Your oil pump will fail., And it will kill your engine. |
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Your oil pump will fail., And it will kill your engine. |
Valy |
Sep 15 2011, 09:38 PM
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#1
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Senior Member Group: Members Posts: 1,677 Joined: 6-April 10 From: Sunnyvale, CA Member No.: 11,573 Region Association: Northern California |
I'm rebuilding a 2.0L and posted a lot of pictures in a different thread.
One of the pictures showed the oil pump and Jake immediately noticed that the pump failed. Went back to the engine and saw how the oil pump touched the cam gear and shred off the nits holding it. Being such an anal guy, I took same time today to understand why did the oil pump fail? The red axle in the picture above it the one that protruded through the pump cover. There's nothing that holds it in place except the friction between it and the cover! So Why does it move? This red axle goes into a cavity of the oil pump case (rightmost in the figure). The cavity is almost snug-fit to the axle but oil can infiltrate around the axle into the cavity. When the pump works, there is a bit of oil pressure in the pump that causes the oil in the cavity to push the axle out; just like a hydraulic piston. The force is small but it's constantly there. As the axle moves, more oil flows in and that keeps pushing the axle out. Over the time, that axle is pushed out of the pump cover until it starts touching the cam gear, shredding the nits that hold it. Eventually, the nits will brake or the axle will block the movement of the camshaft and something else will brake or your camshaft bearings will give due to the vibration inducted by the hits. The aftermarket oil pumps are build differently, with no axle that can protrude into the motor, making them a good upgrade to your old original pump. Make yourself a note to replace that old oil pump at the first occasion. I will even recommend to create that occasion before it's too late. |
HAM Inc |
Sep 16 2011, 01:18 PM
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#2
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Senior Member Group: Members Posts: 846 Joined: 24-July 06 From: Watkinsville,GA Member No.: 6,499 Region Association: None |
At one time Jake had a small mountain of T4 pumps with that failure. Saw it with my own eyes. Didn't look like a rare occurance to me. And it is very conceivable that the pump shaft would do it's damage very slowly over time and be difficult if not impossible to hear over the engine and road noice.
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914_teener |
Sep 16 2011, 04:21 PM
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#3
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914 Guru Group: Members Posts: 5,205 Joined: 31-August 08 From: So. Cal Member No.: 9,489 Region Association: Southern California |
At one time Jake had a small mountain of T4 pumps with that failure. Saw it with my own eyes. Didn't look like a rare occurance to me. And it is very conceivable that the pump shaft would do it's damage very slowly over time and be difficult if not impossible to hear over the engine and road noice. Not to speak of what Jake would say....and I do respect his experience. There are many moving parts here. Nobody has done a failure mode analysis here. So to say every stock pump is to blame or to be a potential failure of a motor would be an absolute and not necessarily accurate in every instance. Are they prone to wear with age?...most likely. But there are many other factors that affect a failure. The 3 O rings on the space shuttle boosters were engineered to seal off hot gases for a set period of time at a certain temperature range. In this case the failure mode was if the temperature dropped below 32 degrees. BOOM. In this case they knew that it was a problem.......just doesn't get that cold in Florida very often. Cost decision? Maybe. I am sure the German Engineers had their own design criteria...and failure ranges. Perhaps there was a lifecyle done here....I don't know. This doesn't even address manufacturing variables and quality. Jake's solution is simple. They are prone to failure with age and use...don't trust them....make it new or better. This is what this forum is about....what is better? (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/popcorn[1].gif) |
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