I got a ping

[satarunner]

Like the title says it's just a ping ( one ping) it happens when I'm cruizing at say 35 then wood it to the floor. I get one ping then then it sounds fine no pinging. I had a 180 thermostat in it when it was new and it had the ping. I thought it was just because the motor was new and tight so I put a 160 thermostat in it and it stopped the ping unless the motor temps got over 175. now that the motor has 300 or so miles on it I put the 180 thermostat in and it pings. I know these motors will run hotter than 175. could this be a lean ping? it only happens when I floor it could it be that I am not getting a big enough secondary accel pump shot? this is a description of my motor.

I have a stealth aluminum headed 512 with 2" TTI headers, 11.3:1 compression (93 octane gas), MSD 6AL, MSD pro billet dist mechanical advance, 3500 rpm stall, Edelbroch rpm intake, Holley 950 HP carb ( I forgot what jets I have in it) IIRC the power valve is a 2.5 ( it maks about 7 inches of vacuum) initial timing is 18 and total advance is 34. Spark plugs are 2 heat ranges hotter than 440 source recomended I think they said champion RJ12JC
and I run RJ14JC.

Cam info from cam card

Gross valve lift intake .564 ex .564
Duration @ .006 tappet lift intake 295 ex 307

These specs are for cam installed @ 106.0 intake centerline
Duration @.050 intake 251 ex 257
lobe lift intake .3770 ex .3770
lobe seperation 110.0

 

[satarunner]

here is a video of the car with the 160 thermostat no pinging during this video

 

[69 Runner]

I'm thinking you have to much timing and/or advance in it. Check to see where your advance comes in, how much is in the distributor, and where it hits total advance.

 

[iraqivet01]

Geez that thing sound terrible, you need to sell it immediately to me.

 

[68383GTS]

I also smell rubber burning LOL

 

[wannadrag]

Sounds good.Plenty of compression for pump gas?

 

[daredevil]

I would try the reccommended plug. Maybe its causing the detonation as it doesnt shed the heat fast enough till the pump shot hits it. too hot of plug will ping. My combo,s similar and if 34 is the total its cool and mine likes about 18 initial too. Hey welcome to fbbo.

 

[satarunner]

I had a colder plug in it the one 440 source recommended. It pinged with them in it also but the plug was too cold according to this site http://4secondsflat.com/Spark_plug_reading.html and it was a heck of alot in more responsive with the hotter plug. Thank you for the comments and the car is not and will never be for sale it' replacing one that I had when was 18 that I sold and regreted it ever since. This car is supposed to be in the May issue of Mopar Max magazine but not positive of the issue yet.

 

[satarunner]

Sounds good.Plenty of compression for pump gas?

I know it's alot of compression for pump gas. I tried adding a couple gallons of C-12 race fuel (108 octane) to a full tank of gas it did the same thing. The motor didn't like it at all it felt like it was way down on power.

 

[moparstuart]

welcome

 

[dantrap]

That's a lot of comp. for 93 pump gas. And i am shocked the VP did not help. If you have some jets laying around i might try stepping up a 2 sizes to get some additional fuel into the motor. The timing sounds ok for the initial but we have run more for total advance on the dyno. But that will not help your problem. We have found most of our street mopars with alum heads do not like our local 93 with over 10-1 comp. unless you pull a lot of timing out, and that kills performance. Whats in that 950 for jets ? around 91s. Let us know how you make out, good luck.

 

[satarunner]

if I remember correctly I have 78 jets front and 81 rear. I have a full set of jets up to I think 100 so I have room to play around. I replaced the plugs about a month ago because one of them was shutting down on me after idling at a stop light but would come back to life at about 2,500 rpm after less than 250 miles on the motor. When I pulled the plugs out they were too clean almost like they were fuel washed. I changed from autolite to champion plugs and went up a little on the heat range. I am running a sec power valve I have read that some people block off the sec power valve anybody know why? Could this be causing some of my problem? 69 Runner I have 18 initial timing 34 total all in by 3,000 rpm. What's a good temp to run this motor at?