Dusty Dude
Well-Known Member
Hello All,
Really need some help here folks. I built a 383 based 496" stroker for my '69 Coronet which is bolted up to a '75 727 filled with John Cope and A&A parts. The converter is a Hughes 3,000 stall unit. The flex plate is a stock Mopar part that came with the car and at the time of assembly looked to be in good condition.
440 Source stroker kit.
Stealth CNC ported heads.
Howards hyd roller cam and lifters.
Harland Sharp roller rockers.
Mopar M1 single plane with ProForm 1050.
Engine has been broken in and runs great. It has all the usual clatter that goes along with the roller stuff at idle. The last time I ran the engine after changing out the break-in oil I noticed a deep sounding rattle that is audibly the same as you walk around the front of the car. I have a stethoscope and I have listened everywhere I can and all I hear is what I would call normal mechanical noise so at this point I am stumped.
My question is, is it possible that the flex plate has broken around the crank bolts? The noise is very noticeable inside the car and also while driving it into my garage. I have never experienced a broken flex plate so I have no idea what that sounds like. The fit-up of the converter to the flex plate was good when I mated the engine and trans together before installation so I'm sure I didn't shoot myself in the foot on that one. I have no idea what kind of life the flex plate had before we got the car so wouldn't be surprised if it died.
Also gave all the pulleys and accessories a good looking over and listening to and all seems well there.
Any help would be greatly appreciated.
Thanks All
Really need some help here folks. I built a 383 based 496" stroker for my '69 Coronet which is bolted up to a '75 727 filled with John Cope and A&A parts. The converter is a Hughes 3,000 stall unit. The flex plate is a stock Mopar part that came with the car and at the time of assembly looked to be in good condition.
440 Source stroker kit.
Stealth CNC ported heads.
Howards hyd roller cam and lifters.
Harland Sharp roller rockers.
Mopar M1 single plane with ProForm 1050.
Engine has been broken in and runs great. It has all the usual clatter that goes along with the roller stuff at idle. The last time I ran the engine after changing out the break-in oil I noticed a deep sounding rattle that is audibly the same as you walk around the front of the car. I have a stethoscope and I have listened everywhere I can and all I hear is what I would call normal mechanical noise so at this point I am stumped.
My question is, is it possible that the flex plate has broken around the crank bolts? The noise is very noticeable inside the car and also while driving it into my garage. I have never experienced a broken flex plate so I have no idea what that sounds like. The fit-up of the converter to the flex plate was good when I mated the engine and trans together before installation so I'm sure I didn't shoot myself in the foot on that one. I have no idea what kind of life the flex plate had before we got the car so wouldn't be surprised if it died.
Also gave all the pulleys and accessories a good looking over and listening to and all seems well there.
Any help would be greatly appreciated.
Thanks All
