Wecome To RVs and OHVs

This blog is all about RVs (recreational vehicles) and OHVs (Off Highway Vehicles), camping, and survival
and how they work together to provide wholesome family fun and great learning opportunities.
Many posts are intended to familiarize novice campers and RVers with RV systems and basic camping and survival
skills. But even experienced RVers and campers will enjoy the anecdotes and may even benefit from a new
perspective. Comments, questions, and suggestions are encouraged.

Sunday, April 26, 2015

The Venerable GM 454 Engine

Many gasoline powered motorhomes are fitted with a Chevrolet 454 "big block" V-8 engine.  You will find them on many older Class A's based on the Chevrolet P-30 chassis and on the modern Workhorse Chassis.  They are generally quite powerful and reliable, but not particularly stingy when it comes to fuel economy.  I've owned several 454 powered Class As, ranging from 28' to 35' and they all pretty much got about 6-7 mpg -- up hill, down hill, head wind, tail wind, towing a trailer, driving solo, sitting in a parking lot.  A popular saying is that a 454 can pass anything but a gas station.  I like the power of the big block engine in a motorhome, especially when towing my enclosed motorcycle trailer.  I have tried motorhomes and pickups with the smaller 350 engine and found fuel economy was even worse (especially when towing), while lacking the pulling power of the 454.

Over the years the 454s have developed a reputation for a few specific issues you may want to watch for if your RV is thus equipped.  For starters, they tend to generate a lot of heat.  The typical solution is to improve the exhaust system, replacing the stock manifolds with headers, enlarging the exhaust pipes, and installing free flow mufflers.  I've seen the stock manifolds on more than one motorhome glowing cherry red after climbing a steep hill.  That kind of heating contributes to warped manifolds causing noisy and dangerous exhaust leaks.  Upgrading the exhaust system will have other benefits beyond getting rid of heat.  A more open exhaust reduces back pressure and lets the engine "breath" better.  I experienced a very dramatic demonstration of the affects of a restricted exhaust system when I blew out the "donut" gasket between the manifold and the exhaust down pipe on one of my 454s.  I was climbing a gentle hill at the time and the motorhome jumped forward like it had been kicked in the butt when that gasket blew out.  A better exhaust is one of the key features of the famous "Banks Powerpack".  Another major component of the Banks upgrade is an improved air input system.  Together these two changes typically deliver both improved performance and better gas mileage, which is a pretty good deal since most performance modifications improve power at the cost of fuel economy or fuel economy at the cost of power.

That heat also translates into well known starter problems.  The starter is necessarily tucked in right under the right exhaust manifold where it is exposed to very high temperatures.  The most common symptom is hard starting when the engine is hot.  The starter binds up inside and can't overcome the internal resistance with enough force to turn the engine over.  Over time, the problem further damages the starter so it doesn't work well anytime.  After market high performance and geared starters are available and are said to help mitigate common 454 starter problems.  Another common heat related problem is melting of wiring on the starter.  You may also be able to install a heat shield to keep some of the heat from the exhaust manifold from impacting the starter directly.  There are at least two kinds of heat shields.   One is a metal plate that helps reflect heat from the  manifolds away from the starter.  Another is foil wrapped, insulated blanket that wraps around the starter. 

There is another problem that is often mistaken for a starter problem.  The symptoms are much the same.  The starter will turn over once or twice and then stall.  This is often due to a faulty ground strap between the engine and the vehicle frame instead of a dead  battery or worn out starter.  Over time the connection between the ground strap terminal and the frame can become rusted or corroded so it doesn't make a good connection.  If you experience starting problems that would be one of the first things to check.  Many times it can be corrected simply by cleaning the terminal and the spot where it attaches to the frame.  Or you may want to replace the entire ground strap, especially if it is small or flimsy to start with.  And old fashioned braided steel battery ground strap about an inch wide is a good choice if you have to upgrade.  I've even heard of at least one RVer who added a second ground strap on the right side of the engine.  Perhaps he has a "Valley Girl" mentality ("For sure, for sure.").  A second strap shouldn't be necessary, but it certainly won't hurt.

You may find folks who recommend an oversize oil filter to increase oil capacity.  They will often claim it will even help dissipate engine heat, especially if the filter is equipped with cooling fins.  I tried the oversize filters on a couple of my rigs and can't say that I noticed any perceptible difference.  However, having nearly an extra quart of oil in the system certainly won't hurt anything (except a small pain in your wallet for an extra quart at each oil change and the extra cost of the oversized filter).  The extra filter area may also be more efficient at removing contaminates.  It could reduce contamination and prevent unnecessary wear.   Anything that helps keep the oil cleaner longer is a good thing. The impact of these factors is difficult to measure.  The oversize oil filter is usually available as a direct replacement for the regular spin-on filter, but will be a lot longer.   The consensus I found in my most recent research is that over sized oil filters probably aren't worth the extra cost, but if it gives you peace of mind, it certainly won't hurt anything.  I put it in the "good to have", not the "must have" category.

On the subject of filters, there is another filter worth thinking about:  the air filter.  First of all, you always want to keep your air filter clean.  A clogged air filter will significantly reduce mileage and performance.  I like to use a K&N reususable air filter.  They generally allow greater air flow than standard paper elements and can be cleaned and reused over and over. They are a bit pricey to buy, but since they don't have to be replaced frequently, they pay for themselves over a few change intervals.  The improved air flow gives better power and better fuel economy.  Regular cleaning consists mostly of knocking off loose dirt; scheduled in depth cleaning calls for washing the filter in an approved solvent and re-oiling it with K&N filter oil.

Most 454s are equipped with fan clutches that engage and disengage the fan depending on the temperature.  You can usually hear when the fan kicks in or off  from inside the coach.  The sound can be quite dramatic.  Many drivers mistake it for downshifting when the fan kicks in.  If the fan is always engaged or never engages, the clutch may be faulty.  The purpose of the clutch is to engage the fan when it is needed for cooling.  If it is on when it isn't need, it puts some additional drag on the engine, which could have a slight affect on fuel economy and performance, and it may prevent the engine from reaching proper operating temperature by over cooling the radiator.  If it never engages, the fan will never operate, resulting in overheating.

Speaking of radiators, I've seen some motorhomes equipped with what I would consider to be undersized radiators.  I'm not talking about the square inches of surface or height and width, I'm talking about the number of rows of cores inside.  The more rows, the better it will cool.  If you have consistent overheating problems you should have the radiator checked.  First of all, there can be internal deposits that restrict flow and significantly reduce cooling capacity.  This can be tested with an optical sensing thermometer.  If there are places the radiator is hotter than in other places, there is something restricting the flow, most likely some kind of internal blockage.  Secondly, you might have a radiator with only a few rows of tubes in the core.  If boiling out  and rodding out the radiator to get rid of deposits doesn't solve your problem, check with your radiator shop about upgrading to a heavier duty radiator with more core tubes.  Unless the extra thickness pushes the radiator back into the fan or interferes with something out front, a heavier duty radiator should bolt right in where the original was without any modifications required.  Of course the heavy duty radiator will be more expensive than an OEM replacement, but the improved performance is well worth it.

Big blocks rock!

Monday, April 13, 2015

Shake Down Cruise

Shake down cruises probably apply mostly to RVs, but even tent campers can benefit from them, especially when you are just starting out or have purchased new equipment you need to try out.  The purpose of shake down cruise is to familiarize yourself with use and operation and to try out all systems and equipment and see if there are any problems that need to be addressed.

A shakedown cruise should be fairly close to home, in case you find any major issues you need to deal with.  If you need to test a motorhome or tow vehicle you'll want to make the trip long enough to properly exercise the mechanical components and capabilities but you probably shouldn't take off on a major trip (inter-state or cross-country) until you're sure you have the bugs out.  Sometimes you can check out a lot of things by "camping" right at home, although you will need to do at least some driving to exercise and prove vehicle mechanical systems.

Hopefully weather will allow you opportunities to check out both heating and air conditioning systems in your RV an/or other vehicle.  We found a recent shakedown cruise in April in Utah was ideal.  Days were warm enough to test the A/C and nights cool enough to use the furnace.  Be sure to exercise all the major systems and watch for any signs of failure or poor performance.  Plumbing leaks on RVs, even new ones, are fairly common.  Look for wet spots or drips beneath your RV or on the walls or floor.  If the 12-volt water pump cycles when you don't have an fixture in use you probably have a leak in a pipe or connection that you should track down before your next trip.  Until then, turn the pump off when you are not actively using water to minimize leakage and resulting water damage until you can fix the leak.  If you have an older camper with a pressurized water system it will lose pressure even when you aren't using any water if there is a leak.  If you are camping in a campground with hookups, watch for wet spots and listen for hissing sounds that might indicate a plumbing leak.  Sometimes you can hear water flowing at the faucet. If you do when no water is being used in your RV you probably have a leak.  It could be a leaky hose or a problem inside the RV so check hose and connections first.

If your RV refrigerator uses more than one power source (gas, 120 volts, 12 volts) be sure to try all the options.  Electrical connections can corrode or vibrate loose and insects may build nests in the propane gas lines and burner.  A build up of dust and debris on the cooling coils may seriously reduce performance or you may discover you need an auxiliary fan on the coils.

Tent camping shakedowns can be done in your own back yard unless you need to test out your vehicle.  It is especially helpful to learn how to setup a new tent before you have to do it under the stress of doing it in camp, possible with adverse winds and weather, and in front of other campers.  It is also a good idea to make sure all the components are there and in good condition while you are where you can get replacements or make repairs before you head out camping.  Checkout your camp stove and lanterns.  Test your sleeping bags and sleeping pads so you can make adjustments before you are totally dependent on them.  I once discovered my favorite 10° bag was useless even at 40° because it had been too tightly rolled in storage for too long and had lost virtually all of the insulating properties of loft.  In most places all there was were two thin pieces of nylon cloth; all the padding had been compressed to nearly nothing.  Unfortunately that happened on an actual outing and I had to make do.  Had I taken the time the check things out beforehand, I would have been able to replace the bag (which I did at the first opportunity) or at least bring along some extra blankets instead of freezing at night.

Make a list of any findings.   Your list might include provisions you need to restock and any additional items or equipment as well as any required repairs and desired updates.

Shake it up (er, uh, down) baby!