pinging issue

[high perf mopar]

heres a difficult one that i have not come across b-4..freeway speed pinging..doesn't seem to do it cruising on back country roads under 50 mph.dont hear it.starts pinging,,very mild,not a constant rattle,just intermitant,,,at 65+ mph.appx 2900+ rpm's.38-4000 stall dynamic converter with positive angle blades..lowers street rpm by appx 300+ rpm's. appx 10.1 compression eddy rpm heads,60333 lunati solid roller.106 center,110 lobe sep..6 pack intake,,outer jets at 81..center at 76.6.5 power valve.31 squirter..blue cam,,fast shot.

timing doesn't seem to effect it,,before the jet change 110 octane race gas still pinged the same!!,,NO CHANGE..but, i installed the coldest plugs  from ngk  v-groove 5671..A-11,,down from A-9's and it did eliminate some of it..WTF!!!are there any colder plugs for the application than ngk's A-11??14mm x 750 lenght that people r using? timing is at 35 total,,no vacuum advance..pics r of the new A-11 cold plugs installed today and appx 40 miles up and down the freeway on shell 91 octane calif gas..any thoughts??

now according to my book the outer top of plug says im rich enough on jetting but the ground strap says im still running too hot of a plug....180 temp down the freeway...pic is of #5 cylinder.

BTW,,the rear bumper has a whiteish haze over it above the exhaust cutouts..............

[cudabob496]

if not affected by timing or octane, maybe:

something lose in the valve train,
or header leak?
valves need adjusting?


or maybe plugs gapped too much?
distributor problem

[Chryco Psycho]

I too am wondering if it is detonation or a smilar sound from something else , what RPM ar eyou cruising at ?

[nqkjw]

Sounds lean to me.
Is your centre carb a 350?Is it your primary carb?If so 76s is a whole lot of jet already.
Vacuum leak?

Also interested in this comment in your signature since I love multiple carbs.
 

chrysler 3x2 competiton carbs mech,what chrysler should have done.

Do you have a thread on your setup somewhere?
Are they the Direct Connection mechanical replacement carbs?
I have a set of those on a std sixpack manifold but I also have an STR-14-6 manifold I was thinking of setting them up on.
I also am running a homemade 6pack setup on a Weiand Superstock manifold on my barracuda.I used 2x350s as the outboard carbs and they are my primaries.The centre carb is a 650 and is my secondary(or thirdary as I call it )

[Chryco Psycho]

the center carb should be closer to 72 jets , powervalve might work better with a 3.5 or 4.5 "

[high perf mopar]

I too am wondering if it is detonation or a smilar sound from something else , what RPM ar eyou cruising at ?

at 65+ mph is when the pinging starts,rpm's around 28-2900..i too was thinking what else but in varying speeds it comes and goes with throttle pressure..the cold plugs did help it..

[high perf mopar]

if not affected by timing or octane, maybe:

something lose in the valve train,
or header leak?
valves need adjusting?


or maybe plugs gapped too much?
distributor problem

i have not retried race gas since the plug change and richening the ctr carb,,just adj valves,,headers r good.35 on the plug gaps.

[high perf mopar]

Sounds lean to me.
Is your centre carb a 350?Is it your primary carb?If so 76s is a whole lot of jet already.
Vacuum leak?

Also interested in this comment in your signature since I love multiple carbs.
 Do you have a thread on your setup somewhere?
Are they the Direct Connection mechanical replacement carbs?
I have a set of those on a std sixpack manifold but I also have an STR-14-6 manifold I was thinking of setting them up on.
I also am running a homemade 6pack setup on a Weiand Superstock manifold on my barracuda.I used 2x350s as the outboard carbs and they are my primaries.The centre carb is a 650 and is my secondary(or thirdary as I call it )

at 72 on the ctr jets the plugs indicated a lean condition..
yes they r 4782-4783 direct connection mech race 6 pack setup..acc pumps on all 3 carbs    they have been great..
do a thread search here on the 472 4783 carbs..thanks.

[high perf mopar]

the center carb should be closer to 72 jets , powervalve might work better with a 3.5 or 4.5 "

using 72 ctr jets the plug indicated a lean condition,,plug base ring was only coated dusty black about 3/4 surface area..smells hot.powervlave at 6.5 is based upon a 9" vacuum reading in gear stopped..at 76 jets the plug pictured gave me that reading..based upon that pic it says to me it wants a still colder plug.      .but,who makes a colder plug than ngk -11...

since its summertime here in calif, maybe i'll just roll the window and let the rushing air drown out the noise      it could also be too much dynamic compression,,the intake timing at ABDC is 51...im going to try another recurve today of the msd dist and see how it does,,im at the point to where i might have to live with a little ping....

[high perf mopar]

o.k.switched to a 4.5 power valve,77 jets,retuned the carb,hooked up the vacuum advance,manifold vacuum..it cleaned up the rear of the car,,75% less haze on the rear bumper...

it is responding now to less total timing,,if i time it at 35 it'll ping consistantly down the freeway no matter what..twist the dist back a couple degree's,,appx 1/16-1/8 inch,ping comes and goes,,and so does throttle response down low...still when the outers r opened up it roars!!

so basicly if i stay off the freeway it's not broke,,,,no place to buy race gas today,,,once it cools down i will recurve the dist from the 18 degree black bushin..18 degree's intial..down to the blue one,,14 degree's intial and time it to 34 total..   

[cudabob496]

maybe distributor timing curve is messed up somenhow?
maybe try a new timing curve that brings up total timing farther down the rpm range.

http://www.bing.com/images/search?q=msd%20timing%20curves&FORM=BILH#view=detail&id=05712038E571461C7D8EA9E10A4C5B7DB8DEDDAA&selectedIndex=9

[high perf mopar]

maybe distributor timing curve is messed up somenhow?
maybe try a new timing curve that brings up total timing farther down the rpm range.

http://www.bing.com/images/search?q=msd%20timing%20curves&FORM=BILH#view=detail&id=05712038E571461C7D8EA9E10A4C5B7DB8DEDDAA&selectedIndex=9

thats the msd map page im going by.black button with the heavist springs they have which puts all the timing in around 3500..it doesn't like less intial,it has devoleped a off idle hesitation with the 18 degree intial bushing installed,,down from the custom 20 degree i was using.as soon as it gets off the bottom it freakin roars!driving along in 2nd and stab the outer carbs the tires start burning..the ONLY tuning problem i have is the ping which in trying to eliminate i think has caused other issues...nothing like detuning an engine    on back country roads where i spend most of my time no issues,,lower rpm and speeds..freeway,,here we go.

thing is with these summit valve covers compared to the thicker M/T units alot of valve train/motor noise is being transmitted...but ping/detonation is noticeable also..i dont remember it doing this before i adjusted the valves???but after adjusting them it gained alot of power...lunati calls for 16 thousands lash...i set them cold at 12 going by crains cold setting chart..i think if a valve was hanging open after warm up i would know it.......

[cudabob496]

there's the answer? before valve adjustment, not doing it, so valve adjustment is the problem. Something may be loose.

[high perf mopar]

there's the answer? before valve adjustment, not doing it, so valve adjustment is the problem. Something may be loose.

well, valve adjustment among other things,,i think that if it were a hung open valve it wouldn't blow the tires off today like it did when opening up all carbs,,and then idle fine,,but i did just read something interesting concerning a lean condition with the outer carbs butterflys opened by way of there idle screws(direct connection 6 pack carbs have idle screws on all 3)  causing a lean condition because the motor is not pulling only thru the ctr carb down the freeway.sucking air thru partially open butterflys.i currently have the outboards involved in the idle settings!!!

the last combination loved the settings but this one is being picky...MAYBE this is some of my problems!just maybe..in theory makes sense....im starting to feel pretty good about this..those carb settings were changed after the lash adj...too dark to test today...my neighbors will hear me tomorrow   

[cudabob496]

well, valve adjustment among other things,,i think that if it were a hung open valve it wouldn't blow the tires off today like it did when opening up all carbs,,and then idle fine,,but i did just read something interesting concerning a lean condition with the outer carbs butterflys opened by way of there idle screws(direct connection 6 pack carbs have idle screws on all 3)  causing a lean condition because the motor is not pulling only thru the ctr carb down the freeway.sucking air thru partially open butterflys.i currently have the outboards involved in the idle settings!!!

the last combination loved the settings but this one is being picky...MAYBE this is some of my problems!just maybe..in theory makes sense....im starting to feel pretty good about this..those carb settings were changed after the lash adj...too dark to test today...my neighbors will hear me tomorrow   

could you have had an over-rev that may have bent a pushrod? Then rod can hit against head, making a noise.