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Yes, as the bolts break, the manifold bases burn out, the little heat tubes burn out and as the eight gaskets start to leak and fail, the carb heat process’ long-term weaknesses start to show. But, as written by poetess Edna St. Vincent Millay (sounds like our kind of gal!): My candle burns at both ends; Now, for a couple of thermally-controlled butterflies in the ram heat tubes-one on each side and controlled by temperature sensors in each manifold. Little details like that allow current engines to start and run smoother, more efficiently and with less pollution. I recall that manifold heat is controlled in IC-engined airplanes. And variable runner length intakes are also used to capture the ram effect so effectively, if crudely, done in the F-K engines and later in the Max Wedge engines, but not the ’55-59, ’62, ’64 base or ‘65 letter car engines. Racing and hot rodding have driven the steady improvement of engines and Chrysler letter cars often led the way—as they still do with the SRT-8’s, standard hemis, V-6’s and fours. Consider that putting a small number of specialty engines on the road and race tracks and monitoring performance and problems constitutes one gigantic lab. Note: My insurance company sticks a high performance surcharge on my 2005 hemi Durango with 4WD. I’ll bet they’d really stick me if I had a nice SRT-8 392 (love the displacement) hemi 300c. Acoustically, thermally, combustibly and C300K’ly, Rich Barber Brentwood, CA From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of John Grady I just communicated with Jamie Hyde, he tells me no exhaust heat control at all on J, (he is in the middle of doing one) so must be same on F. I stand corrected on that. Sorry for confusion on my part, never thought much about heat riser detail in context of rams before today. , I have that heat riser rattle in my head for all cars, I guess. He mentioned max wedge guys are reproducing the, (or a) , dual choke cable, in process.... I cannot understand how Chrysler expected that “no control ram heat” design to work right. Heat under the ram carb would go up when engine hot, or hot day, even more with WOT, or cruising at 80 mph, exactly wrong. And be slow to heat up off idle too. Really strange design to have no control at all of under carb heat? And for sure it ate away aluminum on exhaust side, but not sure if thermal or corrosion. Maybe why 400Hp F apparently had water heated passages? Related to Rich’s point, on the varying strategies to operate in line quads, ? were different CFM size WCFB in use over the 55-58 period? If smaller ones early on, maybe that was why parallel opening? Two (actually 4!) large primary throats would not work well at low RPM. I also thank Rob Kern for that excellent narrative in current Brute Force on what he went through on his C ; I am doing a C, right now, certain pitfalls now have excellent warning posts!! I also thank Rich for sending it to me. It is great stuff. From: Rich Barber [mailto:c300@xxxxxxx] Our ’55 C-300 came from the factory with two thermally-actuated chokes. They were actuated by a stream of air heated in a tube in the RH exhaust manifold and bled into the carbs through the choke body. The tubes were wrapped with (gasp) asbestos to help keep the air hot. The hot air would then heat the coil springs in the choke bodies and open the chokes. I’m not sure, but I believe the hot air flow continues into the carb continuously. For whatever reason, the original owner in southern Colorado had the automatic chokes removed and replaced with two manual chokes with knobs under the dash. The installation looks very professional, apparently with Carter parts. I must admit that I appreciate the absolute control over the choke process. I have an electric fuel pump feeding the mechanical fuel pump and allow it to operate until a change in pitch indicates the carb bowls are full. Then, just a little choke, a pump or two and a nice quick start. (Yeah, I know, there is a risk of pumping gasoline into the crankcase if the mechanical pump diaphragm fails. There is a heat-riser valve on the RHS exhaust manifold that forces RHS exhaust to the LHS exhaust pipe via the intake manifold. This quickly provides carb heat and enables the chokes to be manually pushed open. This works fine in mild to hot CA and should also work in IA this time of year. Additionally, both carbs on our ’55 are hard linked together and feed the engine simultaneously. Secondaries are flow/velocity controlled. I believe the ’56 300B cars were also hard linked and that later hemi’s were connected by progressive linkage that did not open up the front carb until ¾ throttle or more. Perhaps that was for economy reasons. I get better mileage towing our ’55 on a trailer behind our Hemi-rango than when driving it. For those few conservative and cautious drivers that bought cars having one or two four-barrel carbs, the unused bowls and carbs could gum up with the residue from evaporated leaded gasoline. Along with other gearhead teens, I was always willing to take grandpa’s Chrysler out and blow the cobwebs out of it with WOT runs. One of my buddies’ granny had a Cad Eldorado with dual quads and we were ALWAYS willing to exercise that beast. I recall the dealer once replaced the carbs after her complaints of rough idling and operation in Des Moines—on her dime. Backfiring and black smoke might emit as the junk gas was displaced with good stuff and the internal passages of the front carb were partially opened. Often, carb cleaner had to be poured into the intake while racing the engine to dissolve the gunk—the blue black exhaust showed the results of the cleansing. Gasoline in the ‘50’s also had its problems with deposits. Big oil then started adding detergents such as Shell’s TCP (tri-cresyl phosphate, not tomcatpee) that helped clean the carbs and maybe even the intake valves and combustion chambers. C300K’ly, Rich Barber Brentwood, CA (Got maybe ¼” of rain last night—so much for the bloody monsoon season) From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of John Nowosacki I believe the 'one choke for two carbs' on inline setups also applies to the 55-58 Hemi engines as well. On Thu, Jan 30, 2014 at 11:18 AM, <kmaniak@xxxxxxx> wrote: John: With all due respect, I feel compelled to offer a few clarifications regarding the manifold and carburetor set ups on the letter series Chryslers. The in-line twin carburetor set up used on the E and H was designed in such a manner that the front two barrels of the rear carburetor was the primary fuel supply to the entire engine at start up and low speed operation. Therefore, there was need for only one choke, located on the primary barrels of the rear carburetor as Mike describes. The rear carburetor secondary barrels, and well as the front carburetor barrels, only opened after the primary barrels were at least one-third to one-half open. Both carburetors fed all eight cylinders simultaneously. The cross ram engines differed from the in-line engines in that each carburetor only fed four cylinders. At start up and low speed operation, the primary barrels of both carburetors were required to operate, with each carburetor feeding only four cylinders. As such, two chokes were required, one for each carburetor. Given that the '60 & '61 cross rams had automatic choke pull offs, and each worked independently of the other, I can see how a lack of synchronization could really mess up cold start engine performance and drivability. And I agree that the manual choke set up used on the J and ram K provided synchronization. The manual choke was also cheaper to produce, and I think Chrysler was pushing "cheaper" when building the J and ram K. Now I need to touch for a moment the subject of the "exhaust heat riser valve". To be clear, this special valve was a thermostatically operated butterfly valve installed just before the exhaust flange on the passenger side "log style" exhaust manifold. The purpose of this valve was to temporarily restrict exhaust flow from the right side of the engine and force a portion of the exhaust gases from the right side of the engine through the right cylinder head, then through the base of the one piece intake manifold, then out through the left head. This allowed the exhaust to quickly heat the intake manifold for quicker warm up and better cold start drivability. On engines with intake manifolds and carburetors installed between the cylinder heads, only one "exhaust heat riser valve" was installed on the right exhaust manifold. The cross ram engines did not have carburetors mounted between the heads. The cross ram manifolds included blocker plates that capped off the upper center exhaust ports in each cylinder head. As a result, exhaust gases did not flow from head to head on a cross ram engine. Therefore, no "exhaust heat riser valve" was required or installed on the ram engines. Each ram manifold receives exhaust flow from the respective exhaust manifold below it on a continuous basis. Hopefully we are all on "one page" now. I welcome any comments or differing opinions. Chris the K MANIAC
-----Original Message----- Only one carb was connected to your setup? So you started on 4 cylinders..? The J setup manual choke split in two if I remember right , made both carbs do exactly the same thing.. What you want ... They should have had one choke control and cross link the carb fast idle and choke mechanically. Not sure why they did not do that. Would have cost less and worked right.. What they do matters less ----than they do it together. Exhaust heat riser valves both have to be in sync too. Or you get loping idle , stalls when you push D on cold days, equals starting it 5-6 times . If you had manual choke on both, (J) , it just let you raise idle high enough manually when cold to cover up all this. But still harsh D engagement was the norm. Tests that fine front U joint on 60 -61, too!!. “Clang” !!---J had a little looser converter, not as harsh maybe. And they are a bear to start if they get badly flooded , not sure why..My .02: = maybe gas sits in a deep puddle at bottom of ram under carb till it is good and ready to evaporate out, (no other way out) but a squirt of ether and away you go. On regular manifold, that gas would run down into ports. Despite working on these on and off for what 50 years now, I admit to lots of suffering along the way. Can do in minutes what used to baffle me for a day. One key thing I found is that many, if not most of the carbs have destroyed adjusting needles by now , due to all the playing with them..if you see a ring or step worn circumferentially around the needle, no question -- it is junk. Cannot be adjusted right. That ring comes from “golden screwdriver “ and going too tight into hole, prior to “backing out 1.5 turns” . I found new Edelbrock needles (spare parts from them) are beefier and fit and work even with possible damage in carb body..taper is slightly different. .# 1 thing you can do about frustrating drifty funky idle setup. ..that changes by itself every time you look at it. I mistakenly junked several “untuneable “ ‘defective” carbs before knowing that, After careful rebuilds, still the idle problem remained ..... From: Michael Moore [mailto:mmoore8425@xxxxxxx] John, I have owned my 300H since 1965 or so. When I got my car, it had a very nnicely installed manual choke. It was a very clean installation, which I thought was factory for a while, using one of the unused round knobs beneath the dome of the instrument panel. The unused knob had a set screw and was used to connect to a choke wire which went to the rear carb. It was actually, I thought, much more useful than my curent electric stove choke. I only removed it because it would gradually creep into the choke position as the engine vibrated, so I frequently had to push the choke back in. Sometimes, on a long trip, I woujld only notice it when I realized the engine wasn't running right and would find the choke fully engaged. Otherwise, I thought the car started easier as I could momentarily choke the crap out of it if it was cold and as soon as it fired start coming off of choke. Mike Moore 300H On Jan 29, 2014, at 4:21 AM, John Grady <jkg@xxxxxxxxxxxxxxxxx> wrote: Another aspect of this was very poor choke pull off on ram cars ; one side pulls off before other even today . Certain types of cutomers would not deal with this in 60 , 61. I was there , one person i know had rams pulled off 383 61 plymouth wagon over terrible idle /cold start /warmup stalling isuues in Boston ... New car . J and K (?) had manual chokes to ensure syncrony . Ram cars are cut a lot of slack today , but remembet at meet in maine it took 5 club membets half an hour to start a perfect flooded F
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