LocostUSA.com

hmmmmm....

looking at the pics of this `53 resto/hotrod made me think (what is sometimes a bad thing )



more details here; http://www.jalopyjournal.com/forum/showthread.php?t=629357&showall=1

i do have aluminum front and rear craddles that let me drop the drivetrain if there is need for major engine or transaxle work ...



... so it does not make sense (from a weight standpoint) to build a traditional ladder frame with a removable cab and bed on top of it.

what do you guys think about making the cab/bed an integral part of the frame with just the front/rear fenders and the hood removable ?!?

this would save a lot of weight, mainly in the center tunnel ;
there is no need for covering the structural center tunnel with additional sheetmetal in the cab
same goes for the rocker panels (they are probably rusty anyway) ;
the rectangular tubing of the frame could replace the rocker panels
etc ...

_________________
- Stephan -

a picture is slowly forming in my head ...

there is a lot of chassis engineering awesomeness in the new C7 Vette ;



notice the removable center tunnel "stiffener" plate that turns the open U into a torsional stiffer closed box-tube ...
that is definitely a detail that i`m going to shamelessly copy (and probably the susp subframe braces as well)

i think i will re-use the factory frame cutoff "stubs" (black) that will arrive with the drivetrain ...


.. and tie them together with a formed steel plate center tunnel and two large (thin wall) box tubing sections that will replace the rocker sheetmetal panel of the stock cab.
for safety sake (and to have a strong mounting point for modern 3-point belts) i`m thinking to add a 1.75 x .120 DOM rollbar to the cab
(i personally would even add an A-pillar rollbar loop)
the rollbar could tie direct into the box tube rockers and also support the back wall so that i can weld the bed sides to it.
additionally i`m thinking to add underdash "spreader" bars that would tie the door hinge/A-pillar uprights to each other and to the center tunnel & firewall
(and ultimately into the front frame stubs)
this will also give me a strong point for hanging the pedal box and steering column (and greatly reduce cowl shake)

basically i`m thinking to turn the old "cab on frame" truck into a "unibody with subframe"

... just thinking out loud ....
any suggestions are very welcome

_________________
- Stephan -

Stephan
Look at both the Vette and Viper center tunnel designs and the sectional width and height used. The close out plate on the Vette tunnel, if I recall increased the torisional resistance by more then 10% for the ZO6 chassis. Big time improvement. But aligning all the small bolt holes was a PITA. The front ditch joint would tend to spread, but with a steal fire wall you should have less of a problem. I would suggest a couple small tube "X" braces bolted across the bottom of the tunnel, since you will have a lot more ground clearance. I do not think the 1950's box will carry the uni-body loads. Several of these type builds use the S-10 chassis. Dave W

There's a lot of work doing a classy job on a project like this. So looking at your C6 chassis it seems the best place to add 10 inches is in the cylinder region. Make a U shaped cut around both chassis engines. Then saw a V4 off one engine and weld it onto the other one and tidy up. With a big job like this you should "offer" the V4 part a couple of times before you actually weld it.

At this point you can just drag the truck body around behind you. It'll probably still carry stuff fine too.

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
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wut?

i think i lost you somewhere between U-cut and V4

but actually your right that adding wb could be done in front of the cylinders by sliding the engine (with torque tube & transaxle) back a couple inches
but then it will probably create a footbox space issue
nah... i think i leave the drivetrain as it is

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- Stephan -

Was watching the show Roadkill on youtube. If you have not seen it I would totally recommend you watch them. In the latest episode they have a segment where they talked about a guy who specialized in custom autocross trucks. His name is Rob MacGregor and he is the owner of No Limit Engineering. Looking him up on google showed some good ideas on a frame, heck you can buy one of his for 12,000

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Brian

Brian
thanks for the headsup ...
but no thanks
if you add up all the options like brakes, coilovers, and and .............. your looking at probably ~$20k for just the chassis
and then its still a imho grossly outdated design with solid rear end and all

FYI the rolling C6 drivetrain as pictured was "only" $8550 ... and this includes engine and transmission
considering all the nice parts you get with it i would call it a real bargain.

_________________
- Stephan -

the project officially started :



yesterday my friend Ryan dropped off the Vette drivetrain crates and the truck...



... as well as an insane heavy 3/4" thick steel plate that i will use as a fab surface plate/welding table



Ryan and me feeling like kids on Christmas day



now i just need to reassemble the drivetrain and then i can start with taking measurements & the CAD drawings



Cleveland pick-a-part did a outstanding job wrapping and crating everything
... nice to see a business that cares that you get your stuff undamaged

btw
GM made us a gift: the front subframe crate is already machined and drilled for two engine/ wb positions :smokin:
the stock 105.7" wb Vette and a 107" wb position that is off-set to the passenger side by .75"
what is just about perfect for the truck ! ... thank you GM

the not so nice thing was that i wanted to quickly remove the composite leaf for easier frame setup
(and that i can cycle the suspension to check for clearance)
... needed over 2 hours and complete disassembly of the front suspension to get that darn pre-loaded B%@# out of there

_________________
- Stephan -

was busy;
stripped & capped everything on the engine that i dont need for fabbing and re-assembled the rolling drivetrain



notice how far the engine is set back by using the "long WB" mounting holes
i`m used to wrench on taller things so it is kinda strange to see this extremely low slung drivetrain sitting at ride height for the first time...



my bro`s reaction; "its a frigging skateboard with a V8 !!! "



the 3/4" engine off-set to the passenger side is giving me more clearance for the steering shaft
and it will probably also give me a little more room for the driver footbox



i discovered that there are two common machined planes at the front and rear subframe,
so i drilled two 2x2x.125" tubing sections to bolt them together
the two tubes will later sit on the big steel surface plate
this shoul bring the two clips to the same level
with diagonal measuring and a rotary laser i should be able to square the clips to near factory specs

after some measuring and thinkering with the chassis i decided to scrap the 'large box tube' idea.
i have more room under the cab then what i expected so i`m going with a tubular space frame instead
something similar to this sriiimotorsports chassis ;







found the pics at SRIII Motorsports Inc.

round tube gives me a lot more freedom in shaping the frame tightly around the drivetrain

the factory frame cutoffs have a .75" id corner radius, so i`m going to use 1.5" DOM tubing
this allows me to blend the cutoffs clean & nicely into the space frame.

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- Stephan -

Stephan,

you keep adding at the end of your posts a line about comments, clearly you are in no need of any thus far in the build, although i will be keeping my eye on you from a far, just in case.

you know exactly where you are going on this build.

when you used the alternative engine holes that set the motor sideways as well as back, has this affected the alignment of the front and back cradles?

its a pitty that you can't move the diff forward in the rear cradle to solve your wheel base problem, in fact, can you just mount the cradle to your new chassis for the suspension and mount the diff directly to the chassis in a more forward location, having your drive shafts angled backwards to the wheels, you are obviously conversant with steep CV angles.

_________________
this story shall the good man teach his son,
and chrispin chrispian shall ne'er go by,
from this day to the end of the world.
but we in it shall be remembered.

How about a simple structure to mount the front cradle forward the other 3" or so you need to match the wheelbase?

That is if the engine and firewall can coexist that way.

Better weight distribution that way too.

_________________
mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.

John
using the off-set engine mounting holes puts the complete drivetrain on a slight angle...
but it is only a very small degree of miss-alignment at the rear CV`s

i noticed that the rear axle shafts pointed slightly forward,
so i removed the rear cradle and machined the transaxle mounting holes to slide the cradle back by 3/4"





its only a small increase in WB... but may as well do whatever is easy to do

after i had the cradles bolted down and squared/aligned i started bending the lower tubes...



needed 3 bends each tube to squeeze them tightly around the fuel tanks and so that they still fit under the cab/sidesteps



with the upper tubes in place i started with the cross-over connetions;





most of the X-bracing in place;





started boxing-in the tube to frame cutoff connections;





today is shop cleanup day ... should be able to start fitting the cab onto the frame sometimes next week

_________________
- Stephan -

finish welded the main frame, bolted the cradles back on
and rolled the whole thing out onto the street for some pics;



the frame looked large on the welding table,
but down on the ground it is very low profile













now i need to take the body apart so that i can start fitting the cab
cant wait to see how it will look

_________________
- Stephan -

Wow Stephan. That is just amazing.
What do you do for the afternoon. Take a little snooze?

_________________
Martin


My build log:
viewtopic.php?f=35&t=14520&start=0
My build video:
https://vimeo.com/143524140 password "matovid"

G'day Stephen,

Firstly Wow what a great project you are creating, have loved ever picture and txt you have posted. Please please keep them coming.

I have just commenced the same build, here in Brisbane Ausralia, only difference, is i'm using the Cadillac rolling drive train from an XLR-V (2009) and my truck is a 1950.

I was very excited to see you are using the frame cutoff's, and am desperate to do the same (along with using my existing original 3100 chassis, however as you will see from the photo my drivetrain has not come with these cutoff's. I've search high and low and can't find a set anywhere (any chance you would know where is could get my hands on them ?

Looking forward to the next instalment

Cheers mate.
Shaun