so a few days ago I finished rebuilding my D16Y7 engine in the 96 civic, the car does seem a tad bit more responsive, not sure if it has to do with completely cleaning the throttle-body(little dirty), Idle air control valve(already clean), or Intake(full of sticky oil residue from having the PCV valve completely disconnected for about 10k miles when I first bought the car and was clueless regarding maintenance).

Problem: The bearings already on the vehicle looked good enough and the crankshaft looked really good as well, but the mechanic (he is well in his 60s & and still working on cars) who sometimes helps me if I get stuck, strongly recommended replacing all the main & connecting rod bearings. I figured no harm could be done and I went ahead & bought Sealed Power bearings. After installing the new bearings, I had the oil pressure light on and had a loud rod knock around 2k rpms (the car was not driven around), I opened up the bottom end and saw quite a few metal shavings in the pan and the when the bearings were removed, they had quit a bit of wear on them. Apparently the were the wrong size...I ordered standard. I put back the original bearings back in and no more oil pressure light on and no more knock.

Something odd though, every time I start the car now the oil pressure light comes on for a second, goes off then comes back for a split second and then goes off & doesn't return. I don't have any plastique(some material stated in the OEM repair manual) to measure the bearing size, nor the equipment to really measure it. This oil pressure light did not exist before the rebuild (the split second oil pressure light when it comes on the second time).

Should I leave it as is and keep driving since it definitely is more responsive then before?

or should I try to replace the bearings with the right size this time?
The identification on the back of the original (main & connecting rod) bearings was "ACL 0.25", I'm not sure if ACL is the OEM supplier? maybe that writing means ACL 0.25mm over-sized/under-sized?

Please do advice on what you guys think, I rather have it right then wrong because the piston rings and all the seals/gaskets are new.

Please let me know if "ACL 0.25" stands for over-sized/under-sized ONLY if you are 100% sure. Again the crankshaft looked in really good condition each time I had to take off the bearings.

 

I'm sorry you are having the expensive method of learning.

Just for your information and not to be caulky... The tool required is called plastigauge.

And ACL bearings are after market bearing not OEM.

Your mechanic friend was offering decent advise at replacing the bearings but assumed you knew how to do so properly.

If you don't have a micrometer to measure the journals you need to take the block and crank into a machine shop to measure it all for you so that you can get the proper sized bearings. And then on install you still double check them with plastigauge to verify the proper clearances.

What you did may have definitely harmed the crank and changed your bearing requirements so the originals now are out of spec. You may also have some scoring on your crank journals further complicating things.

At the bare minimum you need to take the crank and block into the machine shop and see if the crank needs a micro polish and let the machine shop tell you what size bearings you need for both the mains and the rods. Then install properly with the use of plastigauge and multiple loosen and torques of the fasteners to get the proper stretch.

 

Take it to a machine shop.