distributer cap mods?

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pjc360

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Is there anything a guy can do to a distributer cap to make it last a little longer? Is it ok to drill a little larger hole on the top to let more air escape?
I have a crane cams hi-6 cd ignition with a crane cams lx91 coil and i'm running a mopar performance distributer, the cap i have is a Wells gold with copper inserts and the contacts become corroded very quickly withing about a month to a month and a half. I know i need to get better plug wires, currently have stock replacement 7mm wires and i'm sure a good 8.5mm wire with a lower reistance will help keep my caps lasting longer, i'm also running the special echlin rotor with the longer rotor segment to try and help keep the cap lasting longer.
It's just once the cap gets bad enough inside i start getting a stumble and hesistation and i tore apart my carburetor looking for the issue when it was the distributer cap the entire time.
I'm thinking about just drilling a larger hole in the cap to allow some air to escape out of there, i have my plugs gapped at .045 inch currently running champions rc12yc plugs.
 
Somewhere on the www and it seems to me it came from MSD.............was advocating that very thing. Very high energy ignitions generate more ionization which is evidently detrimental to caps / rotors.

I can't find the photo, but what I saw had quite a few small holes around the outside of the cap, just above the dist. case. I would assume there were also at least one or a few on the top of the cap.
 
Are you sure corrsion is what you're seeing ? The caps come with a lubricant on the contacts that is invisible initially. After use that lubricant turns to a white-ish powder.
It's very common for the novice to go in there with a pocket knife and scrape away all the lubricant.
Back in the 80s Ford had a problem with their pickup coils melting down due to heat build up in the 3.8 V6 distributers so the added a atmospheric vent to those caps.
I suppose one might hand fit that vent into a different cap. Its purpose wasn't moisture related though so...
To apply a small bead of grease where the cap meets the base was somewhat common for slant 6 owners too since that distributers location made it more prone to moisture getting inside.
 
I,ve had the same dizzy cap on mine for 4-5 years. I belive it's a NAPA cap
and rotor. Has a vent built in. No problems. I'd stay away from those Wells
brand stuff. Get a good one from a major store. Those chain stores like
Autozone, Checkers, O'Reily's get a cheap manufacture to build for them.
 
Here is a picture of a vented cap found at rockauto.

A distributor should also have a vent in the bottom of housing.

At ignition voltage, tarnish on the copper is insignificant. What is most important is cleanliness of the insulation and lack of tracking
 

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i have that exact same cap that you just posted a picture of carlson, that cap you posted is the wells gold series cap with the copper contacts, thats the exact same cap i have right now. Abnd it does have a vent on the top of it, its just not a very big one at all, thats why i was thinking i might could drill a hole in the top of the cap.
 
i was thinking maybe drill a hole in that black plastic piece, or just take that black plastic piece off the cap to expose a larger hole.
 
Too much vent may not be a good thing, may add to moisture on damp days. Engine heat should easily drive out normal moisture with standard vent.

A CDI ignition can easily burnout standard suppression wires. I had a set go from 5K Ohms, to meg-Ohms after a year.

Also about crank case ventilation, fumes can go past the distributor shaft bushings, if there is positive pressure. My first thought what to check for your problem. Is oil clean?
 
well now i have a bigger issue to find because my miss fire is back again wich i thought i had eliminated, what a freaking nightmare!! Brand new distributer curved and phased, brand new crane cams cd ignition and coil, brand new spark plugs, brand new spark plug wires, brand new cap and rotor and i have a miss fire, how is this even possible? Blows my mind that there is a missfire.
I had been chasing down a miss fire for a very long time previously and found it to be a vaccum leak at my intake manifold, put a brand new intake manifold gasket on it and that cured my plug fouling miss firing issue for almost 2 months and now its back again... Unstable vaccum while its idling, i know this is a miss fire issue, i just dont know where to look next. Compression test yeilds 150psi on every cylinder wich is real good since i am at 4000 feet above sea level. So what in the hell is the issue here? I'm running 15 degrees initial timing 33 degrees total timing with another 10 degrees of timing at an idle from vaccum advance on manifold vaccum. I'm out of ideas
 
My guess is intake leak. You might check intake bolt torque, instructions for fiber gaskets suggest re-torque. Do you have water or oil loss, or water in oil?

Check for ignition on each cylinder with timing light. Blink should follow idle. A missed blink may indicate misfire.
 
no water in oil or oil in water, this engine doesnt even have 20 thousand miles on it. It has a brand new fel-pro intake manifold gasket, i used al brand new bolts and washers and torqued the intake down.I have steady vaccum at idle with my vaccum gauage, before when i had the vaccum leak on intake my vaccum was un-stable at idle.
This is something else, and i'm starting to think its fuel not ignition, If i first fire the engine up there is no miss at all, and i can let it idle for 20 to 25 minutes with no miss while at an idle, then i go drive it around and let it idle after driving and the miss is there, Also it is extremely cold here where i am, doesnt cold wether lean the carburetor mixtures out? I'm thinking this cold wether wich is 5 to 10 below zero has my mixture too lean at idle. My plugs are not fouling like they did when i had the intake manifold leak ether, so the steady vaccum at idle and not fouling plugs makes me think its something other then a vaccum leak at the intake manifold.
And when i put this new intake manifold gasket on a month or so ago, i sanded and cleaned the heads and the intake and i used the edelbrock gasgacinch sticky stuff thats supposed to help form an even better seal. I'd just be very suprised if it was a vaccum leak at this point, plus yesterday i sprayed wd-40 all along the intake and listenend for change in idle and didnt hear one.
Right now i am running a 600cfm manual choke edelbrock performer carburetor and i have .092 jets in the main circuit and .092 jets in the secondary circuit and i am running the 7047 metering rods with the silver step up springs, I was told maybe a one size smaller metering rod might help this situation? because the fuel at idle goes past the metering rods and down the jets correct?
 
I guess it may have another intake manifold gasket leak. Becasuse it's doing the same thing it was doing before when it had a vaccum leak. I just dont understand how in the hell it got another intake manifold leak. The one i have on it now isnt even 3 months old. And i used all brand new bolts and washers and torqued the intake. So beats me how its leaking again.
 
Did you use Felpro Permatorque gaskets? Edelbrock instructions says not to use, they will lead to leaks.
 
Don't drink the cool-aid Don is serving you. If your going to run vacuum advance,it should be hooked up to the "Ported" side of the carb. No Chrysler ever came from the factory with its vacuum advance hooked up to full manifold. An original Carter only had one port on them.You guessed it,Ported.The ported side on your Ede,is the passenger side port.
For tunning purposes,take the vacuum advance out of the equation,plug it.

Use the "Orange" spring. It's what the carb came with from Ede. It works.

Why are you running 92 & 92 for jets ?
Just curious how you came to this conclusion ?
That carb came with 100 & 95 jets from the factory.

Your over thinking the cap.

Give the Champions to your gardener for his lawn mower. (No disrespect)
Get yourself a nice set of NGK'S ,or Autolites,in that order.

Steady vacuum is good. Hopefully you have all vacuum leaks solved,otherwise your chasing your tail.

Hopefully your Crane electronics are compatible,and have been wired correctly.
 
The reason i run .092 jets in the carburetor is because i live 4000 feet above sea level, so the stock jetting was a little rich, And i have tried talking to don about the possibility of running the vaccum advance off of ported vaccum and he freaks out about that, he is so set in his ways of tuning there is no talking about tuning if the vaccum advance is not on manifold vaccum.
I have to admit, when i first put my new intake manifold gasket on, and no i did not use the fel-pro permatorque gasket, i used the fel-pro gasket part number ms95392 wich is the stock replacement intake manifold gasket for the 5.9 magnum and the 5.2 magnum engines. I used permatex ultra black on the end seals, but one thing i forgot to do and i feel very stupid for not doing... is i forgot to re-torque the intake manifold bolts after it cooled off from running it. So, since i forgot to re-torque them could i have another vaccum leak at the manifold? because it is behaving the exact same way it did when i had my first vaccum leak at the intake, running lean at idle no matter what i do to the mixture screws, same old thing happened first time around when i had the vaccum leak at the intake.
I do not think i can blame this issue on the vaccum advance being ran off of manifold vaccum, and in fact what i was going to say is when i first fixed my vaccum leak the intake manifold and i set my initial timing to 15 degrees total timing at 33 degrees with another 10 degrees of timing added at idle from vaccum advance on manifold vaccum this engine ran so strong and so well, it would idle as smooth as butter and the plugs looked terrific and it ran very strong, So this engine runs well with vaccum advance hooked to manifold vaccum and it runs cooler at an idle on manifold vaccum, and i feel as if it has sharper throttle response with the vaccum advance on manifold vaccum. I have ran ported and manifold vaccum to the vaccum advance and i have to be honest, it runs better on manifold vaccum.
I think i have another vaccum leak at the intake because i didnt re-torque my dam intake bolts after running it, I got another fel-pro gasket for 20 bucks and i am going to try this one more time this weekend.
My plans are too, pull the intake and the old gasket off, scrape the old rtv off of the block, clean everything as well as i can, apply edelbrock gasgacinch to both sides of the intake manifold gasket and to the bottom of the intake (around the ports) and apply the gasgacinch to the heads (around the ports) I use studs when dropping the intake so i know that it is straight. This time around i think i might try the right stuff gasket maker this time around on the intake end seals instead of the permatex ultra black because the right stuff is said to be ready to run imidiatly after installation, and the ultra black takes 24 hours.
The symptoms of this miss fire i am having are the exact same as when i had a vaccum leak at the intake manifold, but sparying wd-40 around the intake did not reveal a leak, but i'm told it could be leaking under the intake. So i will try this one more time, and most importantly i will not forget to re-torque the bolts after running it for awhile and letting it cool down. How many ft lbs of torque should i apply to the intake manifold bolts? they are 2 inch long 5/16 course thread bolts. So i'm guessing 15 to 20 ft lbs of torque should be sufficient, correct?
 
You have just got to be the most obsessive person I've ever heard of. There are LOTS of thoughts, just one example, on how to set up timing, besides what "Don" says.
 
67Dart273 said:
You have just got to be the most obsessive person I've ever heard of. There are LOTS of thoughts, just one example, on how to set up timing, besides what "Don" says.
Click to expand...

And we have found some common ground...Thank you sir !
 
PJC.....here's your problem.
You start a post on why your car is running so crappy.
We give you sound advice,and you tell us "Thats not what Don says".
You do this " Everytime" you start a thread.
So you need to either start a thread,and give us some respect for taking the time to help.
And then putting our advice to use.
Or call Don up,and have him try and help you. Because his help has gotten you so far.
 
I'm not disagreeing with your advice at all, in fact a member said sounds like a vaccum leak to me, so here i am agreeing that it most likely is because it has the same symptoms as it did before with a vaccum leak at the intake manifold.
I have read pages and pages of discussions on vaccum advance, not only on mopars but chevy, and ford. And i came to the conclusion there is no right answer. The right answer is go with what your specific engine and combonation wants and or likes.
 
And i recall asking multiple times on this site on how to properly set vaccum advance up on ported vaccum and never got any answers... It's alot easier to set vaccum advance up on manifold vaccum with a dial back timing lite compared to trying to set vaccum advance on ported vaccum where you cant see how much timing it is adding while the engine is idling.
 
If you believe it's the intake leaking: Take a straight edge to your intake manifold & heads at the gasket surfaces & check for straightness by trying to insert a feeler gauge between the flat surface(where the gasket seals) & the straight edge. And by straight edge I mean a precision ground straight edge, not just a metal ruler or piece of scrap. If you can't get one at least take the intake manifold to a machine shop & they'll check it for you. Anything more than .002"-.003" & you have problems & need resurfacing. Measure accross the surface in the middle, accross the top & bottom, up & down the short edges & between each port & diagonally across the entire gasket machined surface. A pattern kinda like an asterisk. Never clean the surfaces of an aluminum manifold with a 3m scotch-lok cookie wheel or equivalent on a die grinder or dremel. It'll take too much material off & may cause leaks. Always scrape it off by hand.
 
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