Ney guy here.

[PalliP]

Thanks.
I was going to make a pinoin support down to the cross tube in the bottom.  Do you think that is enough?
That reinforcement in the shoulder hoop, isnt that for under 6 sek?  Can I take the extra tube and Slice it upp by length ena weld it back together on the shoulder hoop?
Regards.
Palli

[rooman]

Palli,
        tying the front of the third member to the crossmember is acceptable as a pinion support and most were done like that in the past. I usually add tabs to the bottom of the housing and run a K from there to the chassis. As Bruce commented, having a sleeve in the shoulder hoop is a good idea in any case even if it is not required at the performance level that you are predicting as most sanctioning bodies are afflicted by "rule creep" where what was good one year may not be in the future. Are you are talking about cutting a piece of tube lengthwise and shrinking the diameter to make it fit inside the shoulder hoop?

Roo

[dreracecar]

I think he was talking about clam-shelling the outer which is not the way to do it. The required sleeve is an internal sleeve. Split the 1 3/8 length wise(it will expand for a tight fit) Split the shoulder hoop, insert sleeve and weld back together and use roset welds to indicate that sleeve is present.  I like to to use a 5/8 hole to roset and weld around the perimeter and have the inner sleeve visable.

[PalliP]

I tought it was to be on the outside, it explaines everything to have it on the inside.  It is easy to modify it now.
I have a nother question, diagonal tube that goes from corner to corner.  Why is it welded to the uprights only?  Why not in the corner and welded to both horisonal and vertical tubes.
Borrowed a photo from Clint Jobbs to show you.
Thanks again for good answers, you guys are one step closer makeŽn a 4x4 guy a dragracer

[GlennLever]

I tought it was to be on the outside, it explaines everything to have it on the inside.  It is easy to modify it now.
I have a nother question, diagonal tube that goes from corner to corner.  Why is it welded to the uprights only?  Why not in the corner and welded to both horisonal and vertical tubes.
Borrowed a photo from Clint Jobbs to show you.
Thanks again for good answers, you guys are one step closer makeŽn a 4x4 guy a dragracer

I wonder if the jig that chassis is sitting on is strong enough?

[dreracecar]

Its just a quicker way of fitting the diag. If one is fitting corner to corner(the aircraft way)one has to fit an uprite then diag then uprite. If both diag are fitted you will not be able to insert the diag because of its length.

[PalliP]

Ofcourse, then you have to weld in some big holes if you are going to fit the dialog afterwards.  Thanks alot, you are helping me a lot.

[slingshot383]

When coping the diagonals to fit the uprights, use a piece of 1/4" stock for your offset from the main tubes.  Makes the spacing consistant and gives you room to completely weld the tube. Don't forget to drill your gas holes as you go so that you don't blow out your weld.

[janjon]

Regarding the advice below:

 "Also at this time before you go further I would cut the shoulder hoop (between the front rollbar and the foward seat uprite) and install the inner (sleave) tubing support, Now is the time even tho you might not need it now for the spec, it might happen later or you might go up in class or sell the chassie to sombody else."

 Current copy of 2.4C seems to agree with the edition you posted the diagram from. I'm a little confused as to the necessity of the interior reinforcement tube as you described.
 If I'm reading the spec correctly, the "upper frame rail" is defined as beginning 2" forward of the rear motor plate upright, and extending rearward to the vicintity of the rear end upright and the forward seat upright, at which "shoulder hoop" begins to exist, with step-up maybe required if the two entities are not one and the same, (the larger seat hoop tubing at 1-1/2 x .058).
 This would seem to allow the upper frame rail / shoulder hoop to exist as one piece, as it appears to be on PalliP's car, or to consist of as many as many as 4 individual pieces, butt-spliced and sleeved as many as 3 places.
 So I don't see why you would want to put a splice there if it's already one continuous piece meeting the spec in the case of the shoulder hoop, and exceeding it in the case of the upper frame rails???
 Is there maybe some more advanced spec that would require the splice there

Thanks for any insight,
John Williams

[rooman]

John,
        Bruce's suggestion was not to add a splice as such but to enable the insertion of an inner sleeve to support the front hoop of the cage. I don't have a copy of the SFI 2.6 spec (7.5 and slower) in front of me as I build all of my cars to the 2.2 or 2.4 standard and both of those require the sleeve.  As Bruce noted' at his projected performance level and due to where he plans to compete Palli's car may not need the inner reinforcement at this time but rules "creep" is a fact of life and being a step ahead is always a good idea.

Roo

[wideopen231]

 I inserted the sleeve before bending the lower bends at motor. I pushed it to where I needed it and rose bud welded it in place.It would have been easier to cut ant put in place. On rear where roll bar connects to shoulder hoop I don't think I have to have its since my lower rails turn up and are directly under roll cage bars? Hope I read it correctly that this was ok.Oh yea 6 point cage.

[dreracecar]

Couple of points here
  With 2.4 only the shoulder hoop needs to be 1 1/2 x .058  2" foward of the rear end uprite and foward of that my step down to 1 3/8 towards the motor plate. The insearction of the 1 3/8 fully into the 1 1/2  to the shoulder hoop bend covers the inner support tube requirment.
  The splice between the foward seat uprite and front hoop is for single dia shoulder hoops in that area if its a continous bend. Years prior, one could add another uprite to the foward roll bar hoop down to the shoulder hoop, but this was for older chassies where splicing it at that point would create too much work.
 Those that can get the hoops bent in a single piece, have the bends on the same plane, and the front motor plate timed and angled exactly--my hats off to you. I find that by making it 4 piece I can that the rear hoop on my flat and are able to twist the foward sections to center the rear hoop and line up the front half. If one is of on angle or rotation in dealing with long wheelbase chassies, a little bit here makes a huge difference over there

[janjon]

Dre sez:

"Those that can get the hoops bent in a single piece, have the bends on the same plane, and the front motor plate timed and angled exactly--my hats off to you. I find that by making it 4 piece I can that the rear hoop on my flat and are able to twist the foward sections to center the rear hoop and line up the front half. If one is of on angle or rotation in dealing with long wheelbase chassies, a little bit here makes a huge difference over there

 Valuable insight there, thanks. I will bear that in mind If and as I build somethink.
John

[rooman]

Bruce is correct (as usual).  I have access to a high dollar mandrel bender (as well as my in shop unit) so I bend shoulder hoops and top rails in batches. I make the lateral leg of the shoulder hoop long enough that I can make the wide cars that some of my larger customers need for comfort. For the regular one I just shorten the leg. Likewise with the forward portion of the top rail (motor to rear end/cage front hoop). By having some extra length I can trim it to suit where the motor is located. As Bruce notes, being able to rotate that bend at the motor upright sure makes it easier to get the front half of the car aligned. The same applies if you use an arched cross member to mount the steering box. Using two bends and splicing them in the middle allows you to vary the height  relative to the frame while still having the bends land on the upper rails. If you want it higher just leave the tail of the bend longer and splice to fit. If it works for Don Long it works for me.

Roo

[janjon]

Goodie, so what works for Don and Bruce and Kevin, will work for me...
It's awesome that chassis builders like yourselves are willing to share hows and whys, techniques and philosophies.