No Oil pressure
#11
09-26-2010, 04:03 PM
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#12
09-28-2010, 12:32 PM
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Well I have to disagree because I have seen many OEM cranks with many variances in their thickness. On a regular basis using a 0 bearing should be sufficient; however this is the case I am making in point. In this case the crank is most likely ground further down like a -1 or -2 not to mention the ware because he didn't have it ground.
What has happened is the Original Poster (OP) placed too small of bearings on the journals and this caused too large of an opening between the bearing and the crank. As oil gets forced through this opening to lubricate you get oil pressure (which is actually back pressure). If the openings (clearances) are too large you get no oil pressure. If they are too small you get too much pressure and the oil can’t move fast enough through the bearings and crank that it scorches and failure is imminent. Not enough pressure, well you get slop and failure is imminent.
So the OP put a larger weight of oil inside to see if he got more pressure. If you get more pressure then your bearing clearances are too much and that is what the test showed us, not to mention he didn't plasti-gauge.
Get the specifications and some plasti-gauge and measure the clearance. If it is too much get a bigger bearing tell you get it to the larger end of the specifications. The reason I say the larger side is because the crank is most likely worn and not perfect so that gives you room case there is any lobe in the journals, but at the same time you are still in specs.
Also, I have seen a few motors with different bearing measurements on different lifters but usually not OEM. Just check all the bearings while you got it out.
As for starting a blaze........Most of us are all friends and some have strong points in the tech world and there are also the soft points. This is a learning curve and that's one of the reasons we are here.
What has happened is the Original Poster (OP) placed too small of bearings on the journals and this caused too large of an opening between the bearing and the crank. As oil gets forced through this opening to lubricate you get oil pressure (which is actually back pressure). If the openings (clearances) are too large you get no oil pressure. If they are too small you get too much pressure and the oil can’t move fast enough through the bearings and crank that it scorches and failure is imminent. Not enough pressure, well you get slop and failure is imminent.
So the OP put a larger weight of oil inside to see if he got more pressure. If you get more pressure then your bearing clearances are too much and that is what the test showed us, not to mention he didn't plasti-gauge.
Get the specifications and some plasti-gauge and measure the clearance. If it is too much get a bigger bearing tell you get it to the larger end of the specifications. The reason I say the larger side is because the crank is most likely worn and not perfect so that gives you room case there is any lobe in the journals, but at the same time you are still in specs.
Also, I have seen a few motors with different bearing measurements on different lifters but usually not OEM. Just check all the bearings while you got it out.
As for starting a blaze........Most of us are all friends and some have strong points in the tech world and there are also the soft points. This is a learning curve and that's one of the reasons we are here.
#13
09-29-2010, 04:18 PM
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Plenum
badwrench,
I had the same problem when i first got my 99 durango. I bought it for 800 bucks because it had low to no oil pressure and the guy had no idea what was wrong with it. He overheated it and the plenum failed, and it caused a "combustion" type thing (sorry im not a mechanic) in where the pistons are (sorry again) and it ended up that there was a hole in one of the pistons from it. I ended up replacing the piston, replacing the oil pump and replacing the plenum gaskets. Truck ran like a dream when I almost tripled my money back and sold it.
Not sure if it will help you but try the oil pump and plenum gaskets
I had the same problem when i first got my 99 durango. I bought it for 800 bucks because it had low to no oil pressure and the guy had no idea what was wrong with it. He overheated it and the plenum failed, and it caused a "combustion" type thing (sorry im not a mechanic) in where the pistons are (sorry again) and it ended up that there was a hole in one of the pistons from it. I ended up replacing the piston, replacing the oil pump and replacing the plenum gaskets. Truck ran like a dream when I almost tripled my money back and sold it.
Not sure if it will help you but try the oil pump and plenum gaskets