Engine wear and what to do about it
Most of the wear in an engine happens at start up. Research has indicated that 50 to 75% of your engine's wear happens at start up. When the engine runs an oil film between the engine parts avoids metallic contact and wear. At startup there is no oil pressure and no oil film.
So to reduce engine wear wouldn't it be nice to already have oil pressure and only then start the engine? Well there are systems on the market who can do this trick, and these so called prelube systems seem to work quite well. We will look into this system a bit further.
The system basically consists of:
* An inlet from the oil sump of the engine, often a pickup point is used in place of the drain plug.
* A hose from the oil sump to an electric oil pump with built in check valve
* A hose from the pump to the oil-sender or the oil filter of the engine
* An electronic control module that start's the pump when the ignition is on and switches on the pump for a short period after the engine is switched off.
Now before you start the engine you switch the ignition on and the pump starts to run. You can see the oil pressure rise on the oil pressure gauge. Then you start the engine. The system also switches on after the engine is switched off to enable the hot oil to cool down and carry away excess of engine heat. This is a very important feature if you are using a turbo because the system keeps lubricating the turbo bearings. Remember the turbo still turns at high speed after the engine has been switched off.
So should every body buy one?
Not necessarely because there are a few points which may help in your decision.
* Most wear comes from startup, however the preluber only lubricates the bearings and such. The piston, cylinders and cam lobes still don't get any extra lubrication. So you can expect only longer life of your main bearings and camshaft bearings. In practice most engines are worn because of worn pistons and cylinder bores not because of bearing wear. So this reduces the positive effect of the preluber.
Also, a standard SD1 engine which only does around 5000 miles a year doesn't need the preluber because it's cylinder's and pistons need a overhaul sooner than it's bearings.
* When running on petrol, on cold start ups the rich fuel washes away the oil film on the cylinder, resulting in a lot of wear. When running on LPG this effect doesn't happen. So LPG engines have less wear on the cylinder and piston. For a LPG engine the prelube system has its advantages because together with the high mileages an LPG engines normally makes the bearings are likely to go first on these engines instead of the cylinders and pistons.
* If you are using expensive cams, crankshafts and such a preluber system is also worthwhile.
* The six cylinder cylinder head is quite sensitive to clogging oilways. The clogging can occur because of high temperatures when the engine is switched off and the engine still gives off heat. The preluber systems keeps the oil in circulation after switch off and supplies cool oil to the head preventing clogging. The valve gear on the sixes is also more stressed than normal systems because two valves run from one lobe. So cam wear will be especially high on start up. With the preluber the oil pressure will be built faster and although a preluber will not directly oil the lobe it will reduce the delay time before the oil reaches the lobes and so reduces wear. As you see a preluber with the sixes isn't a bad idea.
* Running a turbo? No question about it a preluber is the way to go!
