Oil Pickup Filter?

[Yard Dogg]

When I tore my engine apart I discovered that my main bearings had been gouged from foreign particles entering the oil ports. I found crap logged in the oil pump pickup in my gear case.

I looked at the way the oil is pumped through the engine and want to clarify it. It looks to me, like the oil pump picks up the oil, then sends it to a T in the upper case half. From there it splits and goes to the cams, and to the oil filter. From the oil filter it goes to the crank case. So doesn't that mean that the cams are getting unfiltered oil?

Also, I find it strange that my mains suffered damage from foreign material since they are supposedly getting filtered oil. I'm just wondering if anyone has come up with a better screen for the oil pump to prevent this problem. I was thinking of getting some tighter woven stainless steel screen material and installing it in front of the usual oil screen.

[petejw]

hi yard dogg, id be real careful in putting
anything in front of the original oil screen
could cause a restriction, if ur oils clean
and regulary changed then u shouldnt have a problem.

looking at the manual, the oil goes to the filter straight
from the oil pump.
clymers pg93

[Yard Dogg]

When I get my case halves back from their bath, I'll look again.

[motoman]

hi yard dogg, id be real careful in putting
anything in front of the original oil screen
could cause a restriction, if ur oils clean
and regulary changed then u shouldnt have a problem.

looking at the manual, the oil goes to the filter straight
from the oil pump.
clymers pg93

+1.......oil sump to pump......pump to filter....first.

[bikerphil]

Yep, but if your filter gets clogged, the bypass valve in the cup bolt will let dirty oil thru to the rest of the engine. Dirty oil is better than no oil, not by much.

[Yard Dogg]

I got my cases back today. I asked the dude at the shop how much crap came out of my oil ports and he told me he spent an hour just cleaning those out. He said there was a lot of crap and metallic stuff in there. I'm glad I spent the $35 on a good cleaning. I wanted to make sure they were degreased and dried thoroughly before I sandblast, LOL. I don't want any sand sticking inside anywhere so I can make sure to blow it all out. I will still tape off everything I can to prevent it, but you can't ever stop all the sand it seems like. Oh, if anyone has one of the tubular placement pins for the crank case halves, I need one cause the shop lost one of them. I'm going to try to find a replacement at Ace, but it seems to be an oddball metric size.

[Lamric]

...From the oil filter it goes to the crank case.....

No, the oil from the sump gets sucked up through the oil pump strainer then goes from the pump to the outside of the oil filter, through the filter then up the filter bolt (aka bypass valve) to the crankshaft & cams.

[petejw]

Yep, but if your filter gets clogged, the bypass valve in the cup bolt will let dirty oil thru to the rest of the engine. Dirty oil is better than no oil, not by much.

phil makes a good point,
i also remember reading a cpl of years back
there was something going on with some1s oil filter bolt,
cant remember exactly i think the ball getting stuck/being pushed up against
the spring or something, just have a check of the oil filter bolt
and the way the internals are sitting.

[Yard Dogg]

Yeah I looked the case over again and it does appear that the oil gets filtered first. Brain fart. Well, I got my cases painted and lookin sharp. I'm just waiting for a few parts and that baby is going back together. I just ordered paint for the rest of the bike. This XJ will be a force to be reckoned with this spring.

[MPittma100]

Lubrication flow

Hi,

It is a good idea to use other than sand to clean your (aluminum) cases. Sand is too aggressive. Glass bead is the better choice.

The oil filter bypass is a necessary evil in most engines due to a number of reasons: cheap filters clogging up, too long between oil changes, and revving an engine when it is cold. Never have figured out why people do that?

Bad thing about the bypass is, when it does open, any trash in the oil goes all through the engine. Good thing about the bypass is that it opens when a filter gets clogged or if the oil is too thick (cold). So, you really do not ever want to block a filter bypass off on a street machine. But you certainly need to be sure that it is working properly.

In racing engines, the bypass is always blocked off. No unfiltered oil ever goes anywhere. The only part that may get damaged in the event of a metal failure is the oil pump itself. But the crank, cam, and bearings remain unscathed. In these engines, the oil is changed very frequently and the oil pressure, which is 80-125 psi, is monitored closely. There is also a light that will come on at 20-30 psi if the filter clogs. This gives you time to react without hurting the engine.

MP