Home » Public Forums » GMCnet » Knock Sensor for carb engines? (Can it be done?)
| Knock Sensor for carb engines? [message #271104] |
Tue, 03 February 2015 11:27  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Just wondering if anyone has a way to install a knock sensor that powers a gauge or light when it senses detonation? I'm talking about a non-EFI/ECU engine.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: Knock Sensor for carb engines? [message #271115 is a reply to message #271104] |
Tue, 03 February 2015 15:27  |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Hey Kerry:
Wallys suggestions are pretty good.
Here is an "out of the box" type of idea. I think I would like to try it too because my fuel injection project is on hold due to time. SOOOOO:
Are you as good with electronics as you are with Aluminum?
Here is a pretty easy little project and circuit you can build. It worked for the Lotus Guys.
http://www.impconcepts.com/espritv8knocksensoralarm.htm
You can put a 454 knock sensor in the 455 block here.
http://www.gmcmhphotos.com/photos/knock-sensor-install-efi/p46370-knock-sensor-install-3.html
This drain hole is where the original 455 sensor is placed so I'm trying it here but I've seen a nicely machined knock sensor adaptor that uses a pan bolt, and I've also seen them threaded into the front motor mount bracket. The fuel injection guys could confirm the best idea.
Best Regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: Knock Sensor for carb engines? [message #271120 is a reply to message #271115] |
Tue, 03 February 2015 16:55 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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John Heslinga wrote on Tue, 03 February 2015 13:27Hey Kerry:
Wallys suggestions are pretty good.
http://www.gmcmhphotos.com/photos/knock-sensor-install-efi/p46370-knock-sensor-install-3.html
This drain hole is where the original 455 sensor is placed so I'm trying it here but I've seen a nicely machined knock sensor adaptor that uses a pan bolt, and I've also seen them threaded into the front motor mount bracket. The fuel injection guys could confirm the best idea.
Best Regards
Many of the EFI folks have the sensor in the water jacket as the picture shows. Sometimes we have had situations where the water jacket location was too active and I have heard of them going in the front motormount and heads. The water jacket works for me.
BobR of EFI EBL fame says it is harder to stop a knock than to prevent it so when we have a range of RPM and MAP (sorta like vacuum) that knocks, he has us pull out spark in that range so it never gets started. All that being said, I was charging up a hill recently and heard it rattle for a second The EBL pulls 3 degrees when knocking is detected.
I like the idea of the sensor systems that know which cylinder is detonating. I have no proof but would not be surprised to find that only certain cylinders start pinging... I would guess in the back because of heat but our intake runners are such that cylinders are probably not getting an equal mixture.
Our first coach had a little knob that would reduce spark. It was not connected and I converted to EFI almost immediately.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Knock Sensor for carb engines? [message #271122 is a reply to message #271120] |
Tue, 03 February 2015 17:16 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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George, remember what I said about leaning these engines out. Gasoline is
waaayyy cheaper than burned pistons and valves. Rich mixtures do not knock
like lean cruise mixtures. Pull a little spark advance out and let these
engines live a long happy life. Jus' Sayin'.
Jim Hupy
Salem, Or
78 Gmc Royale 403
On Feb 3, 2015 2:56 PM, "George Beckman" wrote:
> John Heslinga wrote on Tue, 03 February 2015 13:27
>> Hey Kerry:
>>
>> Wallys suggestions are pretty good.
>>
>>
>>
>>
> http://www.gmcmhphotos.com/photos/knock-sensor-install-efi/p46370-knock-sensor-install-3.html
>>
>> This drain hole is where the original 455 sensor is placed so I'm trying
> it here but I've seen a nicely machined knock sensor adaptor that uses a
>> pan bolt, and I've also seen them threaded into the front motor mount
> bracket. The fuel injection guys could confirm the best idea.
>>
>> Best Regards
>
> Many of the EFI folks have the sensor in the water jacket as the picture
> shows. Sometimes we have had situations where the water jacket location was
> too active and I have heard of them going in the front motormount and
> heads. The water jacket works for me.
>
> BobR of EFI EBL fame says it is harder to stop a knock than to prevent it
> so when we have a range of RPM and MAP (sorta like vacuum) that knocks, he
> has us pull out spark in that range so it never gets started. All that
> being said, I was charging up a hill recently and heard it rattle for a
> second
> The EBL pulls 3 degrees when knocking is detected.
>
> I like the idea of the sensor systems that know which cylinder is
> detonating. I have no proof but would not be surprised to find that only
> certain
> cylinders start pinging... I would guess in the back because of heat but
> our intake runners are such that cylinders are probably not getting an equal
> mixture.
>
> Our first coach had a little knob that would reduce spark. It was not
> connected and I converted to EFI almost immediately.
> --
> '74 Eleganza, SE, Howell + EBL
> Best Wishes,
> George
> _______________________________________________
> GMCnet mailing list
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| Re: [GMCnet] Knock Sensor for carb engines? [message #271157 is a reply to message #271122] |
Wed, 04 February 2015 01:43 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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James Hupy wrote on Tue, 03 February 2015 15:16George, remember what I said about leaning these engines out. Gasoline is
waaayyy cheaper than burned pistons and valves. Rich mixtures do not knock
like lean cruise mixtures. Pull a little spark advance out and let these
engines live a long happy life. Jus' Sayin'.
Jim Hupy
Salem, Or
78 Gmc Royale 403
On Feb 3, 2015 2:56 PM, "George Beckman" wrote:
Jim is right. We absolutely cannot have the mixture lean other than when on flat, no wind, not too fast "lean cruise" conditions. When I put on Exhaust Gas Temperature gauges we found out some real eye-openers:
1. Lean Cruise (16.4:1 air to gas) runs cooler than regular 14.7:1. That makes sense because their is more air and less gas. But EFI Lean Cruise disengages at the first hint of a pull. Freeway overpasses cause it to disengage when using cruise control. With EFI Lean Cruise diminishes it leanness as the throttle is opened. By the time it drops out the mixture is not really lean but is about at "normal".
2. "Normal" everyday mixtures of 14.7:1 shows a exhaust temp rise that is alarming the moment the rig begins to pull. 150 degrees in 30 seconds on a slight incline. Not a hill, just a almost imperceptible incline. That is right... not lean but normal air fuel is too lean.
3. PE, Power Enrichment (on carburetors its the power valve) better engage at about 46% throttle on a TBI fuel injection. Forget about Wide Open Throttle. 46% and no PE and the heat will go through the roof and in seconds not minutes. We are not talking about the water in the radiator. We are talking about how hot the combustion chamber is. Valves and pistons have to live in there.
So, I have said it before, I would not fiddle with jets or start bending things on a carb if I did not have a wide band O2 sensor and exhaust temp gauges.. In fact, with a carb or EFI I don't think I would want to drive q 12K lb. coach without a wide band O2 sensor to let me know if the carb or EFI is actually still mixing gas properly.
Bob Drewes (man I miss that guy) said it at Santa Rosa, CA in 2009 or so... We were talking about gas economy... Bob said, "Boys, get your spark right, first."
Spark control made the biggest difference in gas mileage for me and I still get between 8-10 depending on whether I am towing or not. Ha! Gotta love it.
(And No, Jim, I don't stare at gauges all day. I look out and have a great view. But if it coughs or pings or sputters I want to know if whats up. If I am climbing at 50 mph in second for 10 minutes, I like to glance to see it is in PE and all the temps are normal. 50K miles with EFI)
BTW, the 46% throttle for PE is not my number... that is GMs number, right in the chip programming. They were not messing around. There EFI guys who tried changing that setting but I know of no one who has not gone back to GMs original settings. GM did a lot of R&D.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Knock Sensor for carb engines? [message #271169 is a reply to message #271115] |
Wed, 04 February 2015 06:55 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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John Heslinga wrote on Tue, 03 February 2015 15:27...Are you as good with electronics as you are with Aluminum? ...
NO, I'm not...I'm definitely not. However Emery's album is extraordinarily well done and complete and I'm willing to give it a try. I'll print the parts list and try and find a Radio Shack that is still open.
Emery, if you are reading this, building these things would be a great workshop/seminar at a rally.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Knock Sensor for carb engines? [message #271376 is a reply to message #271169] |
Sat, 07 February 2015 20:56 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Kerry,
I have an OEM carb and an OEM distributor both supplied by Dick Paterson on an engine built by Ken Frey about 75,000 miles ago. I
replaced the timing chain at about 50,000 miles and timed the engine as per Dick's instructions (12° advance at idle). John Sharpe
and I checked the timing and set up the carb as per the MM and it runs and idles great.
I'm wondering if you follow Dick's instructions and/or the Maintenance Manual is a knock sensor necessary? I don't think I've ever
heard Double Trouble knock.
Regards,
Rob M.
-----Original Message-----
From: Kerry Pinkerton
NO, I'm not...I'm definitely not. However Emery's album is extraordinarily well done and complete and I'm willing to give it a try.
I'll print the parts list and try and find a Radio Shack that is still open.
Emery, if you are reading this, building these things would be a great workshop/seminar at a rally.
--
Kerry
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Knock Sensor for carb engines? [message #271380 is a reply to message #271376] |
Sat, 07 February 2015 22:06 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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USAussie wrote on Sat, 07 February 2015 20:56...is a knock sensor necessary?
necessary? NECESSARY? Since when has something needed to be NECESSARY? LOL!
Seriously, just something else to build. Btw, I went by Radio Shack and got everything but a couple resistors. I happened to have a box of resistors of various sizes I'd given my much more electronically competent buddy a couple years back and in there are what I needed so when I find time I'll build it.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: Knock Sensor for carb engines? [message #271385 is a reply to message #271104] |
Sat, 07 February 2015 23:43 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Kerry:
I'm Looking forward to your write-up on this project.
John
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: [GMCnet] Knock Sensor for carb engines? [message #271412 is a reply to message #271376] |
Sun, 08 February 2015 12:15 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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USAussie wrote on Sat, 07 February 2015 19:56Kerry,
I have an OEM carb and an OEM distributor both supplied by Dick Paterson on an engine built by Ken Frey about 75,000 miles ago. I
replaced the timing chain at about 50,000 miles and timed the engine as per Dick's instructions (12° advance at idle). John Sharpe
and I checked the timing and set up the carb as per the MM and it runs and idles great.
I'm wondering if you follow Dick's instructions and/or the Maintenance Manual is a knock sensor necessary? I don't think I've ever
heard Double Trouble knock.
Regards,
Rob M.
-----Original Message-----
From: Kerry Pinkerton
NO, I'm not...I'm definitely not. However Emery's album is extraordinarily well done and complete and I'm willing to give it a try.
I'll print the parts list and try and find a Radio Shack that is still open.
Emery, if you are reading this, building these things would be a great workshop/seminar at a rally.
--
Kerry
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Unsubscribe or Change List Options:
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Rob,
My 455 is equipped with a Dick Paterson distributor as well, and my base timing is set at 12 degrees advanced at idle. I have experienced pre-ignition knock under certain conditions, such as towing my Jeep. on a trailer (approx. weight - 4,000 lbs.) over Castle Dome Mountain Pass, just east of Yuma, AZ on I-8. The elevation is about 27' at the beginning of the climb and is a pretty steep grade for a few miles.
My solution was to install an MSD dash timing control that allows me to adjust the timing from the driver's seat. I have the base timing set with the adjustment knob at about 8 degrees. This allows me to retard the timing by that 8 degrees if necessary to eliminate the knock. I can also advance the timing an additional 8 - 10 degrees if I am cruising and under very little load, or at a higher elevation. Fortunately, my hearing is still good enough to hear the pinging when it starts, but if it was not, I can see the need for a knock sensor.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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