: oil pump spacer driver

07-04-10, 08:46 AM
getting ready to finish up a stud job on a 4.0 northstar and I want to be sure the oil pump driver spacer is oriented correctly. when putting the spacer in does the shoulder face the damper or the crankshaft? That is; does the damper butt up against the larger flanged shoulder of the spacer or does the damper butt up against the non-flanged smaller side of the spacer?

Mark C
07-04-10, 10:12 AM
Oil Pump Installation
Tools Required
J 36660-A Torque Angle Meter

Install the oil pump drive spacer into the oil pump so that the drive flat engages the pump rotor.
Position the oil pump on the crankshaft.
Install the retaining bolts.

Apply upward pressure on the pump while tightening the three retaining bolts. Tighten the bolts in the sequence (1, 2, 3 - left bottom, right bottom, left upper looking at engine from passenger side) shown.
First Pass Tighten
Tighten the oil pump mounting bolts in sequence to 10 Nm (89 lb in).

Final Pass Tighten
Tighten the oil pump mounting bolts in sequence an additional 35 degrees using the J 36660-A .

07-04-10, 10:43 AM
well thanks for that but i don't think it really answers the question, at least not in a way i understand.

07-04-10, 12:57 PM
The pump drive spacer goes on the inside - crankshaft side of the oil pump body - as opposed to the harmonic balancer side ???

See if the oil pump picture for your engine explains any better - www.rockauto.com - click in the INFO icon to enlarge.

07-04-10, 01:33 PM
the spacer i have has two flat edges that fit into the pump to turn it. the problem is i can insert the spacer in from either side (front or back) and one side of the spacer bigger than the other. i've inserted the spacer from the back and tightened the pump to the block and inserted it from the front and tightened it to the block and it looks like it could go either way.

i just finally found this pic

and supposing this picture is accurate the LARGER end should go toward the engine rather than toward the crank pulley.

follow yet?

07-04-10, 01:53 PM

k. see in this picture the spacer is big on one end and normal on the other. i can put the spacer into the pump in either direction and both look to fit correctly. which way does the spacer need to go in? does the large end butt up against the ENGINE side of the crank or the BALANCER side of the crank?

07-04-10, 11:36 PM
anyway, the reason i ask i just did a 4.0 aurora (jake's studs) for my boss's husband and I gave it back to them yesterday. out of all the parts lying around the only thing that gave me any trouble was trying to remember the spacer orientation. it seemed to make the most sense and look the best with the big end tgoward the engine side. they messaged me last night and said a little bit before they made it home the car told them low oil pressure and only showed 3 psi.

I had driven it and gave it every chance to get hot and screw up but beside a noisy lifter on startup it had been perfect. so, i thought back to when i was putting it back together...did i tighten the damper enough, is the spacer right???

i went and got it today and (94 degree ambient temp) brought it back to my house (30 minutes) and the lowest observed pressure was 10 psi at hot idle while sitting at a light ~750 rpm. this is with the AC on full and everything. Engine temp a slight bit above the 200 mark.

I decided to tighten the balancer up a bit more, maybe got about 30 degrees out of it and dumped the oil (did the assembly lube thin it out?). I had used the walmart super tech stuff which i thought i heard shell made but replaced it with pensoil high mileage. On the way home, again the lowest observed pressure was 10 psi. I even took it to an unshaded parking lot and let the temp get up to 240 where the fans kick on and the pressure never dropped below 10. While on the freeway ~1800rpm 60 mph pressure was a rock solid 30. Right around 2000rpm pressure would start to climb past 35 and even after while fully hot it had no problem hitting the high 40s while accellerating.

Everything sound tip top or am I missing something?

Mark C
07-05-10, 09:21 AM
The drive space does go in with the shoulder facing the engine block. The harmonic balance locks it between the balancer and a step on the crankshaft (or the primary cam drive gear), if the harmonic balancer is loose the spacer can slip and you won't get much, or any oil pressure out of the pump. The torque spec for a balancer is 37 ft-lbs then 120 degrees of rotation.

07-05-10, 05:20 PM
here's a bit larger version of waspie's diagram; just found it in the STS service manual by Helm/GM.

Looks like the larger, or flared, end goes against the crankshaft snout shoulder - toward the block.

07-05-10, 06:12 PM
thanks for the last two replies. seems almost like no one wants you to know which direction it goes in. anyway, i'm satisfied that everything is working as it should.

07-06-10, 07:23 PM
Well - sorry I couldn't help you, but when I did my HG job, I left the primary chain and gears and oil pump installed. It seems like most people take them off, and maybe the FSM even tells you to do that, but I saw no reason to remove them, and I figured that a few less things for me to screw up!