knock in my 5.7 litter Chevy van with low oil pressure after having the intake replaced?

Question

after knock started i replaced the oil pump oil pan gasket,rod bearings...this doesnt knock all the time mainly at an idile or at a low speed but still no oil pressure

Answer 1

First thing to do is install a shop guage into the motor's oil sender to see what the pressure actually is. Don't rely on the electrical one that's installed. If you do have low pressure and the motor used to have good pressure, what probably happened is a bunch of crap got into the motor when you were sanding the gasket area of the intake. You'd think the filter and all would protect against this, but it makes it through. You will have to pull motor to inspect for the damage within the bearings. There is a possibility that some of the lifters could have split apart and caused an internal leak as well.

Answer 2

Sounds like you installed the pump wrong. The knock is from oil not reaching the rockers. Which means your heads are not getting lubricated and that's bad. Open it back up once in check if the oil pick up isn't too low in the pan and blocked. Most likely that is the problem, but I would still pull the pump off and make sure it is spinning. Do not drive the van for now till its fixed or you could warp a head.

Answer 3

Chances are the original oil pump screen blocked up and starved the crank assembly of oil. On a semi-worn out engine this scenario results in a destroyed bottom end in just a minute or two of running time. Replace the engine with a guarantee'd remanufactured long-block assembly. Be sure to have the new and old engines side by side during the 'outfitting' phase for proper reconstruction. Be sure to address the radiator and other external systems for age/poor maintenace related issues.