Thread: Oil pressure again!

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Ya might not remember my last post since it's been awhile but I asked about idle oil pressure. Well my oil pressure has dropped to 8 lbs. now. This engine has less than 500 miles on it! This is my first attempt at building a V-8 and to tell ya the truth, I'm already about fed up with it. Next Friday I'm pulling the engine again and am going to redo the bottom end, again. My question is this. As I am now very limited on cash, O'reilly's has reconditioned cranks with matched bearings for about 100 bucks. Has anyone had any experience with these cranks? I would also like to say that I am a fair mechanic. I have built all my own Harley's. I'm just saying this so ya know that I am not mechanicaly ignorant. Any suggestions would be greatly appreciated. Thanx in advance.

It happens even to professional rebuilders who do this all day long. We have set a policy at my marina that we will not install any rebuilt engine, only brand new, because we were getting 10-20% failures right out of the box. This is even from some of the top names in remanufactured engines.

I rebuild my own engines because I like to do it and feel I can save some money. (that may or may not be true in the final analyis), but I hold my breath for the first couple hundred or even thousand miles until I am a little confident everything is ok.

Here is the problem in just doing the crank. It could be cam bearings, or a galley plug, or so many other factors that you may not solve the problem. You have got to tear into the entire engine and make sure everything is to spec. Have new cam bearings installed and make sure they are indexed correctly, install a new oil pump, it is cheap insurance. Mike everything and make sure no bearings show any scoring. The teardown is going to be the thing that dictates what you fix. What oil and weight are you running?

Don

I'm running Valvoline 10W50 racing oil. The machine put together my short block and I put together the rest.

The best advice is to re-read the last paragraph in Don's post until you completely understand what he's trying to tell you. You won't know what your REAL "problem" is until you've done a full analysis (yeah, yeah, PITA isn't it?). For example; have you checked for fuel dilution yet? If that were the cause, rippin' the engine apart would be a complete waste of time and money. Guesses are fun, but can be costly...........for you in this case, not us.

you may want to go back and check the rod and mains a new crank may not do much if the bores are to big on the rods and mains if this was done recon rods and a line bore or hone and on a chevy running oil clearances on the rods and main can be any were from .001.5 to 003 so you need to go back and read back thru the old post i can not tell you any thing new on this and i do not think anyone can .with out really looking at your engine .

Thanks guys, There is no fuel dilution. Like I said, next Friday I am pulling the engine and checking all the tolerances. I have some ideas as to what happened and when I find out, I will post it here.

If it is a small block Chevy I wouldn't be too concerned. They are know for low pressure at idle, and it doesnt seem to bother them.

What is the pressure other than at idle. The formula is generally 10 lbs/thousand RPM is acceptable.

Not that its the problem,but 10w-50 Like gear lube at start up and like water when up to temp or is that backwards? The short block was done at the machine shop,then the machine shop needs to find out what is wrong.Did they put the oil pump on or did you?and which oil pump did they recommend and what bearing clearances did they use?The block may be set up for racing and have to have hv hp oil pump.

Originally Posted by shawnlee28

........or is that backwards?

Yup, sure is!