I was wondering if you good folk could pass you view on a worry of mine.
As i'm sort of rebuilding the bottom end of my very old FJ11 i stripped and checked the oil pump.
The tolerances are fine but the pump and gears shows scores where something has passed through, you can feel the scores.
The question is (i think i know the answer already) is the pump scrap?
I'm guessing the scores will let a small amount of oil past and lower the overall pressure.
Ta
Boot
I would say, if you are worried about it, and have access to a new one, and you already have it apart, replace it...............Otherwise, smooth any rough burrs and reinstall it.
I believe the oil pumps on these engines are plenty durable, and I can't recall hearing of one of them failing...........even after 200,000 plus miles.....
Maybe the legends racer guys have had experience with this
pulled one out of a legends car motor that had no splines left so they do fail.
Quote from: Bootxjr on October 21, 2012, 05:02:29 AM
The tolerances are fine but the pump and gears shows scores where something has passed through, you can feel the scores.
The question is (i think i know the answer already) is the pump scrap?
I'm guessing the scores will let a small amount of oil past and lower the overall pressure.
Boot
Boot,
You are correct that the scores will cause a bypass within the oil pump and you can lose pressure if excessive scoring. The other issue, like mentioned prior is the splines. If the scores begin to gall and raise the load on the pump they are prone to stripping the oil pump shaft splines.
Here is the
new Yamaha oil pump (http://www.rpmracingca.com/proddetail.asp?prod=Engine%3AOilPump) listed on my website.
Randy - RPM
Thanks all.
I think i'll sort a newer pump just to be safe.