1965
Thread Starter
Safety Car
Joined: Nov 2000
Posts: 4,761
Likes: 138
From: Clinton Township MI
Cruise-In III Veteran
ANSWER TO 1965 Solid Lifter-Kinda' Soft Thumper in Bottom End
Well surprise, surprise AND this was a most pleasant surprise. Found the root cause to my soft thumper when the motor was hot/fully warmed up. Visit all the background here and listen to my concern:
http://forums.corvetteforum.com/c1-a...ottom-end.html
Turns out after dropping the pan (and starter and partial exhaust and idler arm), the root cause of my soft thumper was my flywheel dust cover getting just touched enough by the flywheel bolts when fully warmed up. I for sure thought there was something letting go on the bottom end of the motor.
My neighbor, Jim Minton and I proceeded to check the thrust bearing clearance thinking the crankshaft might have had too much play (we noticed some fine lines on the front end of the pan. We setup a dial indicator and proceeded to find the measurement was within spec (.007). Motor has 24K miles on her and good oil pressure. So we're scratching our heads and decided to get another set of experienced eyes on this.
My go-to guy is Paul Richards. 5 minutes sitting in a roll around looking at the exposed innards of my 327, Paul just starts tapping the dust cover. She's kinda dished towards the flywheel....hmmmmm. Let's pull it down and look at it. Damn! That flywheel was definitely being chewed for awhile. The very tip of the flywheel bolts were shiny. A little 1/4" trimming of that radius and some tapping with a rubber mallet to true the flatness of the cover and all is quiet with my motor.
While everything was exposed we checked the torque on all the mains as well as the rod bolts...all clicked to spec OK
Sometimes you get lucky and it's the little things that give you grief/fix.
Pics of dial indicator and chewed up flywheel dust cover follow.
Jim
In God We Trust!
http://forums.corvetteforum.com/c1-a...ottom-end.html
Turns out after dropping the pan (and starter and partial exhaust and idler arm), the root cause of my soft thumper was my flywheel dust cover getting just touched enough by the flywheel bolts when fully warmed up. I for sure thought there was something letting go on the bottom end of the motor.
My neighbor, Jim Minton and I proceeded to check the thrust bearing clearance thinking the crankshaft might have had too much play (we noticed some fine lines on the front end of the pan. We setup a dial indicator and proceeded to find the measurement was within spec (.007). Motor has 24K miles on her and good oil pressure. So we're scratching our heads and decided to get another set of experienced eyes on this.
My go-to guy is Paul Richards. 5 minutes sitting in a roll around looking at the exposed innards of my 327, Paul just starts tapping the dust cover. She's kinda dished towards the flywheel....hmmmmm. Let's pull it down and look at it. Damn! That flywheel was definitely being chewed for awhile. The very tip of the flywheel bolts were shiny. A little 1/4" trimming of that radius and some tapping with a rubber mallet to true the flatness of the cover and all is quiet with my motor.
While everything was exposed we checked the torque on all the mains as well as the rod bolts...all clicked to spec OK
Sometimes you get lucky and it's the little things that give you grief/fix.
Pics of dial indicator and chewed up flywheel dust cover follow.
Jim
In God We Trust!
Last edited by 6T5RUSH; Mar 16, 2014 at 03:59 PM. Reason: added comment
Drifting
Joined: Jan 2013
Posts: 1,772
Likes: 196
From: Asheville NC
Status
Phil
Thread Starter
Safety Car
Joined: Nov 2000
Posts: 4,761
Likes: 138
From: Clinton Township MI
Cruise-In III Veteran
trying to get this topic started and hit enter...see above.
Drifting
Joined: Jan 2013
Posts: 1,772
Likes: 196
From: Asheville NC
Good Information
Well surprise, surprise AND this was a most pleasant surprise. Found the root cause to my soft thumper when the motor was hot/fully warmed up. Visit all the background here and listen to my concern:
http://forums.corvetteforum.com/c1-a...ottom-end.html
Turns out after dropping the pan (and starter and partial exhaust and idler arm), the root cause of my soft thumper was my flywheel dust cover getting just touched enough by the flywheel bolts when fully warmed up. I for sure thought there was something letting go on the bottom end of the motor.
My neighbor, Jim Minton and I proceeded to check the thrust bearing clearance thinking the crankshaft might have had too much play (we noticed some fine lines on the front end of the pan. We setup a dial indicator and proceeded to find the measurement was within spec (.007). Motor has 24K miles on her and good oil pressure. So we're scratching our heads and decided to get another set of experienced eyes on this.
My go-to guy is Paul Richards. 5 minutes sitting in a roll around looking at the exposed innards of my 327, Paul just starts tapping the dust cover. She's kinda dished towards the flywheel....hmmmmm. Let's pull it down and look at it. Damn! That flywheel was definitely being chewed for awhile. The very tip of the flywheel bolts were shiny. A little 1/4" trimming of that radius and some tapping with a rubber mallet to true the flatness of the cover and all is quiet with my motor.
While everything was exposed we checked the torque on all the mains as well as the rod bolts...all clicked to spec OK
Sometimes you get lucky and it's the little things that give you grief/fix.
Pics of dial indicator and chewed up flywheel dust cover follow.
Jim
In God We Trust!
http://forums.corvetteforum.com/c1-a...ottom-end.html
Turns out after dropping the pan (and starter and partial exhaust and idler arm), the root cause of my soft thumper was my flywheel dust cover getting just touched enough by the flywheel bolts when fully warmed up. I for sure thought there was something letting go on the bottom end of the motor.
My neighbor, Jim Minton and I proceeded to check the thrust bearing clearance thinking the crankshaft might have had too much play (we noticed some fine lines on the front end of the pan. We setup a dial indicator and proceeded to find the measurement was within spec (.007). Motor has 24K miles on her and good oil pressure. So we're scratching our heads and decided to get another set of experienced eyes on this.
My go-to guy is Paul Richards. 5 minutes sitting in a roll around looking at the exposed innards of my 327, Paul just starts tapping the dust cover. She's kinda dished towards the flywheel....hmmmmm. Let's pull it down and look at it. Damn! That flywheel was definitely being chewed for awhile. The very tip of the flywheel bolts were shiny. A little 1/4" trimming of that radius and some tapping with a rubber mallet to true the flatness of the cover and all is quiet with my motor.
While everything was exposed we checked the torque on all the mains as well as the rod bolts...all clicked to spec OK
Sometimes you get lucky and it's the little things that give you grief/fix.
Pics of dial indicator and chewed up flywheel dust cover follow.
Jim
In God We Trust!
Phil
