Notching rear sub-frame tubes

Today was a bunch of notching with the mill and grinding wheel. We ended up tacking both sides of the rear sub-frame together and finished notching all of the connecting members. Just need to triple check some dimensions and come up with a jigging system to hold the sub-frame sides at the correct angles while tack welding them. The pictures should explain what I’m saying easier than I’m explaining it:

You may ask why the tubing extending forward of the subframe has run so long. Part of that is design; some length is necessary to cope the long runners of the frame back there. The other part is clueless-ness. What do I mean by that? I mean we are somewhat clueless as to how the 4g63 oil filter housing and oil pan are going to fit in the frame. Add on top of that, the fact that we need to get the half-shafts as straight as possible….

Here is the start of the jig to hold the 3D structure of the sub-frame sides together:

Hope to have the rest of the sub-frame tacked together by the end of this week. It’s coming along!

Starting the rear sub-frame

In some ways the rear sub-frame should be easier than the front, and in some ways harder. We are using left over tubing from the 24′ sticks we had to buy for the roll bending. The jig won’t be quite as self-explanatory, because we have to deal with the upper side tubes of the sub-frame being 2″ diameter here, instead of 1.5″.

You can tell from this picture what is being done. We’re going to construct the sides of the sub-frame first, dealing with the difference of tubing diameter by offsetting those tubes over the edge of the actual table using sections of 2×4’s with milled flat sides for accuracy. All of the 2×4 pieces are being offset from the edge of the table by using plate aluminum of the correct thickness, and locking them into place before screwing them down by using a few sturdy clamps. It’s turning out very well so far.

There are a few decisions to be made on the overall dimensions of the sub-frame. For one, we’re dealing with a different motor here. Not only is it a different make of motor meaning the dimensions won’t be the same, but the intake and exhaust are on opposite sites on our motor choice when compared to the ‘real’ Atom. We are going to attempt to get all of the dimensions close enough to keep the half-shafts as straight as possible both from a bird’s eye view, as well as a ground level view. This could be tricky…

The build has begun!

I know this doesn’t look like much, but it’s a pretty crucial section of the car. The front subframe is constructed fully of 1.5″ x 0.65″ tubing and the same tubing will be used for a majority of the rest of the car. At this point, we have the tubes all coped and they fit very tightly. This will really help when welding it up as there won’t be any gap to fill.