Distributor ventilation help please!

[Esel Mann]

I just noticed that the distributor vent hose plus the hose to distributor fitting were both disconnected from the distributor.

I also noticed that the fitting which mates the hose to the distributor has a threaded round end for distributor side connection. The hole at the distributor however is oval. WTF???

Here are my questions:

- In comparison with a picture of the ventilation kit our host offers, it would appear that the fitting I have is likely not the correct one?

- I see that each distributor has these oval openings. Are both supposed to be ventilated?

- If only one is to be ventilated which distributor oval opening should it be? I am concerned that if someone was willing to take a shortcut on such a simple fitting piece they are also capable of selecting the wrong oval opening.

- The origination date on the door jam sticker indicates 08/92 despite the fact my 964 is titled as a 1993. I'm thinking any type of distributor ventilation may have been added after it left the factory?

Here in this picture you can see (a) the hose plus adapter are both disconnected from the distributor, (b) one of the oval openings is exposed, and (c) the other oval opening is capped:


Here is this picture is what I suspect to NOT be an original fitting for attaching the hose to the distributor:

[Esel Mann]

Un Fing believable, for some reason the same pic was uploaded twice

Ok, here is what the first picture should have been (Sorry):

[LouZ]

The proper dizzy connector is an oval piece of plastic. I can't find the piece as a separate item, it is only available as a kit (connector & hose) from our sponsor for ~$13.

[Esel Mann]

LouZ, thanks for your reply!

Ok, so the fitting I have is not the correct one.

With the fitting clearly not the correct one, before I make the buy for the kit from our host, does anyone know if:

- Are two needed? One for each distributor?

- If only one, which distributor is the correct distributor to attach to?

[LouZ]

It just goes to the primary. Take a look at your pix, you will see an oval "plug" in the secondary.

[Esel Mann]

LouZ,

Thanks for your reply! Time now to place an order with the host for some parts!

[Traveller]

Originally Posted by LouZ

I can't find the piece as a separate item, it is only available as a kit (connector & hose) from our sponsor for ~$13.

Distributor breather pipe.

Part number: 993 602 121 00

List price: $1.91 and even less from Sunset Porsche.

[Esel Mann]

Traveller, thanks for your reply!

I looked up your suggested part. According to the parts diagram, it would appear that the mentioned part, 993 602 121 00 is some sort of gasket (breathable or vented?) which goes between the distributor and distributor cap. It is not a hose which interconnects with the oval distributor openings (which I suspect were originally intended to be used to visually see the belt for inspection). I'm thinking that this gasket implementation differs from the original hose ventilation implementation but if doable is the preferred over the hose ventilation implementation.

Perhaps the gasket implementation is the final Porsche solution to ventilation of the distributor?

Do you (or anyone else) perhaps know:

- How does one identify or tell if the distributor in the 964 would support the gasket ventilation solution? Is this doable for all model years?

- If the gasket solution is doable, does that mean the hose ventilation patch can be removed and thus simply return the hosing to ventilating the rear signal housings?

- I presume that both distributors would have this gasket?

[LouZ]

Take a look at this string of threads from the Rennlist forum:

Put in some work! - Page 3 - Rennlist Discussion Forums

[bazar01]

On my 1993 964, only the primary has a vent fitting. Get the distributor ventilation kit from our host. $14.

Pelican Parts - Product Information: 000-043-202-52-M100

Here is a pic of mine.

[Esel Mann]

LouZ, wow! I took a look at that Rennlist posting. It made the issue very clear.
I may need to simply refer to Rennlist for 964 issues in the future. I've never dealt with the ventilation before but had my suspicions regarding a single hose implementation. Steve over there supports the idea for the dual hose (which makes sense to me) implementation.

SOB, and I just ordered (1) ventilation kit. If I had known a few days before I would have ordered 2. Now I need to order another.

Traveller per Rennlist, your part number would appear to be this fitting as I call it. Once again PET never fails to point to an incorrect part in the assembly to cause confusion....

So.... Double hose here we go...

[Esel Mann]

Bazar01, take a look at the Rennlist posting LouZ points to. Be sure to peruse all 3 pages.
They discuss the ventilation hose work around. I'm doing the double hose implementation per their suggestion.

[Esel Mann]

I inquired with PP in regards to the part number that Traveler provided in his post, 993.602.121.00. What was found is if one refers to the PET diagram from the Porsche website for the 993, the part (#7A in the diagram) is indeed the rubber hose to oval bung fitment/adapter. The diagram on the the PP page for the part incorrectly refers to it as part #7 of the diagram. Which is some sort of gasket with a different part number. Hence the source of all the confusion. According to PP customer service, a request has been submitted to correct the part called out in the diagram on PP's part page.

Second vent kit is now on order to allow me to implement the ventilation as per the Rennlist posting (upper to the air ducting, lower to the tail lighting vent). I'm still sore though that I had to pony up more for shipping. I would have happily ordered it with the first kit if only I had known. It's really too bad there was nothing here at PP to indicate 2 kits should be ordered for what would appear to be the proper way to vent the distributor.

So hopefully this thread will shed some light for anyone in the future should they choose to go the Rennlist double vent setup route.

[Traveller]

Originally Posted by Esel Mann

Second vent kit is now on order to allow me to implement the ventilation as per the Rennlist posting.

Sorry for the late reply, but it seems that you got things straightened out with respect to the part and part number.

As for using two vent kits, I take it to vent each distributor, I'd bet that it is hardly necessary. The distributors are interconnected and there are enough air leaks in them to vent any ozone using the one and only vent kit that Porsche installed.

[bazar01]

You would think the pressurized air will be enough to purge the distributor housing of ozone contaminated air from the high voltage arcing. The distributor is not totally sealed so I am good for one vent for now.

[Esel Mann]

Yay! I just received the 2nd vent kit from PP. The double port implementation is now complete. So for completeness, I'll post the before and after pictures.

Here was the single port implementation I inherited:



Here is the double port implementation. No more T adapter. Lower port goes to the tail light vent, upper port goes to the engine bay blower motor ducting:

[Traveller]

Originally Posted by Esel Mann

Here was the single port implementation I inherited:

Was that a Porsche design? Why would they T off and go to the tail light?

Originally Posted by Esel Mann

Here is the double port implementation. No more T adapter. Lower port goes to the tail light vent, upper port goes to the engine bay blower motor ducting:

I would have thought they would have used a Y to feed each distributor if venting both both of them. Here they are going into the primary, out the secondary and into the taillight. Unless they are using the low pressure behind the car to draw the air out.

Anyway, the single vent has worked well. Why change.

[Esel Mann]

Hi Traveller,

That first picture with the T adapter was simply the way it came when I bought my 964 (I'm the 4th owner I believe). I have to say though I suspect it was a Porsche implementation simply because there is no second hole drilled into the engine heater blower duct like per the TSB March 29, 1994. The TSB being an after the fact type of work around.

The T adapter permits both the distributor and the rear tail light (driver side only?) to be provided with air from the engine heater blower duct.

The Porsche recommendation in that TSB is per your setup, a single hose going into the upper oval port of the distributor. From what I can gather they felt the distributor assembly is not very well sealed hence any air being provided should circulate and exit via the non-sealed nature of the distributor. I know, I know, if Porsche stands by it it must be correct as well as ok. Hence why F with it?

Well my reasoning behind Fing with it is I'm not a fan of relying on the supposed non-sealed nature of the distributor. With what I see in my engine bay, whats to stop the leakages from being clogged up with gunk over time? Upon reviewing all 3 pages of the post on the "list which shall not be mentioned" which LouZ referenced, I felt that the double port solution to be more appropriate and more robust. So I implemented the double oval port solution which guarantees an exit for the air. Like the Porsche TSB, the top distributor is fed air from the engine heater blower duct, it flows into the distributor and out the bottom oval port and into the rear tail assembly for ventilating that.

[bazar01]

There are four holes in the bottom of the distributor which I believe are enough to vent the ozone build up once it is pressurized by the fresh air supply from the electric blower.
Here are the pictures when I replaced the belt on my dsitributor.