 oil pump questions |
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| brant |
 Oct 25 2021, 10:56 AM
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#1
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914 Wizard  Group: Members Posts: 11,620 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains 
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@Superhawk996
I'm remember past discussion about oil pumps failing. I guess I didn't pay enough attention as I don't remember how they fail... here are 2 from my shed the 2nd mounting boss... not the tang drive, but the similar round "plugged" passage next to it.... one has what looks like ping marks and a plug that is flush with the top of the casting the other has a plug that is down inside of the casting is this the failure method? or is it the actual tank that migrates? thanks for the education brant Attached thumbnail(s) 
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| 914sgofast2 |
Oct 25 2021, 12:30 PM
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#2
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Senior Member Group: Members Posts: 614 Joined: 10-May 13 From: El Dorado Hills, CA Member No.: 15,855 Region Association: None |
It’s the pin that migrates out and starts rubbing against the camshaft gear, then leading to catastrophic engine failure. The pin with the punch marks around the periphery has started on that road to destruction. The pump where the pin is still recessed has not yet started on that journey.
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| Superhawk996 |
Oct 25 2021, 12:48 PM
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#3
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914 Guru Group: Members Posts: 5,779 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch
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I think this gets oversimplifed greatly that somehow T4 pumps are bad or a hopelessly flawed design.
The idler shaft doesn't migrate of it's own accord. It moves because of overheating the engine (for various reasons) and the differing thermal expansion between aluminum and the steel idler shaft. The shaft can be pinned to prevent the possibility of this movment. Here is a post I started involving my own investigations and comparisons of pumps. The one with the idler shaft deeply inset is likely a T1 shaft and not the T4 OEM idler shaft. I've found this in two used pumps I've purchased http://www.914world.com/bbs2/index.php?showtopic=338311 There is no possibility of the driven gear and drive tang migrating outward without literally grinding way, way into the face plate. @brant |
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