Cam questions for a MILD 440

[wyrmrider]

Problem with advancing the stock cam is that the exhausts torch
The opening ramps are SO SLOW that you get a jet blast and the closing ramps are even longer and slower

[blykins]

How many times have you tried it?

[wyrmrider]

Me- Lots of times
361 413 Trucks and Motorhomes Gas and Propane
440 Motorhomes and Buses Gas and LPG
440's do not like a lot of overlap and it pays to keep the valves on the seats as much as possible in a non race car
I've run 383 SS and 413-426 Wedge and 440 and larger
Heavy vehicles work best with 248@006 intake 192 @,050
For a lets call it a loaded application, a truck or in this case 2.88 gear 256 @006 is about right (260 in Crane)
you can get .300 cam lift at that duration but what you really want is as much at .200 as possible
The stock cam was for emissions and to have minimum warranties- long service life
Many of the aftermarket replacements say "our version of " and tighten up the LCA to 113 or 112 and the lobes are not even close to factory profile
Cane has an actual Blueprint
If OP has a cam that is serviceable he can try the 4+ degree advance but you are just moving the problem around
the Non Magnum 383-440 260 advertised and around 204 @50 with about 330 lift cam would be a better choice if he has one
I would not spend any money on a 220@.050 Voodoo cam for a low compression tall gear build
We did cam tests for Mopar and confirmed that a one size larger than Magnum Direct Connection cam in a 3:31 gear with Magnum converter road runner cost 60 ft time
I've put cams in several 413 & 440 D Bodies with the tall gears- but 10:1
No way would I run a Magnum cam or bigger in an 8;1 street/ daily driver motor

[My427stang]

We are going to have to disagree on this one just like our 390 thread a year ago or so

Advancing the cam won't change exhaust (or intake) seat to seat duration. I'd also say if they are burning valves on a naturally aspirated motor it needs some ignition timing more than anything.

I think it'd be hard for me to believe that other than a truck, bus or RV, run hard at a constant throttle, would want only 248 adv and 192 @ .050 too, it's a big engine with reasonable intake port volume. Plus, if they are valve burners like you say, why shorten seat to seat even more?

Again, I'd personally advance the stocker, and it wouldn't be +4, it'd likely be +6 or even +8, but that Voodoo is mellow and would complement the heads, especially if he advanced it a bit

[DaveMcLain]

We are going to have to disagree on this one just like our 390 thread a year ago or so

Advancing the cam won't change exhaust (or intake) seat to seat duration. I'd also say if they are burning valves on a naturally aspirated motor it needs some ignition timing more than anything.

I think it'd be hard for me to believe that other than a truck, bus or RV, run hard at a constant throttle, would want only 248 adv and 192 @ .050 too, it's a big engine with reasonable intake port volume. Plus, if they are valve burners like you say, why shorten seat to seat even more?

Again, I'd personally advance the stocker, and it wouldn't be +4, it'd likely be +6 or even +8, but that Voodoo is mellow and would complement the heads, especially if he advanced it a bit

The reason for not advancing the cam very much when the static compression ratio is very low is because an early exhaust opening sends the EGT sky high. The low compression engine tends to have a lot more heat in the cylinder later in the power stroke than if the compression ratio is higher. Dumping it early puts more of that heat out the pipe, dumping it earlier by advancing the cam isn't the way to go. I think the recommendation of 200 degrees at .050 or so duration is totally correct along with a tight lobe sep and no advance.

[wyrmrider]

Here's a fact
shortening the cam on a 440 bus (plus raising the CR and adding quench) reduces the EGT by around 800 degrees
Never had the full instrumentation on my Motorhome but exhausts no longer glow cherry red
Incidentally "D" Body is the up to 66 IMPERIAL body on frame

[My427stang]

But this isn't a bus...and it won't run like one and won't generate anywhere near the EGTs of heavy working vehicle

Its a 4000 lb car with a 440 and 2.88 gears. Sure, it's tall, but its not a dump truck, motorhome, or school bus at constant throttle at 3700 rpm all day with a load.

Maybe I am missing something, but a 445 FE, with a set of off the shelf alum heads and 9.8:1 compression and a Comp XE262H cam, has a HP peak that flattens out from 4500 to about 4800. Torque peaks around 3000 rpm at generally around 500 ft lbs

I do understand that this motor has at least a point less compression which would drive torque down, but look at that hp peak in terms of RPM, how low do you guys want to drive it? That 262 is pretty small, drive it down with a 256 adv cam? where do you expect to peak and why would you have it peak there? You think that really is going to change the drivability?

This is where I think we are getting into ridiculous arguments. I have a hunch any of these cams would be undetectably different on the street in this car. Advanced stock, 262 Voodoo, or 256 or 260 Wyrmrider advertises, you haven't yet sold me on any criticality for this engine in this car.

BTW, my 445 FE, I know different engine and more compression, 9.8:1, runs a 282/236 112/104, lashed at .014 cold (way tight), in a 4200 lb 4x4, heads flow 277 at max lift and it has a 750 and a ported RPM intake. I have no issues down low with 33 inch tall tires and a 3.50 gear, I even used it to move my 4000 lb trailer and it was happy. I just don't get why you want to choke this motor so much for use in a passenger car.

[wyrmrider]

You're right
A truck or bus is easier as they are not geared that tall and have a tight converter
He has the equivalent of a Chrysler Imperial with a loose "Magnum" converter
The Magnum combination was not designed to work with tall gears
That's what the standard 440 big converter and 204 cam was designed for
how many rpm will he be turning going down the freeway = with the converter still not fully locked and making heat
The Magnum converter will allow some revs at start off but not near enough for that Voodoo cam
and if he loosens up the converter enough to make the cam work he'll have a Dynaflow
Davae McLain has it right
Have you guys never driven a Big Block Cordoba or Dodge Police Car with the low compression HP engine?
It's not Fun till you get it out on the freeway and hit passing gear- and they do not even have 2.88s

[My427stang]

I think what we are really coming down to is that the low compression/poor quench issue and drivetrain mismatch is the problem, not the cam, because many of the things you talk about aren't cam related and the difference between what you and I recommend won't fix that

1 - Whichever cam he uses if the converter is too loose for the final drive, it'll still be inefficient at cruise, none of the cams will change that at cruise rpm, not mine, not yours.
2 - If he goes earlier IVC, regardless of how he does it, very small cam or advanced small cam, going too far will likely make it ping. That's the same for either of our recommendations
3 - The low compression of that engine will want more ignition advance, but the engine won't like it with a big quench. The cams are not going to significantly change that either, not with all recommendations hitting similar IVC numbers.
4 - I call the EGT discussion a red herring, valid as a concept no doubt, but not applicable due to the use of the engine, it just won't generate that heat and IMHO, the extra cruise advance the motor is likely dying for would likely erase it
5 - I think a tighter LSA like the Voodoo (with the proper ICL to allow the right IVC point) would gain torque when he was driving it harder
6 - The stock cam, 268/284, 214/220 @ .050 0.450"/0.458" lift, 115 LSA, installed at 106 or 108, doesn't sound that radical for a 440, matter of fact, it is milder than a 390 4 barrel cam in some ways and they drove OK with 50 less cubes and worse exhaust
7 - A timing cover set is cheap, I'd be hard pressed to not just try cranking the current cam forward to see how it did. It might just take the edge off until the real problem of compression and quench can be addressed
8 - A good timing curve matched to whatever cam he decides would be another cheap and beneficial improvement, especially at part throttle. I consider that a requirement regardless of the cam. Low compression big bore engines usually really like the right curve for street performance, and it shows more than just a WOT run may indicate

As far as "have I driven one" just about everything that has been driven has come through once or twice, and I get it, low compression, tall gears, loose converter in a heavy car is not too impressive. I lived through the mid to late 70s with BBCs and BBMs in big cruisers and wagons coming in with tall gears with twice the weight and half the power.

However, I just can't agree that the little Voodoo cam, installed where it needs to be, or his stock cam advanced, would not be some improvement, and I equally can't agree that your cam would make it significantly better. I think we are arguing on both sides of a knife edge and in this case, the cheapest way out is the way I would do it.

- Crank the cam forward, dial in the ignition and carb to make sure it doesn't rattle. Just like we all have done on 70s Fords with the retarded timing set. It won't change it into something perfect, but no cam change will when the real problem is compression and quench

[wyrmrider]

CAn't say I disagree with you stang

1 - Whichever cam he uses if the converter is too loose for the final drive, it'll still be inefficient at cruise, none of the cams will change that at cruise rpm, not mine, not yours.
Agree but not an easy fix I usually use Tight RV converter with short cam
It's not just cruise out on the highway where the Magnum converter is as locked up as it can get but midrange around town
What rally does not work is looser than Magnum converter so motor can come up on a big cam given 2:88

2 - If he goes earlier IVC, regardless of how he does it, very small cam or advanced small cam, going too far will likely make it ping. That's the same for either of our recommendations
Agree- however that low compression BBM will ping regardless due to the combustion chamber design
the lower the compression the more throttle it takes to make a given HP and the more they ping
I do agree with your later suggestion to see where the IVC should be

3 - The low compression of that engine will want more ignition advance, but the engine won't like it with a big quench. The cams are not going to significantly change that either, not with all recommendations hitting similar IVC numbers.
Agree but earlier IVC and less advance will work better
It's impossible to get BBM to work right with open chamber or wedge but with low compression

4 - I call the EGT discussion a red herring, valid as a concept no doubt, but not applicable due to the use of the engine, it just won't generate that heat and IMHO, the extra cruise advance the motor is likely dying for would likely erase it
Disagree here EGT is a problem on all low compression BBM even with std cam
YOu have to give them lots of throttle to get them to even move and lots of throttle makes heat and gas mileage sucks- worse with Magnum cam and converter

[wyrmrider]

5 - I think a tighter LSA like the Voodoo (with the proper ICL to allow the right IVC point) would gain torque when he was driving it harder
As you have said in other posts the 115-113-112 etc is irrelevant till you dial in the IVC
Voodoo is not that aggressive _looks about the same as the Purple Shafts or Ultradines or Howards
that said would be better than factory
Tighter lca will help but lca is a byproduct of where the ICL and EXCL lines need to be which are determined by where you want your seat timing

6 - The stock cam, 268/284, 214/220 @ .050 0.450"/0.458" lift, 115 LSA, installed at 106 or 108, doesn't sound that radical for a 440, matter of fact, it is milder than a 390 4 barrel cam in some ways and they drove OK with 50 less cubes and worse exhaust
Hard to compare Mopar or Mopar performance cams with others
seat duration is not @ some lift but is from a height in the ramp with 8 degrees added- funny but consistent
There have been postings of what the .006 is from those that have cam-doctored but I forget
FActory installs advanced but not much

7 - A timing cover set is cheap, I'd be hard pressed to not just try cranking the current cam forward to see how it did. It might just take the edge off until the real problem of compression and quench can be addressed
Excellent Idea but watch the exhaust events and watch heat

I would not spend any money on the Voodoo

[twright55]

I agree w/ almost everything 427stang is saying, except that I think Wyrmrider is correct about the early EVO and the EGTs.
This car has incredibly hot under-hood temperatures. So hot that If you just drive to the store and back, then the bonnet prop is so hot you almost can't touch it. And these cars even came with factory supplied fire extinguishers (mounted in the boot) to put out the frequent under-bonnet fires.
And then you look at the advertised duration figures (however they are calculated) and the exhaust duration is 18 degrees longer than the intake duration!!! I think that's a little crazy, but they must've had some reason for it. But AFAIK, the magnum cam was designed for 10:1CR motors w/ quench, not 8:1CR motors w/o quench. SO the slow combustion of these quenchless, low CR motors in combination w/ the very early EVO of a cam designed to evacuate a faster burn motor is probably a very flawed design to begin with. Advancing this cam would only exacerbate that.
On the other hand, advancing this magnum cam may help more than it would hurt. But the better solution is to go with a cam with the earlier IVC AND a much later EVO...which is practically every aftermarket cam available in almost ANY duration short of 235@ 0.50.
I think the Voodoo 262 cam would totally destroy the magnum cam. It has a MUCH later EVO and quite a bit earlier IVC...how could that NOT be better? I realize it may not be ideal...but that's why I post the OP.

I think people...even people who are quite knowledgeable...spend FAR to much time looking at duration and LSA figures...and not enough time looking at actual valve events. I personally think LSA figures are almost meaningless, except for a convenient way to quickly compare ICL and ECL between cams.
Duration figures are relevant to the engine and what APPROXIMATE RPM range the motor will be used in...not every motor is a 350 chevy.
A 200 @ 0.50 cam will NOT produce torque in the RPM range that I need it...not in a 440. Too much focus on the low CR is like not seeing the forest for the trees. Sure, the low CR will kill torque down low w/ too big of a cam, so some compromise is in order. But over all, the low CR will put the overall TQ numbers down...not totally change the characteristics of the cam. I still need the right cam duration for the RPM range I need to operate in...and the CR doesn't change that.

[wyrmrider]

so far so good on the analysis OP
what rpm do you want to maximise
and
how do you get there with heavy car and 2.88 gears and not have a stoplight to stoplight dog?
WE run big cams in the low CR motors for high rpm only use like Stock Class but not with your gears and converter- and open headers
you could try the advance drill and report back but I would not run the stock cam that way on a long road trip
The magnum cam- there was an earlier one but only 67 had any quench and it not much even with 915 heads
68 and later that long duration exhausts act on Exhaust gas dilution of the intake charge reducing certain emissions
Plot the .006 and 200 on the Jones Cam and the Voodoo, vendors should give you their recommended numbers
report back
Budget-
Around town run the stock 440 cam advanced 4 if you can score one with lifters all sorted out
Road and freeway- run the magnum cam advanced 4 degrees
depends on where you wnat your performance
IF you have to go buy a cam then it get;s tough finding one with squeezed lobe centers to get both intake and exhaust close from a catalog

[blykins]

Why are you so concerned about opening the exhaust valve later? It's very easy to lose power that way...

[twright55]

Why are you so concerned about opening the exhaust valve later? It's very easy to lose power that way...

'Later' is relative.
When the factory cam has an EVO that is 10 degrees earlier than almost every other cam that I can find from almost every after market manufacturer, AND the factory cam is known for grotesquely high EGTs, AND it was designed for 10:1 quenched motors and not 8:1 quenchless motors (with a much slower combustion rate), then yes, I'd be looking for a later EVO...relative to the afore mentioned factory cam.
After looking at a bunch of catalog cams offered by everybody else in the shorter cams, they seem to open around 70 BBDC vs the factory 79. I have to go up to the 240/250 @ 0.50 cams before I find any that have an EVO as early as the factory cam. That alone should tell you something.
Do I know what the ideal EVO is for my motor? No, I don't. But I'm pretty sure it's not @ 79 BBDC.