sbc running better cold????

[heyman]

Hi all. I\'m in Ontario. For the longest time in the summer, I\'ve had trouble with my 406 sbc knocking under heavy acceleration. It would drive me nuts. Recently with the colder weather with winter coming on, I unfortunately had to drive a week with below zero temps. The truck ran great. I can give it all she has and the engine would ping or knock but perform the way it should. My question is when summer comes back I\'ll know that it will knock again. Are there any suggestions from anyone that might help me out? I\'ve played with timing and carburetion but it didn\'t help. Is it the cold air or cold fuel that\'s making my truck run good? Any advice would be appreciated. Thanks http://www.s10v8.com/images/smilies/icon_confused.gif

[MARKYMARK]

most likely its the cold air. as in turbos the colder the intake charger the more ponys. if you have ever been in a demolishen derby after you have blown the radiator and keep going you will start to here the engine spark knock and get weaker. try 3 things to stop knock colder t-stat, higher numerical gears , leanig out carb for better response

[knudsonm]

Time to start running race gas

[stroker1]

Colder air/colder fuel cuts down on preignition. When summer comes again, if you can\'t fix it by changing thermostates, fans, or radiators, try an Air Gap intake, or at least one with no exhaust cross-over. If the intake you\'re using has an exhaust cross-over, try blocking it off. I don\'t know what your emisions regulations are like, but all this will likely hurt your chances with the sniffer. Use as cold a spark plug as you can get by with and as big a gap as possible. That is, if you have a real powerful ignition system. A hotter plug will store heat in the electrode, and help to cause the spark-knock. Maybe even side gap the plugs. It can be a long process.



What\'s your compression ratio??

[redneckgames]

I know its probably a dumb question but what octane gas are you running? If possible go up a couple notches.

[Indiana]

Why wouldn\'t this be a timing issue?

[wild85]

Well 406\'s have cooling problems and the fact that it likely runs hot is giving you pre ignition and spark knock as previously mentioned, your engine will be running cooler from the weather so this is likely the reason.

[mtincher]

i had spark knock problems and i had to go to racing fuel

[afghanimobilerawks]

On 2004-11-28 16:49, stroker1 wrote:

try an Air Gap intake, or at least one with no exhaust cross-over. If the intake you\'re using has an exhaust cross-over, try blocking it off. I don\'t know what your emisions regulations are like, but all this will likely hurt your chances with the sniffer.



on the sniffer, jsut incase you didnt know (which im sure you actually did know......) no need to worry on passing e-tests anymore! your truck is almost 22 yrs old! they stop at the 20th year of the vehicle!

[Scotty_S-15]

Regarding engine heat: a hotter engine (220 deg) will make more power.

.............. OK, there is a big BUT.......... you\'ve got to have sufficient octane, and no knock whatsoever.... and of course a cool intake air, and cool fuel.

.................Since that\'s a tall order, most of us run the engine cool, 180 or less, for most power. http://www.s10v8.com/images/smilies/icon_razz.gif



BTW, does anybody know what temps the NASCAR guys run? I\'m thinking it\'s pretty warm, but dunno for sure.

[wild85]

? for you scotty!



I ran my engine at 220 before and it was gutless as all hell, could barely chirp tires off the line, it had no knock or pinging either. It was 10 at night when I did this also.

[Scotty_S-15]

Wild, I\'ve got no answer for you... But I can tell you that my truck will not perform as expected on the 1/4 mile if it is only running at 160 degrees. (which is very rare, given the amount of time it takes to get through the staging lanes) Seems to perform better at 170 or 180 degrees.

....... Of course, jetting \"on the edge\" could be affecting both you and I. In your case, hot fuel could have been a problem, but not likely is it was 10 deg. ambient....

[wild85]

scotty



Sorry, I meant 10 oclock at night, not 10 degrees, it was like 75 or so degrees though.

[Scotty_S-15]

Hahhaaa, that\'s too funny... (laughing at myself) I guess if it were 10 deg. outside, it\'d be a challenge in itself to get your engine up to 220 without cardboard in front of the radiator... http://www.s10v8.com/images/smilies/icon_razz.gif

[wild85]

yes, it is about that cold here right now, I am trying to break into my car, the damn door is frozen shut from washing it, the locks are good but something is frozen somehwere.

[afghanimobilerawks]

man, wild, im glad i dont live as far north as you! i think it got up to 15 celcius today! was quite warm as i was organizing my crap outside so it doesnt get any more ruined....

[grimpuppy]

Since you still have the knocking and pinging when it is cold I would venture your compression is to high. You may have to back the timing off to get rid of it if you don\'t wanna go to higher octane fuel. You will probably lose some performance if you retard timing but might save a motor. Even though it is performing great now that it is cold it is still pinging and will eventually destroy the pistons. No pistons will withstand prolong detonation not even forged ones.

[wild85]

800km\'s north of here in Thompson Manitoba, it is going to be -35 C.

[heyman]

I have a 160 degree t-stat in it. The intake is the edelbrock performer (not rpm or airgap). The engine isn\'t knocking or pinging when it\'s cold. Just driving around town or even on the highway, I\'d be lucky if the temp gets up to 144 degrees. I\'m running a 2 core copper rad with an 18\" puller fan from a taurus. I have a stock hood without any ram air or cold intake. Should I maybe think about getting ahilborn or street scoop poking through my hood to get away from engine heat? I also have a 1.5\" spacer between the 750 edelbrock carb and the intake.

[heyman]

I am also using 91 octane gas. My compression ratio is 9.4:1.

[grimpuppy]

With that compression you shouldn\'t be pinging with 91 octane. I do not think the tempature is your problem. If anything 144* is to cool of an operating temp. I believe you have a problem with something else and the warmer temps are magnifying it. Trying to run it cooler is going to be a band-aid fix to cover up what is really wrong. Whats your timing set at? What kind of condition are your plug wires in? Maybe the wires are arcing across to each other firing the wrong cylinders sometimes? Try parking your truck in a really dark spot at night and opening the hood while it is running and look for any kind of arcing around the wires.

[stroker1]

Hey,guys!! Anyone remember the article in Popular Hott Rodding called The Power Squeeze!!! Someone on here had the link to it. READ IT!!!

[wild85]

i think I may have posted that on this site a while back

[wild85]

here is the post i made before

compression (http://www.popularhotrodding.com/tech/0311_phr_power_squeeze/)