Rear bumper rubber spacers - Page 2 - Alfa Romeo Bulletin Board & Forums
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post #16 of 167 (permalink) Old 08-25-2018, 08:33 PM Thread Starter
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Rear bumper rubber spacers

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Originally Posted by IRONBLOCK View Post
Hi Edgar,

Thanks for your work on this project. The inside 'web' shape part of the gasket looks good. I suspect the web portion is only 1 or 2 mm's thick, at most. Unfortunately I've already put my gaskets back on the car and did not take any measurements.

However, the shape of the exposed gasket part (the part seen when the bumper is installed on the car) that covers the gap between the bumper segments appears to have the wrong profile in the attached drawing. I measured the best gaskets on my car and the exposed part measures ~8 to 10 mm wide, although some appeared to have shrunk and curled up some. The profile of the exposed part of the gasket is more the shape of a flattened out "D" on my parts.

Here is a link to some pictures of the bumper gaskets on my car. I hope this helps. If you have any questions, please let me know.

https://www.alfabb.com/bb/forums/alf...r-gaskets.html

Here is a photo of the exposed gasket that measures 10 mm wide.

Attachment 1522264

Mark
Mark, thank you for your comments and ideas. I still have the original rubbers but they are not reliable to take any measurement due to the poor conditions. We agree to change the circular exposed segment diameter from 5mm to 10mm and also its shape, adopting the "D" for the straight bumper joint. We will run a 3D printing test for both models and send some pictures. My car bumper is out so is easy to do it.

Thank you again!

Ed Bortolini
72 Montreal - Arancio Metallizzato - Finally Ready
68 GTV Veloce - bianco spino - under restoration
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post #17 of 167 (permalink) Old 08-26-2018, 09:20 AM
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My pleasure Edgar. I wish that I had taken measurements while the gaskets and bumpers were off my car. I am glad you were positively receptive to the suggestions. I had hoped that others would add their comments or suggestions as well.

The material originally used by the factory for these gaskets has an alarming shrinkage rate. This was probably exacerbated by my cars long term storage in a hot storage unit in Arizona. I don't think there would be similar issues with the use of EPDM or I would have suggested increasing the diameter of the bolt hole, since it tended to trap the gasket in position, pulling the rest of the shrinking gasket inside the bumper seams.

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post #18 of 167 (permalink) Old 08-26-2018, 02:25 PM Thread Starter
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Quote:
Originally Posted by Danny Wilde View Post
If it can help, I could make good pics of my original (but really used !!!) ones.

Or even ship one ?
Hello Danny, can you get close pictures from the straight and the upper corner exposed rubber sections? Can you measure to confirm aproximate diameter of 10mm? Thanks for offering to send the part but I think we don´t need it in this moment.

Ed Bortolini
72 Montreal - Arancio Metallizzato - Finally Ready
68 GTV Veloce - bianco spino - under restoration
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post #19 of 167 (permalink) Old 08-26-2018, 02:33 PM Thread Starter
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Rear bumper rubber spacer

Quote:
Originally Posted by IRONBLOCK View Post
My pleasure Edgar. I wish that I had taken measurements while the gaskets and bumpers were off my car. I am glad you were positively receptive to the suggestions. I had hoped that others would add their comments or suggestions as well.

The material originally used by the factory for these gaskets has an alarming shrinkage rate. This was probably exacerbated by my cars long term storage in a hot storage unit in Arizona. I don't think there would be similar issues with the use of EPDM or I would have suggested increasing the diameter of the bolt hole, since it tended to trap the gasket in position, pulling the rest of the shrinking gasket inside the bumper seams.

Mark

Mark, thank you again for the comments and suggestions. Yes, I agree about the original material. During the restauration I tried to use a material called "plastic debrum" very popular in the 60´s and 70´s cars to cover the space between two body metal parts. But it did not work.

Ed Bortolini
72 Montreal - Arancio Metallizzato - Finally Ready
68 GTV Veloce - bianco spino - under restoration
97 V6 - 3.0 Spider - rosso 130
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post #20 of 167 (permalink) Old 08-26-2018, 06:22 PM
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I would like to report that Alfa has corrected issues with their rubber but this is not the case. Currently the 1992, 164-S that I purchased when it was new, is being refurbished. The rubber shift bellows for the gear selector on the transmission has turned to hard broken chunks of rubber, several of the plastic electric connectors are deteriorating and falling apart. I'd like to think that things are better now for the 4C, Giulia and Stelvio but I wonder if anything has really changed. Italians must take a lot of pride in being metallurgists; to be a polymer engineer must not be considered as an important career.

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post #21 of 167 (permalink) Old 08-29-2018, 12:17 AM
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Edgar, Mark,

In the spare parts manual, theres are 2 different references for the 4 spacers.

It seems like they are made of a different material (2 + 2)

Best,

70' Ghibli SSS (one-off - featured in Octane UK #183 + Octane Deutschland #38)
63' 2600 Touring H-Top S.1
64' 2600 Touring H-Top S.2
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post #22 of 167 (permalink) Old 08-29-2018, 04:28 AM Thread Starter
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Rear bumper rubber spacers

Quote:
Originally Posted by Danny Wilde View Post
Edgar, Mark,

In the spare parts manual, theres are 2 different references for the 4 spacers.

It seems like they are made of a different material (2 + 2)

Best,
Danny, in the TAV.129 part list page I am seeing only the left side indication as follows: upper corner rubber 105.64.59.490.00/02 and botton straight bumper spacer 105.64.59.490.00/01. There is no indication of these parts at all in the right side. If you are seeing something different, like 4 part numbers, please let me know.

The "set" we are developing comprises two rubbers for the left and two for the right side. So, with one set you are ok for the entire rear bumper.

I am planning to upload the first 3D parts this evening so we can check together how it fits.

Ed Bortolini
72 Montreal - Arancio Metallizzato - Finally Ready
68 GTV Veloce - bianco spino - under restoration
97 V6 - 3.0 Spider - rosso 130
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post #23 of 167 (permalink) Old 08-29-2018, 04:34 AM
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Edgar,

No difference between right and left side, but between top and bottom.

The bottom 00/01 is made of "Vipla" (????)

The top one, 00/02 of plastics.

I Googled and found that Vipla is a material made of polyvinyl chloride.

No idea what it is or any difference.

70' Ghibli SSS (one-off - featured in Octane UK #183 + Octane Deutschland #38)
63' 2600 Touring H-Top S.1
64' 2600 Touring H-Top S.2
74' Montreal
66' Moretti 1100R
76' Fiat 130 Coupé
68' Datsun Roadster 2000 Racing...

16' 991 GT3 RS soon...
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post #24 of 167 (permalink) Old 08-29-2018, 07:40 AM
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Pls note that for me the material of the repro has strictly no importance.

70' Ghibli SSS (one-off - featured in Octane UK #183 + Octane Deutschland #38)
63' 2600 Touring H-Top S.1
64' 2600 Touring H-Top S.2
74' Montreal
66' Moretti 1100R
76' Fiat 130 Coupé
68' Datsun Roadster 2000 Racing...

16' 991 GT3 RS soon...
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post #25 of 167 (permalink) Old 08-29-2018, 10:02 AM
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Hi Edgar,
Why don't you choose the best material that you find works and make these parts. Too much input from all of us is confusing! As long as it is made of SKP (Some Kind of Plastic), I am sure it will be fine. Almost definitely superior to the original stuff!
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post #26 of 167 (permalink) Old 08-29-2018, 10:12 AM Thread Starter
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Quote:
Originally Posted by Danny Wilde View Post
Edgar,

No difference between right and left side, but between top and bottom.

The bottom 00/01 is made of "Vipla" (????)

The top one, 00/02 of plastics.

I Googled and found that Vipla is a material made of polyvinyl chloride.

No idea what it is or any difference.
What a find Danny! Yes, VIPLA is a well known material. BTW plastics in the 70´s were just starting after second WW developments of Catalin, Bakelite and Plaskon.

Here is the first 3D run of the two parts made out of a rigid plastic printing thermoplastic filament called PLA (Polyactic Acid) which is made out of sugar cane in Brazil and for this reason is biodegrable.

I expect to make corrections including the proposed 10mm exposed region and generate a second set of parts but printing in a different material which is flexible, called FLEX.

For comparison there is a 8mm diameter pencil.

Mark, I will install these PLA parts in the real bumper tonight and send pictures for your evaluation.
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Ed Bortolini
72 Montreal - Arancio Metallizzato - Finally Ready
68 GTV Veloce - bianco spino - under restoration
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post #27 of 167 (permalink) Old 08-29-2018, 10:26 AM
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Great work Edgar!
Now I am going to ask you - can you make the 2 Small Parts for the Ends of the Front Bumper? They go between the Outside Top of the Bumpers and the Small Curved Horns. I don't know anyone who makes these. Thanks!
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post #28 of 167 (permalink) Old 08-29-2018, 12:34 PM
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Hi Edgar,

Those parts are exciting to see. Is there a flattened D in cross section; I can't tell from the picture.

You are right there are only two different gaskets for the rear bumper:
one for the upper rear corners
one at each end of the lower center part of the bumper.

All four gaskets appear to be made of the same material. I found another photograph I took of the upper rear bumper gasket which sort of conforms to the shape of the bumper. There is a tight 'inside corner' that honestly leaves very little room for the gasket, so it tends to get distorted.

Name:  Montreal bumper corner gasket 8 or 10 mm.jpg
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post #29 of 167 (permalink) Old 08-29-2018, 02:03 PM
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Edgar, A pocco a pocco...!!!

70' Ghibli SSS (one-off - featured in Octane UK #183 + Octane Deutschland #38)
63' 2600 Touring H-Top S.1
64' 2600 Touring H-Top S.2
74' Montreal
66' Moretti 1100R
76' Fiat 130 Coupé
68' Datsun Roadster 2000 Racing...

16' 991 GT3 RS soon...
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post #30 of 167 (permalink) Old 08-29-2018, 07:56 PM Thread Starter
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Quote:
Originally Posted by IRONBLOCK View Post
There is a tight 'inside corner' that honestly leaves very little room for the gasket, so it tends to get distorted.

Attachment 1523072

Mark
Hi Mark, I can´t read the number in your picture. Is it 10mm?

Ed Bortolini
72 Montreal - Arancio Metallizzato - Finally Ready
68 GTV Veloce - bianco spino - under restoration
97 V6 - 3.0 Spider - rosso 130
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