So, i have had a couple 7th gen civic motors with spun main bearings or big ends sitting behind my shed outside for a few years now. I was buying civics, replacing parts and trying to flip them for a while but didn't make any money. The spun bottom end bearings in these motors seem to be quite common. Anyway, I decided to take one apart to better understand how these motors worked and to see what went wrong.
So, i tore it all apart, found some strange designs by Honda but,sticking to one topic, i believe i found out the cause of the wrecked motor.
Some background: this particular car the motor came out of had 77,000km (48k miles) and was driven by a woman in college. She didn't take great care of it bodywise. I gathered oil changes were done at a decent time mileage wise (from the stickers) but that the the time intervals were a bit long between. Engine oil level was fine when i got it and no one would be stupid enough to add oil after it seized and exploded like this. when i drained the oil it looked old, not like new oil had been added so i do not believe this was oil starvation from lack of oil in the sump.
keep in mind that some people on this site believe that oil can last forever and some people are still having good oil analysis after 40k miles.
So the results of the teardown basically in the order i saw stuff:
- holes punched through both sides of the motor by a broken connecting rod on the cylinder farthest from the flywheel.
-Rocker tubes and arms quite worn- way more than an engine i tore apart with 300k a while back. Camshaft wasn't too terrible on the lobes but the 'bearings' of the camshaft were scored up.
-oil pan full of metal flakes. Small Pieces of connecting rod everywhere, biggest piece was punched through the baffle.
-oil gallerys full of metal flakes. And i mean like a good thick layer of it, and hole punched through gallery by connecting rod.
-the piston from the connecting rod that broke had hit the valves and bent them, messed up the piston pretty good.
-main bearings scored heavily and the one farthest away from the flywheel was crushed and cracked.
-big end bearings scored up worse than mains. The one from the broken connecting rod was in the pan obviously but the one beside it was spun and crushed. Mushroomed out quite a ways actually. The connecting rod beside that was black. The others weren't spun but it looked like the backs of the bearing inserts had been scored up a bit, which is weird.
-oil grooves on all bearings had metal flakes in them and where the 2 halves of the bearings meet had built up metal filings on most of the bearings.
- cut open oil filter. Its a powerflo made by purolater. It had a thick layer of metal filings on the clean side, bypass valve stuck open by filings, inside of can and pleats full of metal. Filter media torn.
Those are the facts, my conclusions are this:
I think the media was torn from new rather than right before the engine cratered, just by the looks of how it was torn. I think that oil was going through the tear and not being filter right from the time this oil and filter was put in.
That started wear as particles were not being filtered out.
Oil was thin 5w20 to begin with and probably got fuel and water diluted over time with short trips in town to college.
Cold starts all winter -20c normal temps down to -35c is common. with the car probably parked outside and who knows if she plugged it in. That would obviously cause the bypass valve to open.
This bypass valve takes a lot of pressure to fully open. We have a very sensitive scale at work and i stuck a screwdriver against the valve and pushed to see what it took to crack it. 13 pounds to start opening it. I didn't want to damage the scale by pushing too hard but on the bench top pushing as hard as i can with both hands only gets this valve open about 1/8inch. The bypass opening is 0.5square inches so it takes 26psi differential pressure just to crack it! it takes a ton of pressure to fully open, probably more like 80-100psi differential pressure i would guess (40-50 pounds of force on the 'spring'). At 1/8in fully open thats 0.314 sq in that it lets oil in through. I don't think thats much, but i could be wrong. as a comparison i cut an amsoil filter apart yesterday. its bypass valve starts to open at 6.6psi and is fully open at 17.6psi, a total of 0.58sq inch of opening. so the amsoil has an almost properly spec'd bypass valve (8psi is opening spec for the Honda filter) and almost twice the area for the oil to flow through
Anyway, so, media tear lets metal or other abrasive particles through, bypass valve being in the back of the can takes any metal not stuck down well to the media or any metal loose in the can after shutdown and puts it back into your bearings. That causes more wear.
First bearing gets spun, girl keeps driving it.
Bearings get worse and worse, more and more metal, bypass is open all the time because filters plugged other than the tear and then the second bearing spins.
Then the one spun bearing catches, seizes, welds, or falls right out and that causes the connecting rod to break.
Engine shuts down and car gets towed and i buy it and replace motor.
So in my opinion using a purolater filter with a tear caused an engine with only 77,000 km (48, 000miles) to self destruct to the point where its not rebuild able nor is any component reasonably usable. Block has holes punched in it
Pistons are done
Oil pump would be scored up
Pan has a hole in the baffle
Head has bent valves and worn camshaft 'bearings' which aren't replaceable inserts.
Rockers and rocker tubes are toast
Valve cover is good though!
i almost don't want to upload photos because they really don't do it justice. especially the photos of the oil filter. my best camera is an old iphone and it didn't do a great job. the inside of that oil filter was like a can of glitter-photos don't show that well. i tried hard to get a good photo of inside the oil galleries but it just wouldn't. same with the bearings, photos just don't do it justice. im also not uploading many as i do not have much data on my internet plan. sorry. please open up the photos fullscreen to look at if you plan to comment. you miss a lot otherwise.
Thoughts anyone? Or a different destruction scenario? should i contact purolater and ask them to pay for the motor?
inside oil gallery
bearing
holes
whats left of the rod
media torn on both ends of the pleat
So, i tore it all apart, found some strange designs by Honda but,sticking to one topic, i believe i found out the cause of the wrecked motor.
Some background: this particular car the motor came out of had 77,000km (48k miles) and was driven by a woman in college. She didn't take great care of it bodywise. I gathered oil changes were done at a decent time mileage wise (from the stickers) but that the the time intervals were a bit long between. Engine oil level was fine when i got it and no one would be stupid enough to add oil after it seized and exploded like this. when i drained the oil it looked old, not like new oil had been added so i do not believe this was oil starvation from lack of oil in the sump.
keep in mind that some people on this site believe that oil can last forever and some people are still having good oil analysis after 40k miles.
So the results of the teardown basically in the order i saw stuff:
- holes punched through both sides of the motor by a broken connecting rod on the cylinder farthest from the flywheel.
-Rocker tubes and arms quite worn- way more than an engine i tore apart with 300k a while back. Camshaft wasn't too terrible on the lobes but the 'bearings' of the camshaft were scored up.
-oil pan full of metal flakes. Small Pieces of connecting rod everywhere, biggest piece was punched through the baffle.
-oil gallerys full of metal flakes. And i mean like a good thick layer of it, and hole punched through gallery by connecting rod.
-the piston from the connecting rod that broke had hit the valves and bent them, messed up the piston pretty good.
-main bearings scored heavily and the one farthest away from the flywheel was crushed and cracked.
-big end bearings scored up worse than mains. The one from the broken connecting rod was in the pan obviously but the one beside it was spun and crushed. Mushroomed out quite a ways actually. The connecting rod beside that was black. The others weren't spun but it looked like the backs of the bearing inserts had been scored up a bit, which is weird.
-oil grooves on all bearings had metal flakes in them and where the 2 halves of the bearings meet had built up metal filings on most of the bearings.
- cut open oil filter. Its a powerflo made by purolater. It had a thick layer of metal filings on the clean side, bypass valve stuck open by filings, inside of can and pleats full of metal. Filter media torn.
Those are the facts, my conclusions are this:
I think the media was torn from new rather than right before the engine cratered, just by the looks of how it was torn. I think that oil was going through the tear and not being filter right from the time this oil and filter was put in.
That started wear as particles were not being filtered out.
Oil was thin 5w20 to begin with and probably got fuel and water diluted over time with short trips in town to college.
Cold starts all winter -20c normal temps down to -35c is common. with the car probably parked outside and who knows if she plugged it in. That would obviously cause the bypass valve to open.
This bypass valve takes a lot of pressure to fully open. We have a very sensitive scale at work and i stuck a screwdriver against the valve and pushed to see what it took to crack it. 13 pounds to start opening it. I didn't want to damage the scale by pushing too hard but on the bench top pushing as hard as i can with both hands only gets this valve open about 1/8inch. The bypass opening is 0.5square inches so it takes 26psi differential pressure just to crack it! it takes a ton of pressure to fully open, probably more like 80-100psi differential pressure i would guess (40-50 pounds of force on the 'spring'). At 1/8in fully open thats 0.314 sq in that it lets oil in through. I don't think thats much, but i could be wrong. as a comparison i cut an amsoil filter apart yesterday. its bypass valve starts to open at 6.6psi and is fully open at 17.6psi, a total of 0.58sq inch of opening. so the amsoil has an almost properly spec'd bypass valve (8psi is opening spec for the Honda filter) and almost twice the area for the oil to flow through
Anyway, so, media tear lets metal or other abrasive particles through, bypass valve being in the back of the can takes any metal not stuck down well to the media or any metal loose in the can after shutdown and puts it back into your bearings. That causes more wear.
First bearing gets spun, girl keeps driving it.
Bearings get worse and worse, more and more metal, bypass is open all the time because filters plugged other than the tear and then the second bearing spins.
Then the one spun bearing catches, seizes, welds, or falls right out and that causes the connecting rod to break.
Engine shuts down and car gets towed and i buy it and replace motor.
So in my opinion using a purolater filter with a tear caused an engine with only 77,000 km (48, 000miles) to self destruct to the point where its not rebuild able nor is any component reasonably usable. Block has holes punched in it
Pistons are done
Oil pump would be scored up
Pan has a hole in the baffle
Head has bent valves and worn camshaft 'bearings' which aren't replaceable inserts.
Rockers and rocker tubes are toast
Valve cover is good though!
i almost don't want to upload photos because they really don't do it justice. especially the photos of the oil filter. my best camera is an old iphone and it didn't do a great job. the inside of that oil filter was like a can of glitter-photos don't show that well. i tried hard to get a good photo of inside the oil galleries but it just wouldn't. same with the bearings, photos just don't do it justice. im also not uploading many as i do not have much data on my internet plan. sorry. please open up the photos fullscreen to look at if you plan to comment. you miss a lot otherwise.
Thoughts anyone? Or a different destruction scenario? should i contact purolater and ask them to pay for the motor?
inside oil gallery
bearing
holes
whats left of the rod
media torn on both ends of the pleat