Nutmeg State 4X4

Clutch Technique
Engaging Options
by Terry Howe & Jefe

Editors note: These are advanced techniques to be used by experienced 4 wheelers. The situations described may be inherently dangerous and the driver must assess and decide upon the appropriate driving technique for any given situation. This article simply presents some optional techniques to consider.

Clutch Technique - Engaging Options

Anyone who has done some serious four wheeling is probably familiar with the technique of 'key starting'; using the starter motor to move the Jeep, in gear with your foot off the clutch pedal. This is most often used when restarting a stalled Jeep on the trail or when you need to move very slowly through a short, tricky situation. The technique is a very useful one, but the value of the technique is sometimes overstated. There are drawbacks to using it. Moving the Jeep with the starter puts a high stress on the starter and flywheel. Sometimes, it is more appropriate and safer to start with the clutch disengaged.

Engine Braking

Normally, on steep descents with a manual transmission, the best technique is to shift to a low gear and descend using engine compression to slow your descent, keeping your foot off the brake. The RPM's should be kept in the middle range so you can add or subtract power to maintain control. Engine braking is by far the best technique for long descents because brakes tend to heat up and fade with this over use.

When the descent becomes extreme, the engine braking can actually decrease control. Sometimes a hill is so steep, your Jeep will just begin sliding down it and your low gear is too low. The tires begin sliding because they are not rotating fast enough to keep traction and you in control. In this case, it is best to shift into 2nd or 3rd gear, depress the clutch pedal, and ride the brake. If you get into trouble, you can momentarily ease out the clutch and
use power to straighten out. You need a good touch on the brakes, you don't want to start skidding; just enough
to slow you down a bit.

Keeping the transmission in 2nd or 3rd is can be very handy if you are in a very steep descent, and the nose of your Jeep is going to hit the bottom hard with the risk of rolling over on your lid. What to do?

Let out the clutch and give it some power just before you hit bottom. Even if the rear tires come off the ground,
the front tires will be pulling you out of an endo. [This doesn't feel natural, but it is the appropriate technique]

This technique works great on short extremely steep descents where overheating the brakes in not a concern. If the descent is long and engine braking isn't working, maybe you shouldn't be doing it, or maybe you should pick a higher gear for more effective engine braking.

Key Starting

Using the starter to get out of bad off-camber situation can be a life saver. The starter will move you without the
sudden engagement that can happen with a clutch. Jerky movements can often cause a roll, so the use of the starter to move the vehicle is often the best way out of a bad spot. Sometimes you may find yourself stalled, mid obstacle. The choice is to either back off or finish the obstacle, and using the starter motor can sometimes be the easiest way back out or over. Often you'll see someone try to key over an obstacle they just couldn't make under power. Running with the starter does not increase traction or ground clearance, so this normally doesn't work.

The starter is smooth because it has no jerky engagement like the clutch and it will turn the engine slower than it turns at idle. It is really your ultimate crawl ratio, of course if your engine fires up, you won't be crawling at that speed for long. For those with fuel injection, it may be wise to install an on-off switch for your ignition. It may be impossible to just turn over your engine in order to move the Jeep without it actually starting it.

All this 'key starting' is tough on the flywheel and starter. It tends to chew up the teeth on the flywheel and the
flywheel isn't fun to replace. Normally a machine shop can press off the ring of teeth on the fly wheel and turn them over or replace them, but the labor involved in removing the flywheel and replacing it is substantial.

The starter teeth can also get pretty chewed up from running on the starter. Eventually they may tend not to mesh well and the flywheel and starter gear may wear more quickly. For people driving late CJs, the Ford starters are only about $25, but people driving Wranglers will find the Mitsubishi starter is closer to $100. This gets pretty pricey if you are going through a starter or two a year. Many savvy Jeepers buy the 'guaranteed forever' starters and keep a spare on hand.

The best thing to do is only 'key start' when you must, or when there is a clear advantage in doing so. If you haven't 'key started' before, it's worth a try to learn it before you need it. It is an unusual feeling if you haven't done it before. Always do it in the lowest possible gear to minimize strain on the starter.

Excerpt from http://www.off-road.com/jeep/

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