Chevy distributor cap condensation issues

[cubandeathgrip]

I may drill into my new cap. duplicate the summit cap placement of their vent..then glue a self made rain cap on it.

 

[L31MaxExpress]

I may drill into my new cap. duplicate the summit cap placement of their vent..then glue a self made rain cap on it.

I drilled and tapped the distributor base in place of the existing vents. Went to a 1/8" NPT fittings with 90* hose barb ends.

 

[skylark]

If I recall correctly there is a vent with a screen in the bottom right of the distributor. It may be plugged.

 

[GoToGuy]

Did you guys read the bulletin? Any thoughts?

 

[L31MaxExpress]

Did you guys read the bulletin? Any thoughts?

Knocking the screens out did not do a thing for me. Vacuum venting and brass terminal cap and rotor were a longer lasting cure.

 

[Caman96]

Did you guys read the bulletin? Any thoughts?

Knocking the screens out did not do a thing for me. Vacuum venting and brass terminal cap and rotor were a longer lasting cure.

I’ve haven’t noticed an issue with this, but may try it anyway. I do have an Acdelco Marine brass terminal cap for next replacement. How restrictive are the screens anyway?

 

[Road Trip]

Knocking the screens out did not do a thing for me. Vacuum venting and brass terminal cap and rotor were a longer lasting cure.

Your solution makes sense. Suck out the ozone (O3) and purging it with ~20% oxygen (O2)
and 80% inert Nitrogen.

Color me sold.

 

[454cid]

I wonder if there's something about the small block that is harder on caps than the 454. I don't have an issue with them. I think I'm only on my third cap, including the original, at over 300K miles.

 

[L31MaxExpress]

I wonder if there's something about the small block that is harder on caps than the 454. I don't have an issue with them. I think I'm only on my third cap, including the original, at over 300K miles.

Went through that many in the first 3-4 years.

 

[Road Trip]

I wonder if there's something about the small block that is harder on caps than the 454. I don't have an issue with them. I think I'm only on my third cap, including the original, at over 300K miles.

I think that an argument can be made to support your hypothesis.

Although I'm not an expert on ozone generation, I think it's a fair
assumption that the higher the arc Kilovolts are, the more O2 is
converted to O3.

Digressing for a moment, one of the things you learn from maintaining/repairing
25KW airborne radar systems is that if you lose your waveguide pressurization,
you *will* encounter high voltage arcing inside between the walls. (You find this
because the reflected power back into the transmitter damages the magnetron.)

Conversely, plenty of pressure = happy, non-arcing radar system = happy pilot
because he can track the bogey at the merge.

...So what does this have to do with our ignition systems? After watching the
parade of sparks back in the day plus watching modern automotive scope dope
troubleshooter videos, I firmly believe that the peak voltages required to fire across
the spark plug gap varies constantly. And the higher the dynamic cylinder compression
pressures (ie: the more the throttle is open) the higher the voltages required to
jump the gap.

Let's assume that we have a heavily loaded (close but still legal) truck or Suburban.
Pulling a specific grade, at the speed limit, 80° day, 1000' altitude, etc.

Under the hood is a L29 454 (290 hp, 410 ft/lbs ~56ci per cylinder) and you are requiring 300 ft/lbs
of torque at the flywheel to maintain a steady speed. This will require a certain throttle angle,
resulting in a specific MAP reading, with a resulting percentage filling of each cylinder.
And when it comes time to ignite that charge, it will require so many KV to be able
to jump the gap against that specific pressure.

Now, let's take that same scenario and replace the 454 with a stock L31
(255hp, 330ft/lbs, ~44ci per cylinder) being asked to deliver that same 300 ft/lbs of torque.
It can & will deliver the necessary power, but now each smaller cylinder has to work closer
to it's max, the percentage of charge is higher, and therefore the KV required to jump
the gap against this denser charge is increased.

There's no free lunch. The small block delivering the same power as the big block
is working at a higher duty cycle. And my theory is that this higher duty cycle is
reflected back into the distributor cap, so ultimately in this scenario the ignition system
is being worked harder. (higher KV)

Bringing this back to the beginning, more KV = more ozone generated.

Understand that the 'short burst at max power' quarter-mile guys reading this would think that
you've been burning too much incense in your bedroom. But people that tow
heavy loads often, and have both SBC & BBC Vortecs in their rigs in their fleet
(and keep careful records) might observe a parts consumption trend like this in their data.

A little food for thought. Hope you stopped reading before indigestion set in. :0)