to change out the electronic control module like underwear. Still no change just a pile of good used parts.

lakeside53
12-25-2013, 09:30 PM
Most engine degreaser is highly alkaline.

flutedchamber
12-25-2013, 09:38 PM
No direct experience with MSD HEI products, but I have seen that extreme tracking when the ignition timing was set with a overly advanced initial setting. The spark goes from the tip of the rotor to the contact in the cap. When the ignition is advanced an overly large amount, the contacts are not near one another and the spark has to jump a distance to the contact in the cap. Multiply that jump by tens if not hundreds of thousands of cycles and you have tracking.

Stock GM HEI caps did have a problem with a orange rust ring on the inside of the cap, resulting in crossfire and ping. A quality cap with brass contacts cured that.

Rookie machinist
12-25-2013, 09:42 PM
Are the pictures you posted of the new MSD dist? The corrosion on the base and all the rust lead me to believe that something enviormental is causing the problems. I have never seen a dist. look like that after a short amount of time. You could also try emailing or calling MSD and showing them the pics, they might have run across this before.

A.K. Boomer
12-25-2013, 09:54 PM
No direct experience with MSD HEI products, but I have seen that extreme tracking when the ignition timing was set with a overly advanced initial setting. The spark goes from the tip of the rotor to the contact in the cap. When the ignition is advanced an overly large amount, the contacts are not near one another and the spark has to jump a distance to the contact in the cap. Multiply that jump by tens if not hundreds of thousands of cycles and you have tracking.

Stock GM HEI caps did have a problem with a orange rust ring on the inside of the cap, resulting in crossfire and ping. A quality cap with brass contacts cured that.


All good replies,,, the only thing about the over advance theory is the fact that the tracking seems to be favoring only a couple pin bridges - that's why I asked about those two particular bridges relationship to gravity due to maybe more conductive dust/material hanging out at the lower level. although that would not prove or disprove yet might help gain some insight,,,

one thing for sure - once this problem is solved and then verified the components should be the poster child for all related subject matter... nasty...

Willy
12-25-2013, 10:05 PM
Have you verified contact between the distributor cap's coil button and the rotor's center contact?

Either the button is burned, or not touching the rotor. From looking at both the center of the cap and the rotor it appears that the only electrical contact is through arcing, as it does not look like there is actually a physical contact. Either way it has gotten the rotor contact very hot in order to bake the rotor material the way it has.

Also I noticed the carbon tracks are heaviest above the trigger module on three cylinders, is this a pattern or do the tracks take random patterns?


http://i1224.photobucket.com/albums/ee374/Jeremy_Hanak/Mobile%20Uploads/B28BF9C1-E433-4F01-AFF3-11A33448AF0D_zpsmvlttqck.jpg (http://s1224.photobucket.com/user/Jeremy_Hanak/media/Mobile%20Uploads/B28BF9C1-E433-4F01-AFF3-11A33448AF0D_zpsmvlttqck.jpg.html)

A.K. Boomer
12-25-2013, 10:22 PM
Watch - we'll go through 11 pages of diagnoses only to find out he's running Lucas plugs...

ahidley
12-25-2013, 10:59 PM
Something is wrong with the carbon button. That is what makes your carbon tracks. It is wearing away too fast. Perhaps the distributor shaft is the wrong length, i.e. too short. (as stated origonally by quadrod ) Or perhaps for some reason the distributor shaft is moving up and down crushing the carbon button? Has the distributor ever been changed? If so perhaps your putting in the wrong replacement cap and rotor??? I have seen carbon tracks apear on only the posts directly above them. But this was on a magnetic pickup, come to think of it it was an MSD too. Are the carbon tracks around the longest plug wires. The longer the wire the more the resistance, thus it would look for an easier path. I didnt see a vaccuume advance on the distributor so I would rule out propane getting in it. If the timming was advanced to much and it was detonateing, then the crankcase pressure may be too high and oil vapor is being pushed into it and burning in the cap? With an electronic ignotion you have to use resistor plugs and plug wires that are NOT metal. Some high end wires have one strand of stainless wire wrapped around the carbon core. That is ok and will not cause radio interferance which gets into the electronic ignition and plays havioc.

CarlByrns
12-25-2013, 11:02 PM
All brass electrodes

There is your problem. It seems counter-intuitive, but I have replaced more brass-terminal "Premium Quality" caps with the exact corrosion issue as your pictures. In the shop, we stopped using brass because of their high failure rate. The OEM distributor caps were almost always fitted with aluminium terminals and they lasted a long time.
On my own truck, Accel was the only vendor offering a "Premium Quality" cap and rotor so that's what I bought. It had brass terminals and it failed within 5K miles with internal arcing due to corrosion tracks. The inside of cap was green and black.
Just to get going again, I put in an El Cheapo cap with aluminium terminals which was still working at +30K miles later when the truck died due frame issues.

Back in the day, brass terminals were a sign of quality, but today not so much. Maybe the brass in today's caps isn't the same stuff they used to use?

Try OEM or equivalent- I'll bet the problem goes away.

kendall
12-25-2013, 11:22 PM
Something is wrong with the carbon button. That is what makes your carbon tracks. It is wearing away too fast. Perhaps the distributor shaft is the wrong length, i.e. too short. (as stated origonally by quadrod ) Or perhaps for some reason the distributor shaft is moving up and down crushing the carbon button? Has the distributor ever been changed? If so perhaps your putting in the wrong replacement cap and rotor??? I have seen carbon tracks apear on only the posts directly above them. But this was on a magnetic pickup, come to think of it it was an MSD too. Are the carbon tracks around the longest plug wires. The longer the wire the more the resistance, thus it would look for an easier path. I didnt see a vaccuume advance on the distributor so I would rule out propane getting in it. If the timming was advanced to much and it was detonateing, then the crankcase pressure may be too high and oil vapor is being pushed into it and burning in the cap? With an electronic ignotion you have to use resistor plugs and plug wires that are NOT metal. Some high end wires have one strand of stainless wire wrapped around the carbon core. That is ok and will not cause radio interferance which gets into the electronic ignition and plays havioc.

A worn thrust washer on the bottom of distributor will allow the distributor drive gear to 'push' the distributor shaft up. Either pull the distributor and check it, or pull cap and turn the engine over by hand in both directions, only go a few degrees around the wrong way, some cam chain tensioners (If equipped) don't like going backwards

Mike Burdick
12-25-2013, 11:38 PM
Jeremy,

Maybe the problem isn't in the distributor but rather the spark plug gap.

What was the spark plug gap the manufacturer recommend to you?

When using propane, the spark plug gap is reduced from what it is if using gasoline. On HEI systems, a wider gap will produce a higher secondary ignition voltage. With higher voltages and bigger spark plug gaps, flash over, or cross firing, is more likely, especially between adjacent terminal posts in the distributor cap.

Peter S
12-25-2013, 11:42 PM
Despite the comments, I don't think propane engines need "more spark", I know a SB Chev on LPG that ran trouble-free (for many years) on factory points ignition, coil, plug gap etc.

So.....all that tracking and erosion....does it have some kind of super coil perhaps more suited to racing? Get rid of it and fit a factory type?

The corrosion surprises me too - never seen the like.

ecortech
12-25-2013, 11:58 PM
This is a well documented common problem with these types of distributors both with the crab style cap and the small dia. Hei cap.
Primary cause is insufficient ventilation, the distributor vents have fine screens that plug up easily.
The recommended fix is to remove the screens and make sure the vent holes are free from obstruction.
If the vehicle has A/C, the line that runs very close to the distributor can drip condensation introducing excess moisture.
Fix is to insulate line to eliminate condensation.
Some applications I have drilled additional holes in the distributor base to increase ventilation.
Later so called updated distributors have larger vent holes to solve the problem, but if they have the fine screens in them they plug up easily.
Removing the screens and making sure the vents are clear should solve the problem.
Most caps and rotors I've purchased for these distributors have an instruction sheet in the box that recommends removing the screens and cleaning the vents.


Ed

C_lazy_F_Guns
12-26-2013, 12:18 AM
What else- is there a discrepancy between the timing of the spark and the relative positioning of the rotor itself? Maybe the positioning is off and the spark is not kept within the range where the rotor contact is close to one of the leadouts. Could be lots of misfiring in this case too.

That is what I see from the black lines in the cap. the rotor isnít pointing at the pole when the coil fires forcing it to jump . . . The further it jumps the more it heats and erodes the terminals. Iíd bet the caps are not timed to the distributors, a sticky mechanical advance will do the same thing to your cap and rotor but having two sticking isnít likely. Some third world numbskull is cutting the notch for the cap or the notch in the rotor in the wrong place for the distributors you have . . . listed the part number for things it don't fit. Then you get arc welding like corrosion all over from the material being burnt off the contacts over and over inside there.

darryl
12-26-2013, 12:58 AM
Yeah, I don't like the look of the center contact either. It does look as though a spark has had to jump there, and it's likely that it would burn it. The products of that burning could well be migrating to the outside, where it would wreak havoc.

1-800miner
12-26-2013, 09:43 AM
I think you are looking at a series of problems. First one causes the next one.
Narrow it down to the first problem.
Install all new parts drive for a week or two then tear it down and investigate.
Which part is the first to start breaking down? Cure that one and the rest of the problems may stop.
It sounds like you are driving them until they screw up ,then investigating.
Try some "preventative investigating"

RandyZ
12-26-2013, 11:04 AM
Why not junk that distributor and install a wide cap HEI. These have the terminals farther apart to reduce arc over tendencies. Might even fix any misalignment issues you have with the shaft. They are a dime a dozen in the junk yards.

Tim-Bob
12-26-2013, 01:36 PM
Poor cap ventilation and I'm guessing high humidity? You live near the coast? An HEI distributor would help and be a pretty easy install.

C_lazy_F_Guns
12-26-2013, 06:03 PM
Why not junk that distributor and install a wide cap HEI. These have the terminals farther apart to reduce arc over tendencies. Might even fix any misalignment issues you have with the shaft. They are a dime a dozen in the junk yards.
That’s what I would have done right off the bat. I’m a bit of a GM hater but got to admit those are some very good distributors. If there is room for it that is the best way to go, one wire to the IGN port and your golden! Don’t know how well it would play with EFI but running LP it shouldn’t matter.

Leadfootin
12-26-2013, 08:53 PM
Change the wires and route such that two adjacent wires at the cap never run parallel to each other within 2". Check that rotor lines up with terminals when spark occurs. Possible reversal of pickup coil leads has occurred and is placing the spark outside of rotor alignment this being a very likely scenario. Plug gaps should also be reduced till rough running is noticed then increased .005"

gambler
12-26-2013, 09:09 PM
don't run platinum plugs. it can cause high resistance in the secondary leading to burning the cap and rotor.

jnissen
12-27-2013, 10:07 AM
This is a well documented common problem with these types of distributors both with the crab style cap and the small dia. Hei cap.
Primary cause is insufficient ventilation, the distributor vents have fine screens that plug up easily.
The recommended fix is to remove the screens and make sure the vent holes are free from obstruction.
If the vehicle has A/C, the line that runs very close to the distributor can drip condensation introducing excess moisture.
Fix is to insulate line to eliminate condensation.
Some applications I have drilled additional holes in the distributor base to increase ventilation.
Later so called updated distributors have larger vent holes to solve the problem, but if they have the fine screens in them they plug up easily.
Removing the screens and making sure the vents are clear should solve the problem.
Most caps and rotors I've purchased for these distributors have an instruction sheet in the box that recommends removing the screens and cleaning the vents.


Ed

WE have a winner. The cap and damage is clearly from moisture. If you have ever run a motor with excessive moisture in the cap you will know what it looks like and that is a picture for the dictionary! The moisture will break down the carbon button on the cap to rotor interface and then all the carbon get redistributed all around. The metal plate clearly shows the damage from moisture as well. East Texas is high humidity and the AC runs likely 10 months or more out of the year. Fix the moisture issues and you fix the problem.

A.K. Boomer
12-27-2013, 11:03 AM
Have to admit it does make allot of sense,
maybe the reason iv never seen anything like it is due to living in semi-arid conditions,

misaligned rotor to cap will totally eat the rotor end and cap gap connections first and then move on to other components - not only that - it will favor one side of the gap connectors more than the other and erode it first and frankly im not seeing that,

the lower plate on the other hand tells an incredible tale of corrosion - the type you may get with locked in humidity...

the incredible carbon trails ARE coming from the eroded central button - and then just re-aligning with the fouling arcs...

A.K. Boomer
12-27-2013, 11:52 AM
How are the bodies on these vehicles? are they rotted away?

vpt
12-27-2013, 12:21 PM
I water proofed my 89 when I was younger by silicone everything shut. I glued the vent shut in the cap, then glued the cap to the disty, then glued the wires to the disty and tot he spark plugs (just the boots).

This was on a ford 300I6 with the disty n the side of the motor. After the sealing up I had that disty totally submerged very often with no problems.

A.K. Boomer
12-27-2013, 12:36 PM
Don't know Andy - if it worked for u then it worked for you -------- but - listen to Guido back on post #8;

"Ionized air inside a stock dizzy cap needs vented."


there is a reason for this as it will help the spark jump huge gaps without being impeded...

Edit; and every time spark jumps even the normal gap it creates Ionized air, then if it builds it's easier to jump larger gaps - then it snowballs and really builds, then it jumps enormous gaps...

jeremy13
12-27-2013, 12:46 PM
Just a little more info the pictures show the old factory distributor and 3 month old MSD cap and rotor. We just replaced the hole thing with a new MSD one. On the advice of MSD tec we bumped the plugs down .005. I like the idea of venting the cap to the intake. I think I'll drill the cap and install a poly hose barb and run a hose to the intake. I'll drill the cap in case it don't work out. I'll knock the vent screens out of the other distributor and give that a try to.

The bodies are in very good condition for there age. One reason we haven't replaced the trucks yet. And that until just recently no one had a factory converted one. Ford just came back out with there V10 in propane we are seriously looking at them.

The other truck we did seal every thing with silicone about 2 months ago. Its still running so well see how that works out.

ecortech
12-27-2013, 01:41 PM
I wouldn't run a hose to the intake it will just create in effect a vacuum leak, really not needed. In extreme cases a hole drilled in the cap will improve things.
I have seen other caps with similar dia. in the past made with a vent incorporated right into the cap.
If you drill the cap you or whomever replaces the cap next time will have to remember to drill the new one.
Drill the distributor problem will not re-occur.
Usually removing the screens and cleaning the vents will fix things.
If there is a A/C line near the distributor insulate it.
In the photos you can see the base and screen is covered in crud, vent probably is at best partially blocked.

Ed

The Artful Bodger
12-27-2013, 02:49 PM
We had a Japanese micro car, a Suzuki LC10W coupe with a 358 (thats cc not ci!) engine and powerful ignition system. They ventilated the dizzy cap by running two hoses, one up into the body away for rain etc and the other into the clutch housing. I can only assume the clutch housing has a slight depression while the engine is running.

C_lazy_F_Guns
12-27-2013, 06:39 PM
I water proofed my 89 when I was younger by silicone everything shut. I glued the vent shut in the cap, then glued the cap to the disty, then glued the wires to the disty and tot he spark plugs (just the boots).

This was on a ford 300I6 with the disty n the side of the motor. After the sealing up I had that disty totally submerged very often with no problems.

Yup we has a military half track on the ranch I grew up on, it had duel ignition systems, 2 distributors, 2 plugs per cylinder and all. They were 100% sealed water tight, the thing had a snorkel and I tested it well as a teenager . . . It’s still there, still running 40 years later and all that was ever done was finger nail file or replace the points.


Because of that I’ve always sealed up the ignition systems and snorkeled on my hunting rigs (also separate the fan belts so it can be shut off for water fording) and they have all been just fine running 100% sealed up. So I don’t buy that it’s poor venting, I’d be more inclined to believe the vents are letting nasty stuff get in there.


I’ve seen many caps that look exactly like that and the reason was always the cap and rotor were not in time with the spark.

WhatTheFlux!
12-27-2013, 06:46 PM
I see two possible solutions here.

One group says it's a venting issue. Caps are cheap enough, vent one and record the results. If there is no improvement or it gets worse try a mechanical rebuild.

vpt
12-27-2013, 07:08 PM
Yup we has a military half track on the ranch I grew up on, it had duel ignition systems, 2 distributors, 2 plugs per cylinder and all. They were 100% sealed water tight, the thing had a snorkel and I tested it well as a teenager . . . It’s still there, still running 40 years later and all that was ever done was finger nail file or replace the points.


Because of that I’ve always sealed up the ignition systems and snorkeled on my hunting rigs (also separate the fan belts so it can be shut off for water fording) and they have all been just fine running 100% sealed up. So I don’t buy that it’s poor venting, I’d be more inclined to believe the vents are letting nasty stuff get in there.


I’ve seen many caps that look exactly like that and the reason was always the cap and rotor were not in time with the spark.


I know, it is also why I question it as well. My 89 ran great for many years all sealed up. Way more than I can say for my prior water adventures with the truck.

A.K. Boomer
12-27-2013, 08:18 PM
I believe we've got it cornered into one of two possibilities - but iv become acutely aware of something, its times like this that I miss Evan the most - don't you kid yourself he would have some very insightful things to say about this and I would be interested in hearing them,

So ------ Evan, if your listening - (I know you maybe checking out the sky/moon tonight --- but) step into this mess and knock some heads around like the good ole days, place is good - but it's just not the same without my big brained buddy from the north...

lakeside53
12-27-2013, 09:42 PM
Ignoring the obvious that there are a boat load of trucks running just fine, and this can be 'fixed", we could go hog wild and create something new ;)

Like.... an air pump, dryer, and filter. Feed the dry air to and pressurize the distributor cap (ignore that it will be hard to seal properly for real pressure, but it will be clean). More pressure, less arcing. Of course, nothing new here - my 1970's plane had a similar system to stop magneto arcing at altitude. Sure got your attention if the pressure failed.

QSIMDO
12-27-2013, 09:55 PM
Did anyone say it yet?

You need new wires!

amateur
12-27-2013, 10:13 PM
Poor PCV system causing combustion gases in crankcase to go up distributor shaft ?

Guido
12-27-2013, 11:13 PM
I just checked with Saltmine. Says he's never had this problem on a Cheeevycar.

ecortech
12-27-2013, 11:17 PM
I have a lot of experience running these HEI ignitions in both stock applications and in oval track race engines.

Older systems can be run sealed up waterproof no problem.

Older more conventional ignitions have no where near the spark energy that an HEI has.

The high energy discharges build up ionized air, called Ozone. This ozone promotes ground fires, cross fires and chain fires inside the cap.

Venting is necessary to prevent the build up.

Moisture can also add to the problem.

With the one piece cap with no vent, the cap works as an air bubble to keep the distributor moisture free when driving through water.


I can't ever remember seeing any of these type of problems until recent years.

Modern engines have leaner mixtures to meet tighter emission requirement.

Leaner mixtures need larger plug gaps for reliable ignition.

Larger gaps need more power to jump the gap.

Older ignition systems were approx. .025"-.030" plug gap.

HEI systems generally run around .060"- 065" plug gap.

As for cap and rotor being out of time with spark, not likely. There is no mechanical or vacuum advance, spark timing is completely electronically controlled.

Multiple caps and rotors have had same problem. Like wise distributor has also been replaced.

In my experience the more expensive, heavy duty, brass terminal, MSD, Accel, Mallory etc.. do not last any better than a good quality stock replacement from the auto parts store.

I do know from my experience that insufficient venting in a HEI system will without a doubt cause this exact problem. I have seen it happen numerous times and have cured it by insuring adequate venting.


Ed

vpt
12-28-2013, 09:01 AM
Larger gaps for leaner mixture? As long as I have been working on vehicles they have always ran from 12-14.7 AFR under normal driving conditions. This holds true for almost every single gasoline engine on the planet.

ecortech
12-28-2013, 11:37 AM
Yep that's right older technology probably closer to 12-13 AFR much of the time. Tighter emission regulations, modern computer controlled fuel injected engines run much closer to 14.7 sometimes on the edge of being lean to meet lower emission rules.
On most older engines if you were to monitor the AFR with very accurate equipment you would find that they are no where near ideal AFR throughout much of the operating range.
Modern electronic engine controls allow much tighter control of the AFR, engines run much closer to ideal AFR over most of the operating range.
Overall engines have gotten leaner as technology has advanced. A leaner mixture requires larger gaps higher spark energy to achieve reliable ignition with no misfires.

Ed

vpt
12-28-2013, 12:40 PM
It was not uncommon for vehicles to get amazing (running lean) mileage many years ago and have no spark problems. My grandfathers 1980 300I6 ford truck got over 20mpg all the time.

CarlByrns
12-28-2013, 12:45 PM
Poor PCV system causing combustion gases in crankcase to go up distributor shaft ?

Either that or a bent shaft or worn distributor bushing. IIRC, Chevys were notorious for a worn oil pump bushing allowing the distributor shaft to wobble.

ecortech
12-28-2013, 08:56 PM
If it was a poor or malfunctioning PCV system I would expect that the inside of the distributor housing would be wet and oil covered.
If the crankcase pressure was venting up around the distributor shaft it would push oil vapor as well as combustion gasses.
The photos look to show dry whitish corrosion on the distibutor base.
I would rule out bent shaft worn bushing OE distributor was replaced with a new MSD distributor.
Unless both the OE and new replacement are both bad, highly unlikely but possible I suppose.

Ed

ecortech
12-28-2013, 09:03 PM
It was not uncommon for vehicles to get amazing (running lean) mileage many years ago and have no spark problems. My grandfathers 1980 300I6 ford truck got over 20mpg all the time.

I am not certain but I would think in 1980 that Ford truck would have been equipped with I think a Dura-Spark Ignition which was Ford's version of a HEI
ignition.

Ed

Doozer
12-28-2013, 09:13 PM
I think DuraSpark distributors have the terminals spaced
even farther apart than GM HEI. I love that system.

--Doozer

A.K. Boomer
12-28-2013, 09:22 PM
I'll tell you what a good system is - no cap at all - now that's a good system...

CarlByrns
12-29-2013, 02:00 AM
I'll tell you what a good system is - no cap at all - now that's a good system...

Man, I hated coil pack distributorless ignitions when they first came out, but, yeah, they're pretty rugged.

A.K. Boomer
12-29-2013, 09:32 AM
I hear you at first - but they are getting them down. nothing to "wear out" - one coil shoots craps and you still get home,

No leaky high voltage wires to worry about, and now that they are going totally individual there's no need for your spark plugs to do double duty like in the transitional stage where they were using two coils on a distributor-less in line four or horizontally opposed four,
You just run low voltage wires all the way up to the plugs and a small individual coil pack, it really is a beautiful thing, my have I seen some changes in engines and controls since I picked up a wrench about 40 years ago.

there's no reason that with resistance measurements and crank and or cam position sensors that if an individual coil pack goes bad that not only does the engine know which one it is but it can also halt fuel delivery to that particular injector to save the cat from turning into a molten pile of goo... and you just drive to wherever you want to go and then get it taken care of when it's convenient... crazy.

I know many people long for the good ole days and in many a way and I do too, but when it comes to engine management and controls I think we've made so many great advances (thanks mostly due to electronics) that there's simply too many to count...
You could not convince me to go back in time that way,,, I would be a kickin and a screamin...

the electronics iv worked with over the years are the most dependable thing iv ever dealt with - In all the years iv worked on Japanese vehicles I found one bad ECU - and it was not even it's fault and was repairable, someone by passed a fusible link due to their being a problemo elsewhere and it blew a little path out of the circuit board that I just re-soldered,

Im no electronics expert but IMO at least with assembly and alignments and sealing and soldering iv never seen higher quality circuit boards... they are a piece of electronics art...

the advancements continue and there's no end in sight - there will be a few "gimmicks" that fade, but by trial and error we keep refining...
If it wasn't for emissions we would have some extremely efficient engines right now - but in a way it's one step forward and one step back as the rules and regs keep getting stacked higher and higher, we need to get off the "parts per million" kick and start judging vehicles by entire volume of pollutants with exceptions for work vehicles and such...


ok - kudos and rants off...

vpt
12-29-2013, 09:41 AM
Whats even better yet is no distributor, coils, wires, or spark plugs at all.

A.K. Boomer
12-29-2013, 10:12 AM
Yes and I think that's right around the mainstream corner,,, but again all controlled by incredible electronics and sensors...

RandyZ
12-29-2013, 10:23 AM
Isn't it funny, how the auto industry is copying what aircraft engine manufacturers did 60 years earlier. Turbo chargers, 4 valves per cylinder, fuel injection and individual coils per cylinder. How long til one of them "discovers" power recovery turbines?

vpt
12-29-2013, 11:04 AM
Isn't it funny, how the auto industry is copying what aircraft engine manufacturers did 60 years earlier. Turbo chargers, 4 valves per cylinder, fuel injection and individual coils per cylinder. How long til one of them "discovers" power recovery turbines?



In the auto industry, first the Japanese have to introduce some technology to the market then finally after a good 10 years the American companies will copy the Japanese. So if you are a die hard American auto fan you have quite some time to wait for anything good to be ruined by a poor copy of an original.

flutedchamber
12-29-2013, 11:15 AM
whats even better yet is no distributor, coils, wires, or spark plugs at all.

diesel

A.K. Boomer
12-29-2013, 11:17 AM
and gas


http://www.gizmag.com/go/4695/


http://www.automobilemag.com/features/news/hyundai-announces-compression-ignition-1-8-liter-twin-charged-engine-256199/


there's all different operating principles recently and on the horizon and some are bound to stick...

every single day new stuff is coming out now and there will be some big changes in the very near future because of it.

Willy
12-29-2013, 04:48 PM
Isn't it funny, how the auto industry is copying what aircraft engine manufacturers did 60 years earlier. Turbo chargers, 4 valves per cylinder, fuel injection and individual coils per cylinder. How long til one of them "discovers" power recovery turbines?

Detroit Diesel's new line of truck engines that were introduced about 2007 use a power recovery turbine. They claim to regain 50 HP and 100 ft.lb. of torque when the engine is operating at maximum output.

Scania in Europe has been using turbo compounding on it's truck diesels since 1991.
I believe Volvo and Iveco also have some industrial diesel engines that utilize power recovery turbines.

I would think the reasons that it is not being used in general passenger car applications are twofold.
First would be the fact that for a power recovery turbine to be effective in producing a meaningful amount of power, the engine should be operating at or near maximum output for a large portion of it's normal operational time. Automotive applications simply would not encounter these types operational parameters.

Second would be that it is not cost effective. Even in many industrial applications one has to balance the price, packaging, mechanical complexity, and control electronics against other cheaper methods of power enhancement and fuel savings.

The Artful Bodger
12-29-2013, 06:13 PM
This is a home shop machinists' forum and presumably we have a few tinkerers among us, maybe one of them will mate an ex-turbo charger turbine with an alternator to recover power to drive engine ancillaries and vehicle accessories, air con, power steering, radiator fans, coolant pump even lubrication pumps could be electric motor driven which would surely leave quite a few extra horses to twist that crankshaft. Just take the belt off the crank pulley and add an electric motor driven from the battery that would be kept charged by the power recovery turbine.