Howdy,

I just purchased a 95 Civic cheap that has an imported motor a few years old. The complain was the engine knocks. I hooked up a mechanical oil pressure gauge and on cold start the oil pressure is 80 and as it warms up it will eventually drop to less than 10 and if you blip the throttle you hear a knock in the bottom end and the pressure does not go up. I pulled the pan and it has sludge in the bottom and the screen had a lot of junk in it. I think I also saw copper flakes in the pan which tells me that is bearing material. Now for my question, could I replace the main and rod bearings in place and get anymore life out of it or should I just replace/rebuild the engine. Also should I replace the oil pump.


Thanks for you thoughts and ideas

Coy

 

I used to do that on my old Ford Trucks when I would spin a bearing. Replace bearings and oil pump. Why take a chance on the old pump with new bearings.

 

well with it.... id say rebuild it. if there is shavings in the bottom of the pan then it definatly needs rebuilt fully! low oil pressure can destroy a whole car! sounds to me like if the oilpan is all sludge then the screen on the pump is probably all clogged up.
IMO if it matters to you replace the motor or do a complete rebuild or replace it. and when you get the new motor if you buy used... do yourself a favor and drop the oil pan and clean it really good as well as the oil pickup screen and reinstal the pan with a new oilpan seal at least!

 

Bearings are shot. Drive it a little and have someone watch the tailpipe to see if it burns oil. That would mean the rings are done too. Sludge is murder on an engine. Especially if it's the non-VTEC engine you can find a whole engine pretty cheap. It's a lot easier to work on the engine out of the car. Quite simple to remove the engine from a Civic.

 

Good advise and thank you. Just thought I would try to repair what I have for a few buck instead of spending a $1,000 for a rebuilt engine.

I replaced the rod bearings, #3 had spun and #2 was getting close. I replaced all 4 sets and started the car with 15/40 oil. Oil pressure at startup was 85 psi. The engine warmed up for 15 minutes and and everything was great. Oil Pressure was still at 45 psi at idle so I went for a short spin. 1/2 mile down the road the Oil Pressure went to 20 psi. I let the car cool for 3 minutes and restarted and the Oil Pressure went back up to 50 psi for about 1/4 of a mile and then dropped. The only noise the engine is making is a tappet noise and no rod or main noise.

My question, does this engine had an oil pressure relief valve and where is it located if it does. My Haynes manual doesn't mention one.

Thanks for your thought and opnions,

Coy

 

if you just replaced rod bearings that might not be the only thing the rod bearing spinout damaged. the crank surface might also be bad. ussually it will screw up the crank journals when they(bearings) go out. you might check the surface of each journal,is it smooth and no gouges?? also you should have to check bearing installation with plasti-gauge for clearance. if you don't know how to do it, a machine shop is best to do it. you might as well look for engine swap if the crank is damaged. you'll probably spend less money. hope that helps.

 

There is a regulator bypass built into the oil pump assembly. I think it opens at 80 psi. The port on the side of the block measures pressure after the oil filter. Try changing the oil filter (again), as there is a lot of bits of stuff in this engine that could have clogged it up.