I feel your pain.  I just bought a C3 and I'm finding myself stuffed under
it quite a bit.  It is incentive to not gain any more weight.  I'd hate to
get wedged under there because I had one too many pieces of pizza!!

Incidentally, I believe you can get more room under the car with a good set
of jack stands than you can with ramps.  At least that seems to be the case
for me.

I'll be interested in hearing about your "pit" endeavor.  I have a
brand-spankin' new 24' x 40' garage that I am starting to wish either had a
pit or a lift.

Ryan

I would suggest you use your talent and forget digging a pit.  Build a drive on ramp tall enough for you to get under, or if your ceilings high enough, look into a hydraulic lift, check
http://www.e-autolifts.com/xl/xl.html#
http://www.e-autolifts.com/4posttable.html
http://www.google.com/search?hl=en&ie=UTF-8&q=hydraulic+auto+lifts&spell=1

 Okay....now that I have this Vette and have given it's new home I need to
 look after it.

    I have these car ramps and am having one HELL of a time getting under the
 car and doing much of anything.
  My wife at suppertime suggests I make a 'Pit" in my hobby shop so here goes
 the question.

     I have a shop in the back yard that is 24 ft by 28 ft with a cement
 floor. I would like to cut a hole through the cement and then am going to
 hand dig the basement or pit.

     I am a welder and own my own business. I own all the tools to do any
 job......My only concern is with how to "do" this project and what to 'crib'
 the walls with or technical info on how to do this without any disasters...

     Did the Google search thing to no avail

      Thanks for any help....regards......jim

Jim spoke thusly...

No...no...NO!  Very bad idea.  I know that it would take an
extraordinary sequence of events, but we can all attest that Murphy
strikes all too often...if something were to go terribly wrong, you have
no place to go.  If you absolutely MUST have that much room under the
car, spend the money (borrow if you have to) and get a lift.  Please.
Dad and Bob can give you an idea of how much they go for (if they want to).

I'm going along with the consensus here.
Grease pits were outlawed many years ago.
In addition to the dangers already mentioned,
people and cars tend to fall into them.

I'm not sure I'd recommend the "pit" approach. It has to be long enough
for you to get in and out of it with the car in place, using steps or a
ladder, which means it has to be BIG and takes up floor space. It could
be a place where groundwater collects, so it has to have a sump pump or
something to bail it out when it's wet. You have to carry everything
down into it and lift it back out again. It's a liability hazard because
someone may inadvertently fall into it, and it needs a sturdy cover that
must be slid or folded off and on every time you use the pit (more floor
space). It may even violate local building codes.

If you have a tall enough garage ceiling (at least 9 to 10 feet), a
4-post lift is a much better approach.

Or, get yourself a large heavy-duty floor jack and a second set of
sturdy ramps; drive onto the first set, chock the front wheels, then
jack up the rear and place the second ramp set under the rear wheels
facing the opposite direction to capture the tires, lower the jack. I
sometimes use this approach on cars with a solid rear axle (jack beneath
the pumpkin), but it may be tougher to do with an independent rear
suspension. I've even then jacked up a corner, placed a solid 2x8 board
under the ramp, etc, etc, to raise the car just a few more inches for
better access on long-term projects (too much work for quick jobs).

=======================================
Jim ....
 
The local planning and zoning people shot me down on a pit many years
ago ...( I am on a well & septic) and they did not think being 30 or
so foot away from my drainage field was far enough...SO CHECK

My dad had a pit in his garage ... and it was about 40 inches wide by
about 12 or so foot long...and deep enough to stand in and work
comfortiby work on mufflers etc..  Not really sure of the
measurements...

The walls were block (again not sure if 4" 8 " or what..) the bottom
was concrete slightly sloping in to the center which had a FRENCH
Drain in the center...

Never caused a problem in all the years he used it...BUT since it did
not have a "cover" over it I bet the building inspectors today would
flunk it pretty darn fast...

Personally I have a couple of 4 post lifts in my garages..(2500-$3000)
all you need is about a 10 foot ceiling ... Actually I only had 8 foor
in one garage BUT a chain saw removed a few rafters and a few 2x8's
braced the roof... so I just created a "well" that the car raises up
into...  

Bob Griffiths  

Good idea.  I think they are great.

For all the nay-sayers,
- I checked with my current insurer (Nationwide) about one recently and the
agent said no problem, he had several homeowners with them.
- one hassle was the supposed collection of toxic or explosive gases.
However, any good ventilation system removes that problem.
- Dad's suggestion of breaking a gas line and the trouble light means he is
missed today's news.  Use a covered fluorescent trouble light that doesn't
break.  As for the fuel leak, you'd rather be laying on your back under a
car?  Besides, how many times to you break a fuel line?
- you can change the oil by the time most have the car all the way up on a
lift.
- people falling in is highly exaggerated. Had one for 10 years, no one ever
fell in. parents still have one after 25 years. Only one car ever fell in -
mine.  I pushed it in by mistake. It caught on the bumper and I had to use
the hoist to lift it back up to get the front wheels on the floor.
- you never hear of a car falling off a pit.
- pits don't fail and drop a car on you.

- pulling an engine is easy with a pit.  Try it with a lift - up, down,up,
down, up, down, up, etc.

- want friends? Put in a pit, you'll be amazed at how many show up to work
in your garage.
- you don't need 12 ft of clearance.
- works on cars, pickups, and so on.
- Price a lift you want to stake your life on?

Hassles/problems:
- insurance killed them in commercial operations
- some city codes prevent it.
- need a drain to remove spillage.  This often is an EPA issue.  (Although,
if you spill two gallons of coolant in a pit or in your drive or flat garage
floor, it is all the same.)  It is possible to do without a drain, but if
you spill a lot, it is harder to clean up.
- need lots of length. On a 14 ft Vette, you really want about 16 ft of pit.
- hard to do brake work on a pit.  But with the drive-on ramp-type hobby
lifts, you can't either.
- you have to cover it or some idiot will fall in just to prove they can.
Of course, more idiots trip over lifts when down or hit their heads when up.
At least if an idiot falls in the pit, you can just cover it over and haul
him away at night.
- covers can be a hassle to fabricate.
- You'll discover it is a great place to store big things, like engines,
hoods, etc., until you have no space to work in it.
- you need a low water table. At least 15 ft in rainy season.
- at the age of most old farts on here, they can't bend over to lift the
covers anymore and don't have the strength to lift them if they could. Crawl
down a  ladder under a car? Most on here couldn't do that for the last 25
years.

Here is how a couple pits I'm closely familiar with were built.

Hole in the floor on one was formed when the floor poured.  It used monolith
type pouring to have thicker concrete at the opening.  The hole was dug by
hand because we didn't have access to a backhoe, and couldn't have gotten it
the garage anyway. A footer was poured by hand and concrete block laid.
Some steel rebar was put down some of the holes. The floor of the pit was
poured off a truck, angled to slope to one end, and the cap of the block
wall under the garage slab was poured at the same time, with some down the
rebar holes.  This was edged to make a lip for the cover to sit in, to
provide a flush floor when closed.  This one was designed to accommodate a
6'2" guy under a Corvette, so the floor is 6 foot below the garage floor
surface. Roughly 14 ft long which allowed room to get in in front of the car
and be able to walk back to the rear suspension.  width was out almost to
the inside of the Vette tires.  Along the wall was two four ft fluorescent
light tubes end to end. It eliminated the need for a drop light most of the
time.  Four outlet box in the middle to eliminate the need of most extension
cords. Two ton hoist on beam over this area.

The other was a hole cut with a concrete saw. The floor was poured first.
Then plywood forms for the walls, with 2x4 bracing, and hanging from the
garage floor.
The walls were then poured.  I never worked in it.

Anther was built similar to the first.  However, it was designed around a
'32 Ford truck hot rod and was not deep enough.  When I had a Vette over, I
had to crouch and still kept hitting my head. It was only about 5' 6" deep
and only about 10 ft long. I had to roll the car over me, work, then roll
the car off. Perfectly sane for a 22 year old desperate to get a clutch
changed in December.

One person I know set the depth such that he could lift the covers (flipped
from side) up to fold on the floor and the car drove on them.

NO PIT!!
Above the floor post power lifts are relatively cheap these days...