I just figured some people would like to see what the inside of the oil pump looks like, whats involved in porting one, and show people how to properly position the pump on the block before torqueing it down.


the first thing to do is dissasemble it. really easy. all the 10mm. bolts on the outside of the pump, then one allen "cap" on the inside and everything comes right out. almost. the pressure relief spring and valve under the allen cap will need some gentle wiggeling/turning to get to come through the threads. be careful with this so you dont scratch the sides of the little piston. set that and the pump gears aside while you turn your attention to the pump's ports.



this pic shows the outlet side after porting. sorry, forgot to take before shots. be very careful not to nick the the edges in the middle that the pump gears set on. make the transitions smooth is all your looking to do. this wont take too long.

as for the inlet side, that the pickup tube goes into, just take out the step that blockes the oil from comeing into the pump. I ported all the way down into the hole, only to realize when putting it back together that the pickup tube goes all the way through this hole. so just take out the step and radius that into the pump.


now you need to make up a shim. Ive seen people recomend .100", and also .150". I decided on the lower number. I used 3 washers from my trusty nuts/bolts box(s). just sifted through until I found a stack of washers that would fit into the allen head cap, and that totaled near the .100" target thickness. whatever you use, just make sure its steel and fits iniside the cap, but that its bigger then the spring that will hold it in the cap.

[IMG][/IMG]



here's a bad pic of my cap with the wshers inside it.



and here's the relief valve/spring/cap goin in. simple. dont forget to clean everything VERY good, and lube everything really well with a thick assembly type oil. I use GM engine assembly lube. its just a very sticky/thick oil that wont clog the oil filter. I also use this for lubing cams, lifters, main bearings, rod bearings, timing chains, everything before/during reassembly.

[IMG][/IMG]

after bolting in the valve, lightly bolt the body onto the block w/o the gears in place. dont tighten the bolts yet. now set the gears into the pump. install two feeler gauges on the sides of the gears to make sure there is space between the gears outer diam. and the pumps I.D.. like so. (sorry for the blurry pic. again)
you can barely make out the feeler gauge on BOTH sides of the gears.

[IMG][/IMG]

after you have it like this, go ahead and torque the 4 body bolts down to 18lb/ft with loctite on the bolts. then make sure you can slide the feelergauges all the way around the pump gears.

now put the cover back on and put loctite on the bolts for the cover, and be very careful when installing these bolts. mine would very easily cross thread if your not paying attention. just install with your fingers and they will thread right in when there straight. torque the bolts to 106lb/in.

done.

 

thank you for the pics - i think most ppl are too lazy to get the camera with oil on their hands at the points you show!

 

Thanks! These are helpful. I was thinking of going with a GMPP pump and just shimmign it myself, looks like thats what i'll be doing now.

Thanks again, very helpful!

-Lurius

 

cool.

 

Very informative - thanks for taking the time to post this!!

 

I assume the shims increase the pumps output pressure via higher spring resistence?

 

Irocss85,

Thank you for taking the time to create this. I saved the info to my hard drive. I now feel confident porting and shimming the new LS6 oil pump that is buried somewhere in my performance parts pile. Thanks again.

 

I have a question. What are the internal differences in the LS1 and LS6 oil pump. What makes the LS6 a better pump?

 

Would it be a problem using brass washers here?

-Lurius

 

it might not be, but I suggested steel washers here only because of the constant moving of the valve/spring against the spacer. why brass anways?

 

For some reason unknown to me the pre 01 ls1 pumps are more prone to sudden failure.

 

I have brass washers the right size lol. I can go buy some steel, just dident know if it was nessicary.

-Lurius

 

For those who bought new ported LS6 pumps, how many of you took it apart to install it with the feeler gauges between the gears and housing like the step above?

 

not me!!!!

 

Anyone else?

 

ive also done it in the passt w/o any probs.

 

I have never gotten a good explanation of what the feeler gauges are doing for you. The center gear is engaged on the crank and there is some clearance between the inner and outer so that the outer will likely float within that clearance anyhow. What am I missing?

 

making sure the housing is centered. same as you'd do for the front/rear eng. covers. if you had the housing jacked all the way over one side, the center gear isnt goin anywhere, and you'll wear out the pump quickly cause you wont have sufficient clearance for oil between the gears and housing. and, making sure you have atleast that much clearance too, as machining tolerances "could" have gotten a little out when the gears or housing were machined. its just an extra precautionary step that anyone can do that doesnt take too much time, exp. if you already have it apart like I did to port/shim it.

I dont THINK there are any alignment dowels behind the pump, are there? havent had one in my hand since I made that post.

 

I put feeler gauges in between the main housing and the drive hub with no oil pump gears in place to center the main housing.
The other thing thats important is the chamfer on the outer ring, it must be installed first (towards the rear of the pump). If this is installed wrong the pump will try and lock-up as the gear will be bound on the cover. Most pumps have a "DOT" on the front of the outer ring, but I have noticed some of the new ones do not.

Kurt

 

So taking a new oil pump and just bolting it on is a no no?