Try backing it off 2 degrees
Engine Rotated Backwards when shut off ???
Thread Starter
Heel & Toe
Joined: May 2006
Posts: 21
Likes: 0
From: Houston Texas
Engine Rotated Backwards when shut off ???
I recently rebuilt my engine to a 383. Finally got it back in and running but when I shut it off it rotated backwards. Not always but it has done it at least twice for sure/
Any ideas what would cause this >???
Any ideas what would cause this >???
Race Director
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It's probably idling a little too high.
JIM
JIM
Thread Starter
Heel & Toe
Joined: May 2006
Posts: 21
Likes: 0
From: Houston Texas
I don't have it tuned too radical in any respect and I'm wondering if this is ever normal on an engine when breaking it in...
I thought maybe timing could be an issue but the timing should cause it to knock if it was too much though ???? I've brough it up to 4000rpm no problems....
I thought maybe timing could be an issue but the timing should cause it to knock if it was too much though ???? I've brough it up to 4000rpm no problems....
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Thread Starter
Heel & Toe
Joined: May 2006
Posts: 21
Likes: 0
From: Houston Texas
from what I've read most engines like about 8-14 degrees advance but could that cause the engine to rotate backwards after shutting off ???
I just doubt that would be the problem (though I agree the timing does need some advancing) just trying to diagnose this problem first.
I just doubt that would be the problem (though I agree the timing does need some advancing) just trying to diagnose this problem first.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Forget the timing,..when you turn the key off, there's no more spark to the plugs.
Your thottle blades are too open at idle and it's idling on the transition circuit. So, reduce the idle speed.
If the problem persists or the engine won't idle, make sure you're running manifold vacuum (which will increase your idle speed, then you can close the TB's further). That should do it.
If not, get back to us,..there are other fixes such as cracking your secondaries at idle.
Your thottle blades are too open at idle and it's idling on the transition circuit. So, reduce the idle speed.
If the problem persists or the engine won't idle, make sure you're running manifold vacuum (which will increase your idle speed, then you can close the TB's further). That should do it.
If not, get back to us,..there are other fixes such as cracking your secondaries at idle.
Thread Starter
Heel & Toe
Joined: May 2006
Posts: 21
Likes: 0
From: Houston Texas
I'm a bit of a novice to all this, so when you say to make sure I'm running manifold vacuum you mean to run full vacuum to the dist. instead of the ported vacuum (carb is holley 650 vacuum secondaries)
also the problem only seemed to happened when it was fully warmed up
btw I took off all emissions stuff when I did the rebuild and I can get it too idle at about 650 just feels like the body wants to vibrate apart.
Thanks for the help
also the problem only seemed to happened when it was fully warmed up
btw I took off all emissions stuff when I did the rebuild and I can get it too idle at about 650 just feels like the body wants to vibrate apart.
Thanks for the help
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Yes, run to a full time vacuum source (manifold vacuum). You don't mentin what carb you have, but if you have a vacuum guage, you can find a source.
If you're currently running ported vacuum, the switch to a manifold source will raise your idle speed. Then you can close the throttle blades using the idle adjustment on your carb and reduce the idle speed to specs. Problem solved, and plus you'll enjoy the benefits of manifold vacuum,..cooler running engine, better off idle performance, etc.
Good luck!
If you're currently running ported vacuum, the switch to a manifold source will raise your idle speed. Then you can close the throttle blades using the idle adjustment on your carb and reduce the idle speed to specs. Problem solved, and plus you'll enjoy the benefits of manifold vacuum,..cooler running engine, better off idle performance, etc.
Good luck!
Last edited by 73, Dark Blue 454; Nov 6, 2007 at 12:25 AM.
