Insulation and Plug Qs

[Hector]

Can this AC insulation be easily found at, say, BMA? Also, I was cleaning in the area of the subframe, and chipped the top of this plug with little effort. It crumbled like a club cracker. What is this plug for, and can I also buy this?

http://www.geocities.com/frothlikn/classic_tan17.html

[winfred]

the plug is nothing, it's just filling a hole

[George M]

Hector,
If you can't find the insulation at BMA, its quite generic and common to all AC systems...including home central air systems...and should be readily available at any HVAC or plumbing supply store or likely a NAPA or auto parts store. Common for this insulation to erode over time due to high under hood temps and repeated thermal cycling over many years.

As to the plugs...they are to prevent ingression of any kind of contamination...mostly to prevent water infiltration. You might also wonder about the holes themselves...why they exist...I am sure many on the board have asked themselves...as any holes in frame rails are counter productive to structural integrity. If you pull the plugs and look inside, they are also walled...for four reasons...to lessen structural compromise of adding the holes thereby maintaining torsional and bending strength...second, prevent further contamination...the other two reasons being function related. The holes exist as 3-dimensional locating datums for construction of the frame from the front rad support rearward during the car's fabrication. Dimensional accuracy is not only key to overall fit and finish of the car but contributes to driveablity and frame rail alignment to allow the suspension to function at its full potential. BMW's attention to detail and adherance to the highest tolerances over and above material selection is one of the things that makes a BMW a cut above ordinary cars. Large pins are part of a master jig/fixture in the assembly plant that control the position of one side rail relative to the other in X, Y and Z direction to maintain precise dimensional correctness...based upon a Geometric Dimension & Tolerancing (GD&T) scheme that prioritizes which dimensions are most critical to function and fit and finish. Its much more than being accountable to high tolerances...its about the hierarchy and interaction of each nominal dimension and tolerance that spells the difference between success and a mediocre design. There are many ill conceived designs out there that won't stand up to the test of production variation. The frame rails are the building blocks for the entire front of the car and set the dimensional foundation...including mounting of both engine and thrust arm cross-members with much higher control than you will see on lesser cars.
HTH.

[632 Regal]

again George all I can say is WOW...

[Hector]

George thanks for the explanation of the hole. Seems like any little thing that doesn't seem to have a purpose had a puprose during the making of the car.

[1992 BMW 535i]

Damn George you make me feel like I'm back in school! Mechanical engineer I think? You guys do even more math than us poor electical engineers...

[Bill R.]

in an x pattern you can tell if everything is true and square.

http://www.bimmernut.com/%7Ebillr/images/frame1.jpg
Hector,
If you can't find the insulation at BMA, its quite generic and common to all AC systems...including home central air systems...and should be readily available at any HVAC or plumbing supply store or likely a NAPA or auto parts store. Common for this insulation to erode over time due to high under hood temps and repeated thermal cycling over many years.

As to the plugs...they are to prevent ingression of any kind of contamination...mostly to prevent water infiltration. You might also wonder about the holes themselves...why they exist...I am sure many on the board have asked themselves...as any holes in frame rails are counter productive to structural integrity. If you pull the plugs and look inside, they are also walled...for four reasons...to lessen structural compromise of adding the holes thereby maintaining torsional and bending strength...second, prevent further contamination...the other two reasons being function related. The holes exist as 3-dimensional locating datums for construction of the frame from the front rad support rearward during the car's fabrication. Dimensional accuracy is not only key to overall fit and finish of the car but contributes to driveablity and frame rail alignment to allow the suspension to function at its full potential. BMW's attention to detail and adherance to the highest tolerances over and above material selection is one of the things that makes a BMW a cut above ordinary cars. Large pins are part of a master jig/fixture in the assembly plant that control the position of one side rail relative to the other in X, Y and Z direction to maintain precise dimensional correctness...based upon a Geometric Dimension & Tolerancing (GD&T) scheme that prioritizes which dimensions are most critical to function and fit and finish. Its much more than being accountable to high tolerances...its about the hierarchy and interaction of each nominal dimension and tolerance that spells the difference between success and a mediocre design. There are many ill conceived designs out there that won't stand up to the test of production variation. The frame rails are the building blocks for the entire front of the car and set the dimensional foundation...including mounting of both engine and thrust arm cross-members with much higher control than you will see on lesser cars.
HTH.

[Hector]

since I've joined this forum, Ive been going to school.


Damn George you make me feel like I'm back in school! Mechanical engineer I think? You guys do even more math than us poor electical engineers...

[Hector]

n/txt

[Bill R.]

http://www.bimmernut.com/%7Ebillr/images/Blind%20plug.jpg
n/txt

[Hector]

http://www.bimmernut.com/%7Ebillr/images/Blind%20plug.jpg