mtnman82

I used cinderblocks/12" wide sheet of pine/ramp under each wheel to do my clutch job. Very stable and worked well. If you search my clutch threads you should be able to find pics. I got tired of lugging the cinderblocks back/forth to do undercarriage work and made myself some wooden blocks - I'll try to remember to take/post pics this evening. I can't remember if I used 2x8's or 2x10's for the sides/braces, and then used 2x4's on the top. To put up on the blocks/ramps, I jack up side to side, doing the blocks first then the ramps if I want to get it up higher. One thing that's maybe not obvious is that you'll need to build a 5th block (for the jack) if you want to put the ramps on top of the blocks.

It may be more stable than it looks, but the vette setup in the link you posted looks like you could push it over from the side fairly easily...... But if he used 2x10's (or 2x12's), it's probably sturdy. IMHO, it's a bit overdone in the sense that you only need supports under each wheel, and also I think it's nice to be to able to roll under the car (or pass tools/stuff) from the side, instead of just the front rear.

gt37vgt

and one more for the ney sayers saying its a death trap .
it can be sealed so oil dosn't get it in.
in air craft and sailing many choose wood over carbon fiber as it can be visually inspected and certified. Also it creeks and cracks before failing witch can be handy.

Bri Bro

I was wondering why not just use four ramps that are made for the application?

http://www.discountramps.com/wheel-cribs.htm
http://www.discountramps.com/low_profile_car_ramp.htm

ninefiveone

So I'm curious... how do you drive up 4 ramps to get the car up?

mclarenno9

I agree with 2bridges... Personally, I would not want to count on the fasteners to take the loads when driving up on the thing. Picture it without the sides, its just a rectangle, which could turn into a parallelogram with any reasonable amount of opposing forces along the direction of the top and bottom pieces. You want some sort of triangulation between the vertical pieces to keep the structure strong in that direction also.

Euro951

Those ramps will support the load fine. Just go visit your friendly engineer neighbor who will tell you why.... If they are built correctly with wood glue and are on a level surface you will be fine. Just don't do burnouts on them

mtnman82

Never saw those!

Don't drive up them, jack it up one side at a time... I had quite a few friends/neighbors ask me "how in the world did you drive up the ramps like that ... ?" when they saw my car during the clutch job...


Here's the pics I promised:







BTW, I did use 2x10's for the sides. When I put the exhaust on, all I used were the wood blocks and there was a good amount of room. If I was going to do the clutch again, I'd put it up on the block & ramps.

Have fun!!!

Dom1

I guess if it is not too difficult to jack it up to such a height this would be a better solution since you can access the car from the sides and less storage space is required..

Here is somethign similar

http://www.myturbodiesel.com/1000q_h.../woodblock.htm

mtnman82

^^ - yup, I like that idea too!

And yes, you definitely need a low profile jack that gets the car up high enough. The new blue one in the pics doesn't quite hack it, but the gray one in the back just barely does (need to put a 2x12 under the jack, too).

Also, it's a little scary when you're jacking up the car higher to put on the 2nd level - just be slow & careful. As scary as it is though, I don't think it'd be as scary as driving your car up something that high & narrow.

2bridges

LOL - well I will tell you I have in fact built a bridge that is in use every day.
Lots of research and consultation was involved and I can tell you WITHOUT QUESTION - static load ratings (for building a house structure for example) DO NOT apply. You have impact loads, transition loads, deflection, and small load points none of which apply for a static application.

do what you want..... but I will say as an informed fellow there is no way in hell my *** will be under something like that. Your call, it's only your life

Bri Bro

When I had done this, I would placed jack stands (on solid cinder blocks as it got higher) on both sides of the car . Then jack a little and adjust the stands to the new height. When the jack get near it max lift, add wood blocks to the top plate. If you have a couple of helpers, it takes very little time to do this. I still keep jack stands on the car on all four corners when on the ramps/wheel cribs, I crush way too easy.

Sure is nice having a lift in the garage I can avoid all of this.

Quinlan

I would listen to 2bridges on this one. These things are NOT safe!
The postings show the plywood on the OUTSIDE of the parallelogram which, I agree, is NOT the safe way to proceed. It does not take advantage of the true strength of a torsion box. I think if the plywood (not OSB) were to be fit INSIDE the side pods, you would then at least be relying on the compressive strength of the plywood, rather than the shear strength of the fasteners or glue.
Having said that, remember, when working on the underside of your vehicle, you will probably be wrenching, tugging, and generally putting sideways loads on the car that will put the ultimate test to your "engineering" abilities......so, in the words of Dirty Harry, "do you feel lucky today?"
And no, I am not an engineer, so take this with a very very liberal grain of salt

vt951

I think those wooden risers are a "natural selection."

The big issue with the risers in the OP is the question of how well they are put together in each instance, how well they will withstand the test of time, and what will the fasteners and/or glue do wehn subjected to all different types of loads (other than vertical).

I think if you're going to do something like this, the cinder blocks look a lot safer (and weather resistant). You might consider putting a few more blocks around each corner and spanning them with a larger piece of plywood. Then the structure would have some redundancy in case one of the blocks fails.

Yes, I am an engineer. Not that you need to be an engineer to realize those wooden risers are dangerous.

Ian Carr

you trust 2x12"s to hold up your house but not your car...

CPR

I agree that some additonal interior bracing is needed (for safety), but the overall design is fine. Not that I would use them

Incremental linear loading is not NEARLY as impactful/destructive in this capacity, and would be no real different than having 8 of your Buddies standing on each one drinking a keg.