Diagnosing Valve Train Clatter
Hotshot
Joined: Jul 2020
Posts: 10,471
Likes: 2,633
From: Near Salt Lake City
Simply use a good digital advance timing light like a Snap On
And you can see exactly what the timing is doing throughout the rpm range
The one I have is a MT1261A thank god I got it 30 years ago when it was only 190.00
They are 450 used now
Should be able to find a jippo that does the same thing now days
And you can see exactly what the timing is doing throughout the rpm range
The one I have is a MT1261A thank god I got it 30 years ago when it was only 190.00
They are 450 used now
Should be able to find a jippo that does the same thing now days
Laughing Gas
Joined: May 2021
Posts: 1,163
Likes: 360
From: Anderson, California
Interesting reading here.
I've a 385 series 429 running a Crane mid-range cam and Crane roller rockers assembled in 1996..
This engine was built by a local machine shop which also balanced the rotating assembly.
No kidding, I was running down the expressway one day when there arose such a clatter. Yep, a broken valve spring.
It has been so many years back, I cannot remember if the valve was an intake or exhaust. Anyway, the Crane spring set uses double springs, so the inside spring kept the valve from dropping and contacting the piston. Lucky. I replaced the broken spring.
I have never pulled the head and have wondered sometimes if the inner spring was in fact strong enough to prevent the valve from coming in contact with the piston while the outer spring was broken. Any thoughts from you knowledgeable guys ?
As far as ported or manifold vacuum, I am running Zero. No vacuum advance because I was encountering pinging.
From memory, I was never successful in resolving the ping until just omitting the vacuum advance.
I cannot give any specifics of what total mechanical advance my set-up has.
I was running down the expressway the other day at 68-mph and had a 35" BFG all-terrain separate at the shoulder on front.
Was feeling lucky running 25-year old tires, but they are all getting replaced SOON with Mickey Thompson baja MTZ P3's in the LT305/70-16 size.
Good to hear your engine is running much better.
As I thought through this broken-spring thread, wouldn't adjustable lifters be worth considering for precise pre-load can be set.
I've a 385 series 429 running a Crane mid-range cam and Crane roller rockers assembled in 1996..
This engine was built by a local machine shop which also balanced the rotating assembly.
No kidding, I was running down the expressway one day when there arose such a clatter. Yep, a broken valve spring.
It has been so many years back, I cannot remember if the valve was an intake or exhaust. Anyway, the Crane spring set uses double springs, so the inside spring kept the valve from dropping and contacting the piston. Lucky. I replaced the broken spring.
I have never pulled the head and have wondered sometimes if the inner spring was in fact strong enough to prevent the valve from coming in contact with the piston while the outer spring was broken. Any thoughts from you knowledgeable guys ?
As far as ported or manifold vacuum, I am running Zero. No vacuum advance because I was encountering pinging.
From memory, I was never successful in resolving the ping until just omitting the vacuum advance.
I cannot give any specifics of what total mechanical advance my set-up has.
I was running down the expressway the other day at 68-mph and had a 35" BFG all-terrain separate at the shoulder on front.
Was feeling lucky running 25-year old tires, but they are all getting replaced SOON with Mickey Thompson baja MTZ P3's in the LT305/70-16 size.
Good to hear your engine is running much better.
As I thought through this broken-spring thread, wouldn't adjustable lifters be worth considering for precise pre-load can be set.
3rd Gear
Joined: Jan 2022
Posts: 3
Likes: 0
I installed two Melling cams in my 400 with that same exh. lift (.512) and wiped both. Ended up with a Comp cam with less exh. lift (~.425 I think) and that was has taken hold, about 1000k miles now. I replaced my springs (Melling recommended) when I rebuilt her and that may have contributed as well, the cams I destroyed didn't sound like a diesel though, just regular valve tapping.
Cargo Master
Joined: Oct 2020
Posts: 2,675
Likes: 784
Interesting reading here.
I've a 385 series 429 running a Crane mid-range cam and Crane roller rockers assembled in 1996..
This engine was built by a local machine shop which also balanced the rotating assembly.
No kidding, I was running down the expressway one day when there arose such a clatter. Yep, a broken valve spring.
It has been so many years back, I cannot remember if the valve was an intake or exhaust. Anyway, the Crane spring set uses double springs, so the inside spring kept the valve from dropping and contacting the piston. Lucky. I replaced the broken spring.
I have never pulled the head and have wondered sometimes if the inner spring was in fact strong enough to prevent the valve from coming in contact with the piston while the outer spring was broken. Any thoughts from you knowledgeable guys ?
As far as ported or manifold vacuum, I am running Zero. No vacuum advance because I was encountering pinging.
From memory, I was never successful in resolving the ping until just omitting the vacuum advance.
I cannot give any specifics of what total mechanical advance my set-up has.
I was running down the expressway the other day at 68-mph and had a 35" BFG all-terrain separate at the shoulder on front.
Was feeling lucky running 25-year old tires, but they are all getting replaced SOON with Mickey Thompson baja MTZ P3's in the LT305/70-16 size.
Good to hear your engine is running much better.
As I thought through this broken-spring thread, wouldn't adjustable lifters be worth considering for precise pre-load can be set.
I've a 385 series 429 running a Crane mid-range cam and Crane roller rockers assembled in 1996..
This engine was built by a local machine shop which also balanced the rotating assembly.
No kidding, I was running down the expressway one day when there arose such a clatter. Yep, a broken valve spring.
It has been so many years back, I cannot remember if the valve was an intake or exhaust. Anyway, the Crane spring set uses double springs, so the inside spring kept the valve from dropping and contacting the piston. Lucky. I replaced the broken spring.
I have never pulled the head and have wondered sometimes if the inner spring was in fact strong enough to prevent the valve from coming in contact with the piston while the outer spring was broken. Any thoughts from you knowledgeable guys ?
As far as ported or manifold vacuum, I am running Zero. No vacuum advance because I was encountering pinging.
From memory, I was never successful in resolving the ping until just omitting the vacuum advance.
I cannot give any specifics of what total mechanical advance my set-up has.
I was running down the expressway the other day at 68-mph and had a 35" BFG all-terrain separate at the shoulder on front.
Was feeling lucky running 25-year old tires, but they are all getting replaced SOON with Mickey Thompson baja MTZ P3's in the LT305/70-16 size.
Good to hear your engine is running much better.
As I thought through this broken-spring thread, wouldn't adjustable lifters be worth considering for precise pre-load can be set.
In this type of application the preload shouldn't make any real difference as long as the lifter is compressed. It could be .020 or it could be .100 and the valvetrain would run quietly either way.
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