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Pepperbilly
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Joined: April 08, 2017
Posts: 977
Location: Seattle, Wa
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 Posted: Fri Nov 24, 2023 1:53 pm Post subject: Type 4 Valve Cover Ear |
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Have always wondered what that ear tab with a small hole on these valve covers was about? I am talking about the 1 exterior tab on the corner that sports a hole. Not to be confused with the 2 interior tabs that are bent to hold the gasket to its seat. All these years and I have no idea what this is lol.
Bill |
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raygreenwood
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Joined: November 24, 2008
Posts: 21521
Location: Oklahoma City
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| Posted: Fri Nov 24, 2023 3:19 pm Post subject: Re: Type 4 Valve Cover Ear |
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| Pepperbilly wrote: |
Have always wondered what that ear tab with a small hole on these valve covers was about? I am talking about the 1 exterior tab on the corner that sports a hole. Not to be confused with the 2 interior tabs that are bent to hold the gasket to its seat. All these years and I have no idea what this is lol.
Bill |
It's funny!.....there is a discussion in the performance forum about type 4 valve cover gaskets leaking, how people seal them etc. (It's nextgen's thread). This was asked there as well. I noted that I suspect that it was the locating pin hole for the flat sheet of steel that the cover started out as when it was put in the stamping die that shaped it.
It may also have been used to hang the valve covers from when they were being painted. That's all I have....speculation. Ray |
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Pepperbilly
Samba Member
Joined: April 08, 2017
Posts: 977
Location: Seattle, Wa
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| Posted: Fri Nov 24, 2023 3:26 pm Post subject: Re: Type 4 Valve Cover Ear |
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Hey Ray, that's good speculation. I am seeing that these tabs can cause ill fitting covers and oil leaks of course. I guess on some heads the tabs can interfere and cause an incomplete seal. I have never had that problem.
Bill |
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raygreenwood
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Joined: November 24, 2008
Posts: 21521
Location: Oklahoma City
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| Posted: Fri Nov 24, 2023 4:47 pm Post subject: Re: Type 4 Valve Cover Ear |
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| Pepperbilly wrote: |
Hey Ray, that's good speculation. I am seeing that these tabs can cause ill fitting covers and oil leaks of course. I guess on some heads the tabs can interfere and cause an incomplete seal. I have never had that problem.
Bill |
The tab is not an issue unless it bent inward or outward. I have seen this happen when people adhere the valve cover to the head and then use a screwdriver through the hole in the ear to pry it off.
In fact...when I was in high school....I wrecked one of my first valve covers this way...learned my lesson both about gluing the VC to the head (do not do that) and prying on it. You should not have to. Ray |
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Pepperbilly
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Joined: April 08, 2017
Posts: 977
Location: Seattle, Wa
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| Posted: Fri Nov 24, 2023 5:27 pm Post subject: Re: Type 4 Valve Cover Ear |
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Over the many years I have removed and installed valve covers on these cars, I have always done it the same way. I make sure all the sealing surfaces are clean as a whistle. I don't apply any sealant, rtv, or anything else. I use caution when fitting the covers. I have really never had a problem with covers leaking. I know this is a controversial subject and there are many factors that can cause leaks. Gonna stick with what works for me.
Bill |
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raygreenwood
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Joined: November 24, 2008
Posts: 21521
Location: Oklahoma City
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| Posted: Sat Nov 25, 2023 9:25 am Post subject: Re: Type 4 Valve Cover Ear |
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| Pepperbilly wrote: |
Over the many years I have removed and installed valve covers on these cars, I have always done it the same way. I make sure all the sealing surfaces are clean as a whistle. I don't apply any sealant, rtv, or anything else. I use caution when fitting the covers. I have really never had a problem with covers leaking. I know this is a controversial subject and there are many factors that can cause leaks. Gonna stick with what works for me.
Bill |
Oh yes.....lots of controversy. A lot of methods work just fine. I started adhering the gaskets to the valve covers....not the heads.....because of:
1. The fact that I drove my car so much....typically 1000+ milescper week....that it would have required a new set of valve cover gaskets at every 3-4k oil change and valve check.....every month. VC gaskets do not seal well wen repeatedly taken on and off unless they go back on in the exact same position
2. Lots of variations in VC gasket quality over a period of time in the late 90s. Sealing them to the covers fixed the issue mainly be stopping them from moving when you a0ply the bale.
3. Most importantly....I found that with D-jet it is not uncommon to see valve covers that do not leak oil OUTWARD.....but leak vacuum INWARD because our system will pull 20" of vacuum at idle and on overrun with our PCV systems.
It took me a while to track that last one down.
Ray |
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Lars S
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Joined: October 04, 2007
Posts: 786
Location: Sweden
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| Posted: Sat Nov 25, 2023 11:58 pm Post subject: Re: Type 4 Valve Cover Ear |
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I find the theory about the hole beeing used for hanging it when painting the most relevant - try hanging a cover without using the hole and see!
Isnt it also strange that these covers fit best if you mount them with the VW logo (stamped in the outside center) upside down?
| raygreenwood wrote: |
....
3. Most importantly....I found that with D-jet it is not uncommon to see valve covers that do not leak oil OUTWARD.....but leak vacuum INWARD because our system will pull 20" of vacuum at idle and on overrun with our PCV systems.
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Ray, never thougt of that...yes there is sometimes a 20" of vacuum in the plenum but how can there be created a GREAT vacuum in the case/heads (by the tiny hole in the PCV-valve) since the heads are vented by rather large tubes?
//Lars S
_________________
Porsche 914 -72, Bahia Red daily driver 
VW411 2-d -70, White, sold 
VW412 4-d, -73, Gold Metallic, daily driver
Suzuki T500, -69, Candy Gold, sold
Suzuki K50, -77, Black, daily driver
BMW R69S -69, White, sold
Husqvarna 118cc, -47, Black, Sold |
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Pepperbilly
Samba Member
Joined: April 08, 2017
Posts: 977
Location: Seattle, Wa
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| Posted: Sun Nov 26, 2023 12:16 am Post subject: Re: Type 4 Valve Cover Ear |
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Lars,
On Goldie I have one side with the VW logo right side up and the other upside down and no leaks. I really don’t think it makes a difference unless something is bent. It’s however you can obtain the best fit.
Bill |
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Lars S
Samba Member
Joined: October 04, 2007
Posts: 786
Location: Sweden
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| Posted: Sun Nov 26, 2023 12:47 am Post subject: Re: Type 4 Valve Cover Ear |
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| Pepperbilly wrote: |
Lars,
On Goldie I have one side with the VW logo right side up and the other upside down and no leaks. I really don’t think it makes a difference unless something is bent. It’s however you can obtain the best fit.
Bill |
Yes Bill, the upside down logo thing just popped up in my head... but I dont remember why and it might just be a myth.
/Lars S
_________________
Porsche 914 -72, Bahia Red daily driver
VW411 2-d -70, White, sold
VW412 4-d, -73, Gold Metallic, daily driver
Suzuki T500, -69, Candy Gold, sold
Suzuki K50, -77, Black, daily driver
BMW R69S -69, White, sold
Husqvarna 118cc, -47, Black, Sold |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21521
Location: Oklahoma City
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| Posted: Sun Nov 26, 2023 10:55 am Post subject: Re: Type 4 Valve Cover Ear |
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| Lars S wrote: |
I find the theory about the hole beeing used for hanging it when painting the most relevant - try hanging a cover without using the hole and see!
Isnt it also strange that these covers fit best if you mount them with the VW logo (stamped in the outside center) upside down?
| raygreenwood wrote: |
....
3. Most importantly....I found that with D-jet it is not uncommon to see valve covers that do not leak oil OUTWARD.....but leak vacuum INWARD because our system will pull 20" of vacuum at idle and on overrun with our PCV systems.
... |
Ray, never thougt of that...yes there is sometimes a 20" of vacuum in the plenum but how can there be created a GREAT vacuum in the case/heads (by the tiny hole in the PCV-valve) since the heads are vented by rather large tubes?
//Lars S |
The heads are vented INWARD....not outward....by full manifold vacuum from the plenum to the oil chimney through that 12mm hose.
The flow of the type 4 D-jet PCV system is like this:
It starts at the aircleaner>>>>filtered air goes through that hose to the splitter/flame trap bolted to the case just forward of the cooling shroud>>>>flows through a hose to each head/rocker box>>>>flows through the rocker boxes/through the pushrod tubes and into the case>>>> through the Z-baffle cast into the top of the case>>>>through the oil chimney which is another sideways Z-baffle and is an oil seperator>>>>through the PCV valve>>>>through the 12mm hose>>>>> into the intake manifold.
The whole time that air is flowing starting at the air cleaner....it is being PULLED by high vacuum whenever the PCV is open. The PCV is opened mostly by vacuum and only somewhat by pressure. It's a combination of the two.
This is also variable in its timing....which is a big issue with D-jet and PCV.
At various times over the many years I drove my 411s and 412s....every once in a while I had poor connections at the hoses that went to the heads (until I started clamping them).
Because I tracked everything on my cars....it took me a few times that it happened that one of these hoses was loose....that I noticed it when I started looking around for vacuum leaks.....because of a BIG drop in gas mileage. Running rich.
What happens is that anytime one of those hoses or a valve cover gasket has an air leak....its not a problem....UNTIL the PCV valve pops open. When that happens it's venting what would otherwise be a momentary shot of high vacuum to the case...straight to the air.
Yes....it's open to the air at the very starting end at the air cleaner....but that's a long chain of air with several restrictions along the way.
When you open up a BIG leak right at the rocker box with either the valve cover gasket or the hose off....that short span of time when the PCV pops open....makes a HUGE difference in how much vacuum is bled off in the plenum/manifold.
And....that 12mm vacuum line to the plenum....dumps in just a few millimeters from the MPS vacuum hose.
I have said for many years that the design of PCV valve itself and its location of where it is plumbed ....seemed to be a very poor afterthought. Even if there are no vacuum leaks....every time the PCV pops open for a second of two....it affects the vacuum (fuel mixture) at the MPS.
This is unplanned enrichment. The ECU has no say in it....and it's random in its timing.
I found years ago that you can get around all of this issue (all but a large vacuum leak in the otherwise sealed loop)....by getting rid of the spring/flap mechanism inside of the PCV valve (which is broken on most high mileage cars anyway).....and just install a SMALL fixed orifice.
You keep it small so it bleeds off very little vacuum from the manifold. Being at constant vacuum....this orifice keeps the case evacuated and clean....and its no longer a variable pulse to the MPS. It's a constant vacuum bleed.
It requires a small adjustment to the MPS to get fuel mixture down to normal. It makes for better tuning and driving especially in traffic. Ray |
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Lars S
Samba Member
Joined: October 04, 2007
Posts: 786
Location: Sweden
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| Posted: Sun Nov 26, 2023 11:08 pm Post subject: Re: Type 4 Valve Cover Ear |
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| Pepperbilly wrote: |
Lars,
On Goldie I have one side with the VW logo right side up and the other upside down and no leaks. I really don’t think it makes a difference unless something is bent. It’s however you can obtain the best fit.
Bill |
Looking at the valve cover I would guess that the recommendation (wherever it comes from) to have it mounted with the VW-logo upside down is due that the cover is not fully symmetrical.
Besides the "ear" there is a 20mm section at the very edge of one of the corners for anti heat cover warping(?). Having the logo upside down means that this section will be at a higher position (less risk for standstill leaks?) then when having the logo the natural way.
However if this would have any significant impact i guess that VW would have written about it and put the logo so it is at its normal, readable position, when the cover is mounted correctely.
/Lars S
_________________
Porsche 914 -72, Bahia Red daily driver
VW411 2-d -70, White, sold
VW412 4-d, -73, Gold Metallic, daily driver
Suzuki T500, -69, Candy Gold, sold
Suzuki K50, -77, Black, daily driver
BMW R69S -69, White, sold
Husqvarna 118cc, -47, Black, Sold |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21521
Location: Oklahoma City
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| Posted: Mon Nov 27, 2023 8:55 am Post subject: Re: Type 4 Valve Cover Ear |
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| Lars S wrote: |
| Pepperbilly wrote: |
Lars,
On Goldie I have one side with the VW logo right side up and the other upside down and no leaks. I really don’t think it makes a difference unless something is bent. It’s however you can obtain the best fit.
Bill |
Looking at the valve cover I would guess that the recommendation (wherever it comes from) to have it mounted with the VW-logo upside down is due that the cover is not fully symmetrical.
Besides the "ear" there is a 20mm section at the very edge of one of the corners for anti heat cover warping(?). Having the logo upside down means that this section will be at a higher position (less risk for standstill leaks?) then when having the logo the natural way.
However if this would have any significant impact i guess that VW would have written about it and put the logo so it is at its normal, readable position, when the cover is mounted correctely.
/Lars S
I am glad others notice these oddities and not just me! 
Per your comment from a few posts back with regard to the logo orientation. I saw your comment and was working out a reply and am glad that Pepperbilly commented as well.
My 2 cents and as I have commented in other valve cover threads even just last week:
I have never PERSONALLY found that the valve cover logo orientation made a difference. BUT.....by the time I had owned my first 411 and transitioned into my 1st 412....which is high-school into college, I was not into the very fine detail like that and there was no easy place to really get that information in 1979 to 85 if it were not in a book somewhere.
By not far after that I had changed to adhering my gaskets to the valve covers with RTV so I would probably never see a difference in logo orientation.....if there is a difference.
And.....I do believe that there must be something to it because there are enough smart people and skilled people that I know who SAY they have found a difference.
I would also say that virtually anything different than factory someone might do like.....adhering gaskets to valve covers.....different gasket types and materials.....any of that could change the equation.
I will also state this. A year or so before I started using RTV between gasket and valve cover......I started being really meticulous about valve cover install and the steps I used. It really helped and I have never strayed from it.
1. Insert the gasket in clean valve cover. Before I started using RTV, I very slightly ent the upper and lower tabs inside of the valve cover to hold the gasket to the cover as tightly as possible l. This REALLY helped.
A year or so later when the local stock of gaskets available seemed to be either old or really poor quality...distorted, rough, would not easily lay flat....is when I moved to RTV and never looked back. Anyway....step 2.
2.oil gasket face with clean motor oil.
3. Make sure bale is on the bottom and resting on the heat exchangers.
4. Place lower edge of valve cover against lower rail of head making sure that the lower edge of the valve cover is hard against the outside of the head.
This is important because if the lower edge of the VC is not hard against the head....hooked on the edge....as you lift the bale and it makes contact with the valve cover....it pushes it sideways....upward....causing the gasket to squirm.
5. Put firm pressure on VC to hold it hooked in place I the edge of the head while you lift the bale with a 6" screwdriver.
I always slide the bale up 50% so it holds the VC under its own power while I feel around the edges to make sure it's still exactly where I put it....then lift bale until it snaps in place.
As far as why the VC's always seem to have the logo in the same orientation with regard to what side the tab is on....is because most likely the logo is stamped in at the same time with the same die that forms the VC....which is why I partly believe that the tab is a die orientation aid.
Also, has anyone else noticed the 2nd VW stamp on their valve covers? It's very small and on the inside. I believe it is a QC stamp. I will post a picture shortly. Ray
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Pepperbilly
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Joined: April 08, 2017
Posts: 977
Location: Seattle, Wa
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| Posted: Mon Nov 27, 2023 11:52 am Post subject: Re: Type 4 Valve Cover Ear |
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The best thing VW could have done is manufacture these covers with a “U” channel. The gasket would then fit within this channel with no where to go, eliminating all these problems and worries. Probably a cost consideration I am sure. Wondering if there are aftermarket covers made with a type of channel like what I have mentioned.
Bill |
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