How to Detect Valve Train Instability
03-07-2017, 09:08 PM
#21
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03-08-2017, 07:59 AM
#22
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You can have your combo SpinTron tested to find problems before installing. The cost is not horrible but can add up if you need to make multiple changes and retest.
What has been changed, upgraded, rebuilt since your last build?
What has been changed, upgraded, rebuilt since your last build?
03-12-2017, 10:03 PM
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03-13-2017, 08:01 PM
#28
There was a video link posted recently in regards to that. It's amazing how much movement there can potentially be with simply rolling the engine over. Imagine what it's doing at 6,000 rpm. Can be time consuming and often overlooked but so important. Correct length pushrods for starters and offset rockers might be needed as well as stud girdles. If money isn't a factor I personally really like the Jesel sportsman series shaft rockers.
03-13-2017, 08:07 PM
#29
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setting the heads up properly to begin with is critical... valve springs, correct length pushrods, good rocker arms, these all play a roll, but the valve spring stack is the most commonly overlooked thing in head construction/assembly, spring surge is a component killer!!! a very wise man taught me that, and a well placed video confirmed it...
03-14-2017, 07:14 AM
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The engine is a new build still in the tuning stage. I am planning ahead for season to learn what to look for as to running clues or parts condition that indicate valve train instability before any big bang (hopefully). Previous engine I was lucky and it lasted 350 hours untill refresh. Found that exhaust valve train had insufficient spring for the heavy valve and 5800 rpm. Exhaust valve seats heavy brinneling. Lucky was that those WOT runs were a minute portion of that 350 hours. Subsequently Performance Trends Engine Analyzer Pro software modeling of that engine showed how bad the lofting would be and cam markings confirmed it. Current engine is designed to have no lofting running to 5600 rpm power peak. However I do not know if harmonics could still cause instability and damage so I want all the insight as to what to look for when engine is running and parts condition inspection after some running. I really don't want to get into all the details on my engine in this post. Lots of my other posts here in on all aspects of its history back to 2005. It is a NA engine, 520ci currently with custom cam and valve train I designed for max WOT power. I do not plan to improve or 'upgrade' anything unless testing shows it is needed.
The suggestion to check spring retainer lock tightness is the kind of info I am looking for.
The oscilloscope thought as well in the form of maybe a linear knock sensor mounted to the heads and recording signal to lap top as audio file for audio playback and/or for later processing through spectrum analyzer software.
What else in parts condition or running characteristics is symptomatic evidence of valve train instability?
The suggestion to check spring retainer lock tightness is the kind of info I am looking for.
The oscilloscope thought as well in the form of maybe a linear knock sensor mounted to the heads and recording signal to lap top as audio file for audio playback and/or for later processing through spectrum analyzer software.
What else in parts condition or running characteristics is symptomatic evidence of valve train instability?
