VAFC Malfunction?
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Joined: Jun 2003
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From: Titusville, FL
VAFC Malfunction?
A freind of mine works as an automotive technician with a guy who used to be the master tech at a local performance shop, they were talking about what could have caused my intake and only my intake cam to jump 180º(described in more detail in my " Origional Thread ").
The idea that they came up with, is that my vafc malfunctioned when i was starting the car locking the rocker arms and preventing my cam from moving, pushing the belt over the cam, then when I went to start the car again it turned and pushed my valves down on the cylinder coming up. I don't really see how it would have worked, also heard it second hand from my freinds freind but it makes a little since...its about the only theory thats beliveable to put my intake cam exactly 180º opposite my exhaust cam, with the crank at tdc.
Has anyone ever heard of a vafc malfunctioning like this or, anyother examples of where just one cam decided to skipped time?
The idea that they came up with, is that my vafc malfunctioned when i was starting the car locking the rocker arms and preventing my cam from moving, pushing the belt over the cam, then when I went to start the car again it turned and pushed my valves down on the cylinder coming up. I don't really see how it would have worked, also heard it second hand from my freinds freind but it makes a little since...its about the only theory thats beliveable to put my intake cam exactly 180º opposite my exhaust cam, with the crank at tdc.
Has anyone ever heard of a vafc malfunctioning like this or, anyother examples of where just one cam decided to skipped time?
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Joined: May 2005
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From: Colorado
Sorry, that's definitely not the problem. All the VAFC could do is tell the car to kick into vtec and modify the map sensor signal.
Even if the VAFC did cause the the rocker arms to be locked into the vtec position (i.e., you tried to start the car with VTEC engaged), the rocker arms only lock so that they all follow the larger camshaft lobe. There is physically no way that the VAFC caused your rockers to lock and the cam to stop spinning with the timing belt. Even with VTEC engaged, the cams will still spin with the timing belt... if they didn't, you'd be skipping teeth everytime vtec engages while you're driving.
If your cam skipped teeth, there's onlyone reason it could've happened. The tension on the timing belt was not enough to cause the cam to spin with the belt.
This could be due to: 1) the camshaft was providing too much resistance, so that it was easier for the timing belt to skip teeth over it instead of turn it (i.e. it was easier to skip a tooth than to spin the cam).
2) The timing belt was not tight enough. so that it was easier for the teeth in the belt to lift up and over the cam gear instead of spinning it with the motor.
I'm betting its #2. Your timing belt was probably loose. Did you work with it (or have any work done to it) recently? If so, its possible that whoever worked with it last did not tension it properly, which could definitely cause this problem. Perhaps your tensioner is going bad: If the timing belt was tensioned with the right procedure, but the tensioner was bad, it can cause the tension to still be less than optimal.
Even if the VAFC did cause the the rocker arms to be locked into the vtec position (i.e., you tried to start the car with VTEC engaged), the rocker arms only lock so that they all follow the larger camshaft lobe. There is physically no way that the VAFC caused your rockers to lock and the cam to stop spinning with the timing belt. Even with VTEC engaged, the cams will still spin with the timing belt... if they didn't, you'd be skipping teeth everytime vtec engages while you're driving.
If your cam skipped teeth, there's onlyone reason it could've happened. The tension on the timing belt was not enough to cause the cam to spin with the belt.
This could be due to: 1) the camshaft was providing too much resistance, so that it was easier for the timing belt to skip teeth over it instead of turn it (i.e. it was easier to skip a tooth than to spin the cam).
2) The timing belt was not tight enough. so that it was easier for the teeth in the belt to lift up and over the cam gear instead of spinning it with the motor.
I'm betting its #2. Your timing belt was probably loose. Did you work with it (or have any work done to it) recently? If so, its possible that whoever worked with it last did not tension it properly, which could definitely cause this problem. Perhaps your tensioner is going bad: If the timing belt was tensioned with the right procedure, but the tensioner was bad, it can cause the tension to still be less than optimal.
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Joined: Jun 2003
Posts: 330
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From: Titusville, FL
Thank you for your input servion....I was really skeptical about the vafc malfunction to begin with but hearing something like that supposibly from someone who has worked alot with honda motors makes you stop and second guess yourself.
The timeing belt did need to be changed on it however it still had good tension all around the tensioner seems to be fine as well...i'm left with maybe it just skipped time when I was driving, its got a new timing belt now and new valves and valve springs...now all I need is a valve lock which I launched across the garage and can not find anywhere.
The timeing belt did need to be changed on it however it still had good tension all around the tensioner seems to be fine as well...i'm left with maybe it just skipped time when I was driving, its got a new timing belt now and new valves and valve springs...now all I need is a valve lock which I launched across the garage and can not find anywhere.