Penny Gets A Diaper
Apr. 8-15, 2007
 Penny in Lynn's garage. |
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Easy To Find The Way Back Home
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Penny has been leaving a trail of oil drops everywhere she goes (left).
Lynn confirms that the leak is coming from the rear main seal (center) and buys a replacement seal kit (right).
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In principle, Lynn should never get lost while driving Penny. She is dripping enough oil that he should be able to follow the trail back home, like the bread crumb trail that was left by Hansel and Gretel in the fairy tale by the Brothers Grimm.
Lynn thinks that he knows the source of the problem, it's a faulty rear main oil seal. He confirms this by removing the clutch and flywheel access cover. Sure enough, after the engine warms, a steady oil leak can be seen dripping off the rear of the engine in the area of the rear main seal. At warm idle, the oil is leaking at the rate of about one drop every couple of seconds.
This is way too frequent for Lynn's comfort. Everywhere Penny parks, she leaves a four inch diameter puddle. When he parks, he can usually see a trail of oil drops on the pavement going back the way he came. If she sits in one spot at an idle, she will leave an even bigger mess. He won't drive into friends driveways because of this.
Although Lynn has a pan in the garage to catch the bulk of the oil where she sits, there's an ugly trail leading up the driveway into the garage. Something must be done.
Lynn buys a new rear main seal kit. This is the easy part. As many people will know, the rear main seal is buried deep in the engine. Located on the crank shaft of the engine just after the last main bearing, the seal is supposed to keep oil supplied (under pressure) to that bearing from leaking out of the engine. The best time to replace the seal is when the engine is out of the car and upside down on an engine stand.
Lynn thinks about how to replace it with the engine in the car. At a minimum he needs to remove the transmission, engine oil pan, remove (or loosen) the main bearing caps, then maybe he might be able to install a new seal. Even if it all works as Lynn imagines, there is a very real possibility that the new seal won't be properly fit and cut, and the new seal might still leak.
In fact, Lynn suspects that Penny does have a relatively new oil seal. The engine has clearly been rebuilt recently and Lynn can't imagine any sane person rebuilding the engine without installing new oil seals. It's likely that the seals were simply improperly installed.
The First Attempt
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Here are some photos of Lynn's first attempt to create a trough to catch the leaking oil.
A copper tube is split open and soldered to the inside of the flywheel cover (left, left center).
After reinstalling the cover, the end of the copper pipe (arrow) is where the oil should drip (center).
A plastic jug is suspended under the oil pan to collect the oil (right center, right).
Evidence of the system working is seen as dirty engine oil is collected in the jug after an
extended test drive (right).
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While watching the oil drip off the end of the block during his confirmation of the source, it occurs to Lynn that maybe he could somehow collect the oil. This would only be a temporary fix, but it would take the pressure off Lynn for the moment, allowing him to wait until a later date when he could remove the engine from the car and do a proper fix.
There's already a hole at the bottom of the flywheel cover where the oil leaks out. Unfortunately this is too low on the car to place a collecting bottle. That bottle would be quickly scrapped off by contact with the road or a curb.
Lynn briefly considers running a tube from the flywheel cover hole to the intake manifold, using the intake vacuum to draw the oil into the engine to be burned in the combustion chambers. He quickly rejects that as an environmentally unfriendly solution to an environmentally unfriendly problem.
Lynn hits upon the idea of creating a little trough higher in the flywheel cover which will give him enough height that he can capture the oil by a gravity feed to a suspended bottle. Using copper tubing and an old cooking oil bottle he creates a diaper for Penny.
Once he starts the car Lynn immediately identifies one problem with his design. The flywheel is apparently lightly touching the copper tubing and a unpleasant chatter is heard. The volume of the noise quickly subsides as the flywheel cuts the needed clearance in the copper.
Lynn sets out on an extended test drive. There's clear evidence that the system is at least partially working as he finds dirty oil in the collection bottle when he gets home.
He's disappointed to see that Penny is still leaving a puddle while she sits in the driveway idling. The diaper is catching some, but not all or even most of the leaking oil. Lynn has gotten close, but he's not yet satisfied with the result of his initial effort.
A Second Effort
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An improved trough that extends the full width of the cover is created (left).
This system is now catching most of the leaking oil (right).
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Lynn makes a second attempt and tries improving the concept by making the trough wider. Using flat steel he create a trough that extends the entire width of the flywheel cover.
Once again a defect in Lynn's design is evident as soon as the car starts. The flywheel is lightly touching the trough somewhere and it make a racket. Although the sound is reduced somewhat after the engine runs for a few minutes, it doesn't go away like it did with the copper trough. The steel trough isn't as soft as the copper and it's resisting being worn by the spinning flywheel.
After disassembly, adjustment and reassembly, the new trough is only making a faint "ticking" sound when the clutch is depressed. Lynn will fix that later.
More important, the new trough seems to be catching most of the leaking oil. Yahoo! It looks like Lynn has a temporary fix to his leaking seal that will allow him to postpone the fix. If his solution holds up, Lynn will wait until he has the time and energy to pull the engine from the car to do a permanent repair.
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with your comments or questionsCopyright © 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Lynn Kissel
Last updated: May 24, 2009