Slant Six Forum
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knock sensor
https://www.slantsix.org/forum/viewtopic.php?t=55349		 Page 1 of 2
Author:  DadTruck [ Wed May 14, 2014 6:03 pm ]
Post subject:  knock sensor
anyone else using the Caspers Knock sensor gauge?

http://www.casperselectronics.com/store ... earch.y=15

I installed one as part of the 83 D150 upgrade,, through the first 1000 miles, used premium fuel and stock 3874714 distributor advance with 5 degrees initial timing,,, conservative,,,the knock gauge did not do anything other than light up when energized on start up.
Recently,, for the last 500 miles I have changed over to regular fuel, pushed the ignition tining,, with a distributor recurve...

http://www.slantsix.org/forum/viewtopic.php?t=54953

https://www.flickr.com/photos/13718356@ ... 263862760/

driving at 65 MPH, 85 degrees F, hit a incline on the interstate and pushed the throttle to the floor and the knock gauge comes alive with yellow then red indicators,,, so maybe it does work. I did not hear audible knock - pinging,, and I knows what that sounds like... but in conditions where pre-ignition should be encountered the gauge did light up. I'll get more experience over the next months,, but maybe this system does work. I have spoke with the tech help at Caspers a couple of times,, they seem committed. But remind me the gauge was not calibrated to a slant six, but they say the gauge is calibrated to be very sensitive to ignition knock..

By the way,, this slant set up in the 83 D150 is intended to run on regular gas, but push the cranking pressure.
Static: 8.5
Dynamic: 8.2
Cranking Pressure: checked at 1500 miles, engine warm 172 xbar, range of 8 psi over the 6 cylinders,
The plan is to run run maximum ignition advance, so I expect to run into preignition issues and was looking for a method to manage it.
Author:  Sam Powell [ Wed May 14, 2014 7:11 pm ]
Post subject: 
I have that same one in my Dart, and it works well. Where did you mount your sensor? Keep in mind a lean mixture as well as advance timing will light up the gauge. It is a balancing act. If you do not have an AF gauge you will not know if the cause of pre-ignition is fuel or timing.

Edit:, It looks like you do have an AF gauge, and the same one perhaps I am using. What mixture are you showing under WOT when the lights are coming on?

Sam
Author:  DadTruck [ Thu May 15, 2014 5:17 am ]
Post subject: 
mounted the sensor into the threaded opening intended for the block water jacket drain plug,, distributor side of block, lower end of #5 bore.

for a/f ratios, when the knock sensor goes off,, I'll have info late next week
Author:  Sam Powell [ Thu May 15, 2014 8:45 am ]
Post subject: 
What af ratios are you reading at WOT?

Sam
Author:  Aggressive Ted [ Thu May 15, 2014 10:34 pm ]
Post subject:  Pushing the timing envelope
1. What degree stat temperature are you running?
2. What heat range plugs are you running?
3. How big of an exhaust system are you running?
4. How many turns out on the vacuum canister?
5. What jet are you running in the carb?

When you crank up the timing and start to work the engine hard like going over the mountain pass heat can be your enemy on a slant. I run mine right on the edge as far as timing 55 to 60 degrees. I use some water injection to knock the temps back and a 180 stat in the summer. I also run a wide air dam, 2.5 inch exhaust, and 5 turns out on the can. I run NGK UR4's in the winter and 5's in the summer. A #57 jet or larger will run cooler than a #56.
All the above help on those 90+ degree days.

It doesn't matter if the engine is 9.5 to 1 or a stock motor......you will experience the same effects.
Author:  DadTruck [ Fri May 16, 2014 8:12 am ]
Post subject: 
Quote:
What af ratios are you reading at WOT?
I have a couple hundred miles of D150 seat time set for next week,, will post info
Quote:
1. What degree stat temperature are you running?
2. What heat range plugs are you running?
3. How big of an exhaust system are you running?
4. How many turns out on the vacuum canister?
5. What jet are you running in the carb?
1. 195, have picked up a 160 and a 180, think I will put the 160 in for summer use, the trip next week will be with the 195
2. NKG UR5
3. two Dutra's, each feeding their own 2 inch pipe, with each pipe about 34 inches long that connect to a flowmaster Y pipe and goes down to a single 2.25 to a flowmaster 60, exits in front of the passenger side rear tire
https://www.flickr.com/photos/13718356@ ... 786269283/
4. Vacuum canister is an 11R from the Crane kit, out about .75 turn
5. carb is a Holley 2280, R40165 / 4306465,, has a 283 main jet, mech PV .99 and a vacuum PV 1.10,,,

Sam,, you have a Caspers knock gauge,, have you heard audible engine knock when the gauge goes red?

Ted,,I don't think that you have a knock gauge,, so are you tuning (reacting) at the point when you hear audible pinging?

Thanks
Author:  Aggressive Ted [ Sun May 18, 2014 9:59 am ]
Post subject: 
No knock gauge. Working as a sound engineer my ears are pretty sensitive.

On a 11R can I would at least be 3 turns out as a starting point on a truck. I run mine 5 turns out on the Swinger since it is heavy. That is a lot of advance.....with a load and the extra heat........
Do you drive by your vacuum gauge?

Your link does not work.
Author:  DadTruck [ Mon May 19, 2014 5:06 am ]
Post subject: 
Ted,

fixed the link to the exhaust system photos in the May16th post.

concerning the vacuum can adjustment, I agree I have it coming in when ported vacuum is just starting, but I am wanting to push the advance, Ill have more info later this week.
Author:  DadTruck [ Mon May 19, 2014 6:39 pm ]
Post subject: 
here are a couple of videos showing the vacuum gauge, knock gauge, and A-F meter,

the first two are with cruse control on,, about 60 MPH

https://www.youtube.com/watch?v=rrlgsEoVjMc

https://www.youtube.com/watch?v=_9ECaaqMGjk

the next two, around 60, the is cruse off and I go to full throttle
first on is level ground, second is on an incline

https://www.youtube.com/watch?v=gKXFbePjF1s

https://www.youtube.com/watch?v=DFRLmPHjOoE


what I am seeing
at steady 60 mph, nothing on the knock sensor, A-F reads 15.2 to 15.8
manifold vacuum 10
at 60 mph then ful throttle, knock sensor lights, goes to Red,, but there is no audible knock or ping.. A-F goes full lean, quickly recovers to a 17 lean then recovers to 14.2 to 14.6, manifold vacuum 2 to 0
Author:  Dart270 [ Tue May 20, 2014 4:50 am ]
Post subject: 
I bet it is just pinging a little with the momentary lean condition when you floor it. That will not damage anything. Try rolling on the throttle instead and see if it still lights up.

Lou
Author:  DadTruck [ Wed May 21, 2014 5:30 pm ]
Post subject: 
Ok,, here are some facts to consider:

: when the knock gauge lights red, I am not hearing audible engine knock and
1) the knock sensor is indicating in situations where one would expect to encounter detonation. Heavy vehicle, lot of advance, up hills, full throttle
2) the knock sensor is not indicating in situations where one would not expect to encounter detonation. Minimal advance, crusing, down hills..

my analysis is the knock sensor works,, but it does indicate on non audible detonation, which gives the vehicle operator an opportunity to react: lift the throttle, down shift, buy better gas, dial back advance...

and here is more good news, for me anyway
with the A/F mixtures shown in this thread and the recent "light spring" distributor recurve..

Tuesday PM filled up in OakBrook IL, drove to Lisle IL Wed AM,, about 10 miles of Chicago stop and go. Left Lisle, today around noon, got on 88 East set the cruse on 65, ran across 88 to 355,to 80/94 and 65 South to about Brownsburg IN, ran into a major rain storm,, ran the next 15 miles in third gear at about 20 mph to Indy and home.
Fillled up at gas station close to home,, covered 210 miles,, used 9.14 gallons on gas, that equates to 22.975 MPG.

23 MPG running 65 mpg on highway with some city mixed in, in this brick of a truck, is cool, I can work with that.

I have MPG records for this truck going back to when it was new in 1983,, From my dad's records, hignway mpg best was about 18.5 mpg.(he was a lead foot). I drove it prior to the engine mods,, best I got on highway approached 20 mpg, by keeping the speed around 55 MPH.
Prior to the engine mods,, 70 to 75 was about the best it would do, now it cruses at 65 easily,, up hills,,, set the cruse and and forget it.

At 20+ MPG I can raise cain traveling in this truck :D
payback is a beautiful thing. Got 2000 miles on the D150 now,, plan to roll another 1000 by early June.

and it is just a lot of fun to have on the road,, get high five comments at about every place I park, got a "thumbs up' from a guy on 80/94,, and that ain't normal Chicago driver interaction,, where using a turn signal to indicate lane changes is perceived as a sign of weakness.
Author:  '67 Dart 270 [ Wed May 21, 2014 9:41 pm ]
Post subject:  Wow...
I learn so much on this board. I didn't even know that a knock gauge existed...

I will add that I converted to Evans waterless coolant and the pinging under heavy load is noticeably diminished with the Evans coolant..

brian
Author:  Aggressive Ted [ Thu May 29, 2014 4:03 pm ]
Post subject: 
Dadtruck,

Nice Video's.

Sounds like you producing some good low end torque and the mileage proves it, especially for a truck!

I am curious on the vacuum gauge showing around 10" at cruise. What rear end ratio and diameter tires? It would be nice to see it up around 15" average.....longer valve lash may help. .012 and .022. 2.5" exhaust may bring it up too. I know these subtle changes helped the mileage on my 74 Swinger.

Looks like your on your way with a good distributor recurve....now you can try backing off a few turns to see if it helps bring the vacuum gauge up. If not you have a good baseline.

Does your tach work? looks like it is stuck at 1800 rpm.
Author:  Dart270 [ Fri May 30, 2014 6:36 am ]
Post subject: 
Keep in mind that pumping losses are higher in the engine at higher vacuum numbers. Higher vacuum may not give best mileage.

Lou
Author:  Sam Powell [ Sat May 31, 2014 8:45 pm ]
Post subject: 
Would you talk a little more about pumping losses? What is it? How does that effect mileage and efficiency?

Dad truck, can you you point to a post outlining your engine specs so far.

As for the knock gauge, for the most part I have tuned out all instances of lights coming on. It still lights once in awhile, but then I tune some more. I think I can hear preignition when it lights up, but could not swear to it.

Sam
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