Ok...ive got my car running again....Im Autolites 9724 or something like that....but Ive got AFR' heads ....and I gapped them to .035 is that not enough? reason Im asking is cause when I go in the high RPM's its seems liike I get crazy *** spark knock and I watch my tach and it goes bonker plus I can hear it...

I dont know if this is the right forum but Im guessing so since its a stroker motor.


thanks

 

You delivering babies?

j/k

I wouldn't look to gap as causing spark knock. I'd be checking a/f and timing first.

 

A tachometer and rpm isn't going to show you spark knock, not sure what you're seeing there. Check what Slim suggested, timing first. Air/Fuel ratio is fun to look at if you have access to a dyno or Innovate portable unit.. You should have roughly 34-36 degrees of total timing and you need 91-93 octane. Probably 14-16 at idle and 20 in the advance. I run 36 degrees with no advance. You could probably get away with that also with a 3400 stall and 4spd auto. It should run hard with a 100shot too!

An ideal plug would be a NGK TR5 or Autolite 3924. I've run these on motor at .035 and it works for me. They'll also work with a 100 shot and maybe 150-200 but I'd go colder for that just to be safe.... These are gasketed .75" reach, projected tip, 5/8" hex plugs. I think all AFR's use these just like my Darts. Goodluck!


edit...hopefully your digital 6 box isn't acting up like mine was. $80 charge for them to tell me it works fine...Haven't re-installed it yet.

 

yeah ok..the 3924's is what I have and they are gapped at .035 so I should be good to go there.

Now with my timing, Ive been having a problem trying to set timing for a long time..I cant do it the normal way...I called MSD and they told me to disconnect the Digi6 box and try to set timing like that...didnt work!...my box also has been sent back and it works fine according to them and yeah it was $80
I was told by the Jamy with http://www.lsracingchips.com/ to set my initial timing to 6* and the chip would take care of it from there. THat is where I got my chip from.

Well the only way I can set timing is by using a timing gun that has the retard/advance feature on it. SO I advance it on the gun to 29* and shoot the balancer with the lite and it shows 6*
If I shoot with a normal gun I get like 30* while its idleing.
Ive tired everything to set timing but cant do it the normal way. I was going to send my MSD dizzy to have it checked out and MSD told me that would not be bad.
I dont know if I should try and change the ICM and the ESC unit or not.

if someone has there timing set to 6* and then plugs the plug back in...I would like to know what the gun shows so I can set my timing the same and I should be in the right ball park.

but yeah, Im thinking its a timing issue now with the tach and the spark knocking freaking out like it does at high RPM's

 

Are you disconnecting the set timing connector before you check it? Its a tan w/ brown stripe wire over by the passenger side shock tower.

 

yep! and when I do my timing is the same......there is no difference with it plugged or disconnected....

 

If that is the case, then either you arent doing it right, or your distributor module is bad, or the set-timing wire going to it is bad, or something else I havent thought of.

 

i have the same engine also but an lt1 and have the same issue

 

What compression are you running?
what is you dynamic compression?
Those things will affect knock

 

are you asking me or the guy above?

 

You wishmaster.

In the digital 6 msd installation book, it says for a certain compression you should use a certain plug gap.

I see in your sig that you are 10.6. You should have a gap about 40-45

What is your dynamic compression? That effects your pinging and what fuel you should use.

 

as far as dynamic I have no idea...
zero decked
65cc heads
7cc flat tops
felpro 1003 head gaskets


what else you need?


yeah I know I read that so with that said on thier site...what would happen with running a shorter gap? and then with wider gap ...nitrous doesnt like a wide gap ,,,right?

 

Here is a website for figuring out dynamic compression
http://kb-silvolite.com/calc.php?action=comp

Cylinder pressure goes up with nitrous, so what shot you are spraying and static compression effects it.

If you run a 150hp shot, narrow your gap by 5-10

 

I tried to copy what I came up with on that site but I cant for some reason.
Here's the info I put in

Cylinder Head= 65
Piston=7
gaskets thickness=.041
gasket bore=4.166
cylinder bore=4.030
deck=0
stroke=3.750

rod length=6
intake closing abdc@50=43.9

Now its says plus 15degrees...do I add that to the 43.9

when I run it just like it shows I come up with 10.661 static and 09.679 dynamic


does that seem right?

 

They want you to add the 15 degrees.
That makes your dynamic 8.883.

To run on pump gas and not ping, the 8.5 and lower number is what you want.

I have a dynamic of 8.6 and I run 94 octane ethanol with no ping.
I actually found that 94 is better for me than 113 race gas! Good for me considering that race gas is more than double $!