Q45 Oil Pump O-rings

[John Nordling]

Question for Q45Tech.

OK, so I pull the oil pan and clean out the bits of chain guide on my 90 Q45t I purchased with 91.5K in July. Since I still have the plenum, valve covers, and all three front timing covers off, I decide to change the oil pump. At this stage, it is a small investment since I really want to drive this car another 100K with as few problems as possible.

Here's the issue. I ordered the oil pump and the two related O-rings from Joe in Scottsdale. The holes and machined recesses to accept the O-rings in the oil pump are different sizes, but the listed O-rings are the same part number.

The O-rings don't fill up either of the machined recess, leaving about a 1/64inch gap. On the larger recess, the O-ring needs to be pushed over the inside machined circumferance, with the gap on the outside. On the smaller recess, the O-ring needs to be squeezed into the outer circumference, leaving the gap on the inside. The O-rings both set above the surface of the oil pump when installed, but I've never seen a situation like this before. I am concerned that something is amiss and a good seal won't take place, dropping some oil pressure.

Joe does not have an oil pump in stock (since he sold this one to me) and doesn't have a difinitive parts diagram showing the sealing side of the oil pump. I am supposed to call him tomorrow and see if any of their mechanics has installed an oil pump and remembers if using the same O-ring is correct.

Too much money and time invested now to rush this, so I will wait until I hear back. If Joe's folk's have any comments, I will pass them along.

Thanks.............John:)

[John Nordling]

So far, Joe hasn't been able to find anything out from the Scottsdale shop personnel.

Anyone out there ever replaced a Q oil pump?????????

[jtesensky]

I've spoke to my shop foreman & he said he hasn't done one in a long time but he seems to think it should fit snug, or else problems will occur. I don't understand since I sold you the exact o-ring for that model & year (along with the pump). I'm still working on it John, next call is to the Factory, I'll keep you posted...-Joe

[edfishjr]

I just installed my new pump on my 92.When I went to order the o-rings from the local dealer, they ordered two different parts. When I went to pick them up, a different parts guy said they should have both been the same. I took the two that came in, because the originals were slightly different sizes, as are the groove diameters. I don't know what he was looking at.

Both new rings fit snugly on the inner diameter, but do not fill the groove up when uncompressed. (I don't have the engine running yet.)As a design engineer, I know that if the ring will install in the center of the groove and not get so distorted that it kinks against the outer diameter of the groove, it will work OK. Maybe Infiniti figured this out too and started going to a single part.

[DAEDALUS]

Design engineer in Huntsville? You don't by any chance work at a company that starts with "B", do you?

[edfishjr]

Daedalus,

That's a roger on that "B", Mr. El Segundo!

[John Nordling]

I just installed my new pump on my 92.When I went to order the o-rings from the local dealer, they ordered two different parts. When I went to pick them up, a different parts guy said they should have both been the same. I took the two that came in, because the originals were slightly different sizes, as are the groove diameters. I don't know what he was looking at.

This is great news! I have never before encountered something like this, that looks so obviously incorrect. I would prefer to have the two different sizes like you managed to get. Would you be able to forward me the Infiniti part numbers for those o-rings? I would greatly appreciate it.

If Infiniti superceded the old style o-rings with a one-size-fits-all o-ring, you would think that a technical service bulletin exists about the change. Maybe Joe can find out.

John

[edfishjr]

The part numbers on my invoice for the oil pump o-rings are

15053-F650015066-60U00

I don't know which is the big and which is the small. By the way, though my originals were made of the same material, these two differed. One was a reddish elastomer like the originals. The other was jet black, like EPDM, which is a standard material for o-rings.

Good luck, and thanks for the replies to my chain timing question.

[edfishjr]

More info: My driver's side chain had jumped on the sprockets without causing catastrophic damage. How do I know? I counted links. The chain was so brown, that I couldn't see the bright links, but I counted the links between marks. Compared to the right side, I had one extra link between the intake and exhaust sprockets and one extra link between exhaust and crankshaft. This was possible because the chain guide was completely gone. As a result, the flopping chain had cut deep into the snout of the oil pump cover, which is why I replaced the oil pump. My oil pressure was still good, and the engine actually ran, albiet with a few strange symptoms that I couldn't figure out. There are one or two very light scores inside the pump, but I don't have the equipment/skill to accurately measure the clearances. I dropped the engine support beam to remove the pan..what a pain!