How To Maintain The Cylinder Heads On Marine Engines
August 7, 2009 by Chris Wethered
Filed under Boat Engines And Sailboat Hardware, Questions Visitors Are Asking And Answers
Pistons and cylinder heads, get more wear than any other marine engine components. Without regular maintenance the following signs need to be monitored:
- Overheating
- Distortion
- Leaking
- Coughing
- Power lose
cylinder heads providing an air tight seal - the cover
Overheating
This can mean cracking of the cylinder head. The reason for this is adding cold water to an overheated engine. If this is the case, then change your cylinder head.
Distortion
The seal between cylinder head and engine block is not strong. Any unevenness will lead to air, oil or coolant transfer. The temperature differential means added stress and so distortion occurs. Avoid this by tightening the bolts frequently.
Coughing
The gasket beneath the cylinder head maybe leaking. The coughing is due to engine coolant mixing with oil. The worse this gets, the less likely your engine will start!
Power lose
If you experience this then this demonstrates a lot of cylinder wear
Filters
The air intake filter is important to regulating the engine heat. Make sure it is clear at all times
The above signs and reasons, are associated with cylinder head trouble. Usually they are contributory factors, that if monitored as part of the marine engine maintenance process, prolong the lifespan of your motor.
once cover removed, here are the heads
If your analysis leads you to wanting to do a cylinder head compression test, then here is an outline. You ought to be aware, that this test requires an understanding of the comparasion of cylinders and that the outcome may not be totally accurate.
In other words, if you determine that a cylinder is faulty - get it checked by a mechanic before going further!
Compression testing
- Take a dummy injector with a gauge measure
- Remove the injectors, test each cylinder individually. Turn over the starter engine to develop compression and whilst the dummy injector is in position, watch the pressure gauge
- Perform the test with out oil first - dry on all the heads write down the pressures as you go
- Now do the same again - wet, this is were you may notice the gauge pressure increase much quicker!
- If there was no significant increase in pressure, then your problem could lie with the valve seats
- If there is then consider the piston rings
Bare in mind: changing over these parts is tricky and if you are not experienced, could lead to bad experience! (Talk about killing off the fun!)
It's time to pour on the goodies with West Marine! That's right! When you spend over $100 you get 10% discount!
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Eight Inboard Engine Seasonal Checks
August 6, 2009 by Chris Wethered
Filed under Boat Engines And Sailboat Hardware, Questions Visitors Are Asking And Answers
Recently, comments have been left on the posts over a range of topics. Ten seasonal checks for your inboard engine is a drawing together of those questions:
Here are those checks which should be conducted seasonally or when indicated - more frequently.
Securing the mounting bolts
As marine diesel engines shudder, shake and generally produce a lot of vibration, even on good days, you should tighten all the supporting bolts. A securely fastened motor, wont jump out of it's fixtures. The more time your engine is left on, or is working, the more vibrations run through the bolts and loosen them.
Tightening the stuffing box
Ensure that only a few drops of liquid are escaping from the box. If this is the case great. If not then take two wrenches and tighten the nuts accordingly. Release the clamps to check for corrosion, rotate to hose and reclamp at each end. If the hose is cracked or worn - replace. Check over each component that makes up the unit.
Tighten screws, replace worn parts. Once the engine has been running a while check the stuffing box for temperature, if it is hot, then you need to repack the stuff to minimize wear.
Zinc anode part of your seasonal checks?
Gasket head test
Check coolant for oil. Take a glass and partially fill with coolant from the expansion tank. Give it a moment to settle. What do you see? If the liquid is oily or milky in color, then thoroughly go over the gasket head for signs of wear. More information on gasket heads
Exhaust pipe examination
Taking a spot light, examine the pipe for signs of corrosion. When diesel is combusted, thirty five percent of the total amount is driven off as exhaust. This exhaust is highly corrosive and therefore the exhaust pipe will suffer. Signs of weakness maybe masked by oil deposits, jacketing around the pipe and so on. If pitting is visible over the exterior, then the pipe must be replaced.
Belt tensions
Ought to taught and elastic. Some give is good. Cracked belts are dangerous, so replace them. Check all wiring and connects at the same time as belts. Faulty wiring leads to aluminum corrosion
Leaks
Check all hoses, pipes and connectors. Use a clean cloth to determine any leaks. Be sure to wipe underneath them as well. That's where accumulation occurs. Generally the condition they need to be in is soft, and squeezable. Not the pipes of course. If they are in that condition - replace! Search for kinks too. Places where gases and fluids accumulate. If a back log starts then that will lead to a series of interconnected problems later on.
Cylinder gasket heads
Pumps and filters
Check the fuel pump, fuel filters and fuel supply shut off valve. The minimum requirement of the filters is to stop water getting in and to absorb contaminates. Check them daily, or before each use. If after three months you find the bowl needs draining, then you should also clean the fuel tank.
Each time you change the oil, change the filter as well. You need to be able to get a wrench around the canister in order to change the filter. Change the oil seasonally or every one hundred and twenty five hours. Which ever comes first! Remember the fuel injector gradually wears and should be tested seasonally. This makes sure the fuel is being atomized effectively.
Monitor the drip catch tray under the engine and the bilges too. These act as early warning signs as to the health of your motor. This should be done daily or before you fire up.
Water pump
As the cooling of marine engines is critical to safe use, the water pump needs thorough, frequent inspections.
- Thirty percent of energy in combustion is heat
- Thirty five percent is exhaust
- Thirty five percent is usable power
Overheating causes damage very quickly with a series of knock on effects. You need to ensure that regardless as to your type of cooling system (direct / indirect) that the flow of raw water is not impeded. Plus that the impeller is able to operate. Direct cooling systems, require less overall maintaining, as they are simpler. Indirect systems have added components and so are more timely.
It's time to pour on the goodies with West Marine! That's right! When you spend over $100 you get 10% discount!
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