How To: Close the Gap on Triangle Window Seal Options

[Mikey914]

Thanks,
Yes this winds up being about more than making parts. We are currently in the final phase of implementing and a Enterprise Resource Platform, that will really help us to juggle a lot more balls, more efficiently. We've been at this almost 18 months now. One of the reasons we had slowed parts development, it has been a major undertaking for us and I will be happy when we can start using many of the features it has.

I'll take a look and see what I can do on the sub speaker pod. I may be able to figure something out as this is partially started.

[Superhawk996]

@Mikey914

Thanks for this Mark. As others have said, we couldn't restore these cars to the level we do without you. None of this is intended as a dig, just being honest about the realities of installing these aftermarket parts. It is understood that there is a lot to juggle to hit the sweet spot with these.

(IMG:style_emoticons/default/agree.gif)

I think I've been pretty clear that I appreciate what 914Rubber is doing to support the community.

In my opinion, I'd rather have a part to rework than nothing at all. But having said that, personally, I'm willing to pay more for parts that fit and function exactly like OEM than having to spend time reworking parts which then is time I could have better spent elsewhere.

With respect to the business model, If you gain efficiencies that rightfully should go right to your bottom line. You should adjust your pricing as material prices, tooling, labor costs, shipping, etc., all all going to be going up with inflation. I'd much rather that you make quality parts, cover your costs, make a profit, and stay in business rather than seeing you try to win the race to the bottom that cheap pricing forces.

The flip side of it is the customer experience. I'm not shy about reworking a piece to make it suit my needs. However, there are many others that are feeling frustrated that parts don't fit properly and they either assume they have done something wrong or don't have the tools and skills to rework them. Similarly, as 914's get more appreciation and attention in the restoration trade, shops don't want to be spending $50-$100/hr shop rate to rework parts to fit and then potentially disappointing a high dollar customer when fit & finish isn't 100% correct.

I know intimately what it takes to make these parts, and I don't envy what you do and the tightrope you have to walk trying to make it a viable business model. Just in case it wasn't clear, I appreciate and applaud you for making NLA parts available. (IMG:style_emoticons/default/smilie_pokal.gif)

@Mikey914

[vitamin914]

I have used a product called Shoe Goo. On things other than shoes.

I comes in black or clear. I think it would work in this application, maybe better than silicone.

If you try this method for closing up the gap, I would recommend staying with the silicone.

Shoe Goo or Amazing Automotive Goop both have the same basic plastic, Styrene Butadiene polymer. Shoe goo uses toluene as solvent that has to evaporate. Amazing Goop uses perchloroethylene (chlorinated brake cleaner) for the same task.

Both these solvents will dissolve petroleum jelly so it may end up sticking to everything, and the release agent won't work and the sealant may not cure with petroleum jelly dissolved in the goo(p). The solvents can also cause the rubber to swell and once evaporated the rubber may shrink or be permanently deformed.

Interesting side note... A factory trained Ducati master mechanic showed me a neat use for black automotive goop. He uses it as a removable thread locker. Cleans off with brake cleaner when you need it completely gone. It does work for that purpose... I used it to hold down the nuts on the air cleaner tins for the Weber carbs. Tried to undo the nut and the rubbery stuff prevented the nut from unscrewing. It actually tried to tighten the nut until the rubber gave. Kind of like using nail polish to set a trim potentiometer from moving once positioned. Better than relying on that tiny lock washer. I shudder at the thought of that nut going down the carb's throat during a run...

[StarBear]

Thanks,
Yes this winds up being about more than making parts. We are currently in the final phase of implementing and a Enterprise Resource Platform, that will really help us to juggle a lot more balls, more efficiently. We've been at this almost 18 months now. One of the reasons we had slowed parts development, it has been a major undertaking for us and I will be happy when we can start using many of the features it has.

I'll take a look and see what I can do on the sub speaker pod. I may be able to figure something out as this is partially started.

Ouch. Went through TWO "Enterprise" platform implementations over the years. THe last company I worked for thought about it, but realized (a bit due to my input...) the task, complexity, time, and cost for a $4-6B/year company. Don't think the company would have been up to the task anyway. Glad I'm retired now. (IMG:style_emoticons/default/piratenanner.gif)

[Mikey914]

We were "lucky" that there was a grant, and an Oregon company that wanted to do a build out for us. We started allocating time to it immediately building BOM's and build orders, as well as cleaning up our vendors lists and putting many other things in place. I have 2 consultants that are working to bring this online hopefully very soon. We have been very lucky that they wanted to build out a manufacturing and sales company as they know there would be many challenges, and in doing so they would be able to more easily handle both. We did find that the accounting platform was a bit weak, but they are rebuilding it and hopefully it will be everything we need and more.

[bkrantz]

I used Porsche factory (recent production) triangle window seals, and a 914 Rubber main targa seal. And I have the same gap problem at the top, with the channel adjusted all the way forward and inward, and I tried for hours to optimize the fit.

It might be the rubber block that caps the channel. I tried both my new 914 Rubber caps, and the original caps.

[worn]

I used Porsche factory (recent production) triangle window seals, and a 914 Rubber main targa seal. And I have the same gap problem at the top, with the channel adjusted all the way forward and inward, and I tried for hours to optimize the fit.

It might be the rubber block that caps the channel. I tried both my new 914 Rubber caps, and the original caps.

Me too. Mark is justly revered here. Still, i think the part is just too hard and perhaps not quite right. I can see that is not an easy problem for the rubber man to solve, but suggest that the old school approach would be best: new and improved. The good news is that we have a company that listens and a community willing to be crabby. If you make a better part I will buy it.

[bbrock]

I drove 100 miles from Butte to home @ 80mph with top on and windows up last night. I'm happy to report that the wind noise inside the cabin is signifiantly reduced with those gaps sealed. Kicking myself for not taking before/after sound measurements.

[Mikey914]

I keep looking at this and something doesn't look right. Given that the blocks are identical to the factory ones in shape and durometer, what would the solution be here?

There appears to be a 1/2" section of rubber not fully seated, Is it holding it out?

Could the amount of butyl behind the "chrome" be holding it down slightly? I don't think that would be the whole story.

The triangle window looks like the top is seated deeper than the cap. Almost like if the top of the triangle window was shimmed out more it would push the bottom of the cap out more to "close the gap". This appears to be where the failure is. I've seen many of the caps worn and look slightly deformed from the top of the glass pushing it out, but not here. It looks like it's barely engaged.

Why it would sit lower is beyond me. The initial complaint was it was too tight, which would hold it up.

Thoughts??

[bbrock]

I think going a little softer on the vertical seal on the windshield frame would accomplish two things. It would allow the seal to better follow the bend of the channel. As you note, the block of the seal is pretty stiff trying to make that bend so straightens out around the tightest part of the bend and pulls as far as it can away from the channel. It is in the channel, but not tightly following the contour. I actually think that is the bulk of the issue. Second, with a softer bulb, the triangle channel wouldn't be pushed back from the forward adjustment.

[mb911]

I think going a little softer on the vertical seal on the windshield frame would accomplish two things. It would allow the seal to better follow the bend of the channel. As you note, the block of the seal is pretty stiff trying to make that bend so straightens out around the tightest part of the bend and pulls as far as it can away from the channel. It is in the channel, but not tightly following the contour. I actually think that is the bulk of the issue. Second, with a softer bulb, the triangle channel wouldn't be pushed back from the forward adjustment.

(IMG:style_emoticons/default/agree.gif)

I always think about the American muscle car seal market. All of those seals are softer and the reason is the cars fit and finish was a bit sloppy by nature. Well hate to say it but the 914s were as well.

[Superhawk996]

Given that the blocks are identical to the factory ones in shape and durometer, what would the solution be here?

@Mikey914

Of the various replacement seals I've installed, I've found the new seals attachment block (base of the seal) to be significantly larger than what came off the car. As a result, they fit much tighter into the aluminum channels and have less flexibility than what came off the car. I apologize I don't have a picture handy of my car and/or my main targa seal.

Here is a comparison of the base of the seal for the upper window seal that goes into the targa.


In several cases, the OEM seal can be pulled though the aluminum channel with only moderate force. I believe the fact that seals could be moved with only moderate force is the reason the factory "staked" the aluminum channels once they had the seal in place. The OEM seals can sort of the "inch wormed" into and out of the aluminum channel. I found this to be true on my 1st car way back when I painted that one in about 1987. In the case of all the replacement seals on my 2nd car, I've had to install the seal by rolling it into the aluminum channel with a trim stick. Once the seal is in the aluminum channel, it becomes very difficult to move it and it really can't be "inch wormed" very much at all. Likewise, I haven't seen the need to stake the replacement seals to keep them from moving since they are so tight in the channel.

Having a bigger base stuffed into the aluminum channel will affect the overall stiffness of the bulb seal that that window interacts with.

As you stated previously, rubber shrinks and hardens as it ages and leads to a fair degree of guesswork.

I fully understand that engineering rubber parts is 1/2 engineering and 1/2 black art. I cant understate for the community how difficult a job it is for 914Rubber to reverse engineer 50 year old parts. Even more so when you don't have a budget for mass production tooling and a consistent production process that is running day in and day out. Worse yet when you potentially have to make a batch of seals for a minimum buy and then they sit an a self (months, years, multiple years?) and harden in the warehouse. I honestly have the utmost appreciation for what 914Rubber is doing for the community by making these seals -- It isn't an easy job and most don't appreciate just how difficult it is. .

Regardless of that fact. I've done a lot of development in automotive around bushings and seals. Each time a supplier changes, parts usually have to be changed or tweaked to get equivalent performance. With rubber parts, It's not as simple as handing a drawing to two suppliers and getting EXACTLY the same part back from each supplier.

I can't tell you the number of times I've seen a major OEM purchasing department burned by attempting this. They will take a part that was engineered, developed, and produced by Supplier A - send that print to supplier B who promises a cheaper piece price. Parts come back from supplier B but yet, they don't perform as they should. Now purchasing is mad a engineering because they say the drawings didn't contain all the critical characteristics. Engineering is mad at purchasing for resourcing a part that was working fine and manpower is needed to fix it with Supplier B. Supplier A is mad since they are having business taken away to a cheaper competitor. Supplier B sits there looking stupid saying I produced what the print called for - not my problem. Supplier B often knows that they will recoup on the "cheaper" part by the time they get paid for "engineering changes" to the print to now make the "cheaper" part work within their production process. Now I remember why I'm retired!

Simply copying the OEM design and durometer doesn't guarantee an equivalent result when rubber parts are involved

Rubber formulations are not the same from supplier to supplier. One may use a bit more sulfur and a little bit different vulcanization time than the other. Drifts in durometer that are seeming irrelevant sometimes need to the offset by changes to the section of the part. Sometimes the part is the same durometer but ends up with different elasticity characteristics and that affects function. A seemingly small section thickness difference (within print tolerance) between the parts can leads to the need for the some tweaking and/or re-engineering to get the part to perform the desired function when changing from supplier A to supplier B.

This is a long way to say, that simply copying the OEM durometer and dimensions won't necessarily yield the same part, and the same functionality as the OEM part. As the others have noted, I've noticed that what came off the car is softer and more deformable than the replacement part.

[Superhawk996]

There appears to be a 1/2" section of rubber not fully seated, Is it holding it out?

Thoughts??

@Mikey914

I had the same thing happen on my car in the same location. They seal was seated.

What was happening is that the larger base block was so tight in the aluminum channel it was forcing the seal to buckle as it bent around that radius.

In my case, I was able to minimize it but aggressively "stretching" the seal though the channel so as to thin it ever so slightly helping it better conform in that tight radius the same way the OEM seal did. Even when I did get that area of the seal to better conform to the radius, there is still an inability of that window triangle cap and the triangle glass to force the seal to conform to it because the seal is too stiff in that critical area.

Again, may be a combination of part dimensions, durometer, or elasticity differences that lead to that inability of the seal to properly follow the radius of that windshield to header transition.

[mepstein]

No surprise when this came up for sale, i jumped on it.
http://www.914world.com/bbs2/index.php?sho...p;hl=targa+seal

[Superhawk996]

No surprise when this came up for sale, i jumped on it.

Wow! I'm surpised they were still making that seal up though 2007? You gotta wonder if that was just the pick-n-pull date or if they really were running batches of seals in 2007 (IMG:style_emoticons/default/confused24.gif)

[Mikey914]

Ok,
Lets have a conversation on the process.

#1- we want to be as close to OEM as possible unless there is a specific reason. An example was the use of stainless or aluminum for internal clips. We were one of the 1st to take on this added expense that has been adopted by others too.

As far as hardness and size there is a bit more to consider. Rubber will shrink over time, you can clearly see that in the new / old comparison. We look to ward the fits to parts and try to extrapolate what the original size was using a fomula that estimates it pretty closely. This takes multiple samples, and we can actually see when we have an original vs an OEM that was replaced. This is ideal as it helps confirm the side is correct.

As for hardness, there are some standard harnesses that were used, and we can confirm the original while we are working on size. It's easy to say make it softer, but it's actually much more complicated and can actually create more problems. The hardness of the corner blocks are greater than that of the extrusions. The greater the difference, the more likely of a bonding issue. If the material is softer it may not retain as well in the tracks. These are just a few things that must be addressed. When the factory did something there is usually a reason, and small changes can have unintended consequences. I have been educated on this a few times, it's one of the reasons it has taken us more time than expected in bringing some products to market.

There is always the installation technique that can be a variable. I prefer to seat the corner blocks (attach and screw into the frame), then engage the inner edge and push the seal up while seating the outer. It requires working your way down the edge on the outside while keeping the inner edge seated.

I do think it's time for us to put together a formal install video so we can see a technique that works well for us.

I did see that the top of the triangle window glass seems to sit a little lower. It almost looks like if it was 1/8" higher in the retainer the edge would come in and fill the gap.

I did start a thread help us help you to try to deconstruct this specifically, as I would like to address specifically this issue.

You can look for more from us in the future on this.

Thanks,
mark

[GeorgeKopf]

Wow. I am so glad that I found this thread. I spent days installing, removing, and then reinstalling the triangle window rubber and the targa seal rubber. Many times, I adjusted everything that is humanly possible.

On mine, the bottom front of the triangle glass doesn't tuck under the outer lip of the A pillar; it sort of smooshes the lip in. It seems to me that the triangle seal pushes the glass too far forward. I also have the gap at the top of the window suggesting that the shape of the seal is incorrect.

I thought I was going insane (perhaps I did). Thanks to this forum I now know that I'm not alone.

George

[Superhawk996]

George

Look inside the targa seal at the bottom near where the triangle window seal tucks in underneath it.

I had a hard rubber seal stuffer (inside the hollow portion of the targa seal) that was keeping the triangle window from seating into the targa seal properly.

On the left is a hard rubber stuffer from 914 rubber targa seal. I removed this completely and things began to fit a lot better.

On right is softer, compressible, closed cell neoprene type foam stuffer from OEM seal. This is basically used to close out the end of the hollow seal section. Obviously very different vs what 914Rubber was doing.

You might want to read this thread too
www.914world.com/bbs2/index.php?showtopic=379073&hl=Seal

@georgekopf

[burton73]

A little history. Back in 2007 or so you could not get the factory front window seal. People were getting crazy prices for old beat-up ones. I my 73-year-old memory is correct, George at AA ordered like 250 units from the factory and they were available from them. There was a great picture of George on the floor with a stash (inventory of new seals all around him.)

I bought one for my 6 and it was put on many years later by PMB Performance. It did not fit in the area where Brent fixed his. I believe that the problem is Vent window hard rubber piece (CAP) has shrunken down in the center if you look at my picture you can see some of the interior color coming from the backside cars sold so I can't go get another picture.

I think a new cap piece Could be made without the shrinkage to fit these vent window caps.
It would seen like this would be a good item as I think it is on lots of cars could use them. Mine was stored inside a So CA Garage from 1987 on and not ageing in the heat or sun

All the best,

Bob B