Timing questions : New 440 Build

[krigel]

Hi,

I've just started to dial in the 440 in my 68. Forged ICON pistons (10.5:1 actual compression), Comp XE274H cam, Edelbrock e-street heads, Holley 750 vac secondaries, MSD ready to run distributor.

I've set the timing with a vac gauge, and advance plugged, then checked it with a light. With a timing tape, I'm well over 40 degrees initial timing to get smooth vacuum at 11 inches. Any less advance, and the vacuum drops well below 10. Does this not seem ridiculously high for initial timing? If I set it a 12 initial, the throttle response is terrible. If I have it with max smooth vacuum, the throttle response is great. I haven't taken it for a spin yet, as there is still snow on the ground.

Does anyone run this much initial timing on a 440? I haven't encountered this much before. This makes me think I should lock out the distributor. Thoughts?

Also, no vac leaks anywhere (I've sprayed carb cleaner all over the engine bay). I haven't messed with the distributor springs yet. That is next.

[cdr]

Hi,

I've just started to dial in the 440 in my 68. Forged ICON pistons (10.5:1 actual compression), Comp XE274H cam, Edelbrock e-street heads, Holley 750 vac secondaries, MSD ready to run distributor.

I've set the timing with a vac gauge, and advance plugged, then checked it with a light. With a timing tape, I'm well over 40 degrees initial timing to get smooth vacuum at 11 inches. Any less advance, and the vacuum drops well below 10. Does this not seem ridiculously high for initial timing? If I set it a 12 initial, the throttle response is terrible. If I have it with max smooth vacuum, the throttle response is great. I haven't taken it for a spin yet, as there is still snow on the ground.

Does anyone run this much initial timing on a 440? I haven't encountered this much before. This makes me think I should lock out the distributor. Thoughts?

Also, no vac leaks anywhere (I've sprayed carb cleaner all over the engine bay). I haven't messed with the distributor springs yet. That is next.

possible Harmonic damper has spun & the timing mark is off. ign coil hooked up backwards

[WHITE AND RED 69]

I'd check to make sure TDC is accurate and change the springs first. The heavy ones that they ship them with are usually way off. Go with one light silver and one blue and see what happens.

[justcruisin]

As said I would be checking timing marks in relation to piston position with a piston stop, something is off. With that combo you should be running around 16-18 degrees initial plus 16-20 mechanical. You should see around 13" of vacuum at around 800-900 rpm. At what point you will want to see total advance will depend, presuming auto and an 11" converter full advance should be able to be achieved around 2800 rpm without any pinging.

[krigel]

Thanks. It's a 4 speed, so Where would you suggest mechanical advance comes in? It's got vacuum as well. Still 2800 ish?

[justcruisin]

I wouldn't be worried at this stage about that, get your timing marks sorted so you know they are correct, set up your initial then total, if full advanced isn't seen until 3500 it wont matter at this stage, higher is safer at the moment. You can dial that in once everything else is sorted but with a manual trans I would try to get full advance in as low as the engine will tolerate without pinging. With 10.5:1 and that cam you may not be able to get it in at too low an rpm. I would be using at least a 6 series NGK or equivalent possibly a 7, keep an eye on the plugs for detonation. Have you done a compression check, you should see around 180 psi, maybe a bit more.

[krigel]

Ok, so TDC is correct, balancer is correct.

I went back and set timing at 14 degrees, and reset the floats and idle screws. I'm sitting at 10-11 inches of vacuum (I'm at 3500 feet above sea level, so I'm ok with 11). I opened up the MSD distributor, and the engine builder had one silver heavy spring, one silver light. I changed them to one light silver, one blue. Had full advance by 1800 rpm, so I swapped in the other blue spring, and now am fully advanced at 2500. I don't hear any pinging at all in this motor...I haven't hit that point yet. I put in the black advance stop (18 degrees), so I am maxed at 32 degrees right now. The reason I picked that number is my build is very similar to the "Lowly 440" build that was posted on here some time ago. They got max power out of this cam and similar heads/pistons at 32 degrees all in, so I went that route to start with. I may end up putting a few more degrees initial in when I get it out on the street and test it under load.

I also pulled the plugs and they were pretty black. Swapped them out.

It idles ok, but hesitates when you mash the throttle (not under load, as I am still in the dead of winter here, and this is all being done in the garage). I adjusted the accelerator pump to get it as close as I could, but I don't have any different squirters or cams in my garage, so will need to order some to play with it.

I don't know much about this carb. It came off a 383 I had in this car before I built the 440, and it ran really smooth. I haven't taken it apart yet, so I don't know what size squirters it has, what jets, or power valve. So here is the next question:

Anybody with this type of build - What jets are you running? What squirter size? I'm going to go to a 4.5 power valve for sure.

If you have any thoughts, let me know...I'm looking for more of a baseline to start with on this carb so I can buy a few pieces in a range. I don't want to just start buying a pile of squirters, jets, and accelerator cams.

Thanks!!!

[justcruisin]

Sounds like you are moving forward. FBO makes some larger bushings to restrict mechanical advance if you want to dial in some more initial. The bushings supplied by MSD don't limit travel enough IMO. What carb do you have, if you are not driving it the mains and power valve wont come into play until around 2000 rpm with no load. IMO a tunable carb with 4 corner idle, replaceable IFR's and AB's are best for tuning. All you can do is set up your idle /transfer circuits then you need to get it out on the road and see where your at.

[krigel]

The carb is a Holley 4160 750 cfm Vac secondary. I pulled the squirter out, and it is a base 31 squirter that came with the carb, so I am going to try a 35 and a 37 to see if that helps. Also going to jet it down a bit due to the elevation. 3500 feet should be 4 jet sizes, but that seems like a lot. I'll start at 2 and see what happens.

[Challenger340]

It should like 12-14* base/initial Timing, with a curve that allows no more than about 34-35* TOTAL.   You just don't need any more Total with the Eddy's/ICON's and anything remotely close to decent A/F ratio.

You will have to dis-assemble the Holley Dizzy and Physically Lock-out the too much Mechanical advance....(springs are NOT a lock out) because no way 44* Total is going to be safe over time.

4 Spd with a 4160 Tube Feed Vacuum Secondary ?    Why ?  

[Challenger340]

The carb is a Holley 4160 750 cfm Vac secondary. I pulled the squirter out, and it is a base 31 squirter that came with the carb, so I am going to try a 35 and a 37 to see if that helps. Also going to jet it down a bit due to the elevation. 3500 feet should be 4 jet sizes, but that seems like a lot. I'll start at 2 and see what happens.

How are you measuring A/F Ratio ?

"my build is very similar to the "Lowly 440" build that was posted on here some time ago. "

We haven't done any of the "lowly 440" engines for some time, do you mind sharing what yours ended up costing you all said and done ?

[krigel]

Thanks for the input...

I know the carb isn't the ideal carb, but it's what I have at the moment. An 850 would be too much for the mild driving I'm doing with this thing. I know I should have a 750 with mechanical secondaries. That will come in time, I just want to get this one tuned for now.

The dizzy is locked at 32 total (14 Initial, 18 Advance). Are you talking 44 with vacuum? It is all in at 32 degrees by 2500 RPM the way I have it set now.

I'll pm you the cost on the build. I'll need to dig up some receipts for a total.

I'm measuring AF the old fashioned way...pulling plugs, and gauging what is coming out of the tail pipe.

[cdr]

you need more initial & total, 20-24 initial , 36ish total + 4 to 10 on the vac advance ported vacuum, especially at your altitude 

[Challenger340]

Thanks for the input...

I know the carb isn't the ideal carb, but it's what I have at the moment. An 850 would be too much for the mild driving I'm doing with this thing. I know I should have a 750 with mechanical secondaries. That will come in time, I just want to get this one tuned for now.

The dizzy is locked at 32 total (14 Initial, 18 Advance). Are you talking 44 with vacuum? It is all in at 32 degrees by 2500 RPM the way I have it set now.

I'll pm you the cost on the build. I'll need to dig up some receipts for a total.

I'm measuring AF the old fashioned way...pulling plugs, and gauging what is coming out of the tail pipe.

I see you are at 3500ft elevation, I have lots of experience with this as I used to race a 440 Mopar around Calgary Ab(Street & Strip) which is also 3500 FT and higher given Density Altitude most days, and I still Dyno in High River Ab at that altitude.
We like the larger Carbs at elevation for one simple reason.... larger Carb Butterfly's cheat the lower ambient Air Pressure for more HP.
Remember, the Engine doesn't 'suck' anything IN.... the Engine merely creates a 'low pressure' area in the cylinder that ambient air pressure pushes down through the Carb/Ports to 'fill' that low pressure area...... and the larger butterfly's of the larger Carbs are a way to cheat more air into the Engine under the lower ambient pressures, and also remember.... even the stock 440 Magnum Engines factory used 800 Cfm AVS Carbs in '69 with far LESS potential than your 'lowly' style 440 ?   ThermoBogs in the later 70's were 850 cfm... and on and on.... Because BB Mopars are an extremely high Velocity Port and those LIKE Big carbs ? when compared with most other North American V8's ? 454/460 etc

32 degree's all in around 2500 should be good to go and very safe, I was more worried you were trying to run 44* Total under LOAD which wouldn't be advisable IMO ?
But as long as your not seeing Timing 'flutter' using the Vacuum(economy) advance higher it shouldn't be an issue.
You'll have a TON of Fun with that Engine, they are very capable !

[myk]

you need more initial & total, 20-24 initial , 36ish total + 4 to 10 on the vac advance ported vacuum, especially at your altitude 

Yup, I'm told these motors like a lot of initial.  I'm at 18* initial, myself...

[c00nhunterjoe]

you need more initial & total, 20-24 initial , 36ish total + 4 to 10 on the vac advance ported vacuum, especially at your altitude 

Yup, I'm told these motors like a lot of initial.  I'm at 18* initial, myself...

Not just these mopar motors. Its across the board in general. But ultimately its the combination of parts that dictates what is needed. Fwiw, my old 383 ran 26/42 on 93 pump gas and never pinged on iron heads. Not that i would ever reccomend this numbers to anyone on here as that combination is not the norm.

[myk]

26/42?!

[c00nhunterjoe]

26/42?!

On 93 legit pump gas running low 12s on a 383 and 4 speed. Again, NOT the typical combination built on these forums. Ran great for a junkyard dog but it was a high rpm mill, not a low rpm torque builder.

[BSB67]

42° was not uncommon.  Why?  Because the car was faster.  This was from folks that actually did a bunch of track testing back in the day.   But today, the internet says otherwise.

[Ghoste]

So so true, internet has been every bit as much a curse as it has helped.

[cdr]

42° was not uncommon.  Why?  Because the car was faster.  This was from folks that actually did a bunch of track testing back in the day.   But today, the internet says otherwise.

 This ^^^^^^^ Yep, the Dyno says it makes more power @ 36, I say ,so what, it picked up 3 tenths @ 40

[c00nhunterjoe]

42° was not uncommon.  Why?  Because the car was faster.  This was from folks that actually did a bunch of track testing back in the day.   But today, the internet says otherwise.

 This ^^^^^^^ Yep, the Dyno says it makes more power @ 36, I say ,so what, it picked up 3 tenths @ 40

No vacuum advance on it either. Car didnt like it.