86 IROC

iTrader: (14)

Hopefully someone can help me solve this. I did several searches, checked speciffic part # web sites, etc. Came up w/ 4 different #'s - and none of them speciffically denote an LS6 pump. The accepted # for an 01'+ pump was: 12556436, but when I looked it up at GM Parts Direct - no dice. The two #'s that do show up are: 1258665 & 12563964. The 1st part # is the more exspensive of the two, but the desciption doesn't say which one is which.

I'm just looking to put an updated pump in it when I do my cam swap, I can't justify a ported one from one of the vendors right now.

98A4LS1

iTrader: (1)

I ordered an LS6 oil pump from SDPC and received 1258665 ($80). Hopefully, the right pump. 12556436 is stamped on the oil pump itself. I'm shocked SDPC never chimes in to clarify this issue/confusion.

CharlieLed

iTrader: (1)

Why do you think that you need a different oil pump? First of all there is no such thing as an "LS6" oil pump...the reason you see so many differing part numbers is the same reason that ALL GM parts have multiple numbers, GM changes them quite often to reflect changes in their suppliers and/or minor changes to the part itself.
This issue has been a pet peave of mine because there is such a thing as having too much oil pressure and yet no one has been able to document any LS1/6 engine failure as the result of not having enough oil pressure. However, I have seen a number of posts on this forum regarding problems that people have caused themselves after trying to install a new "LS6" oil pump.
Many people have posted on this subject, if I were in the business to sell parts I don't think that I would be too eager to tell anyone that they didn't need my product....

-Joseph-

iTrader: (12)

I've done 2 engines in the past year from failed stock oil pumps. Its not whether you have a certain PSI number, its if you have any oil pressure at all. Many members of the board have gone to start their car and have 0 oil pressure. If driven like that, well you know the story... Its not as common as it appears, but it does happen and mainly to pre-2000 vehicles. Most of the members will replace their pump at the same time as a cam-swap as preventative maintenance, which adds an extra 1/2-1 hour.

86 IROC

iTrader: (14)

Most of the members will replace their pump at the same time as a cam-swap as preventative maintenance, which adds an extra 1/2-1 hour

THAT is why I "think" I need a new oil pump. It's cheap maintenence, my car has great oil pressure currently, but I don't think a new oil pump is over doing it while I'm in there changing the cam. My car has 74K miles and I add to it by the day, I'm sure an oil pump can't hurt.

ChucksZ06

iTrader: (9)

How stupid do you have to be to drive a car or even let the engine run without oil pressure. Handzel does not differentiate the pumps from the other ls series engines so I think they are all the same. Most of the problems with pumps are too large bearing clearances and poor installation or missing galley plugs. New guys make lots of mistakes when working on engines.

CharlieLed

iTrader: (1)

There's no getting around "failed stock" components of any sort. The issue is, and has been for some time on this forum, that people feel compelled to replace their LS1 oil pump with a mythical "LS6" pump because _____ ??? No one seems to be able to fill in the blank. You have made a good point, pre-2000 engines MAY have a problem with the stock oil pump, it certainly appears that you have first-hand experience. In this particular post as well as most others that have "LS6 oil pumps" as the topic, never deal with the WHY or the benefits...in this post the originator says he has a 2000 Z28 which takes him out of the pre-00 category.
As for needing an oil pump after only 74K miles I suggest you save your money. I agree with ChucksZ06, the risk of screwing something up while changing an engine component that is working perfectly fine is a risk that should not be taken. I have personally never seen or heard of a catastrophic oil pump failure on an LS engine, it's not like the old days when pump rods would break or pickups dislodge. Were it not for all the "LS6" oil pump hype people probably would not even consider this action in the first place.

Z'mnypit

iTrader: (58)

Same here, bought mine from GMpartsdirect.com. Heres the info from their site.
Part: 12586665
Category: Engine Oil Pump
Description: PUMP
Min.Qty: 1
Unit Price: $61.75
Quantity: 1
Ext.Price: $61.75
Core Charge: $0.00

bulletLS1

ESTTEMED PUMP GUYS:
remember that GM "declares" many diferent P# from the very same casting.
I mean that the raw casting (#casted) is diferent from the next machining step, then a diferent # is "declared" after assembly and so on, and to make maters worst (at least for us trying to make sense of the numbers) the P# generator is RANDOM!

for the pump, I bought one in ebay ported and polished, and still have doubts, for installation oyu have to dissasemble the pump and slid the gerotor in the timing snout WITH (I think 2mils) of clearance each side, lube gerotors in 90 (!) oil (I think this is for guarantee sucking power when first fired) and my pump came with stock spring presure (I double checked) so I opted for putting two SS washers in the cap for increased preload on the spring, locktigthed everithing (BTW from the porting shop mine came with one striped bolt... SHAME ON YOU!)
and worked absolutly amazing, almost no delay in oil P at startup a very faint tickling from the filling lifters for about 2 seconds, and the oil P (indicated) at iddle was 3/4 of instrument pannel, (Vs half from stock) this was all at start up (cold)

pekkaz

How do the old pumps fail ? Do the gears split of the housing crack or what ? If it's the pressure relief valve sticking that's because people drop **** into their engines while doing cam swaps.

bulletLS1

is not that the pump fails, is because for all know GM is not very proud of the outcome of the system, the OEM pump is marginal because GM determined that even the firing order change (from LT1) needed a thiker oil film there was pumping losses if pressure-flow where higer, and since the mayority of cars where driven by responsible drivers (who also eated their vegetables and take chucks vitamins) the pump was MADE for 65MPH higway speed in 6th -or 4AT...
the casting constraints made it to have lots of internal turbulence that worsens the efficiency.

and YES, **** in the oil, or even worse SHITTY CHEAP OIL!!!!!

Z06er

SD has a nice ported LS6 oil pump done by Katech. Worth every penny. Ported but not shimmed. Works great.