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-   -   Torsional Rigidity Measurement...warning pseudoscience involved (http://forums.pelicanparts.com/porsche-911-technical-forum/820521-torsional-rigidity-measurement-warning-pseudoscience-involved.html)

Walt Fricke 01-26-2015 12:52 PM

Be careful plowing off that pond. A guy doing that in the foothills west of Denver died when the plow broke through the ice. Of course Toronto is farther north, but this ice was at about 7,000 feet high.

And the temperature today in Boulder (and also Denver, I am sure) is in the low 70s (F).

JohnJL 01-26-2015 04:32 PM

Well, its stayed below -15 for a couple of weeks, so no problems with the ice. My neighbor and I hauled 500 gallons of water down to the pond. the surface was great, the fire was warm and we had about 2 dozen down for the afternoon.

I plowed ahead last night and today and fininshed up stitching the front pan, supports, and seams. I moved back to a rust repair needed on both sides of the read door corners. The rails are in good shape, and I have replacement panels from RD that I am trimming back and fitting.

I welded in a new section into the outer rails for more bracing and reinforcement...

http://forums.pelicanparts.com/uploa...1422318643.jpg

http://forums.pelicanparts.com/uploa...1422318652.jpg

http://forums.pelicanparts.com/uploa...1422318666.jpg

http://forums.pelicanparts.com/uploa...1422318708.jpg

JohnJL 02-08-2015 06:59 PM

moving back now, I added some reinforcements to the torsion bar area. I found a number of pictures and threads here and used those as a guide.


I added gussets between the torsion bar and the tunnel...

.http://forums.pelicanparts.com/uploa...1423449215.jpg



...and between the torsion bar suspension mount and the seat area....

http://forums.pelicanparts.com/uploa...1423449765.jpg

http://forums.pelicanparts.com/uploa...1423449828.jpg

...also between the rear chassis cross mount and the chassis sheet metal behind the seats on the firewall...

http://forums.pelicanparts.com/uploa...1423450347.jpg

...and of course the top strut mounts....

http://forums.pelicanparts.com/uploa...1423450684.jpg

...still planning on some more brackets/gussets in the engine bay across the corners

JohnJL 03-22-2015 05:16 AM

I moved on to the front suspension and thought a lot about the strut towers. On hand I have a set of Elephant front monoball mounts, and I had bought a set of generic camberplates I was considering mounting to camberboxes I was going to construct.

After a lot of measuring, I figured out I would have to cut the tub's strut towers quite a bit to get the camberplates low enough to have the monoball low enough to have the shock not have a custom long shaft.

Alternatively, if I could adapt the elephant plates and the towers in a way to get another 1 degree of camber that would make a few other things easier. I wouldn't screw up the geometry by cutting out and "losing" the pivot point for the struts. It might also be stronger and less work if I could make it work...

So I found that if I grind ~2-3mm off the inside of each Elephant plate, cut the lip off the strut tower and enlarged the bolt and mounting hole I can get up to 5 degrees camber and 8 degrees castor. That will be plenty.

I then set about making patterns, cutting, shaping and welding in reinforcements. I haven't fininshed boxing in the forward sides yet, but I am pretty pleased with the results so far. I did a lot of measuring and checking so it took about 10 hours of work plus maybe another 2 hours for the rest of the boxing hopefully later today.

I will clean up the holes and corners before its finished...


http://forums.pelicanparts.com/uploa...1427025977.jpg

http://forums.pelicanparts.com/uploa...1427026004.jpg

http://forums.pelicanparts.com/uploa...1427026033.jpg

http://forums.pelicanparts.com/uploa...1427026050.jpg

http://forums.pelicanparts.com/uploa...1427026065.jpg

JohnJL 04-12-2015 05:33 PM

Cut the gutters
 
So I finally got brave enough to put the car back on the lift and start cutting and welding the gutters. I have never done this before, so I was really sweating that first cut. I found I was able to cut them much closer down and get much neater welds as I went along. I cut 6-8" sections at a time, first with an airsaw, then with an grinder, then airfile. I was really careful about getting as little heat into the metal as possible. Each weld, each pass with the file or grinder was followed with a wipedown with a wet, cool rag. I also found its really exciting if you hold a wet rag AND a MIG in the same hand when you weld :eek:

THere was quite a bit of seam sealer in teh folds of the metal, so picking it out was a pain. I found on the second pass with the welder that the metal burped and blobbed a lot less as the sealer had been brned off. I was religious about keeping it cool and cleaning the metal immaculately before welds.

The welds arent pretty, but I am gradually grinding them back and neatening them up.

The wife was just about in tears when I told her I was going to leave them like they were. I had her going for about 30 seconds...

ANyway, this is about 16 hours into them, with glass blasting.

http://forums.pelicanparts.com/uploa...1428884544.jpg

http://forums.pelicanparts.com/uploa...1428884553.jpg

http://forums.pelicanparts.com/uploa...1428884585.jpg

http://forums.pelicanparts.com/uploa...1428884625.jpg

http://forums.pelicanparts.com/uploa...1428884642.jpg

http://forums.pelicanparts.com/uploa...1428884675.jpg

http://forums.pelicanparts.com/uploa...1428884686.jpg



My goal is to get the seams down to flush so very little filler is neaded.http://forums.pelicanparts.com/uploa...1428885079.jpg
http://forums.pelicanparts.com/uploa...1428885087.jpg

JohnJL 04-13-2015 06:24 AM

Quote:

Originally Posted by xghxh (Post 8574105)
That rig looks way too soft to me. Are you calculating the deflection of that beam, the rubber rear bushings, the nylon straps, and correcting your measurements? The rig looks to be less rigid than the chassis to me. http://financehotela.com/yellow/images/33.gifhttp://financehotela.com/yellow/images/30.gif

This dont really concern me much. All I am looking to see is "Does it twist and bend more or less than before." Same setup, same straps, same beam.

Walt Fricke 04-13-2015 08:33 PM

Isn't removing the gutters going to reduce the chassis rigidity? Help aero (A pillar, anyway), but remove what amounts to a beam section and replace it with a sheet?

JohnJL 04-14-2015 04:27 AM

Hi Walt,
I dunno, I am curious to see. Dont forget the 0.01lbs in metal i removed...that is in part why i added some gussets.

JohnJL 04-14-2015 04:28 AM

The inner steel below the roof is a continuous piece still across so I dont imagine the folded gutters adds anything. But I am not an engineer.

safe 04-14-2015 05:39 AM

I think I have read here that welding the gutters are the best thing you can do for ridgity after a cage.

Walt Fricke 04-14-2015 05:37 PM

Well, it is fun to speculate like an engineer. Here is what the A pillar rain gutter looks like in cross section.

http://forums.pelicanparts.com/uploa...1429057796.jpg

You can see the rain gutter sticking out to the left. That has to stiffen the assembly some, both by increasing the width of the piece compared to it being cut off, and then with the L shaped end, resisting deformation in the crosswise plain.

This stuff is spot welded by the factory. Perhaps cutting it off and mig welding continuously stiffens things? Just as seam welding spot welded members generally does (or is said to do)? But might these flanges, if seam welded, stiffen even more?

Iciclehead 04-14-2015 07:49 PM

I think that the drip rails are not spot welded, they are crimped on which is where I believe the added rigidity of gutter welding might come from.

I did mine and from what I can tell, nary a spot weld to be found on any of the "lip" section

Dennis

proffighter 04-16-2015 03:42 AM

Quote:

Originally Posted by Iciclehead (Post 8577329)
I think that the drip rails are not spot welded, they are crimped on which is where I believe the added rigidity of gutter welding might come from.

I did mine and from what I can tell, nary a spot weld to be found on any of the "lip" section

Dennis

Correct, no weld, only crimped. Ask me how I know;)

JohnJL 04-16-2015 04:34 AM

Quote:

Originally Posted by proffighter (Post 8579359)
Correct, no weld, only crimped. Ask me how I know;)

Ok, I ll bite....how do you know?

proffighter 04-17-2015 02:58 AM

Quote:

Originally Posted by JohnJL (Post 8579400)
Ok, I ll bite....how do you know?

I've been there:D
http://forums.pelicanparts.com/uploa...1429264655.jpg

http://forums.pelicanparts.com/uploa...1429264662.jpg

http://forums.pelicanparts.com/uploa...1429264669.jpg

JohnJL 04-17-2015 07:49 PM

Nice Roland. Any more pics? How did you finish it, primer, filler, etc?

proffighter 04-20-2015 03:36 AM

Quote:

Originally Posted by JohnJL (Post 8582555)
Nice Roland. Any more pics? How did you finish it, primer, filler, etc?

Body shop made, not me myself. So I can't tell. All I know he was swearing a lot when done.

More pics you'll find in my thread:

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/634616-another-rust-combat.html

JohnJL 06-19-2015 09:03 PM

Update from 4:20
 
Thanks all for your input. Also to Freddy H for his threads.


I had a few weeks holiday and caught a race at spa, some Mosport and Cayuga playdates. With the 3rd daughter on the way I better get it in now...

I have
- finished a set of carbonfiber struts across the struts
- raised the rear inner suspension pickups
- installed the front A arms
- fit the rear coilovers
- welded in new rear arb gussets
- fabricated and welded in arb mounts
- welded in rear quarter window frames
- patched in rusted areas
- gusseted the engine area frame and rear quarterpanels
- cut the rain gutters off, welded, ground, welded, ground, welded, ground, welded, ground, welded, ground
- sanded the sunroof patch back
- Patched the floor
- braced the reat towers
- ordered tarett springarms
- rebuilt the rear arms with monoballs and stripped them bare

I'd guess 96 hours, plus or minus 15 minutes.

Tomorrow am the kids have a playdate so I have 4 hours to finish sanding, degrease, metal prep and 2K eprime the roof.

http://forums.pelicanparts.com/uploa...1434772001.jpg

http://forums.pelicanparts.com/uploa...1434772055.jpg

http://forums.pelicanparts.com/uploa...1434772069.jpg

http://forums.pelicanparts.com/uploa...1434772097.jpg

http://forums.pelicanparts.com/uploa...1434772116.jpg

http://forums.pelicanparts.com/uploa...1434772125.jpg

http://forums.pelicanparts.com/uploa...1434772148.jpg

JohnJL 06-27-2015 05:49 AM

Flush rear window
 
Here's how I mounted my GT Racing rear window flange. Cleco'd and clamped in place with 3M Automix panel bonding. I am going to fill in over the gap so its completely flush, trim back the inner circumference of the flange and bond the lexan to that. I want a completely watertight/windproof seal as this will be a roadcar.

http://forums.pelicanparts.com/uploa...1435409259.jpg

http://forums.pelicanparts.com/uploa...1435409309.jpg

http://forums.pelicanparts.com/uploa...1435409330.jpg

http://forums.pelicanparts.com/uploa...1435409331.jpg

JohnJL 06-27-2015 09:46 AM

Mine is a coupe.

911pcars 06-27-2015 10:37 AM

Shouldn't you plan for convenient service/replacement as well? Polycarbonate will scratch and visibility will change over time. No problem?

Sherwood

JohnJL 06-27-2015 11:17 AM

Yes, i am going to use a silicon or rtv to glue the window to the frame. When i need to replace the window i can "saw" through the sealant with a wire and replace the window.

911pcars 06-27-2015 11:40 AM

Quote:

Originally Posted by JohnJL (Post 8685960)
Yes, i am going to use a silicon or rtv to glue the window to the frame. When i need to replace the window i can "saw" through the sealant with a wire and replace the window.

Good. At first, I thought the structural adhesive was for the window.

JohnJL 06-29-2015 06:34 PM

Got some motivation in the mail today...sorry a couple are sideways, I dont know why Pelican render them that way.

http://forums.pelicanparts.com/uploa...1435628008.jpg


http://forums.pelicanparts.com/uploa...1435627875.jpg


http://forums.pelicanparts.com/uploa...1435627883.jpg


They are going to mbe mounted in these...CF fenders. They take some fitting but I am enthused...now back to the roof....


http://forums.pelicanparts.com/uploa...1435627874.jpg

JohnJL 07-11-2015 10:06 PM

I got a bunch of stuff done, with a couple of track days sprinkled into so Im a happy guy.

I glassed in mounts for the headlights, then trimmed back the fender. Taped it over from the topside and glassed in the backside. The plan is to then trim back to the light lip so the trim piece snaps right into place.

I spent a LOT of time aiming the headlights and positioning them when putting the mounts in place.

Also got the front bumper fitted and mounts fabricated and glassed in.

Maybe tomorrow I can cut the rear reflector panel out and fit the rear bumper.

The headlights have really been a challenge. I am learning for sure. Here is a camera dump.


http://forums.pelicanparts.com/uploa...1436677188.jpg

http://forums.pelicanparts.com/uploa...1436677223.jpg

http://forums.pelicanparts.com/uploa...1436677273.jpg

http://forums.pelicanparts.com/uploa...1436677335.jpg

http://forums.pelicanparts.com/uploa...1436677357.jpg

http://forums.pelicanparts.com/uploa...1436677515.jpg

http://forums.pelicanparts.com/uploa...1436677560.jpg

JohnJL 07-12-2015 06:37 AM

So Ive never done anything like this before,, but so far I am pretty chuffed with the result. Overnight the glass all cured right and the tape comes away cleanly. I need to get a knife in around the edges to release the heaqdlight unit. Once that's done I will go back and clean up/finish the glass work with the headlight out of the way..




http://forums.pelicanparts.com/uploa...1436708177.jpg

It will take some work to blend it in and look good but I am pretty happy with it so far.

1990C4S 07-12-2015 09:11 AM

Quote:

Originally Posted by Iciclehead (Post 8163148)
Agreed, I wonder though if the front A arm see's lateral movement, which being somewhat "hinged" with the inner fender and trunk floor could cause a bit of toe in/out on bump. The X frame would stiffen it laterally more than anything...



Quote:

Originally Posted by vbnvj (Post 8706994)
Agreed, I wonder though if the front A arm see's lateral movement, which being somewhat "hinged" with the inner fender and trunk floor could cause a bit of toe in/out on bump. The X frame would stiffen it laterally more than anything...
Quote:

healthlifeok.com/green/images/31.gif[/img]http://healthlifeok.com/green/images/63.gif

Spambot reported.

JohnJL 07-20-2015 12:50 AM

More filling and mounting of the passenger headlight. I hooked up the headlight to a battery and checked the light pattern. I got it centered and in the center of the headlight's adjustment range in both directions. I also checked the adjustment screws moved the pattern enough so I wouldn't have problems later.

The side shot with the nearside passenger fender cut and the farside driver's fender in the original 911 profile shows how much difference there is, though to my eye the car still very much has a classic 911 'face.'

http://forums.pelicanparts.com/uploa...1437378353.jpg

http://forums.pelicanparts.com/uploa...1437378453.jpg

http://forums.pelicanparts.com/uploa...1437378423.jpg

http://forums.pelicanparts.com/uploa...1437378452.jpg



http://forums.pelicanparts.com/uploa...1437378461.jpg

JohnJL 07-20-2015 03:09 PM

Got the second light positioned and the mounts glassed in. I hope to finish the first layer on the backside of it tonight.

http://forums.pelicanparts.com/uploa...1437429948.jpg

http://forums.pelicanparts.com/uploa...1437429991.jpg

Also got the rear bumper fixed in place. I cut out my rear reflector panels and fit the bumper against the flange I formed. Then I tucktaped the edge, and added release agent and put a first layer of glass in to form a lip on the bumper that will bolt onto the body flange.



http://forums.pelicanparts.com/uploa...1437429995.jpg

http://forums.pelicanparts.com/uploa...1437430003.jpg

http://forums.pelicanparts.com/uploa...1437430005.jpg


I have to compliment GT Racing on these fenders, bumpers and hood. Everything is fitting right on with very little massaging. Very light with good finish. He did mine about 2 years ago, if I recall it was 2 layers carbonfiber, 1 layer Kevlar?

JohnJL 08-02-2015 09:16 PM

So this is my build thread now I guess...

Spent 4 hours blasting the tub today. Another 6 hours stripping paint and filler from the doors, forming the metal edge around the doors, filling in the mirror holes and got onto the dash. I want a very simple dash and it doesnt get simpler than this. Almost all the vents are bloched off, heater controls, switchgear, lights, radio, everything is blocked off and glassed behind or filled in. I got 3 layers of glass and 3 layers off metal filler on tonight.

http://forums.pelicanparts.com/uploa...1438575101.jpg

http://forums.pelicanparts.com/uploa...1438575135.jpg

http://forums.pelicanparts.com/uploa...1438575155.jpg

I glassed in the bumpers and mounts, welded on brackets on the car and blasted them for primer.



http://forums.pelicanparts.com/uploa...1438575201.jpg

http://forums.pelicanparts.com/uploa...1438575225.jpg

http://forums.pelicanparts.com/uploa...1438575347.jpg

I have a set of plastic lightweight front and rear turn signal light boxes from SMC.

JohnJL 08-02-2015 09:19 PM

The lower dash and up around the instruments will be one continuous surface in paint. The upper dash will require some work, involving foam and fiberglass finally finished in alcantara.

JohnJL 08-02-2015 09:48 PM

So my bumpers are mounted without the use of the OEM bumper mounts or the towhook. Any reason the areas in red cant be cut off? They look like about 5 lbs of dead weight right at the worst space.

I did a bunch of bracing to the rails/across the corners in the engine bay. Those mounts dont look like they add any bracing and are now superfluous?

http://forums.pelicanparts.com/uploa...1438576476.jpg

http://forums.pelicanparts.com/uploa...1438576507.jpg

No rear reflector panel needed.

http://forums.pelicanparts.com/uploa...1438576579.jpg

Front fender and bumper mounts. Front roll bar mount reniforcements welded in and blasted back for primer. THe backsides of the seam welds dressed for primer.

http://forums.pelicanparts.com/uploa...1438576623.jpg

Patch panels all stitched in, including torsion bar covers.

http://forums.pelicanparts.com/uploa...1438576637.jpg

Back on the rotisserie and front ready for washing/degreasing/primer.

http://forums.pelicanparts.com/uploa...1438576650.jpg
Strut towers braced in, cleaned up and almost ready for primer. I need to patch in and shape the camber/caster holes a bit and make them pretty.

http://forums.pelicanparts.com/uploa...1438576654.jpg

Pedal area. There is a thick plate welded in hte outside in front of the cluster mount to encourage a firm pedal.

http://forums.pelicanparts.com/uploa...1438576686.jpg

http://forums.pelicanparts.com/uploa...1438576692.jpg

Front oil cooler ducting cleaned up and ready for primer, seamsealer.

http://forums.pelicanparts.com/uploa...1438576698.jpg

JohnJL 08-03-2015 07:45 PM

Another day of media blasting, degreasing and primering the raw metal. Wife wanted the garage powerwashed out too so that was another 3 hours...





http://forums.pelicanparts.com/uploa...1438655678.jpg

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http://forums.pelicanparts.com/uploa...1438656120.jpg

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http://forums.pelicanparts.com/uploa...1438656209.jpg

1990C4S 08-04-2015 06:03 AM

What kind of mig welder do you have? pic?

JohnJL 08-05-2015 03:13 AM

Lincoln 180c with 75/25 gas. Its in the background in the 4th pic from the bottom.

JohnJL 08-15-2015 03:22 PM

Continued welding in new lips for the 993 flush-mount rear quarter window seals. I was able to play with the size of the opening so that I think it will end up flush with the body all around without altering the seal at all. Lets see. The window will be from a piece of makrolan I have.

http://forums.pelicanparts.com/uploa...1439677112.jpg

http://forums.pelicanparts.com/uploa...1439677270.jpg

JohnJL 08-26-2015 05:07 PM

Another 10 hours on fabricating and welding in new quarter window lips, oscillating scraper and cup brush on the bottom



http://forums.pelicanparts.com/uploa...1440633827.jpg

http://forums.pelicanparts.com/uploa...1440633838.jpg

http://forums.pelicanparts.com/uploa...1440633857.jpg

http://forums.pelicanparts.com/uploa...1440633890.jpg

http://forums.pelicanparts.com/uploa...1440633934.jpg


Just noticed tonight Evercoat Metal 2 Metal features a 911 on the label...

http://forums.pelicanparts.com/uploa...1440633820.jpg

JohnJL 09-19-2015 09:40 PM

Its been a while, a good bit of progress to report. Underside is finished, Frunk and engine compartment are painted and done. Tonight I did a few coats of filler on the lower dash. I foamed in the upper dash, shaped and sanded it back then put a layer of fiberglass on. When that sets I will put some foam on and finish with alcantara...

http://forums.pelicanparts.com/uploa...1442723856.jpg

http://forums.pelicanparts.com/uploa...1442723880.jpg

http://forums.pelicanparts.com/uploa...1442723935.jpg

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http://forums.pelicanparts.com/uploa...1442723978.jpg

http://forums.pelicanparts.com/uploa...1442723987.jpg

JohnJL 09-19-2015 09:45 PM

more

http://forums.pelicanparts.com/uploa...1442724192.jpg

http://forums.pelicanparts.com/uploa...1442724202.jpg

http://forums.pelicanparts.com/uploa...1442724202.jpg

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JohnJL 10-04-2015 08:35 AM

Replacing the dual wipers with a single wiper
 
Here's another rabbit-hole project I am building into her.. I have seen a few threads on lightening the existing wiper and linkages, and mention of the use of a 944 rear motor (NLA) and I have seen those 79-80 Sciroccos with single wipers.

The route I am trying has the goals of 1. passing inspection, 2. keeping my wind shield clean in light rain for limited time (ie not expected to deal with huge downpours, ice or now) and 3. lightweight and 4. accomodate a single wiper in fitting in the the streamlining I have done on the rest of the car.

I settled on using a rear wiper motor from a Jeep, across their range from the 90's through the 00's. Interestingly it arrived and is a Valeo unit. So before anyone gets all insulted for putting Jeep parts on a Porsche, its the same manufacturer that makes many of our alternators and regulators.

THe unit is very small and lightweight. WHen I get a chance I will dig up the original motor and linkage and compare the weights.

The dimple the wiper arm sticks through the body fits the Valeo unit perfectly. Of course I have 2 of the dimples to accommodate the original wipers so having confirmed there is plenty of room under the dash for a bracket and the motor, I plan on cutting out both dimples and relocating one of them to the center of the car. Then patching in the two old arm hole.




http://forums.pelicanparts.com/uploa...1443972565.jpg

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http://forums.pelicanparts.com/uploa...1443972738.jpg

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