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August 2002 4x4 Truck Repair Questions - Tech Line

Willie Worthy | Writer
Posted August 1, 2002

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Techline
Four Wheeler
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Los Angeles, CA 90048-5515.

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Restore Or Modify?
Question: I have a 1976 Ford F-100 1/2-ton 4x4 that I'm restoring. I can't find any parts for my truck, like a lift kit, etc. Can you suggest any sources?
Denny Steel
Mayerthorpe, Alberta, Canada

Answer: First of all, some semantics: The word "restore" means to put back in original condition. If you "lift" your truck and add aftermarket accessories, you're not restoring it. But perhaps you're planning to rebuild it into something fitting your needs.

As to aftermarket lift kits and other accessories, you're right. I was unable to locate any company that makes a system for your truck. There's just not enough demand. However, don't give up. Parts can be modified or re-engineered to fit your truck. It's going to take just a bit more work on your part.

For example, the specs on your truck's springs are: front, 6 leaves, 48 inches long, 2 1/2-inches wide. They have a deflection rate of 410 pounds per inch and a capacity of 1,400 pounds. The rears are 52 inches x 2 1/2-inches with 7 leaves, a variable rate of 225 to 340 pounds per inch, and a capacity of 1,680 pounds. A couple of things you can do: Order up a Rancho catalog. Toward the back you'll find a chart listing the various spring dimensions the company has available. Compare this to your present springs until you find something close to your needs. You may have to relocate a spring hanger forward or backward a bit to accommodate your new springs, but usually this isn't a hard thing to do. Your second choice would be to find a spring rebuilder and have a custom set built, which will be a bit more expensive.

After the new springs are in, you'll have to figure out what new shocks you'll need, taking into account both extension and compression travel, making sure that the shocks won't top out or bottom out before the springs do. You may just have to fabricate taller upper shock mounts in order to take advantage of your increased spring travel.

Making It Waterproof
Question: I am currently working on an '86 Chevy Suburban 3/4-ton 4x4. The engine is a 350 and I am interested in installing a snorkel kit. Do you know of any manufacturers of such a product for this application, or is it a custom-make project? If so, have you ever written any articles on such projects? What is involved in waterproofing the rest of the engine, distributor, etc.?
Brian Hamilton
Calgary, Alberta, Canada

Answer: We have never seen or heard of a snorkel for your truck. But we don't see why, with a bit of ingenuity, one couldn't be made with some PVC pipe and a bit of flex tubing. Perhaps not pretty, but functional.

As to waterproofing the engine, that's nearly impossible. You can make it somewhat water-tight, at best. Any place the water can get in you will obviously have to seal. For instance, you will need some type of a boot around the engine's dip-stick tube. A properly sized spark-plug boot usually works. With an auto trans you will also need to seal the fill tube. You will need an extended vent hose attached to the trans vent as well as to the differentials. Keeping the ignition system dry is a real problem. Dielectric grease on the spark-plug boots, perhaps a zip tie around the connections, and even some 3M weather-stripping cement at all the connections will help.

Totally sealing the distributor is a no-no. It has to breathe to rid itself of vapors that may leak past the distributor shaft, and to rid itself of the ozone that builds up inside it. When you can seal it, you must add some sort of a vent line or outlet to the base of the distributor or to the cap. When anticipating any water-crossing you could plug this vent for a short time.

The starter can be sealed with silicon or weather-strip cement. Sealing a bellhousing is difficult, so you should not even try to do that. Instead, provide a way for the water that gets in to drain out as rapidly as possible.

A bit of water doesn't seem to hurt the alternator, but you sure don't want to get water into the power-steering pump, so a vent line on the top of the fill-cap is needed. Fans and deep water just don't mix well. Blades can break when they hit the water, which in turn can destroy the radiator. Some people will temporarily put something in front of the radiator to block the radiator from water; as long as good movement is maintained, water will flow around the radiator and not make contact with the fan. Stop for a moment, though, and the fan chops into the water. The solution is to remove the fan for water crossings, but not the drive belt, because the fan is generally connected to the water pump and without the water pump the engine will rapidly overheat. Could be that an electric fan is in order.

Like we said, you are never going to completely waterproof an engine. But following these guidelines, you can make it somewhat water-tight.

Big Meats Or No?
Question: I own a '99 Ford F-150 4x4 pickup regular cab. I get plenty of power from the automatic tranny, stock 5.4L V-8 engine (I've added a K&N air intake and Magna Flow exhaust), and 3.73 gears. The truck is my daily driver. I generally don't haul anything that doesn't fit in my Flareside bed, and off-road use is primarily in the mud and dirt, and in some rocks; but this truck definitely is not a rockcrawler.

I want to replace my stock tires with 35x12.50 Goodyear MT/R tires with a Rancho Suspension and a body lift providing the necessary room. The gearing will remain the same. A local shop said it would not be a problem, but everyone else on my block warns that I am asking for a world of trouble with meats that heavy. According to my buddies, I should expect all kinds of problems with my suspension, bearings, and even steering.

Does this modification require new aftermarket components for my steering? Ideally, I would also like beefier axles than stock, but I'd like to avoid swapping those out immediately if possible. Can the factory originals do the job with such large tires?

My shop quoted me $2,000-plus to lower my gears in the rear-that strikes me as a bit steep. Are there any less expensive methods? What would you worry about (besides fuel economy) given my proposed modifications?

To make up for the added weight of the tires and altered gearing, future modifications include Gibson headers and exhaust, a mass air flow sensor, and a new power chip.
Ricardo V. Santa Cruz
Tucson, Arizona

Answer: Any time you add a component to your vehicle that wasn't a factory option you are going to affect its performance. Sometimes you add a bit of bad with the good. The 35-inch tires fall into this category. Yes, the added weight and size will cause more wear to the steering components, reduce braking performance, and definitely hurt your highway performance. The added ride height will cause more air turbulence that, in addition to heavier wheels and tires, will reduce fuel mileage. The 3.73:1 gear ratio and the 35-inch tires will make the engine unhappy, as when the trans is in Overdrive, the engine rpm will be way below the torque peak. In fact, you will find that the trans will shift down on even the slightest grade.

How much more wear and tear will this cause? That's a difficult question to answer as a lot depends on how hard you use your truck. There are a lot of trucks out there running the same type of modifications you intend to make and seem to survive quite well. The added aftermarket air cleaner, exhaust, and other accessories all will be helpful but the problem is that the engine speed is well below where it was intended to run. The ideal gear ratio should be in the 4.27:1 to 4.56:1 range, the latter being our choice. Keep in mind that both the front and rear gear ratios have to match.

Yes, $2,000 for a single axle gear change is a bit on the high side. Should be closer to $1,000. It goes without saying that anytime you change the ratio in one axle, you must change the ratio in the other. Changing just one is not an option.

Weber For Wrangler
Question: I'm thinking about purchasing a new carb for my '87 Jeep Wrangler (4.2L) and was just curious why I've never seen anything about Weber carbs in your carb shootouts and testing articles. Is the Weber not up to the task of four-wheeling? Or am I just not looking hard enough? Will a Weber do away with flat spots (bucking when I pound on the gas?), or is fuel injection the only solution for smooth acceleration?
John Miccio
Deer Park, New York

Answer: The Weber replacement carb for the 4.2L Wrangler is a great way to go. It's much more tunable and much more off-road-friendly than the stock item and there even is a gain of a couple extra horsepower. The factory carb does suffer from several abnormalities after it has reached around the 50,000-mile mark.

The biggest potential problem with the Weber is that it may not be emissions-legal in your area. This is something that you need to check out yourself.

If you can handle the extra money involved, go with the fuel injection. The Mopar conversion kit really does work as advertised. Something that I have found that is definitely needed is some form of a small inline surge tank for the fuel. The new fuel pump required with the EFI system usually is mounted outside of the fuel tank. When fuel levels fall below a certain point, there will be times that there will be no fuel at the pickup tube, resulting in fuel starvation. Not only will the engine quit, there is also a chance that the fuel pump will be damaged.

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