Again if you have had a custom tune might look into that. Still have the sensor on our 87' with cam and headers.
Roller rockers activate knock sensor's?
Thread Starter
Advanced
Joined: Jun 2009
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From: Victoria Harbour
Roller rockers activate knock sensor's?
I have roller rockers in my 1987. I have read that the knock sensor misreads this and retards the timing?
Any truth to this?
Is the easiest way to check this is to unplug the 1 or 2 knock sensor's on my car and see if it improves?
Found this as well.......
http://books.google.com/books?id=1Ti...sensor&f=false
Any truth to this?
Is the easiest way to check this is to unplug the 1 or 2 knock sensor's on my car and see if it improves?
Found this as well.......
http://books.google.com/books?id=1Ti...sensor&f=false
Last edited by Benny771; Sep 21, 2009 at 09:45 PM.
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
87 has one knock sensor. if the roller rockers are adjusted right I don't believe they should set that off. If after installing them you have performance issues the valves might not be adjusted right.
Drifting
Joined: Jul 2009
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From: https://www.facebook.com/groups/OrangeCorvettes/
There is a special knock module that LT4's have since they also have 1.6 RR's. I'm not certain how it would work with an 87 ECU but my 95 Firebird came with one already in it. That link you posted should be what you need to do to bypass it.
Burning Brakes
Joined: May 2006
Posts: 857
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From: Morrisonville Illinios
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
FWIW
I have the stock '87 knock sensor in my 11:1 full roller 383 and it has no problems. If you are getting knock counts while scanning I would be looking for other problems
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
Datalog it.
I have roller rockers in my 1987. I have read that the knock sensor misreads this and retards the timing?
Any truth to this?
Is the easiest way to check this is to unplug the 1 or 2 knock sensor's on my car and see if it improves?
Found this as well.......
http://books.google.com/books?id=1Ti...sensor&f=false
Any truth to this?
Is the easiest way to check this is to unplug the 1 or 2 knock sensor's on my car and see if it improves?
Found this as well.......
http://books.google.com/books?id=1Ti...sensor&f=false
Pro
Joined: May 2005
Posts: 525
Likes: 0
From: San Antonio TX
Well I have heard some roller rockers are noisier than others. What rollers to you have?
I know my Comp Cam Rollers were noisy on my 84 Z28 (carb) and adjusted properly. I am also interested on what others have to say on this topic because I will be using these same compcam rollers on my 91 vette (TPI).
I know my Comp Cam Rollers were noisy on my 84 Z28 (carb) and adjusted properly. I am also interested on what others have to say on this topic because I will be using these same compcam rollers on my 91 vette (TPI).
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Burning Brakes
Joined: Nov 2006
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From: Portsmouth Virginia 396LT4 435RWHP/400RWTQ Best so far 11.26 @ 123mph
Danny,
I think you will find comp pro mag roller rockers to be typically a little nosier and yes they can effect the knock sensors. This seems to be due to the reduced surface contact of the roller at the valve stem unlike the stock rocker which typically has more valve stem contact area and helps to dampen the noise. That's just part of the roller design to help reduce contact friction for performance gains. Another thing you will find is that using aluminum valve cover on a knock sensor engine in addition to rollers will also enhance the noise even more and can affect the knock sensor. Sort of like the increased noise loose nuts make being shook around in a tin can versus say a plastic container. The factory GM composite valve covers on the LT1 by design help to dampen valve train noise but they just don't always seem to look as nice as aluminum or chrome. I have run 3 sets of the rollers/aluminum covers on current and previous LT1s and have thought about going back to the stock covers just to help with some of the audible noise.
Just food for thought.
Rick
I think you will find comp pro mag roller rockers to be typically a little nosier and yes they can effect the knock sensors. This seems to be due to the reduced surface contact of the roller at the valve stem unlike the stock rocker which typically has more valve stem contact area and helps to dampen the noise. That's just part of the roller design to help reduce contact friction for performance gains. Another thing you will find is that using aluminum valve cover on a knock sensor engine in addition to rollers will also enhance the noise even more and can affect the knock sensor. Sort of like the increased noise loose nuts make being shook around in a tin can versus say a plastic container. The factory GM composite valve covers on the LT1 by design help to dampen valve train noise but they just don't always seem to look as nice as aluminum or chrome. I have run 3 sets of the rollers/aluminum covers on current and previous LT1s and have thought about going back to the stock covers just to help with some of the audible noise.
Just food for thought.
Rick
Le Mans Master
Joined: Aug 2000
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From: Australia
