Mrmerlin

replace the oil pump gear and remove the 1mm spacer behind the woodruf key

Koenig-Specials 928

Thanks Colin & MrM. Damn, you guys are good!

Cheers!

brianrheffron

I am still learning about 928 but have worked on a variety
of Eureopean cars over the years.
Since oil pumps draw unfiltered oil direct from the sump
ithey are usually the first components to show signs of wear.
Unless the pump is nearly new it has been my practice
to fit a new pump whenever the engine is apart.
I have never heard this mentioned in the two years I
have been on this forum.
Before I fitted a pump I would check it over carefully for flaws,
rough edges, etc and "blueprint" it by minimising the clearance
between the gear faces and the housing. This is done by
grinding down the housing by hand using fine grinding paste
on a mirror. I would also shape the oil inlet and outlet much
as you would flow a port or the oil hole on a big end to remove
any restrictions to flow.
Does anyone do this to the 928 pump or are they so good they
don't wear out or need improving.

Mrmerlin

The 928 oil pump is a hi flow pump and they are overbuilt, .
The usual failure mode is for the O ring seals to fail and the pump gear( the one that runs on the belt) to wear out.
The next failure is when someone takes the pump out and rebuilds it with new O ring and radial seals and then they put the outer gear in the wrong way this will quickly cause the outer gear to seize in the housing.

There is a bevel on the outer gear and this must face to the front of the car OR away from engine block/

Mrmerlin

the only time I have heard of oil pump replacement is if a Hi Po motor is being built.
Or if the engine had a bearing failure

Lizard928

I have inspected a number of these gears and have never seen any real wear on them.
And as Stan has said, they are very high output and overbuilt.

If you really wish to prime the system, after replacement put a good highpower drill on it and spin it for a couple min. Then it will be just like a regular start.

hacker-pschorr

How about this?

https://rennlist.com/forums/928-foru...oke-apart.html

Lizard928

I had remembered that failure, but couldnt remember who the unlucky sod was.

Now I know.....

Mrmerlin

Eric, So what was the outcome of the pump failing??
In general terms these pumps last the life of the engine, and this is one of the few that I have seen that had an internal fault
The usual failure modes are listed above but i guess yours would be an exception to that

One other thing when you reinstall your pump pour some STP into the gears this gives the pump a great ability to suck the oil from the pan, and keeps it lubed till the oil pressure comes up

atb

I still think the run out needs to be measured. There is no bearing in these pumps, the shaft just rides in the housing, and the housing wears over time causing excessive play in the shaft. A new seal isn't going to cure it. I'd hate to have someone think their pump is okay just because the internal gears are in good shape and they replace the seal.

Ken Osage measured one on an S4 that he was doing a WP/TB replacement, and it had a lot of play. He ordered a used one, and it was worse. Pulled one out from his own stash that was good (nominal play).

hacker-pschorr

I installed a pump from 928 International and everything has been fine since

The failure was self inflicted.... In one of the photos you can see the nice piece of debris that made it's way into the pump. Who knew the OB's didn't have a screen over the pick-up tube? Well, mine does now!!!

Swapped out the rod bearings shortly after "just in case".

Mrmerlin

Adam any suggestions on how to measure the runout of shaft to pump.
Replacing the front seal wont remove play as you stated.
Also to note the drive gear rides on the face of the block so the block should be inspected for damage

Erik N

Anyone know what the torquewrench setting is on the 3 mounting bolts? Thanks!

Mrmerlin

if you try a search for torque specifications
on the 928 forum you may find a link for a PDF file it has most of the TQ settings that you can download. i will see if i can find the link

Mrmerlin

try this
http://members.rennlist.com/pirtle/s4torque.htm