914-6/904 project begins Options

[mb911]

Tomorrow is going to be fun. Picked up the plate steel to box in the inner cockpit, before I cut the outer longs.
I got 1/4 inch, maybe overkill but I want it to be strong.

Make sure you have the welder set correct for 1/4" 19 volts 300 ipm would be a good setting for thick to thin

[tygaboy]

I'd suggest 1/4" is way too thick. If you're talking about replicating the "traditional" inner long/lower firewall stiffener, kit you'd be more than fine with 16 Ga, 14 at the most. You're adding a TON of weight that isn't doing you much more good than 14 or 16.

Or is this just temporary while you work on the outer longs? If that's the case, you'd be better off with something like Tangerine Racing's door brace kit. I had both my outer rockers off with just door braces and it worked just fine.

[Unobtanium-inc]

Tomorrow is going to be fun. Picked up the plate steel to box in the inner cockpit, before I cut the outer longs.
I got 1/4 inch, maybe overkill but I want it to be strong.

Make sure you have the welder set correct for 1/4" 19 volts 300 ipm would be a good setting for thick to thin

Thanks for the tip.

[Unobtanium-inc]

I'd suggest 1/4" is way too thick. If you're talking about replicating the "traditional" inner long/lower firewall stiffener, kit you'd be more than fine with 16 Ga, 14 at the most. You're adding a TON of weight that isn't doing you much more good than 14 or 16.

Or is this just temporary while you work on the outer longs? If that's the case, you'd be better off with something like Tangerine Racing's door brace kit. I had both my outer rockers off with just door braces and it worked just fine.

I'm trying to add some hardcore rigidity to the center mass of the car. I cut away so much of the car, and the fiberglass body is very thin and will add little if any substance. I also wanted some solidness in case of a crash, again the fiberglass won't help.
In order to have the door pockets for the body fit I have to cut all the long off, everything but the inner wall, which is what I'm hoping to strengthen.
Look at the pics of the test body, you can see how the long gets cut to ribbons.

[Unobtanium-inc]

Tomorrow is going to be fun. Picked up the plate steel to box in the inner cockpit, before I cut the outer longs.
I got 1/4 inch, maybe overkill but I want it to be strong.

I want to help/learn.
I hope I'm not too far away. Teach me

Let's talk once Covid is over, the shop is pretty much closed now.

[rhodyguy]

In case of a crash? "Over"?

[Unobtanium-inc]

Was hoping to get the pieces welded in today but ran out of day and out of metal. The metal place cut one piece down for me, and gave me the short end, not the long end I paid for, so I'll swap that out today on the way home. I did get the two side pieces cut and fitted and the cardboard template is in for the firewall piece. Hoping I can sneak out of the house this weekend and get up to the shop and finish this part up. Here's hoping!

Happy Holidays!!!!!

[Carbon-14]

Monocoque or tubular structure, a beam, stiffening the platform.
Attaching the ends and edges to the existing remains of the 914 chassis must be accomplished by spreading the loads to larger areas, adapter plates and bulkheads of similar thickness light sheetmetal.


https://www.restoration-design.com/store/product/PP301R
Emulating Porsche's perimeter box rails attached to the 914's pan, elegantly.
The corrugated and bossed panels when welded to a clamshell beam with internal integral stiffeners transfer the loads to their ends without buckling and are relatively lightweight. Some modifications will be necessary to fit beneath the 904 grp siderails.
Measuring the diagonal stiffness of the resulting weldment will determine the performance characteristics of the chassis.
Looking good.
(IMG:style_emoticons/default/thumb3d.gif)

[Unobtanium-inc]

Monocoque or tubular structure, a beam, stiffening the platform.
Attaching the ends and edges to the existing remains of the 914 chassis must be accomplished by spreading the loads to larger areas, adapter plates and bulkheads of similar thickness light sheetmetal.


https://www.restoration-design.com/store/product/PP301R
Emulating Porsche's perimeter box rails attached to the 914's pan, elegantly.
The corrugated and bossed panels when welded to a clamshell beam with internal integral stiffeners transfer the loads to their ends without buckling and are relatively lightweight. Some modifications will be necessary to fit beneath the 904 grp siderails.
Measuring the diagonal stiffness of the resulting weldment will determine the performance characteristics of the chassis.
Looking good.
(IMG:style_emoticons/default/thumb3d.gif)

Thanks for the input and graphics. I was a little confused at what you were saying. Are you saying I'm on the right track with the inner pieces I made, or I should get a piece from RD and start with that?

[Carbon-14]

Your solution will work just fine, welded securely to the chassis, like the armor plated hulls of battleships.
(IMG:style_emoticons/default/smile.gif)
Plenty stiff in torsion, a good thing, though with a weight penalty, and likely still below 1800 Lbs ~ 820kgs, all good.
(IMG:style_emoticons/default/evilgrin.gif)
Pressing the plate steel into an L shape would have added substantial rigidity, making holes to lighten the plates would benefit the power to weight ratio, which should approach that of the 904's.
'..for what I got, a carbed 3.2, with a sequential gearbox...'
A centrifugal blower, to get the power up, heh heh, a blown injected 914/904.
https://www.youtube.com/watch?v=t9JB6jRSZD4
Press on regardless.
(IMG:style_emoticons/default/thumb3d.gif)

[mate914]

I like both. Keep the 1/4'' steel and with the clamshell make a boxed frame. Maybe run heating through the small boxed frame to clear windshield. Would also be a safe place for oil lines.
Looks great.

[Bruce Hinds]

That was going to be my question: Why not put the plate on the outside of the inner long to make the C section a D section? Seems like the D would be stronger and only make the thing a 1/2 inch wider.

[Unobtanium-inc]

That was going to be my question: Why not put the plate on the outside of the inner long to make the C section a D section? Seems like the D would be stronger and only make the thing a 1/2 inch wider.

I had no room to spare on the outer wall, the body barely fit.
My solution was to strengthen the last remaining wall of the original long, thereby still having all the original structure, factory spot welds etc, but making the whole thing super strong with the thick steel.
The similarities of the 914 and the 904 are great, but there are times when they diverge pretty dramatically. Probably because one was a purpose built, low production race car, and the other was a production car made for the masses. I'm just glad I'm not terribly tall, because anyone much taller than me (5'9") would have a really hard time in this car.

[Bruce Hinds]

That was going to be my question: Why not put the plate on the outside of the inner long to make the C section a D section? Seems like the D would be stronger and only make the thing a 1/2 inch wider.

I had no room to spare on the outer wall, the body barely fit.
My solution was to strengthen the last remaining wall of the original long, thereby still having all the original structure, factory spot welds etc, but making the whole thing super strong with the thick steel.
The similarities of the 914 and the 904 are great, but there are times when they diverge pretty dramatically. Probably because one was a purpose built, low production race car, and the other was a production car made for the masses. I'm just glad I'm not terribly tall, because anyone much taller than me (5'9") would have a really hard time in this car.

Understood - such a cool project. Thanks for sharing . . . (IMG:style_emoticons/default/popcorn[1].gif)

[Unobtanium-inc]

Ok, was able to sneak away today and get the plate steel cut fitted and welded in, so all in all a pretty good day. I need to finish out the welding but for now nothing is going anywhere and the fit was pretty good. It was nice to turn up the welder (thanks mb911) and do some real thick steel welding. It reminds of when I took my welding class in Brooklyn so many years ago, thick welds that were nice and flowing. It's a lot harder to get those kind of welds on 60 year old cars with sometimes questionable metal that is thin in many spots. This was welding like it was intended to be, a slow flow of metal, joining two thick pieces. It was quite refreshing!

Hope everyone had a nice holiday!

[Unobtanium-inc]

One last shot, wouldn't fit the first round.

[mate914]

That is the ultimate inner long kit.
The one time I saw a real 904 it was tiny compared to my teenier.
Looks good....

[Unobtanium-inc]

Ok, holidays done, back to work. Meaning it took me several weeks to get a day to work on my own stuff. I welded in the plates all the way in anticipation of cutting out the rollbar and the outer longs. I got the rollbar out, as well as the driver's side long. So you can know see why I had to really really reinforce the longs, because there is nothing left!

I think I have to jump back on a 911 tomorrow, but I might split the day, or come in this weekend, so be on the lookout for more updates.

Happy New Year!

[Unobtanium-inc]

No new work, but I recently did a buying trip through VA and stopped off to see my friend Bob Garretson to get him to sign the dash. He had some great stories of racing 935's and the like. Bob and Bruce Anderson originally built this car for IMSA racing.

[Unobtanium-inc]

Ok, the selling season is officially over so the "winter work on your own shit" period has begun. I moved the chassis to another part of the shop today, bigger space but it's next to the wood stove so it will be a hot winter of welding.
Expect regular updates until Spring when we will start pumping cars again.