Just a piece of information I learned tonight from GM. One of the parts guy and I are starting to become real chums . Anyway, back in the beginning posts I had raised a question concerning whether or not my '98 ZR2 came with the A.I.R. setup or not since the manifolds on the old replaced engine were set up for that (they are capped off though). Looked up using my VIN# and discovered my truck did not come with that setup. Overall, '98 VIN "W" RPO "L35" does not have it (good news for me). However '98 VIN "Z" RPO code "K18" does have the A.I.R. setup.

 

Huh.. did not know that...guess you learn something new everyday....

 

Here's something that has me really bent out of shape. I don't know what I did wrong. Though the intakes are still off, I wanted to prime the engine with oil just so I could see that I had oil coming out of every where. I put 5 quarts into the engine and put the filter directly on to the engine oil filter mount since I have the engine on a stand. In other words its not mounted to the adapter which feeds oil thru the oil cooler, etc. Figured 5 quarts of oil should be more than enough. I used an oil prime tool designed specifically for GM V-6,8s.

That's the setup. I hooked up the drill motor to the priming tool and began turning the oil pump. From the diagram in the service manual it appeared I needed the drill motor turning clockwise like screwing in a screw. Everything was turning smoothly (by the way, it's a brand new oil pump) and oil started pumping. Another note, before I put the fuel oil pressure switch in, I did some turning until the oil came to the top of that hole. Then I mounted the sensor. Some oil was coming up through the distributor hole but overall the lifter valley was not filling with oil at all. The pump was definitely pumping oil (meaning it wasn't running dry), it felt very firm once it started, but really no oil was getting into the valley.

All of the sudden it felt like oil pump started "rubbing". A staccato type of rub, almost to the point of a grind. Like the gears inside were rubbing on the casing or something. Took the tool out and the only thing I noticed is the shaft seemed to be more wobbly then I reckoned it should. I can't remember when I connected the shaft extension to the pump shaft using a brand new plastic connector how wobbly it was. I know there was some play, but I didn't take too much notice to how much. So if the wobble is too much, I don't know if it is because maybe that plastic connector broke or if something down in the pump broke. The pump is so basic I don't know what could have broke to make it wobble like that (if it is too much).

Please help with these questions. Why wasn't any oil being pumped into the lifter valley? Why did the oil pump start rubbing/grinding? Finally, what in the hell did I do wrong??

Oil is draining now so I can pull the oil pan off and remove the pump...but what the heck happened? I am putting everything back together by the book and taking it very slow and being very **** from torque setting to the type, amount and placement of sealers.

 

Well got the oil pump off and apart....(what a waste of good oil). There was a little bit of the itty-bitty furry metal shavings on the drain plug magnet. Screened the rest of the oil and there was nothing.

Oil pump looks fine. Gears look great with the exception of the shaft gear has a little bit of shine at the very corner (about 1/8") of the teeth (where the teeth rest against the cover plate). But no gouging, just barely a hint of a swirl. Probably where the furry shavings came from. But besides that, there is nothing wrong with the pump I can see. The plastic shaft connecter is not broken or cracked. There is quite a bit of play where the two shafts come together (the wobble), but it seems normal.

This is the first time I have tried to prime the engine using a prime tool. I know it's got to be me, but that rub/grind just doesn't sound right. It's probably something I am being a complete idiot about. Before I put the pump back in and dump new oil in again. What am I missing? Why won't the lifter valley get oil so I can see it come out of the pushrods? What am I doing wrong? Could it be something else besides the pump and I am mistakenly connect the sound with it? I don't see how that could be, but I'm really stuck on this.

 

Is the oil pressure sending unit installed? If not, pressure will not build sufficiently. It will be "thar she blows" moment and lubricate the garage ceiling! Not certain, but, the balance shaft might get oil from the same passage. When priming, or running, very little oil will be in the valley. You might see a little ooze out from around the lifters, and there will be some splash from the cam lobes and balance shaft bearings, but that's about it. Pressurized oil first goes through the center of the crankshaft, then up through a passage to the lifter bores & camshaft bearings. When the lifters get pressurized, oil is sent through each push rod up to the rocker arms. From there, it drains back to the crankcase through the drain holes in the heads. The timing chain & gears rely on splash only. Not sure if this will help in locating the noise, but there ya go Kinda hard to diagnose noises without actually being there.

 

Yeah I had a little dribble from the oil sending unit hole...but I was watching for it because I wanted to see if it would come up. Put the sending unit in and that's when I started running the drill motor steady. So are you saying that I can't pressurize the lifters with the prime tool and the lifters will not get pressurized until the engine is running? That would satisfy my concern as to why I am not seeing anything out of the pushrods/rockers.

 

No, the lifters should pressurize during the prime and you should see oil dribble at each rocker arm. The only thing that might make a difference, is the crank and cam are not turning and they may be blocking an oil passage in the position they're in. Have an assistant turn the crank, clockwise, while you're priming the pump. See what happens.

 

I bet you that's what I'm missing! I'm in for the night but I'm going to try and get some time tomorrow to put everything back together and turn the crank while priming. Let me ask you this, with the exception of the oil pump, could I have damaged anything (seals, bearings, whatever) by forcing the oil prime with the drill motor while the crank and cam were probably blocking passages?

 

Nope. Not even the pump. You can't hurt the bearings because nothing was turning, (cam, crank, balance shaft). The cam needs to turn to allow the lifters to pump up and bleed down on their own. If you've ever started an engine after an overhaul, without priming, the lifters go nuts hammering away until they pump up. This is why you do the prime, to make sure everything is oiled before starting.

Edit: Keep rolling the crank over while priming until every rocker arm gets oil. Don't have to go fast, just keep it moving.

 

Thanks Captain. I have no doubt you nailed the one simple thing that I was being an idiot about. Like I stated, this is the first time I've used a prime tool. I know what you're talking about with the lifters hammering like crazy. I hate that sound. It's like fingernails on a chalkboard Thanks again! I'll let you know what turns out when I get back in the garage.