: Oil Pump - how to inspect and test out of engine



Loose screw
02-23-05, 10:03 PM
Are there any good reliable ways to inspect, measure and bench test a 94 N* oil pump. With 142k miles on it, I don't want to put it back in service unless I am sure it is still good and will have many years of service head.

BeelzeBob
02-23-05, 11:13 PM
Just take the cover off and look at it. Unless the gerotor set is broken or something hideous the pump is fine. It is almost totally bulletproof. About the only thing that can go wrong with it is if some debris sticks the pressure relief valve open and then the pump will not prime. This is easy to fix in the car by overfilling the crankcase to force it to prime and then draining the extra oil out but if it is on the bench you want to clean it out good and make sure that the relief valve and relief port is clean and free of debris...especially if the engine failed a bearing and generated tons of debris into the oil.......

Loose screw
02-24-05, 12:16 AM
Thanks - the oil was free of signifcant debrie and the pump looked in good shape. Is there any clearances or wear that can or should measured?

BeelzeBob
02-24-05, 10:57 AM
Thanks - the oil was free of signifcant debrie and the pump looked in good shape. Is there any clearances or wear that can or should measured?

NO, not really. Seriously, it is one of those things that either works or it doesn't....LOL. If anything was going wrong with it it would chew itself up pretty fast...if it looks good inside and is clean and no significant scoring or anything then it is fine.

Loose screw
02-24-05, 01:44 PM
Thanks

growe3
02-25-05, 12:02 AM
It is of the utmost importance that the vibration dampener is properly torqued down. Failures to do so can/will cause the oil pump to fail. The pump is locked in place by the very high torque of the dampener against the oil pump inner race.

Follow the directions for tightening this bolt, for your year Northstar. The torque is quite different in the 93-94 (and 95?) engines due to different (larger) bolt size used.

-George

haymaker
02-25-05, 12:40 PM
Are there any good reliable ways to inspect, measure and bench test a 94 N* oil pump. With 142k miles on it, I don't want to put it back in service unless I am sure it is still good and will have many years of service head.
Loose screw. I primed the oiling system using the starter before I installed the engine, just to prove to myself the system would prime and have pressure at the top of the engine. I reassemble the engine with the exception of the intake manifold, (you really need to be careful nothing falls into the cylinder heads open intake ports) cam covers and spark plugs. I fill the crankcase with the correct weight, volume of engine oil and pre-fill and install a new oil filter. I install the starter; battery cables then connect a fully charged battery. Then either connect a remote starter button or jump the terminals on the starters solenoid to engage the flywheel and spin the crankshaft. I like 20 to 30 second engagements of the starter at any given time with a short rest in between to prevent overheating the starter. When you have oil along both cylinder banks at the camshafts the engine is primed. I realize this doesn’t indicate any specific oil pressure but it does prove the system is primed and is capable of pushing oil to the top of the engine. I think the stated oil pressure is indicated at or near 2000 rpm, so no way the starter can come close to that speed.
Once I have oil at the camshafts I complete the engine assembly and installation. At first startup I like to run the engine for 20 to 30 minutes while checking for leaks, oil pressure and coolant temp and level. If any problem(s) or leak(s) develop I shut the engine down and repair the leak(s) or problem(s). After this warm-up period I like to change the oil and filter while the oil is still warm. I pour the warm drained oil through a paint strainer just to see what material has been flushed from the engine. I have had rebuilds that I washed and brushed the block, block passages and thought were internally clean surprise me with some flushed debris at this first oil change. Some may think I waste a lot of oil and filters but its just cheap insurance to me.
BTW did you remove your engine by dropping it out the bottom or did you pull it out the top?

Loose screw
02-26-05, 11:15 AM
I took it out the bottom as I was told that you could get pull the engine out the top. Bad advice. So I bought an engine hoist and then three very good big floor jacks (Sams club has some real nice $150 for $59) You are not suppost be able to do it which such limited equipment but it worked fine - don't fail to wire the floor jacks to the assembly so they can't slip out at the wrong time. Three jacks work well two holding up the rear and on on the front in the center that way the don't get in each others way and the engine is balanced and can be adjusted being supported in just three spots 4 jacks would make it harder and more complicated. You have to have the front of the car up very high and well supported so the engine/trans and jacks can be pulled/rolled out together. It helps to get the rear wheels on some thick boards first to help level the car a little and then use big tall safety stands. A heck of job to do in your drive way but it can be done.

growe3
02-26-05, 11:41 AM
Regarding cranking the engine to prime the oil system; I do not believe that there is any need to do that in the Northstar, and in fact could be harmful to the bearing and bushings. On conventional engines priming by spinning the oil pump can certainly be useful. Usually a drill motor with appropriate extension attachment, to engage the oil pump is used to turn the oil pump at about 1500-2000 RPM

When the Northstar engine is apart (completely or partially), reassemble with engine assembly lube. Wipe or dab on any parts that will move. If you want, dribbling a little oil over some parts that move will also be helpful.

On the Northstar engine the pump is driven directly from the crankshaft. The time it takes to finally push any oil through the system by just cranking with the starter, is time the engine is rotating without any meaningful oil pressure. This can cause quick premature wear, on parts that need pressurized oil to protect them.

Just start the engine; the oil pressure will be there in a few seconds to properly lube it.

-George

growe3
02-26-05, 11:52 AM
I have pulled two Northstar engines out from the top, and guided several users other in the process. I think it is easier to do that way for the owner that does not have access to all of the proper shop tools, and will usually be doing it in the driveway or garage.

With a dealership's room, equipment and deep pockets for specialized tools, pulling from the bottom is a better plan for major engine work.

I know some on this forum have been very creative and have pulled the engines from the bottom, but I still feel it is easier to do it from the top for most home mechanics. It is a pain either way.

-George

Pjs
02-26-05, 01:57 PM
I have pulled two Northstar engines out from the top, and guided several users other in the process. I think it is easier to do that way for the owner that does not have access to all of the proper shop tools, and will usually be doing it in the driveway or garage.

With a dealership's room, equipment and deep pockets for specialized tools, pulling from the bottom is a better plan for major engine work.

I know some on this forum have been very creative and have pulled the engines from the bottom, but I still feel it is easier to do it from the top for most home mechanics. It is a pain either way.

-George

I opted to pull mine from the bottom as well. After pulling the engine off the cradle (major pain) I couldn't imagine trying to do that in the car, not to mention getting all the mounting bolts and brackets into the backside of the engine (Trans side). My fiance's dad and I built a cradle dolly that works wonderful, particularly when trying to get the cradle back under and lined up w/ the body. Here's the link to that thread if you care to see it. If your interested I can supply you with dimensions

http://www.cadillacforums.com/forums/showthread.php?t=23672

eldorado1
02-26-05, 03:03 PM
On the Northstar engine the pump is driven directly from the crankshaft. The time it takes to finally push any oil through the system by just cranking with the starter, is time the engine is rotating without any meaningful oil pressure. This can cause quick premature wear, on parts that need pressurized oil to protect them.

Just start the engine; the oil pressure will be there in a few seconds to properly lube it.



I agree with you..... but..... Just cranking the engine you'll see at max 200psi from compression..... But once it fires, it'll see 800+psi. So, either 20 seconds with 200psi.. or 5 seconds with 800psi..... Neither with oil pressure, I'd take the former. Less chance of 'unpleasantness'.

(numbers are guesstimates)

growe3
02-26-05, 03:30 PM
I opted to pull mine from the bottom as well. After pulling the engine off the cradle (major pain) I couldn't imagine trying to do that in the car, not to mention getting all the mounting bolts and brackets into the backside of the engine (Trans side). My fiance's dad and I built a cradle dolly that works wonderful, particularly when trying to get the cradle back under and lined up w/ the body. Here's the link to that thread if you care to see it. If your interested I can supply you with dimensions

http://www.cadillacforums.com/forums/showthread.php?t=23672

You are certainly one of the creative ones here, and did a nice job on your choice of engine removal.

I still feel that out the top is a better choice for the home mechanic for the reasons I previously stated.

Regarding the various rear brackets, no problem at all. Once you tighten the engine to the transaxle everything else lines right up.

I think the biggest pain was removing a couple of bolts from the exhaust flange to the exhaust pipe. A tight fit in an awkward area. The rest was just basic engine R&R 101.

_George

haymaker
02-26-05, 05:21 PM
Loose screw wanted to know if there was a way to test the oil pump. This is the best way I know to test the N* oil pump with the engine out of the car. I would expect anyone assembling an engine would use oil or assembly lube during the assembly process so the rotating parts (bearing surfaces) would not be dry at start-up. Installing and then starting the engine after all that work not knowing if it will have oil pressure is in my humble opinion, a bit risky (already spun a rod bearing). It is a lot easier to fix any lack of oil pressure issues while the engine is still out on the floor. My engine pushed the oil to the camshafts within 30 seconds of cranking but I didn’t have the bottom of the engine apart his may need a little more cranking. The engine turns pretty fast without the spark plugs. If any parts are going to be damaged the damage will take place if the engine starts and runs without oil pressure not during any starter cranking operation with the spark plugs removed (very little load on the bearings). It’s my understanding from Loose screw’s threads the engine spun a rod bearing. And has concerns about the oil pressure and wants to test the oil pump. Priming with the starter the way I described earlier will test the pumps ability to prime and circulate oil in the engine while the entire engine is still very accessible. The best part being, it doesn’t cost a dime or damage anything.

Chances are everything will be ok. The engine will probably fire right up, prime the oil pump and build pressure. I do wish you good luck.

Loose screw
02-26-05, 08:41 PM
Thanks for the many replies. I do agree that for many people taking the engine out through the top is an easier and safer choice. The exhuast bolts can be removed even if you can see them - use a long extension I could see that after I dropped the whole works. It might be easier to lower the rear of the enging just a little so you can see and well that top fastener. If you can get those off you can do the rest out the top. If you can't drop the works out the bottom carefully. I recently got a shop manual from Helm for $30 + $6.95 S&H http://www.helminc.com/helm/search_service_owner.asp?Style=helm&class%5F2=CAD&mscsid=WMMCCBHCMEB88JVRJSMUUF5R2E987098 absolutely a wonderful bargin and the giant manual is so much better than the small ones at the local parts store every nut and bolt is discribed everything is there in clear to understand detail and a view of everything. I sure wish I had that before i started.

As for priming the engine I agree cranking the engine with the plugs OUT (no load) has little too no chance of doing any damage - if there is any metal to metal contact - at such low RPMs there will be no heat but if that was to occure under compression load (plugs in) or at higher RPMs that same contact could cause plenty of friction, heat, damage and a lot of cursing! One important reason to prime load free is to clear out air pockets in the oil galleys that can take some time to all be pushed out - clear to the rear. This is no time to get in a hurry and fire up the engine. The rear of the engine can't wait 10-20 seconds underload for oil to get air bubble free.

I will do it two ways 4 long no load cranking of 30 second each wait 5 minutes combined it with short cranking 5 second between each longer crank (keeps the started cool enough) together it will give the needed time for the air to bleed out through all locations and all the way to the rear of the engine - together with pre-lubing everything it will be fine. I can't imagine an professional engine builder priming with the plugs in or just firinging it up. It takes time just for the oil filter, even when prefilled to fill completely.

One trick that just occurred to me is to take a new oil filter and attatch a hose to it or to the oil pressure sensor and pump all the oil in under reasonable pressure while turning the engine by hand at first, than pump with no load cranking and then cranking and pumping with the plugs in. I like that idea, over kill - perhaps, but not rediculous. but when it comes to starting a engine if there is a better safer way - do it go the extra mile and treat it like something can go wrong even though you have done everything possible to prevent it.

BeelzeBob
03-03-05, 12:19 PM
You guys are WAY too worried about priming the engine and starting it up the first time.... If the engine was assembled with adequate prelube on the bearings and such then it is fine to just finish assembling it and start it up. It will get oil pressure to the bearings quite quickly. Even a small amount of oil in each bearing for prelube will be plenty to run the engine under idle/no load for long enough to prime the oil pump 10 times.....

If you are concerned about testing the oil pump the no plugs/cranking method would work I suppose.

I honestly don't think that you could hurt the engine using any of the methods described above in reality so it is kind of a moot point anyway.

If you REALLY wanted to be anal about starting a new engine like the Northstar with the pump on the crank centerline then just overfill the sump by 6 quarts when the engine is green. This will partially submerge the crank and rod bearings on rotation and will splash plenty of prelube up onto all parts on the first rotation. Start it up and run it at a low RPM for a few minutes and then drain the oil down to the correct level. This would positively ensure against any damage due to a "dry" start or protect against drainoff after long term storage of the engine between assembly and starting it up.....

The engines with the oil pump on the crank centerline must ALWAYS prime on EACH start. The oil will drain from the pump on the hot shutdown so each startup is an oil pump "prime" event. Most people tend to think that after the engine has run the first time it is "primed" from that point on.....but engines like the Northstar do not stay primed and prime on each start....so....the reality of the oil pump priming after some engine work is put into perspective since it primes each time anyway the engine is started. The pumps and pickups are designed to prime rapidly so it is really not an issue.

Loose screw
03-04-05, 01:27 AM
Thank you, very informative over filling sounds like a wounderful idea to make sure every thing is soaked. I am perhaps overly concerned. But having a bearing spin and finding some of the timing chain pads to be worn clear through and almost cut in half lubrication may have been a neglected issue of the previous owner that I do not want to fail to go the extra mile or two. After doing some additional research it looks like this N* engine is going to be running on Amsoil together with their bypass filter system. I have tried their grease before on a bent front akle's wheel bearing, the bearing was replace several times with a good wheel bearing grease and once with Amsoil until the bent akle was discovered. With the Amsoil grease the bearing lasted 4 times longer and never did totally fail. After that I always keep some around, and the grease is so cheap to use compared to the oil as you never change it and you use so little anyway. They ought to send a small sample to every mechanic to try on their toughest applications, very strong film strength and it doesn't dry out as near as fast.

mcowden
03-04-05, 10:50 AM
Spoken like a true Amsoil dealer... I'm sure you'll be happy to sell us that Amsoil, too, eh? If you want to advertise your crap, pay for an ad and become a supporting sponsor, but keep your ridiculous B.S. out of the forums. I almost had to put my waders on to get through that heaping, steaming pile of crap you posted. You want to sell us a tornado fuel saver and fuel line magnets, too? Roll it up nice and tight and...

BeelzeBob
03-04-05, 11:18 AM
The only times that I have seen the tensioner pads on the Northstar timing chain drive worn out and "cut thru" was when a mechanic loosened the chains and did not keep the chain tensioners from fully extending. The mechanic then reinstalled the chains without retracting the tensioners (not sure how on earth he managed to get the overly tight chains back onto the cam sprockets....) and the extreme chain tension that resulted cut the guides and tensioner blocks.

If they were cut thru to the point of being destroyed it was not a lube failure. Those guides and pads will run for several hundred thousand miles easily with no problems. I have personally never seen one wear out even on high mileage engines and abusive dyno testing. Only when the chain tensioners are improperly installed or not controlled during service will the chain drive be damaged like that.

I am constantly amazed that we put hundreds of thousands of miles on Northstar engines, run them for hundreds and hundreds of hours on the dyno at full power and max RPM and we NEVER have to rely on the magic of Amsoil or bypass filters or Slick50 or ZMax or..... LOL LOL LOL LOL

Loose screw
03-04-05, 07:00 PM
That make sense with this engine the main short chain tensioner was worn down deep into the metal. As you may recall the oil manifold was not positioned correctly, so he did have the main bolts out and may of may have even took a part the rod cap to look at the bearing without replacing it (resulting in it later spinning). I don't know why he messed with the chain but it clearly matches you discription of a overly tight chain tensioner on the main chain. the upper two chain are fine - Everything adds up to - mechanic errors.

I have been searching locally all day for Loctite gasket eliminator 510 in Utah with no luck, is there a nother brand or product that will work as well?