Wednesday, November 22, 2006

VW - Pre-Luber

According to studies by Ford (in the 1960's) and Mercedes-Benz (in the 1990's) the most significant factor in determining the service life of a properly maintained engine has more to do with how often it is started than with how many hours it has accumulated.

Here's why: Go out and jump in your ride. Turn on the key. See those light? One of them is telling you there is no oil pressure. Now start the engine and notice how long it takes for the oil pressure light to go OUT.

You've just started your engine `dry.' How dry depends on a number of factors such as how long the engine has been standing, the type of oil you are using and the ambient air temp. But the basic fact is the engine starts and runs for a period of time without adequate lubrication. No mystery at all as to why this produces so much wear.

Wanna see your VW or Toyota engine last virtually forever? Add a pre-luber. Go on. No big deal. See that screw-top aerosol canister from Harbor Freight? Buy one. Make a mount for it. (Upside down, please). Now pull the Schrader valve and replace it with a 12vdc continuous-duty solenoid valve. You may use a fuel tank purge valve from the junk yard, if you wish. But the real thing -- about $40 -- will work better. Now wire the solenoid valve into the ignition circuit. (Circuit ON, valve OPEN) Then plumb the thing to your main oil gallery.

Now, when you turn on the key about a pint of pressurized oil will be delivered to the engine before anything starts rotating. After the engine begins to run it will pump that amount of oil back into the pre-luber... and will trap it there, under pressure, when the key is turned off. (You may elaborate upon this scheme if you wish but the Plain Vanilla version will work just fine for an engine as small as a Volkswagen.)

If you do a bit of reading on the factors governing engine wear you'll find a lot of data regarding the size of contaminants, filter effectiveness and so forth. It is pretty obvious that full-flow oil filtration is good but all filtration systems contain a potentially harmful loop-hole in that the contaminants must pass through the oil pump before they can be trapped by the filter. (And no, you can't put the filter on the inlet. See the literature. The output of your oil pump is very sensitive to any restriction on the inlet. Low-restriction filters are huge things, unsuitable for use in a car or light plane.)

Since the most destructive contaminants are metal particles wiped from the cam and lifters, and since these particles are magnetic, I added three high-Gauss NIB rare-earth magnets to the outside of the sump plate, converting the entire plate into an extremely powerful magnet. The magnets cost about $10 each and were purchased as new/surplus from American Science & Surplus. That particular magnet is no longer available but they carry others.

Since I fit all of my engines with full-flow oil filters I've no need to remove the sump plate. But after a year of use I was curious as to how well the magnets were working. When I removed the sump plate it held a dense sludge of magnetic particles. To determine the fineness of the residue trapped by the magnets I washed the residue with MEK to break down the oil and passed it through a coffee filter and then a piece of filtering media removed from a new Purolator oil filter. In each case a significant quantity of particulate contaminant made it through the filter... and would have gone into my oil pump and then to the bearings... were it not for the powerful pull of the neodymium-iron-boron magnets.

-Bob Hoover


flybynightkarmarepair said...

Some candidate solenoid valves:|135|296545&id=122213

I've also seen valves that look like they'd work on E-Bay.

Liberal Seagull said...

A point that should be obvious, but perhaps isn't to everyone, is that once the magnets are in place they shouldn't be removed without cleaning the sump plate first. Otherwise all the particles they've accumulated will be suddenly dumped into the oil.