ignition timing

ran again tonight and more of the same.started at 30*and made some passes changing fuel some and got it pritty close in that area.i had trouble with my timing light before so i could'nt be sure what i had.this time i checked it with my light and two others,msd and an old non adj.craftsman,set it on 30*and let it ride.tonight after a few passes i backed it up just to see,have'nt checked it to see how much but at least -4.next pass 60' was 1.21 from 1.24,same 5.49-125mph.last time i did this it was on 24*and ran best.thought maybe it was lean before but now i know it's not so does this mean anything?i've never ran less than 32*on gas so i'm tryen to learn something here.lol.526 cid,4.440x4.250.A460 heads,14.5 comp.6.8 olivers,"holmes"t/r with enderle bird on alky. comp cam 807/814-278/292@50 112cl put in at 109. 2 1/4 headers.timing is locked also.any ideas? just an alky thing?

If I am understanding this correctly when you backed the timing up from 30* to "your guessing" to around 25* the 60' time picked up from 1.24 to 1.21 but the et did not change ?

I would think dropping the timing like that would be like or similar to richening up the fuel mixture , but I would expect some et change with that big of a 60' change.

How do the plugs look as far as the heat mark on the ground strap ?

At this point, I think that we all have accepted the fact that an A-Headed BBF likes about 28 to 32 degrees of timing. I used to run 38 on my big domed piston 514 with Blue Thunder "B" heads.
The last 2 years, I have been using timing as one of my method to slow the car down and adjust it to an ET Index. You would be surprised how much retard (from a 30-32 base timing) that it takes to really slow one down. I have many different combinations of retard that I use, but one of them has the car run with a 15 degree retard after it leaves the line..for the entire pass. It pulled the ET down in the .2 to .3 range, but the MPH was still right there. It does not hurt the engine. At the same time, I also used restrictor plates on the Flying Toilets (a whole different topic) but have seen no adverse effects. The tops of the pistons look nice...normal...the exhaust ports are normal color and the spark plugs last forever. I only change them to make myself feel better.
I just remembered that during last Saturday's race, I retarded the timing 5 degrees because the car was trying to spin the tires from the 1/8 to 1000' part of the track. It only made a .04 to .05 differerence.
Bottom line of all of this rambling.......on my real, it takes a drastic retard strategy to kill lots of power. During one of the initial 605 dyno pulls, I was not a believer in the 30-32 timing, since these are my first A460 heads. I bumped the timing to 38 as I recall, and it responded with a 65 HP LOSS. Other factors indicate that it may have even detonated slightly at that timing. After a scolding from my dyno operator, BBF guru buddy, I have never ever put the timing north of 32 degrees.
Ok..now it is "time" to get some work done.
Keith

It would not surprise me to see an engine launch at the ""correct" or close to "correct" timing not vary on 60 times much.

When you pull the timing out after launch the engine is going to see 2 points gear change/finish line where it wants less timing as the induction chokes. If the timing is pulled at launch its going to slow it down considerably because that is the most important part of the run.

I think Lee is a little lean on the launch because the mph and et should have changed somewhat with that much difference in 60 times unless the difference is suspension related.

KY JELLY wrote:If I am understanding this correctly when you backed the timing up from 30* to "your guessing" to around 25* the 60' time picked up from 1.24 to 1.21 but the et did not change ?

I would think dropping the timing like that would be like or similar to richening up the fuel mixture , but I would expect some et change with that big of a 60' change.

How do the plugs look as far as the heat mark on the ground strap ?

it picked up the first half of the run but lost on the last half.i did'nt have time to put fuel back in it with the timing backed up but i plan to next time.it's crazy how it acts,the response doesnt change but it gets more torque and picks the front up more.i think the converter is hurting the mph.i took .020 out of the high speed and it popped at the line,put it back and it was fine.the heat on the ground strap goes into the turn and the plug gets a little heat in the top,not into the threads.even as i played with the fuel the mph dont change more than 1 and 60' was dead on 1.24.
first pass,
1.244 60'
3.566 330'
5.154 594'
5.513 1/8 125.66mph
second pass
1.245 60'
3.553 330'
5.137 594'
5.49 1/8 126.08mph
third pass was mirror of second but i put the .020 back in the h/s and mph -125.42
last pass with timing backed up,
1.218 60'
3.54 330'
5.135 594'
5.495 1/8 125.27mph
two weeks ago i started with a 95 pill,went to 105 then 110 and picked up every time.put a new plug in every pill change and at the 110 pill the plug looked good as it gets,to me anyway.lol

What spark plug do you use?

Lem Evans wrote:What spark plug do you use?

ngk v-power #8

Why don't you leave the timing up at 30 and make your fuel changes there that you want to go through. Then play with the timing according to what the ground strap and et slip tells you.

You are not going to see a major change in mph with a high speed lean out in the 1/8 about 1-1.5 mph tops and that's running a super rich launch. Your big gains with a high speed is from the 1/8 on.

KY JELLY wrote:Why don't you leave the timing up at 30 and make your fuel changes there that you want to go through. Then play with the timing according to what the ground strap and et slip tells you.

You are not going to see a major change in mph with a high speed lean out in the 1/8 about 1-1.5 mph tops and that's running a super rich launch. Your big gains with a high speed is from the 1/8 on.

i had the timing at 30*when i made the fuel changes,then last pass i backed it up to see what it'd do.it's not a real big change and it could even be that less timing causes it to hook better.it sounds better with the timing backed up,lol.i sure dont want to have another headgasket leak! with the 110 pill the h/s has to be where Spud said,.020 less shim made it pop on topend..020 shim is 5psi.

Are you 100% sure your timing mark on your balancer is dead on ?

KY JELLY wrote:Are you 100% sure your timing mark on your balancer is dead on ?

110%.....it's an ati that had been indexed on the bolts for some reason.i could'nt get the bolts out so i left it that way and checked it with an indicator and marked it.when i had the heads off a few weeks ago i checked it again and its dead on.should i just put more fuel in it and go up on the timing?

I would set timing at 30-32 and put some fuel to it , as long as the 60' is getting better keep adding fuel if the mph falls , open the high speed quicker.

KY JELLY wrote:I would set timing at 30-32 and put some fuel to it , as long as the 60' is getting better keep adding fuel if the mph falls , open the high speed quicker.

10-4,thanks