Help me out on my engine noise....

[vetteboy86]

Here is the link to Trans Am Country where I posted the thread: http://www.transamcountry.com/forum/viewtopic.php?t=23023

 

[gmjunkie]

Here is the link to Trans Am Country where I posted the thread: http://www.transamcountry.com/forum/viewtopic.php?t=23023

I think you may have a broken ring!! Could a little piece of metal got down the side of the piston??:ugh

 

[vetteboy86]

Would the cylinders still build compression if that was the case??

 

[gmjunkie]

Would the cylinders still build compression if that was the case??

Yes!! You may not see any compression Loss at all, or you may see substantial loss in compression!! Just depends in where the ring is broken!! If whatever was dancing around on top of piston,got close to edges it could even collapse the top ring lan a couple thousandths and not allow ring to expand all the way to the cylinder walls and the piston may rock in cylinder and make a noise!! It may be so minute of damage that even a experienced wrench may not see it!! Anything on top a Piston is going to do Damage!! Even just a little dent may cause a Hot spot and burn a hole in piston later down the road!! Could even be a valve seat knocked lose and rattling!! Did you disassemble head,or just look at it and see no damage and assume it was OK??

 

[vetteboy86]

I didn't dissamble the head. It is hard to pin point the exact spot of the noise. I am going to start the car with the valve covers off and look at what the rockers are doing.

 

[vetteboy86]

Well now I am really lost. I ran the car today with the valve cover off and didn't notice anything malfunctioning. The car made noise more during the first minute of run time. Odd thing is that it seems like a big marble bouncing around and then not. Eventually the noise actually went away during 5 or 6 minutes or running. We even ran the car up to 3000 rpms and no noise. What could actually be that unpredictable and that totally intermittent? Look at the link for more updates.....

 

[gmjunkie]

Well now I am really lost. I ran the car today with the valve cover off and didn't notice anything malfunctioning. The car made noise more during the first minute of run time. Odd thing is that it seems like a big marble bouncing around and then not. Eventually the noise actually went away during 5 or 6 minutes or running. We even ran the car up to 3000 rpms and no noise. What could actually be that unpredictable and that totally intermittent? Look at the link for more updates.....

Broken ring,lose valve seat,Broken or egg shaped valve guide, another piece of metal in there somewhere!! Are you sure it didn't crack the piston?? :ugh

 

[vetteboy86]

No did not crack the piston. I am going to try to narrow it down to a location although it is hard to pin point an engine noise.

 

[G Winter]

You said you removed pieces from the cylinder. Did you determine where they came from.Maybe you have something on the other side ?

You said it has a 403. They have a reputation of breaking piston skirts.I have one setting in the garage that had the symptoms of a broken skirt.Been a few yrs but that was a bit of a solid click and changed with rpm up and rpm down, and it did come and go.

If you would need a 403 to build.The price would be right. Not many of those around anymore.The right cam and a little head work and they would pull hard. Larger bore than the 455 with the stroke of a 350.Also the olds block had the best material of almost any US V8 engine. Cyliders hardly wore at all. Hope you find the problem without to much exspence.

Glenn


One thing I forgot, check the balancer they also go bad. Another thing is the thrust on the crank wears on some of the olds engines you get a front to rear crank slap.Gives a really strange sound.

 

[vetteboy86]

The motor is a 455. The motor looked to be in good shape. I am still baffled as to what the deal is.

 

[G Winter]

:duh wonder where I got 403 from. :duh

Glenn

 

[vetteboy86]

Well the noise in the motor is gone. It seemed to so away as the car ran. A guy listened to it and said the motor sounds great. He has been around motors his whole life so that was a good to hear. He thinks it may have been lifter related. I will keep you all posted.