Are there differances in dampners between the big blocks, like there is with chevy motors? I have a 455 that was put together a couple of years ago, supposidly balanced and all. I recently have been driving it (2,000 miles) and it feels like its eating itself at about 2500 to 3000 rpm. Thanks for any help in advance. Ron

 

according to the gm parts catalog, all 455's used the same balancer. p/n 417142.
https://classicoldsmobile.com/forums...-417142-a.html


bill

 

That is the correct superseeded part number for olds V8; However, they did have several part numbers for the olds 455 balancere.

 

They'll swap between big and small block. The exception is the 307 motors. they had smaller ones like hockey pucks.

 

Here's the 307 hockey puck. http://www.ebay.com/itm/OLDS-OLDSMOB...47577c&vxp=mtr

Here's the 350-455 bigger balancer. http://www.ebay.com/itm/New-Harmonic...a0618d&vxp=mtr

 

Thanks for the info, my engine does have the correct balancer on it then. I took her on her first big trip yesterday, and 100 miles from home, blew a header gasket, errrrrr. After pulling the header off, I did get a chance to see that I didn't make the mistake of using Polyurethane motor mounts at least, like I did on the body mounts. Well, back to the drawing board. Thanks again, especialy for the pics, that helped a lot. Ron

 

Not directly related to the OP's question, but didn't the 400 have a one-off balancer for a year or two?

- Eric

 

Hopefully they did a good job with the balance. Normally you would get a balance card with components specific weights listed and also information about any mallory (heavy metal) that may have been added to the crank. Was it internally balanced or externally balanced? You may want to check your motor mounts by brake torquing your engine in gear to see if it lifts up from a broken mount. Check the fan clutch if it has one. Check the water pump bearing by rocking the fan. Check the torque converter bolts. Check the trans mount, u-joints and drive shaft balance. Check for a dead cylinder. I hope you find your problem and it doesn't involve a full tear down. Please keep us posted.

 

They may have changed the crank and the use of different pistons, and did not re-balance the assy.

Gene

 

excluding 260, 330, 425, and early 400
except for most of the vin 9 307's, they also used 417142.


bill