WOW! Seam Welding Gives my Porsche Project Stronger Bones
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- Опубліковано 4 жов 2024
- Does seam welding improve chassis stiffness? Well this week garage time measures the torsional rigidity before and after seam welding on this Porsche 911 restoration project. Seam welding is typically done on race cars to improve the chassis integrity by adding stitch weld beads on top of the factory spot welds. If done carefully this can yield a stronger chassis without adding much weight at all. A WIN WIN. A dial indicator is used to measure the chassis deflection when a strong torque is applied to the front suspension mounts. The same torsion test is repeated after extensive seam welding in the front compartment to measure the improvement. Some simple math is used in this episode to calculate the twisting torque, angular deflection, and torsional rigidity. The results are impressive!
#911Build, #RestorationProject
This video series filmed in my home workshop highlights the technical details of my classic car restoration (An aircooled Porsche 911). I’m starting with a stripped out shell from 1974 and backdating it to the earlier longhood look. (Backdated Porsche means to make it look older than it is). It’s not easy to build a car in a small garage but I hope to inspire other gearhead minded people like me to build something cool with DIY style.
In the first few episodes I will focus on the autobody metalwork to transform this junker into something fun to drive. Extensive metal fabrication is needed to give the body the wide and low stance that I'm looking for. Metal fab can be time consuming but its the detail that set each car project build apart from the rest. My classic Porsche strives to be unique with custom hotrod touches throughout. There will be some rust repair in the front trunk area including the infamous suspension pan...home fab style.
I plan to update weekly videos detailing the customization of my classic sports car. This is a low budget build so I plan to make many of the custom parts myself wherever possible. I hope you enjoy my car vlog that will hopefully become an autocross racer or track car someday.
Engine plans are 3.0L+ with individual throttle bodies ITB
Custom brakes and suspensions mods are also planned.
Please stay tuned for all updates on this project series.
Product and tools info at www.ahhgaragetime.com
My Classic Car Restoration Future Plans
I plan to modify the suspension and brakes with improved aftermarket parts from Elephant Racing and Tarett Engineering as money and time allows. Larger brakes from a late model Boxster will be used since this car didn’t come with any brakes and they seem to be the best bang for the buck. The engine will be from a later Porsche 911 to with at least 3.0 liters and I hope to use a custom individual throttle bodies with a modern injection system and software.
In other words, this build will be a mashup of all Porsche’s best years. The classic look of the early lightweight body with a more modern air-cooled drivetrain. Call it a restomod or hotrod if you like, but I’m going to make it my own with custom touches along the way. Please join me in this detailed restoration journey.
Porsche...there is no substitute
Visit my website at www.ahhgaragetime.com or
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no need to apologize for how you did your measurements... any reasonable person can see that you applied a little science to the problem and got an answer that semi-quantifies what is normally a wishy-washy concept... more stiff, less stiff... I for one, really appreciate you doing this... it is really eye-opening.
Thanks Mike! There isn't a lot of good information out there about seam welding and chassis strengthening. Any measurement is better than nothing.
I did the same measurement for the front strut brace and the roll cage.
In total, I'm convinced that these mods made a big improvement to the cars stiffness.
An upgrade when trying to stiffering, could be to move the gauge to different positions back/forth to help determaine were the flex is in the body. By focusing, it might be possible to get nearly the same results with a lot less work. Like on an classic Mustang were just an fairly simple bolt-on bar under the hood remove 30% of the total front to back flex. Something that makes an diagonal connection behind the rear seat cut another 10%. Big changes from minor modifications. 👍
As an amateur racer and builder, this is a great video. I've caged several cars and seen similar results but never went to the effort to seam weld. My before and after results are even less scientific. Jack up one corner and see how the door closed. I've always seen tangible results. Next project will also be seam welded, thanks for the tips.
Cool, thanks for watching another amateur! My guess is a full cage gives the bigger improvement.
Nice welds Tom you need a good cross bar and your ready for the track.. For me I put just a cross bar.
Yep, but I overkill everything so it will probably look like a jungle gym, ha ha.
very interesting. I knew LeMans Porsches were stitched welded but you really nailed it in this video. My next Porsche will be sttiched welded for sure. You are right on the Targa. When I put mine on the lift forget about opening the doors. This is why a roll cage is a must.
Thanks, every bit of stiffness helps
What works is anyone can repeat your test in their garage without relying on any expensive equipment/labor.
Awesome! I would be honored if someone repeated this or improved it. That's the goal of this channel.
Love this stuff! I have some old racing manuals published by Ford, that talk about seam welding a chassis for trans am racing, it’s always something I’ve wanted to do, and this pretty much seals the deal for me. Thanks!
Cool Dave. I had trouble with weld contamination as you would expect with a closed seam. Clean it the best you can, but it's tricky to get clean welds. It makes a lot of smoke so work in a well ventilated area.
As a galvanized car, does that make your weld fumes toxic?
My car isn't galvanized. All weld fumes are toxic, so it important to have good ventilation.
Another informative video. It’s nice that you are showing not only what to do, but why to do it.
Thanks Dave!
Very cool Tom. Love the equation to back to prove out the improved rigidity. Now thats not something you get on most restoration videos! I have to say, I REALLY look forward to your weekly episodes.
Thank you very much. Check back for the strut bar measurements 😀. Nerdy for the win.
Great video - very informative. I often look to what the rally guys do for ideas on how to improve my car - they almost always seam weld as a start point for a chassis build.
Thanks! I do believe in learning from all disciplines of Motorsports, but rally cars....I love. Best of luck on your channel. I wish you the best!
Really interesting to see you go through the maths to calculate the torsional stiffness of the car. I'm building a Lotus 7 inspired mid-engine car and, in Australia, home built cars need to pass a torsional rigidity test as part of their certification. I was quite pleased when my open roadster style space frame hit just over 5800 Nm/degree (test threshhold was 2800). I have some pics (but no video) of the test setup if you're interested in seeing it. And, as I've commented previously, I have no idea why your channel doesn't have more subscribers :)
Hey Dominic, yes I'd love to see your pics. My email is on the about tab here on UA-cam. I kind of like that I have 914 subs at the moment. Another favorite car :)
Liked and Subscribed - love to see real world testing!!!
Welcome, I hope to have this car on the track soon. Sorting out some transmission issues now
Informative and enjoyable, please keep this work going!
Will do, and thanks for watching!
Now that episode wasn’t expected 🤪 Great to see those positive torsional rigidity numbers which I must admit I didn’t expect to be anything near even 10% 👌Do you have a copy of the 964 RS and 993 RS Body Conversion Workshop Manual? If not I t actually covers all the added 30mm seam welding in detail (Porsche reference it for safety as opposed to TR)... I’ll email you a PDF copy if you’d like to see it 👍 Looking forwards to see what you have planned next 🤗
I'm with you Mark. The results were more than I expected and I could feel it by the seat of my pants. (Ok, bad joke). I found a written passage of the 964 RS manual that talked about the 30mm stitches but no pictures. I'd love your .PDFs my email is in the about section. Thanks.
Not sure about next week, my air compressor may have kicked the bucket.
Garage Time - Restomod I’ll email it to your gmail in the morning 👍 It’s very interesting and covers the full chassis conversion in detail including new brackets added and even removed 👍 I’m guessing they never tested the increased TR created by the seam welding alone since they included the MATTER roll cage for the M003 version of 993 RS and N-GT for 964 hence why they concentrated on the safety elements. I’ve been promised a copy of the specifics of the MATTER roll cage from a contact so when this arrives I’ll also forward on to you as it should cover the seam welding up the B-pillars which is important since most flex is felt across the roof and I’ve seen cars on track actually chip paint off the rear of the doors from torsional twisting stress with simple bolt-in cages = no good 😬 In the meantime here is a link which should give you some inspiration for your own roll cage: www.jackals-forge.com/lotus/993/m003_2.html I also have the FIA guidelines for roll cage fabrication which I’ll include in the email for you... Got one for seats also if you want that which is very interesting 👌I’ll also link below another UA-cam’s channel about roll cage fabricating... this person ‘fingers crossed’ will be doing mine 👍
ua-cam.com/video/rQ3dNN6wEJE/v-deo.html
Awesome, thanks a lot Mark. That saves tons of time.
@@futurenewmedia Will you be using Urchfab to build you an M003 spec cage ?
As long as you're happy with your work and the results, it's all good!
Yeah, I'm excited to keep going!
Good work Tom's Porsche lab!
Thanks!
really liked this video. the ONLY gripe i have is that you did not use a scale on end of the bar you sat on (or under one of the jackstands) to measure a consistent weight. but you admit to that!! so that is admirable. i just would have REALLY liked that. great video keep up the work
Hi Eddie. Thank you for checking out this video. I've repeated this torsional test in newer videos and used bags of salt instead of my weight. Check out the strut bar video and the roll bar install video. Those both improved torsional rigidity too.
I would like to see what your numbers would be changing to weights on the bar rather than your body weight using the same Amount. I think you would have a more concrete answer. Great video!
Yes, there's a lot of improvements that I could have done. As I keep testing improvements to the car the results will start to diminish, so I will need to be more careful with the loading. But for this test anything over a 10% increase is just icing on the cake. Stay tuned.
Great video. You really deserve more subscribers!
Anyone? Anyone seen this before? Ferris Buellers day off.
I like it, That's 18% better for me. I used to be able to do math like that years ago, but it's been so long now, I'm not sure if I could.
You could do it, it's like riding a bike.
Thread resurrection.... Definitely stiffens the car but if stitch or seam weld the chassis am I losing safety without putting in a cage. Removing the crumple zones or pushing them into the cabin is a concern. Was 70's pre-crumple zone?
Safety in an old 911? Good luck. There are no crumple zones or air bags. Some argue the spare tire placement is for front impact protection, but that's as sophisticated as it gets. If you want safety, get a Volvo.
Pretty cool video tom. I would've never thought to measure body flex like this.although I lean more toward domestic american 60s muscle, I'll be staying tuned in.
Thanks, I like muscle cars too. These relatively lightweight sports cars can be tricky to strengthen for the track. Thanks for checking out this channel.
Beautiful work on the welds especially accounting for the seam sealer, did you need to run your welder a little more hot to accommodate for the sealer or no?
Yes hotter. The first 1/4" of travel is messy and then it clears up a bit. Clean the backside too wherever possible. I focus the arc on the double layer and then dip it down momentarily. A little zig zag action.
muy excelente
Gracias!
de nada ; {D
Great video thanks!
16:20 not fully scientific, but its enough to show the "claimed 15% increase" from factory seam welding in the Cars like The Integra Type R, or Subaru Sti 22b, ect, that have had the full factory rotisserie seam welding.
And the modern cars you mention here are already miles stiffer than my old 911. So I'd expect that seam welding would have less of an effect on those modern cars. But it works!
@@GarageTimeAutoResto Very true I didn't even account for that. Older cars are definitely more flex happy.
Not bad for a Tea-Sipper. Not bad at all.
Thanks, I think. My wife is a longhorn and I wear all her gear in the garage, ha ha. I'm going to ask her what all this means.
@@GarageTimeAutoResto I'm an Aggie with a real Porsche - The 914 ! LOL - BTW, loved the video.
Cool are you still in Texas? Any Porsche that runs is better than mine! I love 914's BTW.
@@GarageTimeAutoResto Houston. 914's are great - affordable (kinda) - I'm in the midst of fixing mine (again) as a postal truck ran into it... Donde estas? I love the 911 and what you're doing to it. and, your vids are really great - The link to this one is on 914World; that's how I found it. Good luck!
Huntington Beach, CA. I think I'm a member of 914 world. I'll cruise over and check it out. Sorry to hear about the postal truck. We have friends in Houston that we visit from time to time.
Nice project, and idea to add and measure chassis rigidity. FWIW, there are several discussions on this subject on a popular Porsche owner's forum. This is one: forums.pelicanparts.com/porsche-911-technical-forum/259557-structural-reinforcement.html ......Numerous contributors have added to the knowledge base with some solutions that greatly improve the chassis. Peeps should be aware that the rigidity on most race-prepped cars is achieved by the addition of a mandated roll cage structure that ties front and rear sections into one structural unit. However, that's hardly convenient for a street-based vehicle. But even without a cage, improvements can be gained by non-visible mods to the factory chassis.
Your rigidity calcs are probably more accurate than Mark Donohue's (famed racer-engineer) seat of the pants estimate some 40+ years ago. He estimated it was even worse at around 2000 Nm/deg. I suspect if you continue stitch-welding the interior cabin, your torsional rigidity numbers will continue to improve. Adding rigidity to the interior rocker panels seems to provide a distinctive (as well as non-visible) difference. Best wishes and thanks for your efforts. Looking forward to more videos in your restoration project.
BTW, resting the chassis on the tires and suspension may not be the ideal neutral starting point before welding. An uneven, corner-balanced vehicle will add some twist to the chassis. Better to start with a level surface and provide equal support to the chassis (easier said than done).
Thanks for your message! I have read that Pelican thread before. I will read it again now that I have some experience with this. I'm doing other mods to my chassis that was mentioned in that thread and similar forums. There's a lot of good information in there.
I agree a full cage offers the best improvement.
I did do some levelling of the chassis before when I replaced the suspension pan. Link here.
ua-cam.com/video/RHk3--W7V0w/v-deo.html
The car was in the same position and shimmed the same way when I did the seam welding. I could have done more to level the front versus let it sit in the wheels, but to be honest I don't think any noticeable distortion occurred. If it did the hood wouldn't close. I can go back and check using the same techniques in the above video but I doubt there's any change. My weight sitting in the gas tank support during welding was a bigger affect than then the corner balance issue. Another thing to keep in mind is that the car is very light when it's all stripped out, so the weight of the car is less of factor compared to the strength of the chassis when sitting flat.
I appreciate your comments and hope to see you here again.
Why not just use a constant weight rather than bouncing yourself with your feet partially on the ground. Not really confidence inspiring. But I’m sure it made a difference just not sure it’s the difference you found
I repeated the same test when I added a strut bar and used fixed weights. Check out this video:
ua-cam.com/video/QjGYaeYew8s/v-deo.html
The accuracy was about the same as taking three measurements and averaging the numbers. For me, anything over 10% is just a number. Seam/stich welding is a worthwhile endeavor.
Those are stitch welds, not seam welds.
Agree stitch welds on seams😀
You kind of remind me of Nicolas Cage
Nice, I wish I had his money!
Garage Time - Restomod me to!me to... lol
good video btw doing the same thing on my s13 cool to see I’m not alone you got a sub !
Thank You! Best of luck in your build! Write a question here if you need to and I'll try to get back to you.
This cars are a death trap., twist in a new porsche is 2d 8000 Ib I think.