Main bearing knock symptoms??

[shelbyglhs222]

Can everyone here who has had main bearing failure post there symptoms?? My new motor developed a knock at about 1500 rpms(its louder with load on the motor...only hear it for a split second when revving in neutral). Anyway..it developed this knock at 3 miles and the car has about 420 miles on it and the knock hasn't gotten any worse and the car is still together.

If this was a main bearing issue wouldn't the motor be junked already?? Someone suggested it may be my flexplate or my torque converter, but its too cold outside right now to check. I just dont understand how it could be the flexplate..I torqued down the bolts and put loctite on.

[macncheese]

i wiped out all my rod bearings and all my main bearings. not a whiff of noise. just SUPER low oil pressure. would still spin the tires going into third. of course, NOW it spins the tires in third whenever i want!!!
tony

[shelbyglhs222]

Really??? My oil pressure is amazing...50 psi when cold..25 psi when warm at idle. Goes to about 60 psi when you nail the throttle. No one seems to know what it is..I took it to 3 people. I got 3 different answers . One guy said wrist pin..one guy said main bearing..one guy said torque converter/flexplate bolts loose.

[als]

had the same noise with woody after trans plant had new rod bearings and new pump had great oil psi. flew plate broke around bolts . pulled down pan and put another set rod bearings and still had noise.they way i found mine was run the **** out of it till it broke. was tired of fixing things that weren,t bad.

[shelbyglhs222]

You know come to think of it..I just realized I torqued down the flexplate for FLYWHEEL spec which is 10 ft/lbs more than I was supposed to...hmmmmmm.

[shelbyglhs222]

What happens if the flexplate is installed backwards?

[glhs727]

I do believe that you "cannot" put in the flexplate backwards. It will only bolt in one way because of the bolt pattern. But i have seen cracked/broken flexplates make a lot of noise at low rpms that sounded like rod knock.
Did you drain the oil and carefully look/feel it for any bearing material? If you check it for debri and find none, I might suspect the flexplate. if you have lots of bearing debris, then you better take care of before you ruin your turbo and other parts.
later,
Cindy

[shelbyglhs222]

Yeah I know that...the machine shop who did it offered to take it for a day and see what he can do. I am sure he will drain the oil and look at it.