Hoping for a little help with my engine knock. I finally got my new iroc over to my house and the dam thing drove strong onto the trailer and into the garage but it has a very distinct persitant knock but it has great oil pressure about 30. The knock stays constant through acceleration. It doesn't get worse and it sometimes goes away at idle but not for long? Any ideas I'm doing a tear down starting hopefully in may but i've never heard a knock like this... I'll try to get up a video clip soon. but any ideas in the mean time would be great.

 

Cracked flex plate

 

never thought about the flexplate cracking i'll have to see back it up and take a look through the inspection cover. Thanks for the help i'll have to give that a try

 

Probably won't be able to see it...

Usually they crack around the crank flange bolts.

Might be able to hear it though; put the car up on ramps, take off the converter cover, start it, make sure it's making the noise, get under it with a piece of heater hose, stick it in your ear (my FAVORITE instruction !!!), and probe around and see if it's coming from up in there. Be careful not to get caught up in the ring gear or anything, somehow.

 

thanks alot i'll give it a try here as soon as i get a free minute from school and work. One of my buddies suggesested maybe the harmonic balancer went bad but hes a ford guy so he said he wasn't sure how the 305/350 are setup. Any ideas on the balancer goin bad?

 

i got the same problem as you, motors almost down to a short block right now and im about to pull it (by hand!!!!)

 

Balancers don't "go bad", and if/when it slips, it won't make any noise at all. If it was somehow falling apart, one quick look under the hood (one BRAVE look under the hood...) and you'd see it flopping around. I doubt this one. Check the flexplate. May need to have it magnafluxed to see a crack. But if that's the source of the noise, a $60 flexplate and you're back in business.

 

I recently had a 'knock'... but it was a bent pulley, luckily it was my smog pulley so I did a smog pulley delete on the car.

Just an idea, took me 3 days to locate the knock, I had no idea where it was coming from.

 

just a question not really realted to the post but i have an engine knock and really shitty oil pressure do they relate?

 

Generally yes. The lack of oil between your bearings and the crank is allowing the rods to "knock". Could be caused by excessive bearing wear.