where to set timing with stock carb??

[bracktheron720]

so iv got a stock engine...well pretty much..just a high flow exhaust and air filter..my carb works perfect no problems at all wich suprises me cuz i dont hear many good things about them but its work perfect for now!!so where should i set my timing to get the most outta my basically stock setup...any input would be awesome!oh and how to actaully adjust it too would be nice..iv never had to do it befor..

[PEZi]

the actual stock setting i believe is 5 degress BTDC

however... timing lights can be expensive (unless you rent one) so the best idea is simply to start the truck up... get it to optimal temp... then bump the timing up a little at a time until you get some pinging... the pinging should not occur until you get the engine under load (accelerating or climbing a hill)

once you get pinging, simply back it off just enough to where you no longer have pinging... once the timing is set NEVER change the type of gas you get (89 stay 89, 91 stay 91 etc.)

in most cases you'll find that you can run more timing even in stock form than what the stock setting is set at

[bracktheron720]

perfect thanks Pezi!!and what is this pinging im listening for??is it exhaust or stuff in the head or what??lol like i said iv never had to do the timing on anything befor..

[seang]

It is also called "spark knock," or "preignition." It is like a pingy sounding knock, but not quite as loud as a rod knock.

It is similar to detonation except that detonation is when the air/fuel mix is ignited by: a hot spot, a spot of hot carbon deposit, too much compression for the octane, and maybe something else I'm missing; but that is for the most part. Preignition, on the other hand, is caused by the spark plug itself.
Modified by seang at 10:27 PM 4/5/2010

[PEZi]

^ what he said

the sound specifically will come from the engine area and kinda sound like a golf ball bouncing around to an extent

[BKCowGod]

So here's the next question - what if you have no pinging, everything is running perfectly, smooth acceleration, but after a hard uphill climb your header is glowing red? Back it off a bit?

[bracktheron720]

sweet!!im gunna get on it rite away!!and the exhaust glowing i cant b for sure but on my cycle motors that means ur runnin way lean....just an idea though.

[seang]

If I were concerned about lean conditions, I would read the spark plugs.

I have seen pictures and videos of headers and cast iron manifolds glowing from being hot, easily found on Google. One was from a 1960's Pontiac Tempest Sprint advertisement with the cast iron manifolds glowing, and it wasn't even a cross-flow head! All that heat right under the carbs. Another one I just found (tried to post but the link didn't work) was of a BMW M V8 with a red-hot header. I Googled, "manifolds glowing red hot on dyno."

[PEZi]

So here's the next question - what if you have no pinging, everything is running perfectly, smooth acceleration, but after a hard uphill climb your header is glowing red? Back it off a bit?

yeah... that is a condition of being lean for sure

[BKCowGod]

It's frustrating - my spark plugs are beautiful, my engine runs great, I have zero detonation. If it weren't for that glowing header I wouldn't even worry.

'course I am also running too cold all the time, but that's enough thread hijacking for me.

[bracktheron720]

its all good..yeah i would say way lean if everything else is good..

[flinterman2000]

Glowing headers and cast iron manifolds are also a sign of the ignition being too retarded. Couple this with the carb too lean, and it will glow until it turns white. Pinging is also called ignition rattle and sounds like a metal slug being shaken very fast in a square metal box.

[seang]

Glowing headers and cast iron manifolds are also a sign of the ignition being too retarded.

I was going to say something about this a few posts up, but deleted it because I was going from memory; but now that you mention it.... My dad had this old college book on automobile engines laying around the house when I was growing up, and I remember reading something like this.