IGNITION TIMING - ANY DYNO INFO ?

Carl wrote:Too many variables. I've had iron headed stroker's that liked 28 degrees, iron headed 460's that wanted 40 degrees, and alum headed engines anywhere between. Cam timing, quench, compression, displacement, all play a role. Take it to the track, start with 30 degrees and tune from there.

Getting back on track.

Hel-Arc,

This is the best advice. If you need a good base-line when you first start it up and use it on the street, use 32 degrees. Make sure you get your distributor's centrifugal advance all in by 3000 rpm and the distributor's total timing set at 18 degrees. Set your initial to 14 degrees, so you'll get the 32 degrees total. I would suggest you put a 50/50 mix of race gas and 91-93 octane in your tank until you can do testing to see your engine's octane requirements, seeing that you have over 11 to 1 compression.

After breaking in the cam, rev the engine to 4500 rpm and double check the timing to make sure you indeed have the 32 degrees total.

Hope that helps,

Dave

DJOHAGIN wrote:

Carl wrote:Too many variables. I've had iron headed stroker's that liked 28 degrees, iron headed 460's that wanted 40 degrees, and alum headed engines anywhere between. Cam timing, quench, compression, displacement, all play a role. Take it to the track, start with 30 degrees and tune from there.

Getting back on track.

Hel-Arc,

This is the best advice. If you need a good base-line when you first start it up and use it on the street, use 32 degrees. Make sure you get your distributor's centrifugal advance all in by 3000 rpm and the distributor's total timing set at 18 degrees. Set your initial to 14 degrees, so you'll get the 32 degrees total. I would suggest you put a 50/50 mix of race gas and 91-93 octane in your tank until you can do testing to see your engine's octane requirements, seeing that you have over 11 to 1 compression.

After breaking in the cam, rev the engine to 4500 rpm and double check the timing to make sure you indeed have the 32 degrees total.

Hope that helps,

Dave

wow it's amazing what you can find on the Internet now days..... Did you find all that by your self ???? Wow man you need to enter the Engine Masters you'll be a big hit...... Tune baby tune!!! And the intuition !!! Breaking in the cam !!! Wow !!! Where back on track now cause "dj-o-fakin" says so!!

dfree383 wrote:wow it's amazing what you can find on the Internet now days..... Did you find all that by your self ???? Wow man you need to enter the Engine Masters you'll be a big hit...... Tune baby tune!!! And the intuition !!! Breaking in the cam !!! Wow !!! Where back on track now cause "dj-o-fakin" says so!!

LOL.

Dave

Garllets ran 43* in his swap rat

something made me do it

res0rli9 wrote:Garllets ran 43* in his swap rat

something made me do it

Careful res0rli9, you might add yourself to Dfree's sh!t list. You definitely don't want that.



Dave

Adter 40 years of building and running Big Block Fords, (I hope that might be a long enough period to surpass the novice stage), I have never seen a 466 with a D0VE head and flat top pistons at zero deck, (without figuring it that has to be near 12/1 compression ratio), need more total ignition timing than 38 degrees unless it was in a rain storm or way above sea level.
With a low compression ratio or a dome piston which gets in the way of chamber flame propogation, it would possibly be a different story, (at sea level).

Would it accelerate faster at wide open throttle in lower gears with more timing...? MAYBE ... however, it certainly wouldn't make more power under a high load condition.

rmcomprandy wrote:Adter 40 years of building and running Big Block Fords, (I hope that might be a long enough period to surpass the novice stage), I have never seen a 466 with a D0VE head and flat top pistons at zero deck, (without figuring it that has to be near 12/1 compression ratio), need more total ignition timing than 38 degrees unless it was in a rain storm or way above sea level.
With a low compression ratio or a dome piston which gets in the way of chamber flame propogation, it would possibly be a different story, (at sea level).

Would it accelerate faster at wide open throttle in lower gears with more timing...? MAYBE ... however, it certainly wouldn't make more power under a high load condition.

Randy, you have always been a man to state it like it is. Would it possible then for a 466 (with D0VES, flat-tops, zero-deck) to require 40 degrees of timing at high altitude, and have nothing wrong with doing that? Also, would it be possible for a 466 (with D3s, .010 in the hole, and TRW dome pistons to require 40 degrees of timing at sea level, and nothing being wrong in doing so?

I personally have never done a flat-top D0VE at high altitude, but I have done the D3s with TRW domes with up to 42 degrees here in the bay area, California. That was over 20 years ago. Back then, there wasn't all the info we have now, so readily available. I had a lot of trial and error getting everything set-up back then. A lot of the new members don't know how good they have it.

Thank you,

Dave

DJOHAGIN wrote:

res0rli9 wrote:Garllets ran 43* in his swap rat

something made me do it

Careful res0rli9, you might add yourself to Dfree's sh!t list. You definitely don't want that.



Dave

some how I feel it's not much of a privilage the be on "dj-o-fakins" shit list....... Hey if it matters I've seen over 43 on big block chevys...... Oh yea and I owned them too.... But wait that doesn't count, I didn't find that out on the Internet.......

DJOHAGIN wrote:

rmcomprandy wrote:Adter 40 years of building and running Big Block Fords, (I hope that might be a long enough period to surpass the novice stage), I have never seen a 466 with a D0VE head and flat top pistons at zero deck, (without figuring it that has to be near 12/1 compression ratio), need more total ignition timing than 38 degrees unless it was in a rain storm or way above sea level.
With a low compression ratio or a dome piston which gets in the way of chamber flame propogation, it would possibly be a different story, (at sea level).

Would it accelerate faster at wide open throttle in lower gears with more timing...? MAYBE ... however, it certainly wouldn't make more power under a high load condition.

Randy, you have always been a man to state it like it is. Would it possible then for a 466 (with D0VES, flat-tops, zero-deck) to require 40 degrees of timing at high altitude, and have nothing wrong with doing that? Also, would it be possible for a 466 (with D3s, .010 in the hole, and TRW dome pistons to require 40 degrees of timing at sea level, and nothing being wrong in doing so?

I personally have never done a flat-top D0VE at high altitude, but I have done the D3s with TRW domes with up to 42 degrees here in the bay area, California. That was over 20 years ago. Back then, there wasn't all the info we have now, so readily available. I had a lot of trial and error getting everything set-up back then. A lot of the new members don't know how good they have it.

Thank you,

Dave

Barometric pressure and water content in the air are the most prevalent factors which control the amount of total ignition timing necessary; IF the combustion chamber remains the same. The piston crown topography IS part of the combustion chamber.

Damn I love this thread....

rmcomprandy wrote:Barometric pressure and water content in the air are the most prevalent factors which control the amount of total ignition timing necessary; IF the combustion chamber remains the same. The piston crown topography IS part of the combustion chamber.

Thank you.

Dave

If an engine was going to be ran at high elavation the best thing to do i.m.o. would be to have the cam and compression ratio for that appliaction. At that point the ign. timing may look more like "normal".

We will fire the motor this week and of cousre break in the cam. The dizzy is altered to approx 10 degrees of total advance, we will see what it likes at an idle and at the top and let you know.

we ran these heads on a 460 cast dished piston deal for about 10 years with 175 hp nos. but found out that after all that time 7200 was a bit much and the piston seperated at the top ring land. we always ran 110 octane with 28 degrees base and 38 degrees total and it ran very strong.

very interesting to here that motor effciency is related to alot or a little timing, pro stock guys must run like 10 degrees total.