cribbing ~ undertray bellypan ~ my first attempt

[j12piprius]

I'm planning to do an undertray, based on suggestions by The donkey CRX here. First is to raise the car, then I'm planning to use coroplast or hdpe plastic, and zip ties or screws for attachment.

Update: I made cribbing boxes, and am looking for places to mount coroplast to the frame.

[freebeard]

I use a floor jack and two sets (low and high) of jackstands. What used to take 4 lifts I can now do in two, up to about 18".

In this browser, at this location, the link '14 inch high plywood boxes' just goes to page six of another thread. In this I assume it was to describe a cubical box.

Instead of a box—use two truncated triangles with interlocking slots to make a pyramid. If they are going under the tires, the one going across the tread can be flat and the one with the tread can be curved upward.

Are you going to use new or recycled materials?

A new material I'm going to test is FiberFix tape. It's billed as '100 times as strong as duct tape' but it's inherently double-sided. If it works the way I think it will you'd have to remove anything you tape to the undercarriage with a hammer and chisel.

I've got some to test, if I get off my b*tt I'll post some result here.

[j12piprius]

Jack stands would raise the underside from 7.25" to 16.75", but would be in the way.
Well made 14" wood boxes would raise the underside to 21.25", and provide better access.

Here's a description of cribbing, safety concerns, and details about making the boxes in 2 parts.
I'm planning to make the boxes shown below, described here, but in 2 parts like the previous ones.

[freebeard]

Well that's better. I'd looked through the first nine pages of that thread to see how adequately the plywood box was fastened along the edges, without finding anything.

Cribbing, on the other hand will hold up a house. Just use soft wood instead of hardwood.

[freebeard]

That all sounds good except cutting up new lumber. With a hand saw.

[j12piprius]

I got a HF 3 ton floor jack on sale for $68.88, 10x 96"x 2x4's cut in 1/2 from HD, and a box of 10d 3" common nails, which have more structural stability, less chance of splitting the wood, and a much better price then screws. I might need another piece of coroplast but will wait until checking the underside and seeing what is needed.

I've cut the 2x4's into 40x 10 and 14" pieces with a hand saw, which took a couple of days and was mild exercise. The floor jack lifts the car easily with the wheels more than 6" off the ground. The car was tilting to one side, but that will be high enough for the first level of boxes, and the total will be 6" higher.

The underside looks like this photo from daqcivic's thread on his 92 civic DX. This is a busy week for me, but I'm hoping to finish the boxes by this weekend, then will take a closer look underneath.

[j12piprius]

I've finished the lower boxes, 5 layers and 7 1/2 inches high. I'll try them tomorrow, then make the upper boxes, which will be 6 inches high and 13 1/2" total. The bottom middle 2 pieces of the upper boxes will fit between the upper outside 2 pieces of the lower ones.

[j12piprius]

Cribbing & Jacking

1) I completed the 1st two levels of boxes, at 7.5 and 10.5" high, underbody 15 and 18", but the floor jack with a piece of 2x4 on the top would only put the wheels at 7.5" high.

2) The jack began squeaking a lot and continued. I will lubricate the jack and check the hydraulic levels.

Underside

3) The exhaust, muffler, and a long exhaust tube in the middle are the lowest parts of the car, and get hot, so I might leave them uncovered or else use a screen. There is room for the low hanging exhaust to be raised up higher, but the attachments don't appear to allow any adjustments. There are 2 long metal tubes in a long plastic enclosure full of holes. Can they be covered?

4) From the middle to the sides is relatively the same height but quite rippled. Perhaps a lower, smooth surface will be better. Coroplast can be attached to the plastic sides, and there are metal beams near the center with large holes, but I'm not sure how to attach to them.

5) The front underside, viewed from the middle, is much more open than I'd thought, especially behind the radiator. I will try to cover some, as long as it doesn't interfere with cooling the engine.

6) The underside is most open in the back, around and above the muffler, and on the driver side where there's a big space. It appears that coroplast can be bent down from behind the back tire, then horizontally back and attached to above the back bumper. The underside is all new to me and will probably take awhile to complete. I will start with the back and go from there.

Next:
1) lubricate the floor jack;
2) complete another 3" of boxes;
3) raise the floor jack up 4 to 6 inches higher;
4) figure out how to attach coroplast to the back and sides.

[j12piprius]

1) I bled the floor jack by using this procedure. Another procedure for bleeding and filling is shown here. I lubricated the moving parts, and the jack was already full of oil. The jack raises the wheels to 10.5", the underbody to 18" high, and the jack was much more quiet than yesterday too.

2) I think the 10.5 to 18" height is high enough to work on the underside.

3) I'm not confident of the 1000# capacity of my dolly. If I decide to go higher, then I'll rig up a base to go under the floor jack.

4) Next I will look for places to mount the coroplast to the frame.