Replaced bearings but still knocking

[khartley]

99 non turbo...car was knocking and I changed all rod bearings and now it only knocks lighty sometimes....I thought crank was scarred too badly and it was just going to spin again, but a mechanic told me that it is something (probably bearing metal) clogging something, or the oil pump possibly going out, to cause the #4 bearing to slightly knock sometimes....mostly during acceleration when oil pressure should be greater.

What do you guys think.

 

[98evoIIIpwr]

Did you get the crank checked when you replaced the bearings? Your crank can be bad or even worse your block ( Well either of them are bad). I would say drop the oil pan and see if you have any metal shavings. That would be your first indicator of another spun or eaten bearing.

 

[Defiant]

It's the part between ante and first raise.

Sounds like it's time you got a real machinist, and not someone who takes random guesses at what might be wrong. If you still have balance shafts, the bearing on the rear is failing.

Please use descriptive thread titles in the future.

 

[toybreaker]

Were the rod big ends inspected/machined?

Damaging a bearing almost always makes the big end less than round. Simply replacing the bearing will not change this.

If the car was driven any distance knocking before you did the bearings, it's also quite likely the crank pins aren't round anymore as well.

Pulling a spark plug wire while it's knocking will narrow down which cylinder is faulty.

Defiant may well be correct about the balance shaft bearing, so please check it out before you dissassemble things again.

Please consult a reputable machinist in your area, and have him measure your crank and rods before making any parts purchases, as machine work will be required.

 

[95talon_in_ma]

Did you replace the main bearings too? Or just the rod bearings.
If the rod spun, you should have definately done the mains...
If the bearing was completely spun, you have to have the crank machined. Unless you plan on selling the car right away...
But you probably left the crank in and did the rods only...right?

 

[khartley]

Did you replace the main bearings too? Or just the rod bearings.
If the rod spun, you should have definately done the mains...
If the bearing was completely spun, you have to have the crank machined. Unless you plan on selling the car right away...
But you probably left the crank in and did the rods only...right?

yeah, did it without taking the crank out, since that does require an engine pull (i think?) which I don't have any way to pull it....I didn't do the mains and the balance shafts are still there, and it is #4 bearing...

all I'm asking is if it is possible that it could be just something weird with oil pressure....cause I've dealt with quite a few cars that have had spun bearings or the beginnings of a spun bearing....and this one is completely different. It doesn't ever do it until the engine is at normal operating temperate, and then it will do it sometimes, not always. Sometimes just shifting will make it lightly knock for not even a full second....but sometimes I can drive it normal and it won't knock at all. So I just don't know what to think.

I just want to know if it could just be an oil pressure problem, or if it is possible for a rod bearing to be going out, but to only knock sometimes under load, no other time.