Jeffs1997

I bought this 97 firebird 3.8 with a 5 speed. Sound like horrible rod knock or spun crank bearing. However it hold around 50psi oil pressure at idle (shouldn't have much if any oil pressure right) ????

I got to looking at motor and saw this difference between this 97 firebird and my 97 camaro

97 camaro harmonic balancer







This is the balancer on the 97 firebird







Or is this just a cosmetic cover that just fell off? I also am think clutch/flywheel related

Jeffs1997

Ok, it turns out this firebirds harmonic balancer is from a 98-up 3.8 .... Would this cause balancing issues in this 97 engine?

parkers Z28

Check to see if the fly wheel bolts are lose .. Is the harmonic balancer out of balance ?? is it shaking is the belt squeaking ? I don't thank that a bad harmonic balancer will make a sound like a rod bearing ..?? I have seen several people have there flywheel bolts back out and think it was a rod bearing !!! good luck hope that is your problem

Jeffs1997

I crawled under car today and found this.

On this 5 speed it has sight notches on bottom of flywheel where you can see it.

I took a screw driver and the flywheel can be moved forward and back by about a 1/4 inch.

obviously that is a problem but could the crankshaft have broke and that is allowing it to happen?

Unplugging one plug at a time make no difference.

Idle oil pressure stay between first mark and 60 psi and climbs as rpms do

harmonic balancer does NOT wobble nor does the serpentine belt

under the car it sound like the noise is more around the transmission

constant oil drip from clutch housing

prior owner said clutch was done about 5 months ago


What is your guys opinion ????? broken crank or loose flywheel

brandons94lt1

I had a 79 trans am that I swore(as did several mechanics) that I had rods knocking....it did it particularly bad when I fired up the car...

Turned out that some bolts from the converter weren't tightened down correctly....

Idk here...but good luck man..

Jeffs1997

Paid 1,000 for it and everything works perfect even the A/C. Super clean interior, no dents, very minimal scratches. No tears in seats very light stains on carpet. Very little cosmetic work needed.

So yes it is worthy of even a new engine.

Jeffs1997

pulled 3.8 and found cracked block plus greyish oil oozing out of the rear main seal.

here is the crack ... it disappears behind the starter then I can't see where it goes.





Found this 96 firebird 3.8 for 700.00 as pictured on ebay, I heard it run in the car, it wasn't pressure washed this is the way it came out of the 96 firebird.

Looks like it was rebuilt then the car was crashed. It is very clean.

Jeffs1997

Here is the damage to the old 3.8

Pieces of connecting rod and bearings broken up in oil pan. Looks like one rod bolt snapped and the other threaded itself out.





This is what the crank looked like. I believe the rod nehind this journal was getting ready to leave as well.





here is the piston, it wasn't siezed it just pushed out of the cylinder (surprised it didn't fall down to the crank and disintegrate the engine)



here is the crack, I couldn't get a picture of the rest of the crack but it ran the full length of the block on the drivers side.



chunk missing







when oil pan was deopped this section of the block fell off



it came from here





Yes the motor ran like this, had around 40psi oil pressure and yes I drove it a block like this.

jloshotz

Wow!

Jeffs1997

To answer some PM's here before they are asked again.

The orange motor is yes I know chevy orange, I am not sure why it was painted that color but it is a 3800 series 2.

No pistons showed any damage indicating detonation or any other type of issue.

History known, prior owner said it blew head gaskets, heads were rebuilt and new head and intake gaskets installed. After he got it back from shop it started making the knocking noise. I think it was hydro-locked at some point, why one rod bolt looks like it just threaded out and the other snapped I have no idea.

No the motor was never given any juice or turbo'ed.

No further dismantling of motor will be done.

However heads are for sale LOL.

bigz28man

mrwoopass

Seeing this just expedited my engine rebuild project. Passenger side head gasket is blown, and there's a pretty severe knock on the engine usually amplified by very, very cold weather. Only gets quieter as the car warms up but the sound is still always there.

Nice picks though, best of luck with the rest of your project