Oil pump drive gear plastic broken.. and wear pattern. Opinions?
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From: San Antonio
If a cap can be milled out to be placed on top of and encase it, that might work. Just and idea. Interested in the problem. Putting my engine back together really soon and this small part seems like it could be a big issue.
Mec
Mec
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A while back I had thought of making a box full and selling them.
It would become a regular maintenance item like a timing chain on a rebuild.
If ya stop it from jumping out(if it breaks) with a plate on top then it could spin and not turn the pump right and wear and get cocked and wear the gear quickly.
Cracking at the bolt hole is the easiest place for it to break. It will find the next weakest point on the little arm after that if it has enough load and spin anyway. If the arm breaks at the housing it could go down???? and spin anyway. Again I don't know how much load it will take to mess it completely up,does any body?
Just better not to take the chance on a $10,000+ engine. Many do- not thinking about it and say it's the pump or something else that broke it, after they toast an engine.
The damn thing is plastic,guys.
It would become a regular maintenance item like a timing chain on a rebuild.
If ya stop it from jumping out(if it breaks) with a plate on top then it could spin and not turn the pump right and wear and get cocked and wear the gear quickly.
Cracking at the bolt hole is the easiest place for it to break. It will find the next weakest point on the little arm after that if it has enough load and spin anyway. If the arm breaks at the housing it could go down???? and spin anyway. Again I don't know how much load it will take to mess it completely up,does any body?
Just better not to take the chance on a $10,000+ engine. Many do- not thinking about it and say it's the pump or something else that broke it, after they toast an engine.
The damn thing is plastic,guys.
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Only problem with the needle thrust bearings is if they ever come apart you got those tiny bearing rollers everywhere - not saying that will happen... Whereas the plain thrust washer is more fool proof and will probably last forever since it's always in an oil bath.
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The issue with that is for the front bearing you'd want a tapered bearing which I haven't been able to find one small enough yet.
That is a good point.
Only problem with the needle thrust bearings is if they ever come apart you got those tiny bearing rollers everywhere - not saying that will happen... Whereas the plain thrust washer is more fool proof and will probably last forever since it's always in an oil bath.
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From: San Antonio
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I understand what you're wanting and you could conceiveably do it on the cheap by making the piece as shown and make a wrap around strap and tack it together, or maybe make it with flaps and heat it up then bend the sides down if you can do it sharply enough, or else you might need a milling machine and just carve it out of aluminum (which would be the most trick way of making it). If you only did the top piece without sides, it would still make that assembly a lot stronger than it is. I don't think there's a lot of force trying to turn that plastic part - it's just a holder for the shaft and as long as the shaft stays in there, you should have oil, even if the side of the screw hole cracks away (as long as the screw stays put and holds most of it in there)
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Well roller bearings are not a likely reality. There aren't tapered ones availible in the size necessary, and the only ball bearings availible in the correct size will not work at the RPM that the shaft will see.
I am confident that a oil impregnated bronze bushing and steel thrust washer will work very well. The one I have disassembled in front of me still has no side to side shaft play after 125k miles.
I am confident that a oil impregnated bronze bushing and steel thrust washer will work very well. The one I have disassembled in front of me still has no side to side shaft play after 125k miles.
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Well the one my buddy made did not wrap around, it went all the way back to where the curvature(sp?) on the rear started. It was MACHINED from a piece of billet.
Kevin, if the rotational strain is not cracking just what do you think IS doing it?
The pic at the beginning of the thread looks like rotational loading NOT vertical loading. But I may be wrong, I cant pick up the phone, call a cnc shop, have it made and claim it to be MY design.
I think my buddies(not mine) idea was great and will work. It worked on his car spinning the engine to 7300rpm, many times. It will re-enforce rotational and vertical loading.
David
Last edited by FASTFATBOY; Jan 12, 2008 at 10:28 PM.
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The issue with that is for the front bearing you'd want a tapered bearing which I haven't been able to find one small enough yet.
Kevin Blown 95 TA Only problem with the needle thrust bearings is if they ever come apart you got those tiny bearing rollers everywhere - not saying that will happen... Whereas the plain thrust washer is more fool proof and will probably last forever since it's always in an oil bath.
That is a good point.
Kevin Blown 95 TA Only problem with the needle thrust bearings is if they ever come apart you got those tiny bearing rollers everywhere - not saying that will happen... Whereas the plain thrust washer is more fool proof and will probably last forever since it's always in an oil bath.
That is a good point.
Last edited by 1racerdude; Jan 12, 2008 at 10:13 PM.
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And I think the vibration from the oil pump pulses along with the torque of the screw might be cracking those, so maybe it's worse in a high volume pump where the screw is tight. The torsional load should only be due to friction of the bearings and oil. Maybe a cold start hurts there. Wnenever they have something like this where I work, it's usually due to cost cutting. They cold probably have made it last just by putting a ferrule or metal lining in there.