Printable Version of Topic

Click here to view this topic in its original format

914World.com _ 914World Garage _ oil pump questions

Posted by: brant Oct 25 2021, 10:56 AM

@http://www.914world.com/bbs2/index.php?showuser=22428

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)

Posted by: 914sgofast2 Oct 25 2021, 12:30 PM

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.

Posted by: Superhawk996 Oct 25 2021, 12:48 PM

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.

@http://www.914world.com/bbs2/index.php?showuser=47