Venting plug wires to stop oil from getting into the spark plug wells.

[CPUNeck]

Well I'm testing the theory that the oil contaminates the plug wells due to temperature induced pressure differentials. I found keeping the hole in the plug to be a challenge and here is how I solved it.

 

[SASHO91]

It's due to the fact that the plug well seals are rubber and overtime, after so many heat cycles, they eventually fail.

I think you just put holes into a good set of wires...

 

[CPUNeck]

Ahhh, science you gotta love it. I probably had close to an ounce of oil in the #2 well. So I know the VC seals are bad, now I'll be able to see if the oil is getting into the well from pressure or vacuum.

These are the factory wires still performing and sealing great @ 144k mi and I'm sure they could benefit from retirement, BUT, I have one last mission for them. I'll keep a good log on the progress and report back with pics.

 

[Off Road SHO]

It's due to the fact that the plug well seals are rubber and overtime, after so many heat cycles, they eventually fail.

I think you just put holes into a good set of wires...

The tops don't do anything but cause high and low pressure systems within the plug well. With the tops vented, those are gone and as long as you don't have so much blow-by that your PCV system can't keep up with it, you wont be getting any oil in the plugwells.

Tom

 

[HotRodKid]

pressure or vaccuum ? pressure or vacuum from what exactly ?

its not like the spark plug boots are a tight seal to the valve covers

and FYI, if anything, it would be from a lower pressure in the plug well, as a higher pressure in the plug well would push air into the valve cover.

some of the stuff that shows up on this forum is ********

 

[SASHO91]

The tops don't do anything but cause high and low pressure systems within the plug well. With the tops vented, those are gone and as long as you don't have so much blow-by that your PCV system can't keep up with it, you wont be getting any oil in the plugwells.

Tom

That may be the case, but you can't deny the fact that they DO fail due to heat cycles.
Keeping the pressure difference low (or possibly none) would only "put a band-aid" on the problem. Granted, it may prove useful to do on new plug well seals... but he would need to put new ones in, instead of guessing with the bad seals.

 

[CPUNeck]

pressure or vaccuum ? pressure or vacuum from what exactly ?

its not like the spark plug boots are a tight seal to the valve covers

and FYI, if anything, it would be from a lower pressure in the plug well, as a higher pressure in the plug well would push air into the valve cover.

some of the stuff that shows up on this forum is ********

Well that was a fine example of an intellectual response.

-Well, as I was taught, air expands when heated and contracts (that means shrinks) when cooled. If a sealed cavity is subjected to heating and cooling cycles, that cavity would experience pressure and vacuum.

-If you were to examine the OE plug wire boot design, you would see in fact they have a double inner lip for a positive seal when compressed against the inner plug well, and an outer "dust" seal that covers the outside of the well. Creating a great seal, by design.

-and FYI, if anything, it would be from a lower pressure in the plug well, as a higher pressure in the plug well would push air into the valve cover. Did we miss some of your thought process? Exactly what is "IT" that you're speaking of?

-I suppose the narrow minded English thought Columbus was "********" too, believing the earth was round.

 

[Shoaz]

-and FYI, if anything, it would be from a lower pressure in the plug well, as a higher pressure in the plug well would push air into the valve cover. Did we miss some of your thought process? Exactly what is "IT" that you're speaking of?

"It" is the oil. If there's pressure inside the plug well it'll help to keep the oil out, since it'll be pushing against the oil.

The seal that the plug wire surround makes with the valve cover and environs is, among other things, to help keep moisture out.

 

[CPUNeck]

Yes, I agree, one of the boots' jobs is to keep moisture out. While this will allow the introduction of moisture, it also will allow for its evacuation.

Remember, I'm only attempting to disprove the hypothesis that: "Oil is entering the plug wells by and large due to vacuum created in the plug well when the engine cools down." I also believe that positive pressure can vent from the well easier than air attempting to enter the well to equalize the vacuum in the well. I'm basing this on the design of the plug boot.

I already know that there is a problem with my #2 cylinder. With-out these vents in the plug boots, this plug well filled with engine oil. The only thing I've changed is adding this vent to the plug boot for that cylinder, and now I will watch to see how/if that effects the oil returning to that cylinder.

Also, I will pay close attention to potential new drivability issues created by this mod. (ie. humid air condensing on the walls of the plug wells and causing spark arc) This is a real possibility, especially here in the south.

Just looking to expand our knowledge base.

 

[sdpatt]

The seal that the plug wire surround makes with the valve cover and environs is, among other things, to help keep moisture out.

Exactly. The seal of the square surround is to keep moisture and debris out of the plug well. When the plug is removed, that junk (sand, small gravel) can enter the combustion chamber and do a great deal of damage. The seal can also keep moisture out of the wells during a cold morning when condensation forms on the cold engine or when an unknowing owner douses the engine with a hose to clean it.

There is no way that this seal is designed, or is capable, of allowing a vacuum or positive pressure to build up under the plug seat. Any slight positive pressure would simply press the rubber boot ****** upward like a reed valve. The absence of firm pressure of the seal against the valve cover would prevent the slow buildup of a vacuum in the well due to temperature drop. The non-AGSP32PP plugs with their taller insulators fails to provide the firm contact of the boot ****** against the valve cover.

 

[HotRodKid]

Well that was a fine example of an intellectual response.

-I suppose the narrow minded English thought Columbus was "********" too, believing the earth was round.
[/COLOR]

1) i dont give intellectual responses

2) key words, sealed cavity- sure its sealed against water (sometimes, as snyone who has washed their engine will attest) but only in a zero pressure differential state. that seal will NOT resist even a single pound of pressure.

3) OE plug boot design - so only people w/ OE plug wires will experience oil in the plug wells due to the OE boot design ?

if this is true, how come my 3.0 in the garage has aftermarket wires and oil in the plug wells ?

4) you really didnt understand what "it" was? wow ......

5) actually, alot of people already knew the earth was round, it just wasnt yet proven by someone SAILING around the world. therefor a majority of people wouldnt yet beleive it

 

[HotRodKid]

Remember, I'm only attempting to disprove the hypothesis that:

oh god thank you

please overlook previous "Richard Cranium" responses from me

shouldnt be to hard to disprove, about as hard as me disproving the theory that theres a lion trapped in my closet right now ....

 

[cetroutt]

question?

okay, i really get what you're trying to do here and i think it's a good idea. but i just replaced my plug well seals and valves cover gaskets. put in new plugs (not OE they're, the autolites that everyone says is evil) and reused the OE 166,000 mile plug wires (i know i'm switching them out next payday). i ran the car for aobut 5 minutes to check for leaks (which i found one on the back valve cover [it's my first SHO so i'm gonna make mistakes]) but the next morning i found a very small amount of oil in two of the front plug wells. so is it preasure/vacum or did i put the seals in wrong? putting the seals in seems pretty cut and dry to me but who am i to say. also about the dirt and dust and other crap in the wells. well on OHV engines crap gets into the plugs wells all the time. there's a very easy and inexpensive way to cure it. a can of compressed air, there's probably one next to your keyboard and it works awesome. and as i found out saturday (before the new seals) if the plug well is full (and i mean full as mine was) of oil get a 2 dollar meat injector cut of the pointy tip of the needle and use it to suck the oil out. works so awesome.

 

[Mr Anonymous]

It's due to the fact that the plug well seals are rubber and overtime, after so many heat cycles, they eventually fail.

Yep. I'm gonna go **** myself now...

It's all in the rubber. The rubber dries out, hardens, shrinks, cracks, and leaks. The solution is simple and well-known: replace the valve cover and plug well gaskets every ~60K miles.

The rubber used in newer gaskets is a lot better composition and stands up a lot better over time. For example, the V8 valve cover and plug well gaskets (no, they won't fit the V6) can stay soft and supple up to 200K miles and more. Problem is the gaskets for the V6 are still made from the same rubber compound spec from 1986.

Unfortunately, screwing around with the plug wires/wells is not going to accomplish anything.

 

[SuperHO]

some of the stuff that shows up on this forum is ********

That's almost sig quote worthy, just due to the irony.....................

 

[SASHO91]

Yep. I'm gonna go **** myself now...

:angelnot:

 

[K-Dawg]

I assume pressure differences are the reason that all the other rubber gaskets and seals leak also.

 

[CPUNeck]

K-Dawg, "I assume"

Well we know what happens when assumptions are made. All I'm doing is investigating a plausible theory. Certainly NOT drawing conclusions at this point.

Seems a lot of people here are on the ready to sharp shoot, for no apparent reason

 

[gas it]

What if you leave the spark plugs loose so the oil that leaks from the VC goes into the cylinder? It will never build up in the well. I'll put the pipe down now...........

 

[SHOZ123]

The seals deteriorating with age and oil accumulating in the plug wells is worsened by the V6s anemic PCV system. There isn't enough vacuum on the crank case to prevent a pressure build up so the oil gets pushed into the plug wells.

I plugged the valve cover fresh air intake hose on my V6 once and could only develop an ~1"Hg of vacuum. On my V8 when I do this I generate ~10" Hg of vacuum.