Valve spring breakage
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 3,223
Likes: 666
From: Northeast
Valve spring breakage
Just a FWIW. Car was running great until last week then began to skip, miss.
Did a compression check and in #5 got a reading of "0"
Leak down provided a nice breeze out the exhaust pipe.
Pulled the valve cover and found this:
$3.48 for a new spring and car back to running great.
Did a compression check and in #5 got a reading of "0"
Leak down provided a nice breeze out the exhaust pipe.
Pulled the valve cover and found this:
$3.48 for a new spring and car back to running great.
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Just a FWIW. Car was running great until last week then began to skip, miss.
Did a compression check and in #5 got a reading of "0"
Leak down provided a nice breeze out the exhaust pipe.
Pulled the valve cover and found this:
$3.48 for a new spring and car back to running great.
Did a compression check and in #5 got a reading of "0"
Leak down provided a nice breeze out the exhaust pipe.
Pulled the valve cover and found this:
$3.48 for a new spring and car back to running great.
Racer
Joined: Jul 2004
Posts: 254
Likes: 1
A clean break like a knife cut is heat treat. Improper heat treat of the part. A jagged break is harmonics. The coil is seeing frequency it does not like.
YOu have a harmonic issue. All of the springs have seen this so you need to replace all of them.
YOu have a harmonic issue. All of the springs have seen this so you need to replace all of them.
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 3,223
Likes: 666
From: Northeast
Thank you for the advice.
I know I have some decisions to make about the engine & maintenance (ie. while you are at it) and was hoping to make those during the winter storage. I really posted a FWIW so some owners can see what can happen. Engine has 102,000 miles.
Thanks again.
I know I have some decisions to make about the engine & maintenance (ie. while you are at it) and was hoping to make those during the winter storage. I really posted a FWIW so some owners can see what can happen. Engine has 102,000 miles.
Thanks again.
Racer
Joined: Jul 2004
Posts: 254
Likes: 1
The damper spring, the flat one. Check the bottom and top of the spring that would contact the head and the retainer. If this area is shinny then the engine has seen valve float. In this case you may have some cupped valves and the seats in the heads will be beat up. Worse case would be replacement of valve train parts and some machine work.
Le Mans Master
Joined: Oct 2007
Posts: 7,444
Likes: 970
From: Tennessee/Rhode Island
Bill,
As you know I too broke a value spring on my 78 L-82 in 1985 cruising down the highway, just like you. Drove it home for about 10 miles running like crap before I pulled the valve cover and discovered a broken spring just like yours-looked exactly the same-probably inferior manufacturing/defect. Changed that one spring just like you and have been driving it ever since-66,000 miles now/27 years later-no issues! I did change the rockers to comp cams roller tipped 1.5's in the early 90's when i changed all the valve stem seals along with 16 new pushrods using all the rest of the OEM springs. Probably should have changed all the other 15 springs back then but did not since I figured it was a one off. My experience has been that the secondary spring will prevent the valve from falling into the cylinder as long as you are not revving the crap out of the motor!
As you know I too broke a value spring on my 78 L-82 in 1985 cruising down the highway, just like you. Drove it home for about 10 miles running like crap before I pulled the valve cover and discovered a broken spring just like yours-looked exactly the same-probably inferior manufacturing/defect. Changed that one spring just like you and have been driving it ever since-66,000 miles now/27 years later-no issues! I did change the rockers to comp cams roller tipped 1.5's in the early 90's when i changed all the valve stem seals along with 16 new pushrods using all the rest of the OEM springs. Probably should have changed all the other 15 springs back then but did not since I figured it was a one off. My experience has been that the secondary spring will prevent the valve from falling into the cylinder as long as you are not revving the crap out of the motor!
