New Oil Pump Turning Resistance?

[VETDRMS]

Should there be some turning resistance on a new OEM front case/oil pump assembly?

I am using the mirage stub shaft with a new OEM front case/oil pump on my 2.4 and I just installed the front case. I planned to prime the motor with a drill before installing the timing belt so I installed the pump dry.

I used ample red Loctite on the stub shaft bolt and torqued to 29ft-lb, but not too much as to have any come out under the head of the bolt. I also applied an ample amount of Permatex engine assembly lube inside the stub shaft opening and to the stub shaft. With the gears dry it turned over smoothly but had some resistance, which I thought was probably the thick assembly lube (it is probably around 40F in my garage) on the stub shaft combined with dry gears.

I installed the front case and filled the pump with assembly lube through the pickup and turned it over by hand a bit pumping the assembly lube back and fourth to get it all worked in. I can feel some resistance that is kind of "notchy" when turning the shaft rate of ~4s/rotation. Is that just the pumping resistance of the thick assembly lube? If I turn it slowly, say 12s/rotation it is smooth with a pretty constant resistance. It is easy to turn over by hand and is smooth through the whole rotation. When it was dry with the stub shaft installed it was also easy to run over but had a spot that was a little harder to turn over.

For comparison my 175,000 mile old motor turns over very easy with little to no resistance. It however, stays easy even when turned over with a drill, so it might just be it's pretty worn.

If this is a simple question with a simple answer please excuse my ignorance as I haven't built one of these motors before so I am not familiar with what is or isn't considered "normal".

Should I pull the front case and disassemble the pump?

Thanks!

 

[Devilman]

every new pump ive ever dealt with feels the same way you described

 

[VETDRMS]

Thanks Devilman,

I've had a few people mention that as well.

It turned out to be a good thing I decided to remove it and check the gears. Here are a few observations:

1) The back cover already had a score mark in it from turning it over lightly by hand
2) The back of the driven gear has very sharp edges and some raised burrs
3) The drive gear has some wierd ridges/sharp spots on the tips of the gears (they look like black spots in the pictures) you can catch these with your finger nail.

Any suggestions on what to do with these? I am tempted to try and return this for a new case as this was a lot worse than I had expected it to be.

Thanks!

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[Gooberlog]

Tough call. If it did that just by hand, i'm scared what might happen under load. Eventually it'd probably scrape metal filings in to that oil galley.

My oil pump feels smooth dry but i then loaded the gears with Vaseline and now it feels like molasses kind of. Feels normal to me, cold garage here too. No notchy feeling though, just a consistan resistance on mine.

 

[VETDRMS]

I deburred the gears with a needle file tonight and lightly sanded both faces and the gear teeth with some 800 grit. I turned the gears against the face of the front and rear oil pump case and it feels smooth.

 

[VETDRMS]

I deburred the gears and reassembled the pump and it is as smooth as butter.

I used a flat needle file for the edges of the gears and a round needle file for the "u" between teeth. I then lightly sanded the faces with some 800 grit on a flat steel block to knock off any lips made by the files and hit the gears/teeth with a small Dremel buffer wheel. I only put a small bevel on the gears.

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[VETDRMS]

I am bringing this back up to the top before finishing the motor as I still have some concerns, advice/help is appreciated.

After deburring the gears and reassemblying everything it was very smooth and had no "notchy" feeling. I just primed the motor with a drill and it built oil pressure very fast and had oil at the head in less than 30 seconds. Oil pressure was a steady 50 psi with the drill in low speed.

After priming it I moved the oil pump by hand and it felt easy/smooth but the "notchy" feeling was back on occasion, i could roll past the feeling and then back up and go over it and it wouldn't be in the same place. Shouldn't you feel some of the pumping resistance when turning it slowly? I could see oil coming from the rocker arms even when turning it slowly by hand. Also, when turning the gear over quickly I can hear a gear-like noise, kind of like if there is lash, or you are winding a clock.... It builds pressure fast and I can't hear anything over the drill.

I really want to finish this thing up but this has me concerned? Should I pull it back down or is this normal.

Here is a video I made of what it sounds like:

03170123551.mp4 video by VETDRMS - Photobucket

 

[rx7ttlm]

my oil pump didn't sound like the video. take the gear set, clean the gears with brake clean. and slowly roll them togather and see if there is a stiff part. If there are two teeth that don't quite mesh right they wont show up every turn since the gears that hate each other wont touch every rev. I plan on being in the couv over on paddon parkway tomorrow so maybe I can cruise by and check it out.

 

[VETDRMS]

rx7PM sent

Well the notchy feeling must have just been the pumping resistance/residual pressure from priming as it is very smooth and easy to turn over with no rough spots. I can still hear the gears but I think it's fine.

 

[rx7ttlm]

rx7PM sent

Well the notchy feeling must have just been the pumping resistance/residual pressure from priming as it is very smooth and easy to turn over with no rough spots. I can still hear the gears but I think it's fine.

Ok that sounds about right. That's why I check the gear mesh before assembly.. Jewlers files and scotch brite is what i like most.

on my race engine I run the straight cut gears so there is no axial load. Those things are loud as shit.