cross ram physics

I am thinking of building a 500 inch 440 based engine for my 300G.It will have a 62 727 w/parking drum behind it. Stock valve covers are a must and a hyd cam. The factory long ram or if I can find the "short" version intake. Pump gas,3.23,29" tires. Unforntunetley probably stealth heads and shorty headers,3" full exhaust. How much would the extra cubes tame these intakes? Rod length same question? Camshaft? 4300# curb wt. I full well realize this is no racecar but I don't want it to nose over at 3500 either. Difficult unusual question I know but any thoughts? thanks, Steve

I've never messed with them but I thought that the long ram tubes were tuned for low rpm. On a 500 incher I would think it would be more even lower. I personally don't think that rod length plays a role unless you are looking at from a bob-weight standpoint. On the cam I would look at it this way 413 to 500 is 22% larger. So I would take the factory specs on the cam and do this say 213 at .050 on the intake (just a guess) so 213 * 1.22 is 259.86 then take that difference and split it 260-213= 47
then divide that by 2 gives you 23.5 and add that to the original 213 witch comes out to 236 at .050 . You could do the same with the valve
lift and be somewhere around .550 lift (again just guessing .495) and on the lobe sep. I would stay at or above 110. I must have had a little too much coffee sorry.

Why are the Stealth heads unfortunate?

I am not a guru on long rams, but had a 300F in HS, mounted a set of long rams on my 62 Polara 500 413, and currently have a set on the shelf to install on my replica 62 Polara. I don't believe the extra cubes will lower the manifold tuning, but it will restrict the power band, as the engine will effectively starve for air at a lower rpm. The long rams IMO are rather restrictive flow wise. There is info on line how to DIY modify the long ram tuning to the short ram version, which I will attempt. I am going to efi the manifolds at the same time, as being a wet manifold I suspect, is a big culprit in carb tuning. I from the onset will concede anything over 5K rpm will be pointless. Torque can be fun.

And, if any motor would need or benefit from a hydraulic roller, this has got to be the one, heavy lifters, low speed operation, ability to open/close fast because of the need to assist max flow with a restricted intake.

Yeah, the heads are probably perfect for what you are doing, and look stock like your stock valve covers and long tube intake you plan to run. But yes, what is unfortunate is that the shorty headers are probably the only shelf header that will fit that car.

Sounds like a cool project for sure

Chrysler made three different sets of the "long ram" intakes, long, medium and short divider
That difference made those motors peak at different RPMs on both torque and HP

The last version on the 413 max out at torque@4000+-RPM
and HP at 5000-5300 ish RPM
Not a big performer on a 500 inch but impressive to look at.If you are going that route use a small cam.

You won't need the 3 inch exhaust. 2 1/4 or 2 1/2 will work fine, cost less, fit better and probably sound better in that car.

Cab, they only made two versions of the long ram-intakes.

Steve,
I have exactly that, a 500ci longram engine in my 1960 New Yorker.
Edelbrock heads, shorty headers.
CompCam XR274R-10 – Mechanical roller cam
Adv.dur. 274°/280°, Lift .564"/.570"

Engine is built for torque.

Well then, you have the perfect example, so when does it run out upper RPM steam so to speak?

What would you different if you had to do it all over again?

Screw physics, I prefer real world

I first started out with a 'almost' bone-stock cam in this engine.
Engine pulled like a freight train.

But driveline-vibrations prevented me from driving anything above 80-90mph.

I've ran this setup with 3.91 rear gears and 3.23 gears... The combo liked the 3.23 gears much better, which could tell you the engine doesn't liked to rev.

After a few years, I got 'bored' with the stock sounding engine and installed a XR274 solid roller which I bought from this site used.
Mostly fixed the driveline balance-issues, but there's still some left.

With the roller cam, the engine idle went lopey, the stock stall convertor got a real workout, and the engine felt stronger and liked to spend more time in the higher rpms, while still being a torque-monster.

Two-foot driving is mandatory...

Only thing that I'm still fighting with, is underhood temps.
The roller cam creates more cylinder-pressure and when the engine bay is warmed up, the engine wants to ping.
This is partly a carb(s) issue (bit lean), but mainly also underhood temps, as the engine never pings with a cold engine bay.

Anything I want to change?
- Install a slightly higher stall convertor;
- Maybe add an electric vacuum pump for the power brakes, but the brake-system first needs a smaller diameter MC;
- Add EFI; digital timing and port-injection, or LPG as fuel, which would bring back drivabillity at cold starts.

Do you still have the OEM exhaust/intake warmer plumbing still functioning/in place?

I would think the intakes, even run "wet", would be subject to underhood heat soak. Wonder if as an experiment, by "wrapping/insulating" them on a temporary basis it might counter some "ping" issues.

Is this a "stock" Compression motor?

No, there's nothing under the carb-bowls.
The heat of the headers, and aluminium heads, radiate into the aluminium long rams quite easily, so 'entire' engine bay cooling needs to be considered.

I might also plan to wrap the headers. A double sided heatbarrier coating would be better on the headers I think, but the costs are about 2-3 times the price of the headers alone.

Been also thinking of louvering the hood, to vent out hot air, but that would be a bit extreme perhaps.

Engine compression is (around) 10.2:1cr I recall.
I know I did some cc'-ing and calculations at the time, but lost or didn't write notes. I have some info on my site about this built, but I recently noticed I somehow managed to mix up 2 engine builds do that needs to be sorted out again one day.

Pistons are ROSS with 10.5:1cr spec.
The 440 block is +.030" and the OOTB Edelbrock heads are spec'd at 84cc.
.039" FelPro headgaskets.

How about ditching the hood for a test run?
Problem is, the rad will likely lose some airflow and worsen your issue.

I forgot about your headers. Wrapping them, unless SS tubes, will soon lead to their failure, not a good solution IMO. Maybe an under manifold heat shield with air gap?

I removed the under carb manifold heat chambers on mine to gain some clearance.

Any way to get just cooler intake air to the motor?

Recently during a cold spell here, I took the NewYorker out for a drive and even after some highway driving and back into town, the engine didn't ping when getting on the throttle.

The pass.side would be rather easy to fab a coldair-intake, but the driverside is very crowded and hard to come up with something functional unless I relocate the battery.

(Sorry for the topic-hijack Steve)

Thanks for all the good replies and yes I am wanting to keep it stock appearing so the Chinese heads it will be. The physics aspect was on rod length would the increased dwell time of a longer rod play hell with the sono/ram effect or not and opinions on valve timing and cam advancing. As noted this things tongue will be hanging out by 5200 if it makes it that far but torque should be great. Herman of course I have seen your cars on the Fl site for years and the issues with the surging, I asked over here so I wouldn't get beat up, you would think I was chopping the top and metalflaking it. Helluva crew that replied, Thanks.

One of the Petersen publishing group magazines(maybe Road and track or (EDITED Car and Driver) did a write up on the all Chrysler corp. cross ram intake manifolds a long time ago, they showed all three versions of the long rams
Yours look like the original 1959 and possibly part of the 1960 Chrysler 300 letter car manifold, according to my memory they said Chrysler started shortening up the divider wall in mid 1960 production year and ended up with the shorter designed ones later, maybe only 3 or 4 inches different in length between the medium and short ones

How many bolts do 1961 413 valve covers have? Stock 440 has 6, the early 413's had 4 but I'm not sure when they changed.

Kevin

On my 62 Polara that I grafted long rams on,I ran a mild Crane cam that i haven't clue what the specs were, and then IMO as a teenager decided to help the long rams out, I ran 60's state of "the art latest thing", called the Varicam. Can't tell you how any of it really worked out, as college and girls started to get a lot more attention.

All the BB Mopar motors switch to the six bolt valve covers and heads with the cast in rocker shaft stands in 1964

I think the Terminology used in the topic is confusing.
There are 'Long Ram' intakes, and 'Cross Ram' intakes.

The crossram is high performance piece, and installed as one 'unit', while the Long Ram intakes are a pair.
Cross ram intakes where never factory installed on Chrysler models, only the Long ram intakes upto 1964.

What I recall is the 'Short' Long Ram intakes came in use on the 1963 and 1964 Chrysler 300J and K models, and provided power at higher RPMs. Not quite sure anymore if the Short long rams where optionally available on earlier models.

Also the cam used on the 'Long ram' intakes was intalled retarded.
Installing a generic aftermarket cam will most likely skew the efficiency of the sonic waves a bit in the tubes.


As for Steve's question to using longer rods, increased piston dwell won't be 'seen' by the intake system IMO and hardly have any effect on that.

It will however increase the possibility of engine detonation I would think.

Longer piston dwell is welcomed when building an engine for propane.
Propane is a slower burning fuel and having the piston spend a bit more time at TDC helps so it makes better use of the combustion pressure.

There used to be a Dodge Charger which was converted to Propane fuel and also had longer rods installed to help and make more power.
I have the article somewhere.

I have a 74 440 sitting on the Dyno right now and am waiting for a little warmer weather to fire it up. Current temps are -20°F and Wednesday it's supposed to drop to -29°. I have a set of short rams that I am going to try on the motor along with a few different cams. The cams I have are in the 236-246°@.050 along with a bone stocker. Also going to try cast iron exhaust manifolds and some 1-3/4" headers with them. I have the correct carbs and a set of Carter CS 750's to try.
You can probably find a set of short rams on E Bay.

Looking forward to seeing the results. I have read on various sites as well as heard from owners of ram induction cars that a cam being installed straight up negates the manifolds benefit. This car had been hidden out in a hanger for decades and everything I have swapped out has been ancient ie Allstate shocks, Atlas plugs and wires, Gulf sticker in doorjamb. Was happy with myself that I'd never have to reach under a set of valvecovers again to change plugs and here I buy a wedge car and probably one of the most involved ones w/ issues that predate my MoPar knowledge. I built a 392H/518 in a 58 Ply wagon about ten years ago and felt this way, this sickness comes in cycles

I bet those same XR lobes on a 113° - 114° LSA, and loosening up the lash would clean up the idle a lot, and put power in the motor too. Looks like lash adjustment is no easy job.

Tested a 500 motor on Impastato's dyno years ago in the middle of winter. He feeds outside air to the carb, in this case a six-pack. Air temp was single digits on a clear dry day. Peak power correction was like a negative 30 - 40 hp from actual. Crazy high six-pack jetting like I've never seen before.

4 bolts.

Long rams on my '60 Plymouth. It behaves well on the street, runs high 11's in the quarter. Mine are the 'short' rams. Carbs are Carter Competition 500CFM.

Race set-up:


Street set-up:

my rams are the long version, and previous owners chopped out the four hole dividers at the carb bases. also, the heat chambers under the carbs are rotted through.
so since repairs are needed, is it wise to cut the tubes and remove the dividers, effectively making them short rams ? if so, would cutting the dividers a touch shorter make the RPM usable to around 6k ?
has anyone done other mods to these that work out good ?
i'm also planning on trying a pair of thermoquads.
this is for my humpback with projected weight of 2500 or less.

Factory instructions on converting long rams to the 'short' version:

http://www.1960plymouth.com/drag/LongRam-ShortRam.pdf

Agree on the wide LSA

this is an OLD Harley engine I built, this is a 94 inch Harley, very old design with heads I ported on the large side for cid, it is also EFI, the blue run on the dyno is with a 8 inch long individual runner length, very gutless down low, the red line is with 22 inch runners, everything else is the same, this is only for a 2 cyl, X the results by 4 for an 8 cyl

thank you for that link ! i have never seen that before. looks like a relatively easy task to do. would you suggest repairing the 4 holes at the carb pad, or leave the pad open as it is now ?

The “short” and “long” versions are actually about the same overall length, right?

The term is really referring to the length of the divider wall.......yes?

How much difference in length of the divider wall between the two?

I admire you guys who are willing to mess with that stuff...... but it’s way outside of my KISS philosophy.

question #1 and #2, yes.
the third question, i'm not sure.
my one buddy always says : "why keep it simple when you can complicate the sh!t out of it ?"

also, as you probably know by now, i kind of like to try things that are uncommon, or against the grain of proven knowledge.
and i use what i have because of budget and the "what happens if" mentality i have.

having the instructions on the long to short conversion, and being a retired machinist, this looks like i will tackle this job. my intake setup is complete except carbs, and has been hacked on before i got it. it also needs repair on the exhaust heat plenums, so it needs some re-work regardless.
it looks good, and i have zero invested ! sooo......

The "ram effect" depends on the speed of sound so engine size shouldn't affect it. I'd suggest using the factory cam LSA and intake CL and go symmetrically bigger on the lobes.

There is a TON of wall friction and that depends entirely on the length of the divided section and the overall length. This is like pipe friction, which increases as the square of the velocity. Going from 413 to 440 increases the velocity 6.54%, pipe friction increases by 13.5% I think with the bigger engine the power curve to the torque peak increases and then after the torque peak it drops rather dramatically.

For a 500 inch engine it'd be like breathing through a straw.

R.

IIRC the original tuned runner length is 30"?
Deduct 10.5" for the un-cut remainder as per the instructions: 19.5" is now siamese.
I have no idea how any math works out here, but Chrysler almost certainly did multiple back-to-back tests before releasing the mod.
The question: how dependent on the original (mild) cam specs is the new 10.5" length, and would you want to second-guess it?

Personally, if I liked it simple the bowtie brigade would suffice. I m one of those guys that have always been drawn towards the quirky stuff. I've also wondered how and why something works. The worst thing someone can say to me is you can't do that or it will never work. I guess I'm a bit stubborn and bullheaded, more often than not they are correct. But, once in awhile I prove them wrong and that's very satisfying.

I had thought of the wall friction but figured increased swept volume would speed up the charge. Not to beat a dead horse but am I the only one who thinks the longer rod with corresponding longer dwell would increase the ram effect of the moving column of air? Or do you think the head wouldn't "see it" as Herman said. Dogdays I appreciate your cam remark.

are you perhaps, my brother from another mother ?
exactly my way of thinking ! around here, i'm a misfit with my brand loyalty. as always, most are brand x and y, so i get busted on constantly.
plus, all of my wounds are self inflicted.

Pretty much sums it up! My little foray into turbochargers has been a steep learning curve. All the damage I've done has been my own fault. I generally know how hard I can push something without destroying it. Sometimes my NEED for more hp overcomes any common sense I may possess.

Interesting tech article from Hughes Engines that shows flow test of a 'short' long ram compared to more traditional intakes.

Hughes Intake Manifolds Tests

w/r/t longer rod with corresponding longer dwell would increase the ram effect of the moving column of air
IMHO some change will be the IVC point (in terms of remaining stroke at the same crank position) will be later with the same cam, which allows a longer window of inertia fill ABDC, but the change is so small with any rod you could use to be more easily accomplished with retarded intake.

I'm trying to reconcile the new 10.5" of IR to the 15" used in the cross-ram?

That was a worthwhile read.

The Op may not like though.

I'd read that awhile back but not since I've had the car, couldn't remember where it was thanks for posting. No weeping here, Intakes stay with the car.

I have a 61 G and getting ready to order a cam. The engine builder and I discussed this Voodoo hydraulic roller (smallest they have for this engine). What do you guys think? Engine is 30 over 413, 10 to 1. Car to be restored to stock but has ross pistons and new rods

adv duration 262/270
dur .050 211/219
gross valve lift .507/.515
LSA/ICL 112/106
RPM 1400-5400

Sounded like good torque cam to move this boat around

The best way to wake up this manifold is to ditch the Carter carbs and install a set of Holley vacuum carbs. Made a very big difference on mine.

Digger73 (Mike)

1850's? Does the Holley directly bolt on?

The bolt pattern is different, which means you need either to plug the holes and re-tap the manifolds (!!!), or use adapters (which add plenum volume and vertical height to the install). IIRC modest plenum volume was a key element in making the 4,500 lb. car with 2.93 axle and low stall speed responsive in traffic - I drove a 300F back in the day, and you wouldn't know what was under the hood unless you looked.
http://www.thecarburetorshop.com/Four_barrel_mounting_flanges.htm

Before you do that: in my (somewhat limited and ancient) experience, the single biggest tune up problems with AFB is poor tip-in response - without attempting to modify the air door counterweight.
I agree it's annoying (especially to match them), but there are hints as to where to remove or add weight to match your plenum, pump shot, idle quality, stall speed etc.

If I remember correctly, with OEM style air cleaners, there is not a lot of vertical underhood clearance ( 300F & its been nearly 50? years ), I would think an adapter and a taller carb might get one into trouble?

No...
the best way to improve them is to install throttle bodies and machine for fuel-injectors near the heads.
This improves cold starts by preventing fuel from forming back on the tube-walls again.


How about extrude hone these manifolds? Or something more DIY and less expensive and install a large sanding roll on a flexible extension and grind away the casting roughness in those tubes (eventhough a smooth surface won't always mean flow is less restrictive compared to an as cast-surface texture).

your memory's working, there is not much above the air cleaners and I figured the afb's were the small footprint carbs.

Apparently you missed Als post. His 60 Plymouth runs 11's like clockwork with two 500 Carter's. Take it from me as I run against him. The car is dead on all the time.
Doug

i have thought about this idea for several years, just machining a couple of plates that would sandwich between the heads and intakes to position the injectors and fuel rails.
as my panel truck project will not have a hood, height of the intakes at the base means nothing.
however, in the world when these were new, there was not much under hood room for adapters and ail filters.

Al's car runs hard have seen it many times He is also a decent fella, took and posted a pic of my 58 wgn on a different site for me once, no disrespect Al I forgot, I coulda PM'ed you on this.

The original 300F & G cars had a removable panel for spark plug maintenance in the inner fender accessible only from inside the wheel well.

And again, if my memory serves me correctly, the panel's main purpose was to visually verify indeed, the motor had 8 plugs.

Which makes me think adding real headers might cause another dilemma, like setting valve lash hassles. Have yet to hear many add headers, even with cutting off the plenum floor chambers.

When I changed the plugs a few mo. ago I didn't know that and with all the swivels and wobblers and extensions I have I was Cursing engineering and respecting mechanics of the past some who are still here. When I later saw the access covers it didn't dim my respect for the mechanics however, you could eliminate the whole inner fender and these rams would still be a pita.

My cam's a little bigger (but so is my engine). Also a hydraulic roller, Hughes Engine:

Duration @ .050 228/236
lift .510/.533
LSA/IC 108/104
RPM 2800-6600

I also have a high stall converter. It will flash to about 3000.
RPM

Thanks longram. I was hoping with the smaller cam I would stay away with having to mess with the convertor. Not sure you can get convertors for the old 413 crank??
I was also hoping new technology was better than trying to run a 60 year old cam in that car. I am not sure if the cam I have is stock either
Thanks

The XR274R solid rollercam I have in the 496ci has to following specs;
Adv Dur. 274/280°
Dur @ 050" 236/242°
Valve lift 0.564/0.570"

I'm still running the setup with a stock stall convertor (1964 PB727), but I would advice against that.
The temperamental engine (because of the lousy fuel distribution at idle) makes 2-foot driving pretty much mandatory.

Fuel-injection or a gaseous fuel like Propane would solve most of these problems I'm sure.

I've had two different vehicles, a 1 ton car hauler and later a 1 1/2 ton class a motorhome, that ran on both gasoline and propane.
Neither one ran as good on propane as they did on gasoline Horrible fuel mileage and a lot of power loss on propane
The motor home was on straight propane when I bought it and it had very little power, I mess with the mixer and got better power and ended up with horrible mileage
I removed that system and put it back on gasoline only and got better power and mileage, it did run hotter also More power = more heat

Not clear to me, these were also long ram propane conversions?

Also thought Propane is always best suited when a decent upgraded CR can be added to solution, which you did not mention?

I would also think Propane on a long ram setup would be a rather "hot" temp wise intake charge, because of long exposed rams and lack of heat of evaporation contribution of the fuel.

Installing a propane fuelsystem on a low compression 'turd' (smogger) engine only results in ending up with a bigger turd engine.
Propane likes its own set of properties in an engine like proper timing-curve and increased compression ratio for instance.
If a gasoline engine is not optimized for a different type of fuel, it will orcourse never make more power.

For long ram intakes, propane, being a dry gaseous fuel, would be better to use as there's no chance of fuel re-clinging to the tube walls again during cold intake temps and slow airspeed during idling for instance.
Also carb heating is not desired as it only makes the air less dense which means less fuel entering the engine.

The long ram could indeed be functioning as a heat sink so maybe a reflective coating or other kind of thermal barrier would help here.
But we might be straying offtopic as I don't anyone converting there longram system to propane that easily here

Isn't there a financial advantage in your country to convert your cars and light trucks to propane?
BTW both of those vehicles had low compression H.D. industrial motors for regular gasoline, not optimized for propane.
I spent nine months in Germany in 1967/1968 in the U.S. Army, I was shocked on how much the government fuel taxes where on gasoline over there back then
I remember paying around 23 cents for premium a gallon in SO CA before I got drafted in 1966 and a tiny bit more two years later
A G.I could by fuel ration coupons for gas from the PX on base with no taxes on it for 21 cents a gallon for regular or 23 cents a gallon for premium and the Germans were paying 91 cents a gallon up to 95 cents a gallon out of the same pump(fuel was sold by the liter, not gallons but the math worked out that way back then)
I hate any government that doesn't serve the people who pay there salary as safe and efficiently as possible

Yes propane is popular overhere because it is less taxed then gasoline.
1 Liter of (liquid) propane (LPG) is about €0.58 ($0.66) x3.785 = $2.55 p/gallon.
1 Liter of Gasoline is about €1.58 ($1.80) x3.785 = $6.81 p/gallon.

My daily driver is a '73 Dodge Dart with a 11.3:1cr iron headed 360ci under the hood and runs on propane.

Propane as normally used has a big disadvantage, that being that when it is vaporized and heated it takes up a lot of room in the airflow. The most power is made when the fuel goes into the combustion chamber in very small droplets which then vaporize for combustion. And if a very small percentage of the liquid fuel vaporizes in the intake manifold it cools the charge down and makes the air denser. So contrasting that wiht propane which is all vapor before it passes the intake valve and you can see part of why it doesn't make power.

I think there is power to be made using the propane's latent heat of vaporization to cool the charge down, possibly even using some sort of eductor effect to induce more air into the chamber.

R.

So how is liquid Propane metered in this typical automotive format? Seems with a boiling point of -50F ?, it would be rather difficult to get it even past the intake valve.

dogdays is correct; Propane lacks the cooling properties gasoline has because it doesn't vaporize anymore after the 'convertor' (vaporizer).

Liquid propane injection works through a convertor, in-tank pump and fuel-temperature sensors and let the ECU compensate injector timing, because a 'warmer' fuel will mean there's more pressure behind the injector, so a shorter injection time is required. I'm not sure if the fuelpump-pressure from the tank is regulated as well but wouldn't be surprised if they do.

Besides the low boiling point, liquid propane is also under pressure. So the moment it's injected, not only will it return to vapour quickly, it also depressurizes which draws more heat from the surrounding.

I remember reading a article about how much BTU each type of fuel contained in a liquid gallon, diesel then was suppose to have around 230,000 BTU (at the time of that article) (the new low emission diesel fuel now has around 130,000 BTU is what I've been told on here ) premium gasoline had around 110,000 BTU, methanol alcohol had 89,000, ethanol alcohol had 85,000, propane (I may have these gas liquid gas figures mix up ) had 58,000, butane had 57,000 and natural gas had 55,000.
I don't think this article show Nitromethane fuel numbers
If I am remembering these numbers correctly you can see why most big commercial trucks, trains and ships use diesel power for moving stuff

Heavy engines and equipment needs torque to get moving or do work. The best way to create torque is to build compression.
With high compression you need a fuel makes use of this and works in such an environment.

A long stroke crank design also plays a big part in max torque output applications.

Long stroke allows short, light, flat piston with high static CR.

There is some information concerning the long ram set up in this book. I can't remember how much but i do remember seeing charts that illustrated how much more torque they produced and where in the rpm range:

Scientific design of exhaust and intake systems

30" tubes, tunes at 2,800.

We are jumping around here on different subjects, the long stroke comment I made was in reference to the solutions another suggested on moving "heavy' vehicles, and the "thinking" the best way to gain torque was thru compression which I am not in agreement with as an end all. In gas powered typical street applications, with pump gas there is effectively a CR limit, and any gains chasing smaller CR increases eventually results in diminishing returns.

However there is practically no limit on increasing stroke, and the benefits from larger crank leverage that affords in achieving greater output torque numbers is also nearly unlimited. I am not for a second stating there are not downsides by increased stroke, mainly its a better design path for gaining increased torque then approaching a capped CR limit.

And since we are now discussing different formats here, most heavy "vehicles" are diesel, have long strokes, have heavy pistons, and pistons are often contoured.

Stroke producing torque was identified as mythical around 1940.