Greg_E

iTrader: (4)

I'm doing a cam install and upgrading to the LS6 ported oil pump at the same time. I read JMX's writeup and also checked my GM service manual and both are in agreement that you just bolt the new pump on (With the usual cautions about the O-ring etc.) I remember seeing an episode on one of the DIY TV shows, I think it was "Horsepower" where they went through a more involved process where they loosely mounted the pump temporarily shimmed both sides evenly to center it, (I think they may have removed the pump cover to do this step) and then tightened the four mounting bolts. With the pump properly centered, they then went back and removed one bolt at a time, applied loctite and torqued it to spec. Is this added step necessary or recommended?
It's not a job a want to do twice, so I want to get it right the first time. Also has anyone done a writeup using this procedure?
Thanks for any help.

Katech_Jason

iTrader: (19)

I have never seen any of our engine builders doing that. Just wondering, is it our pump?

Zick

iTrader: (18)

I read that in the LS1 build up book, or whatever it was called. I didn't do it when I put my LS1 in.

Lithium

iTrader: (47)

I really dont think anyone does that.

Just put it in and tighten up that bolt.

Gary Z

I completely disassembled the pump and first installed only the empty housing. This makes it very easy to get the o-ring installed properly. Then I installed the rotors, and then the cover. With the bolts only finger-tight, I turned the engine over a few times (by hand, of course) to be certain everything was centered and nothing was binding. Then I torqued down the housing, then the cover. No problems after 3k miles.

618HAWK

iTrader: (361)

Yes I have read this as well. It is to make sure the pump is center on the crank snought to prevent uneven wear with in the pump. Ie .002 shims-feeler gauges were used 180 deg apart while the housing was torqued down. Then remove each bolt, one at a time, lock-tight-torque and then install pump cover.
I would say you could probaly get away with out doing it but whay take a chance.

98A4LS1

iTrader: (1)

I know the driven gear (ie outer larger gear) must be installed with dot facing the front of the engine or housing cover.
Does it make any difference which way you install the drive gear ie inner smaller gear? It appears you can flip it either way.

eallanboggs

iTrader: (1)

Only one gear has a locator "DOT" on it so when I used the disassemble method I only concerned myself with the one that had the dot. Removing the drive and driven gears makes getting the pickup tube up into the input port of the pump a whole lot easier because you can wriggle the empty pump body around while your jiggling the pickup tube back and forth to get it started into the port. Once you get it in there you then put the shims in place not before. It's probably a good idea to at least get the pickup tube flange bolt started before you install the shims and start turning the 4 screws in place. As a matter of fact it's probably a good idea to install the drive and driven gears before you install either the shims OR the bolts because once you do the pump body won't move around as much and it's a whole lot easier to get those gears in place if you can rock the pump body around a little bit as you slide the gears home. I know GM says the pump needs to be centered with a feeler gauge (concentric with the drive sprocket), but you'll find that it is basically self-centering because once the drive and driven gears are placed into the pump body there isn't a whole lot of space between the gear and pump body faces. Add to that the 4 mounting bolts and there isn't a whole lot of room for adjustment. Put oil on the gears and body during this process.

98A4LS1

iTrader: (1)

Thanks Eallanboggs, good explanation/points. I was just making sure about the drive gear ie inner gear, my GM service manual does not mention anything about whether or not it makes any difference which way you install the drive gear. Both sides of the drive gear appear identical. Could someone confirm this? Thanks in advance!

Gary Z

I should have mentioned that I marked both rotors with a Sharpie pen before I removed them from the housing - a Sharpie resists oil. I do not remember there being any shims.

Greg_E

iTrader: (4)

I believe it is one of your pumps. I purchased it through Thunder Racing whick you list as one of your vendors.
I searched through some video and finally found that episode. They removed the georotor and checked for .002" clearance between the driver and pump housing all the way around. At least according to them, it is a very important step to prevent the georotor from destroying itself and sending bits of metal through the engine. I suppose it can't hurt to check it.

Greg_E

iTrader: (4)

That is correct. The .002" shim or feeler gauge is just used to check/set the clearance, and is then removed.
Thanks for all the replies guys! I've learned alot from this forum.

Katech_Jason

iTrader: (19)

That would be our pump.

oange ss

iTrader: (50)

so centering the pump with feeler gages is teh correct way ? or extra insurance ?

Gary Z

Inserting a feeler guage between the driven rotor and the pump housing seems like very poor practice to me. The housing is aluminum and you do not want to scratch its inner surface. Coat all parts with Mobil 1 and assemble carefully.

oange ss

iTrader: (50)

how does GM do it ?

98A4LS1

iTrader: (1)

Also, can someone confirm the orientation of the drive (inner) gear ie does it matter which side faces the front of the pump housing?
Thanks

Greg_E

iTrader: (4)

They didn't say the driven rotor. They were checking clearance between the housing and the portion of the crank sprocket that drives the georotor in the pump.

Gary Z

Sorry, but I don't understand. If you said they checked the clearance between the crank sprocket and the drive (inner) rotor, that might make some sense but I really don't see how a feeler guage is helpful here. I do agree with eallenbogs above:

J&J Speed Shop

iTrader: (8)

You have never seen your engine builders center the housing on the crank/timing chain drive? How do you engine builders center the pump so there isn't wear on the housing & aluminum shavings in the oil?

That is the correct way to do it

I don't agree with this statement at all. You can certainly assemble the pump and **** the housing so it is rubbing against the lower timing gear/oil pump drive. That is why GM sells a tool to install it, because for safety sake it should be centered so there is no housing wear. If you don't believe me put the oil pump on put all 4 bolts in a tighten them so you can still move the pump and you will see there is still room for movement to contact the pump housing