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  #401  
Old 03-18-2013, 08:28 PM
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MeanMike MeanMike is offline
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Quote:
Originally Posted by aggie91 View Post
Not trying to start an argument, but to clarify a few things about this subject. I understand where you got your 26,000 lbs of force, but remember that typical 1018 mild steel has a Yield Strength of about 50,000 PSI and an Ultimate Tensile Strength of about 60,000 PSI. Since you must go above the Yield Strength of the material for it to deform (Balloon), you would have to apply more that 30 psi to the tank. I would not test at more than that pressure. Trying to find a bubble of soap from a small pin hole using very low pressure is time consuming, but that same hole will leak gas and vapor easily. From a safety point of view, the limit for air nozzles per OHSA is also only 30 psi if that nozzle should come into contact with your skin. I would always wear safety glasses when doing anything like this, even the soap blowing out of a small hole could get in your eye...

Clint is an engineer so he should be able to figure this testing out without much of our help. Like entropy, I would recommend using a gas tank sealer after you are satisfied your welding is good and the sealer would just help seal up any small pin hole leaks.

I have one of those mechanical engineering degrees also, but I don't need it to know that 30psi in a tank is dangerous. But, what do I know. Go pressurize a flat sided 18 guage tank (that has nothing more than resistance welds holding it together) to 30 psi and prove me wrong.
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  #402  
Old 03-19-2013, 06:01 AM
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You could pressure test with helium. That stuff sneaks out of very tiny holes. You could also run a layer of solder over the weld when you are done welding. Good tinning flux and some 50/50 runs nice. Shay
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  #403  
Old 03-19-2013, 01:41 PM
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Quote:
Originally Posted by MeanMike View Post
I have one of those mechanical engineering degrees also, but I don't need it to know that 30psi in a tank is dangerous. But, what do I know. Go pressurize a flat sided 18 guage tank (that has nothing more than resistance welds holding it together) to 30 psi and prove me wrong.
I measured some of sheet metal I cut out of this tank and it appears to be roughly 0.030 thick. I suppose that would be 22 gauge? It is not particularly thick.

Some simple calcs to get a rough idea, ignoring bending stresses (!) and assuming plane sections remain plane:
Worst case longitudinal stress: Stress=pressure*area/(thickness*perimeter) = 30psi*24in*36in/[0.030in*(24in*2+36in*2)]=7,200psi.
30
Worst case hoop stress: length*pressure/(2*thickness) = 36in*30psi/(2*0.030in) = 18,000psi

Bending stresses can not be ignored. The article I linked above has the basic theory to calculate the stresses, but I don't have time at the "moment". I have a feeling 30psi would be questionable.
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  #404  
Old 03-19-2013, 06:41 PM
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The failure would be at the weld seam halfway along the long edges. Once the center of the flat side bulges it's going to point load the welds at the center (it will draw in on the short side and look like a neck bowtie). We did some modeling of a rectangular vessel not long ago for a code check, and it failed in the corner joints on the long side. It tries to become round in the center.

If all you have is a mig, mig it. But if you have access to a tig, tig braze it with some everdur. I've sumped a few of old steel fuel tanks and I've just tig welded them with mild steel filler. If it's clean, it 's pretty easy to get it leak free. Since you're working on the top, it won't ever see any head pressure, so a structuraly strong weld is less critical.
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  #405  
Old 03-19-2013, 11:01 PM
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JaysinSpaceman JaysinSpaceman is offline
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I never pressure test tanks with more then 5 PSI. That and some soapy water and you can find any leaks at seams. I pressure tested a stock tank that I modified and found three leaks ate the factory seam that didn't leak fuel when the tank was full. Never pressurize a automotive tank with more then 5-10 PSI MAXIMUM, even 10 PSI is starting to get fairly dangerous.

Jaysin
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  #406  
Old 05-06-2013, 04:11 PM
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I'm almost embarrassed to admit I bought a Harbor Freight portable band saw and cobbled a stand for it out of scrap material. I drilled through the cast aluminum body and bolted it to angle iron, welded to a piece of square tube. I am not sure yet if I want to build out the rest of the stand because it works just fine in the vise and I can still carry it around without unbolting this part. We'll see. I would like to add a larger cutting table to it before using it for anything thicker/larger than sheet.



I swapped in a Lennox 18tpi blade and tackled my first project - a bracket to hold the Bussman fuse/relay center.



I bent the bracket using a combination of my press brake for some bends and the vise for others. I wish I had a box/pan brake for this kind of work. The bracket places the fuse holder about 1/2" away from the mounting surface to give room for fingers to remove the lid. It is mounted to the core support using some rivnuts. It still needs to be cleaned up and painted and I need to do some final trimming around the terminals to give room for wiring.







I also welded the v-band flanges onto the headers. Here is one of them. I used my Millermatic 180 at about 3.5/50 with 0.023 wire. The collector is 16 gauge. It could have used a little more heat. I used 3 tacks evenly spaced followed by continuous welds from tack to tack (thanks Jaysin for your suggestion in another thread). The welds aren't perfect, but should do the job. I put a male on one header and a female on the other so if I ever have to replace the exhaust I will only need to buy one v-band assembly. I think I will coat over this with VHT.





I also picked up some reducers, o2 bungs, tube, and a mandrel u-bend for reworking the exhaust. Unfortunately the way things were bent up for the 350 won't work for the LS, so I am going to redo most of it. It is going to be 2-1/2" back to the old 2-chamber Flowmasters w/ turndowns. Eventually I want to rebuild it with a better set of mufflers and go over the axle out to the back, but I think this will be good for now.

I bought 3 o2 bungs. The engine requires one per side, but I want to put a 3rd in for tuning. Any ideas on where it should be placed? Is there a prefered side and how far from the other O2s should it be? The sensors are large so I don't have a lot of options for mounting them. My current plan is to put them just behind the v-bands mounted horizontally to fit in the area in front of the transmission pan. Are wideband O2s any larger than the factory heated O2s?

The rest of the project has seen some progress, just nothing worth photographing. I modified the passenger side coil spring adjuster and now have both sides of the suspension fully assembled sans shocks and swaybar endlinks. It's nice to know i could put the wheels on it and roll it around again if needed (it's been on jackstands two years now). The suspension has seen a lot of changes: I did the Gouldstrand modification the "hard way" for camber gain, added a Hellwig 1-1/4" hollow swaybar, much stiffer AFCO 600lb/in springs with coil adjusters for ride height, and Global West upper control arms to achieve more caster.

Other odd jobs: I trimmed the intake manifold cover to give more clearance at the back for spark plug wiring, rounded off and painted the transmission dipstick mounting tab, swapped a bad tie rod end, and torqued some miscellaneous fasteners. I have also been collecting odds and ends parts for doing the transmission cooling lines and wiring, etc. Should be plowing through more progress soon.
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Last edited by TheBandit; 05-06-2013 at 04:23 PM.
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  #407  
Old 05-07-2013, 02:18 AM
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zimsport zimsport is offline
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I would highly recomend making your exhaust with 3 inch, and make an x pipe. Dont use one of those pre made ones, just make your own. Bend the pipe in around 45 degrees and then back out so the 2 sides touch in the middle. Where they touch just cut a hole and weld the 2 together. It needs to be fairly close to the collectors, similar to an h pipe. It will give you a ton of mid range torque and actually quiets the exhaust down, yet giving it a deep sound....Here is what we did to our LM7 truck motor in our lemons car.....Made a huge difference with a stock motor/cam combo with 170,000 miles over 2.5 inch exhaust.

https://www.facebook.com/photo.php?f...type=3&theater
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  #408  
Old 07-08-2013, 11:16 AM
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I may do that. It seems 2-1/2" is small for this application.

E38 ECM is mounted to the firewall via rivnuts and vibration isolators from Grainger.







After measuring a section of wiring to run along the inner fender, I pulled the sheet metal to get access for on-engine wiring. I finished some final trimming on the AC compressor bracket and mounted the starter for wiring purposes. I ran the first few runs of wiring and started looming some of it, but ran into a few small obstacles. For example, I am switching to an LS3 bolt-down MAP sensor (Bosch) which has a different connector from the LY6 clip-on MAP sensor (Delphi), so I need to obtain the right connector. I had BP Automotive make a pigtail for me from the MAP to the ECM pins (below). The old connector for the LY6's original Delphi MAP sensor is on the left. The new connector for the LS3 Bosch sensor is on right. BP did an awesome job with this little pigtail - the crimps look identical to the factory ones and he used the factory-correct color coding. I will have to modify the tune for the different sensor.





Here is the first bit of wiring. This is a wye (or is it a "w") for the throttle body, MAP sensor and MAF sensor. The wires run down the timing cover and I secured them with one wire loom clamp at the top. The braided split loom is Techflex F6 from furryletters on eBay with regular old 2:1 heat shrink to finish the ends. I used non-adhesive harness wrap from PSI Conversions.





I also routed, wrapped and loomed the starter solenoid wire, crank sensor and passenger side knock sensor along this route. I'm not sure yet how I want to secure the loom; I don't like adding the wire loom clamps on fasteners important for oil pan / timing cover sealing.



Below you can see where the wiring will exit the front of the engine down by the alternator. It is nicely hidden behind the water pump. Most of the wires will not need any lengthening or shortening for the way I am routing the wires over the inner fender to the firewall.



I am now working on the driver's side of the engine and came to the first pigtail that needed lengthening - the water temperature sensor. I reused the connector body with new 18ga TXL wire and terminal ends. This connector uses Delphi GT150 female terminals while the E38 uses Molex MX64 terminals.



I have two ratcheting crimpers I bought specifically for this job. The first one I bought new for $68 (shown in bottom of photo with black handle): Waytek #509 / Delphi 12155975 which does wire and seal crimps for Weatherpack 280 and Metripack 150. I need it for the WP280 terminals going into the Bussman fuse center and I'm using it to crimp the wire part of the GT150 terminals even though this tool is not specific to the GT150 and does not include the GT150 seal cavity.. Nearly all sensor connectors on the LY6 harness are GT150s. The GT150-specific tool is Delphi 15359996, but I don't plan to buy it since I can get by using my existing tools.

I bought the second crimper used off ebay for $65. It is service tool J-38125-641 (which probably also has a Delphi number, I just don't know what it is). It does the Molex MX64 terminals that can be found on the E38 and similar ECMs. It does both the wire and insulation crimp simultaneously.

Here is a great resource that shows some of the different types of terminals, how they are assembled, and lists service tools:
http://www.weber.edu/wsuimages/autom...%20Booklet.pdf

(below) My Molex MX64 (ECM pin) crimp right vs factory crimp left. The lighting/angle makes my wire/conductor crimp look bowed/banana shaped, but it is straight and in person the crimps look identical.



(below) My GT150 crimp bottom, factory crimp top. I had to make the seal crimp with pliers because my crimpers for Metri-Pack 150 / Weather-Pack 280 terminals doesn't have the cavity for doing the small GT 150 seal crimps. It looks awful but I think it will work fine. I am pretty sure the wire/conductor crimp for the GT 150 is the same as for the Metri-Pack 150 - my wire/conductor crimp looks identical to the factory crimp.



Progress is a good thing. There is something about wiring that's therapeutic for me. I am getting into a wiring zen and can't wait to get back into the garage to do more.
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Last edited by TheBandit; 07-09-2013 at 02:05 PM.
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  #409  
Old 07-08-2013, 12:50 PM
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juicedz4 juicedz4 is offline
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Nice progress!

Wiring is "fun". Normally it takes me 2-10 ideas on how to route something before Im happy with it. And then a week later I think of idea 11.

Dan
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  #410  
Old 07-08-2013, 12:51 PM
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Haha, ain't that the truth!
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  #411  
Old 07-15-2013, 12:13 PM
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No photos, but I am having a really good time with the wiring harness. The detective work has been entertaining and for some reason the whole cutting, terminating, wrapping, and looming process is proving highly therapeutic. My plan is two main runs: one from the front/bottom of the engine and one from the rear top. I have the front/bottom run completely done now. It includes the throttle body, MAP, MAF, cam actuator, cam position, coolant temp, alternator, crank position, alternator, knock sensors, starter solenoid, and main ECM ground (to the passenger head). So far I have only used soldering to extend the two wires coming from the alternator because it had some weird terminals on the connector and I didn't want to wait for another custom pigtail. Otherwise everything is continuous wire with a crimped terminal at each end. At this point I've terminated 29 of ~75 planned ECM terminals, not yet half way done. Most of the work will be wiring the ignition coils. They are 4 wires each, 2 of which are power and ground which means a whole bunch of wire junctions/soldering. On top of everything going into the ECM, I have a few relays and a half dozen or so fuses to wire in, plus making some custom circuits to interface a tach, OBD connector, etc. I can see why people spend $500-600 on a plug & play wire harness - it is well worth it if you don't have the time, skill or desire to do this kind of work.

Marching on toward an eventual start-up.
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  #412  
Old 07-16-2013, 10:41 AM
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How to take apart a typical metripack / GT connector like the one below. This specific connector is for the coolant temp sensor.



First, remove the "TPA" (terminal position assurance) component. It has snaps on either side which can be pried open slightly to remove.





The next step is, I believe, optional. I remove this cover component. If you dont' remove it, you can insert a tool through the front to unsnap the terminal, but I think it's easier and less error prone to remove the cover. Depending on the size of the connector, it may be held on by one or multiple snaps which you can pry with a small (jeweler size) flat blad screwdriver.





With the cover off, you can see the terminals and how they're held.



To remove the terminal, you first shove it forward as shown. This unseats the plastic flexure that keeps it from pulling out.



Now you can pry the flexure up slightly to unsnap the terminal.



And you can slide it back out by pulling on the wire.





To reinstall, push the terminal all the way in and pull back to make sure it's snapped/seated into place. That's all there is to it.
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  #413  
Old 07-16-2013, 10:41 AM
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Other random images. Here are my par (top) and subpar (bottom) solder joints for extending the alternator wires. The joint shown on the bottom could have been a lot better if I did a better job twisting the wire strands.





Random photos. So much to do yet.





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  #414  
Old 07-16-2013, 11:22 AM
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alwaysFlOoReD alwaysFlOoReD is offline
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Thanks for the tutorial. Some of those ends are a @%%#$& pain in the %*&^*!!!! until you figure them out.

Richard
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  #415  
Old 07-16-2013, 05:11 PM
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Originally Posted by TheBandit View Post
There is something about wiring that's therapeutic for me. I am getting into a wiring zen and can't wait to get back into the garage to do more.
Read through your thread, and all I can say is...Awesome job so far. Keep it up.

That loom you're using really makes it look professional. How is it to work with? I was thinking of using the same on my engine harness.

I know what you mean about the wiring. I feel the same way. I recently made a whole new harness for my truck project and loved doing it. Wire by wire, connection by connection. Some people call my crazy for enjoying wiring.
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  #416  
Old 07-16-2013, 05:25 PM
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Thanks! The loom (Techflex F6) is very easy to work with. They say to cut it with a hot knife so the braids wont fray, but I have been just cutting it with scissors and passing a flame across the end afterwards. I wouldn't use this stuff for a mud/dirt toy because it would likely collect that kind of stuff. It is not going to keep moisture, oil or grime away from the wires inside, but it will keep them from chafing/rubbing on things and keeps them together nicely for a clean look. You can see through it a little, so keep that in mind. I am wrapping all my wires in non-adhesive harness wrap so you only see black when you look at it.
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Last edited by TheBandit; 07-16-2013 at 05:27 PM.
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  #417  
Old 07-16-2013, 06:38 PM
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Thanks for the info. I'm using the non-adhesive wrap too. Got it from oldfuelinjection.com. Stuff works great. I wonder how it handles a little heat, because there's some wires running down the side of the intake. Won't be touching, but close.
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  #418  
Old 07-22-2013, 12:59 AM
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Are you refering to the loom? If so, the techflex is rated to 257F continuous and melts at 446F.

I'm now finishing up the even/passenger side injector wiring. I replaced all the pink (+12v) wires because they were too short, but the ECM wires are going to be shortened. I thought a lot about how I wanted these to route. I was very tempted to put them under the intake plenum cover, but ultimately decided against it due to accessibility. This was a very time consuming section of harness, but I am happy with how it turned out.















It would look a lot tidier to me if the loom ran perfectly straight instead of naturally wavy. Maybe I should put a rod in there or something lol.
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  #419  
Old 07-22-2013, 10:07 AM
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JaysinSpaceman JaysinSpaceman is offline
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I think it looks great, the slight waviness makes it blend in with the humps and bumps on the manifold. I think most people wouldn't even know it was there once the engine is up and running. Nicely done.

Jaysin

P.S. Unless you can make the wiring perfectly straight and parallel to the fuel rail it's likely that it would stick out more then the wavy wiring. Like two colors that are almost the same but not, they clash.

Last edited by JaysinSpaceman; 07-22-2013 at 10:11 AM.
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  #420  
Old 07-22-2013, 10:55 AM
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Very nice work, Clint! Really clean. I also like wiring, must be because I'm anal-retentive.
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