Intake Manifold vaccum pressure...
Thread Starter
Burning Brakes
Joined: Apr 2005
Posts: 1,109
Likes: 2
Intake Manifold vaccum pressure...
Hello, I have a 94 Vette ZF6.
My optispark was replaced and the rotor exploded due to high revolutions under full acceleration.
I modified the optispark providing a vacuum line that goes to the intake manifold but did not want to drill the distributor cap for another line that would supply air because I did not want to promote a crack in the distributor cap.
This is usually done to remove moisture from inside the opti as a preventive measure .
I think I screwed up by providing only vacuum from the intake manifold. I have the theory that when the car was under acceleration the vacuum at the intake manifold was so high that it may have collapsed the distributor cap just enough to let the rotor make contact and then explode.
Does somebody know what is the vaccum generated at idle, and at 5000 rpms? Maybe I would need to make some kind of valve that closes the vacuum line to the optispark when the rpm's are going up.
ANy thoughts on this?
My optispark was replaced and the rotor exploded due to high revolutions under full acceleration.
I modified the optispark providing a vacuum line that goes to the intake manifold but did not want to drill the distributor cap for another line that would supply air because I did not want to promote a crack in the distributor cap.
This is usually done to remove moisture from inside the opti as a preventive measure .
I think I screwed up by providing only vacuum from the intake manifold. I have the theory that when the car was under acceleration the vacuum at the intake manifold was so high that it may have collapsed the distributor cap just enough to let the rotor make contact and then explode.
Does somebody know what is the vaccum generated at idle, and at 5000 rpms? Maybe I would need to make some kind of valve that closes the vacuum line to the optispark when the rpm's are going up.
ANy thoughts on this?
Last edited by Kinkajou; Jul 25, 2005 at 02:20 PM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Actually manifold vacuum is highest at idle and goes to nearly zero when you crack the throttle.
If the opti cap is of similar construction to the dist cap on my L98 I cannot imagine manifold vacuum deflecting it. So I don't think you can get too much air pressure onto the cap to do that damage.
If the opti cap is of similar construction to the dist cap on my L98 I cannot imagine manifold vacuum deflecting it. So I don't think you can get too much air pressure onto the cap to do that damage.
Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
Actually we had a guy popping optisparks left and right on a toyota truck with a LT1. Turned out he was sourcing a HI vaccum port (like behind the throttle body) when he should have been sourcing before the throttle body.. (hardly any vaccum.. just moving air around)
Putting intake vaccum directly on the optipark without any check valves or restrictors is a bad idea.
Putting intake vaccum directly on the optipark without any check valves or restrictors is a bad idea.
