318 timing

Since I have had my car back we have been messing with the timing. It seems to get better everytime its advanced. right now its about 15 degrees. It runs great but I don't think it has reached its full potential. What does everyone think the timing should be set at.

Here are my mods: 1974 318 Duster
-Bored .30 over
-3 angle valve job with port and polish
-340 cam and lifters
-340 valve springs
-edelbrock performer intake
-edelbrock 500cfm 4-barrel
-new distributor, spark plugs, wires, coil
-windage tray
-manifolds (not headers)
-all new pistons and rings
-compression should be at least 9.0

what does everyone think. Thanks

You only listed 1/3 of the timing curve. You set initial with the distributor position. What about the centrifical and vaccum amounts? Also, there is the curve..that is...when the advancing comes in. IMO, the carb should be bigger, and may give you that "limiting" feeling on the 318 once you get past 2-3000 rpm. Even tho it's snappy off idle. I would think 15° initial, 20-24° centrifical, all in by 3000, and whatever the vaccum has in it would be fine.

i agree with moper, its all about how much centrifugal curve, vacuum advance curve and when and how fast it comes in. on iron heads , i would suggest no more than 37-38* total(w/o vacuum) and initial is set until you get starter load then back it off. each engine will take initial and total differently. also , try a eddy 600 cfm(1406).

I would agree with the other guys on that I only worry about the total advance and set it to that which Mopar recommends @ 34 degrees. I really don't care were the initial ends up as long as I have my 34 total and the motor doesn't ping.


Chuck

I've always done this! make sure youv'e got good gas,mid gr. to premium,advance till it pings, back off timing 2-4 degrees,it should be ok. always run good gas and don't try to tune it with old gas, even when you play with your jetting or advance curve, it must not ping! don't rely on the timing marks as gospel. I've seen them out by 10 or more degrees! If you want to, verify the mark by going to tdc on#1 cyl and confirm it. old vibe damps sometimes slip if the rubber is old. Your timing chain should be checked for slop too if in doubt. This sounds like a good combo - good luck!

moper said:

..when the advancing comes in. IMO, .

Click to expand...

what is "IMO"???

In My Opinion

thanxs!! i could'nt figure it out..

It's an internet disclaimer

I read that the timing for my truck is 6 degree's. It didn't say btc or atc. I found it off autozone website. Well I check the timing because I am getting a backfire/pop at idle speed in park and when driving during deceleration. I set the timing light degree dial at 6 and the mark lined up with 8 degree's btc. When I set the dial at 0 it was about 10 degrees BTC. I set the dial back at 6 and turned the distributor until the mark on the dampner lined up with 0. the pop is still there.

Can someone explain to me in laymen terms the results of advanced timing and retarded timing. I am assuming advanced is BTC and retard is ATC.

Pop can be resulting from toehr stuff. Tell us more about the truck's engine. MIlage, maintenance, year make model...

Timing basically is adjustable because the dynamics of the fuel burn and the angle of the rod vs the crank have to be kept a thte premium time setting, even tho the rpms of an engine change constantly. If you ran at say 1000rpm 100% of the time, one timing setting with one type of fuel would be perfect all the time. In general, the higher the fuel's motor octane number, the slower the fuel will burn. In todays world, the fuels burn very rapindly. New engine are designed to work with that. Old ones aren't. As rpms rise, the exact moment the burn has to start moves frorward in "time" both in milliseconds, and in crankshaft degrees. So your end result is the maximum amount of pressure on the piston top from the burn as the rod exerts the most leverage on the crank throw. More timing advance means (generally) more power at low rpms. Initial timing is the base amount, and affects idle power and smoothness. Centrifical advance couples the spark timing to crankshaft speed, so the amount of lead increases at the rpms do, until the total amount is reached at a certain rpm. Most performance curves have that rpm between 2500 and 3K rpm. Vaccum advance couples the spark lead to engine load too. So at light loads, the spark will advance even further, because it helps economy without affecting power. So when you looks at advances, they all build on each other, and they all need to be synchronized to the systems they act with. In a case of a truck with high miles, say with early heads and no unleaded seats, I would be looking for a bad exh valve if you pop at idle and under light load. My '70 does it all the time...lol.