For the average Saturday night racer, common car floor jacks are either too heavy or too inconvenient to use at the track, and buying a full-fledged racing jack is too pricey.

One solution is to take an inexpensive jack and, with a few modifications, turn it into one that will give your race car a lift without lightening your wallet.

The base jacks, found at auto parts and discount stores, sell for around $18 to $30. Their flaw is having a handle, which must be moved from the pump to the valve and back to raise and lower the jack. Having to do this under the car, and sometimes in the dark, is a pain.

Their best feature is that they weigh only about 25 pounds. At two tons, the capacity is more than sufficient enough to raise one end of the car. The lack of speed in jacking up a car is of little importance unless you are making pit stops. Numerous strokes may be required to reach full height.

The base jack we used for this project is a Larin 4,000-pound model that we bought at an auto parts store for $18.99. Similar jacks are available from many sources. Our modified jack is designed mainly for use in the working areas at dirt tracks.

Modifications Begin by spreading out the jack and the handle parts. Remove the pins holding the pump-handle socket and lift it out. Next, weld the handle into the socket and also weld the handle halves together if yours has a two-piece handle. We like a tee handle, so we welded on a crosspiece.

Obtain a washer with a 1-inch hole. Weld this to the handle about 12 inches from the inner end. This will now be the guide for the hydraulic hose, which will operate the valve.

Stand the jack on its nose by propping it up against a workbench. This will keep hydraulic fluid from running out when the valve screw is removed. Purchase a piece of ½-inch hydraulic hose about 20-inches long with a ½-inch male pipe end on one end only. Remove the O-ring from the valve screw.

Shield the machined section with tape. Insert only ¼-inch of the valve into the hydraulic hose fitting. Weld the valve end to the hydraulic hose fitting. Clean off the burned tape, replace the O-ring and re-install the valve screw. At this time you may also re-install the handle, slipping the hose into the washer. Twisting the hose now operates the valve.

Next, remove the wheels (they can be saved for a future project). With a torch or saw, cut off the wheel brackets.

The front axle should be welded to the jack sides for strength. Grind the sides of the jack smooth.

Cut out a steel plate. It should be 12-inches long, eight-inches wide and at least a 12 gauge (.104-inch) thickness. Anything thicker is fine, but it is heavier. Give one end an upturn, and this will make sliding the jack under the car easier. This skidplate keeps the jack from sinking in soft dirt. Weld this plate to the bottom of the jack on each side, extending the upturned end 2½ inches in front of the jack.

The pivoting jackplate flange also can be removed to gain an additional ½-inch collapsed height. On the jacking surface, build up each corner about 1/8 of an inch with weld for some traction points. All together, these modifications should yield a 3¾-inch collapsed height. Best of all, it weighs only 23 pounds!

Questions or comments? You can reach Sleepy Gomez via e-mail at sleepy.gomez@worldnet.att.net