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Looking for "plumbing" onfo on a Dodge 426 Hemi engine

I am building the Revell 1:6 scale model of this engine. Simliar to

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I have the older version (1964?) which had a round chrome air cleaner, not the shaker scoop. It has dual carbs.

I'm trying to add details to this model but I have never been that intimate with a 426 Hemi. I have found some good reference photos on the web and I already added bunch of bolt castings, remounted the distributor and detailed the alternator. I also replaced kit's PCV and Vacuum Advance hoses and the PCV valve with more realistic looking parts. I also replaced the fuel lines and added a throttle lever return spring.

But I can't find any good info on the rear part of the engine. And the kit has some odd parts in it. FIrst there are 2 black lines (metal on the real engine?) which go from the back of the intake mainfold to the end of the right header. What are those for? Are they supposed to be there?

Next is a white plastic part which looks like either metal or plastic hose/tube. It is called choke control tube and it connect from the choke activator on the side of the rear carb to the end of right exhaust manifold. Is that correct? Is it a metal or plastic piece on the real engine? Is it supposed to be painted white?

I've seen many electric choke controls and mechanical (bi-metal) controls. Those usually sense the intake manifold's temperature. I never seen one attached to the exhaust header via a tube

Any info will be appreciated. Peteski

Reply to
Peter W.
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Not a big fan of the Mopar, but can clue you in on old Fords.

They used a steel tube going from the manifold, to the choke. As the gas heated the spring, the idle speed cam would drop, slowing the idle rpm. What wasn't obvious, was that the spring also moved a small piston in the choke housing itself, which cut off that flow of hot exhaust gas that was ported to the butterflys, gas that heated the area on Autolite carbs to prevent icing and help atomize the cold gas.

This was in addition to the small exhaust crossover in the intake manifold that would warm the bottom intake plenum area.

If all was adjusted right, would give faster pulloff than manifold coil that Chevys used, or hotwater types. Downside was it the motor ran really rich, would soot up, then do a rotten job at pulling the choke off in a reasonable time.

Now some mopars used a heat riser, that would valve the flow of gas to the intake crossover, and out the other manifold. that big crossover would also heat the choke spring, so would pull off much faster than the Chevy, maybe a little quicker than the Ford. Bad thing was, those risers would stick, and really mess things up, like choke coming off _very_ slow if stuck open, and if closed, would always route exhaust gas to the crossover and not out the manifold, and engine would run poorly, and overheat even.

Many guys used to wire them open, or removed altogether if headers were on, and live with a cold blooded engine.

For the other tube, were you talking about the larger preheat hose that went to the aircleaner? That heated air also helped with preventing bogging in the cold

** mike **
Reply to
mike

You might take a look at this. There is lots of info here

classichemi.com

Reply to
Count DeMoney

Mike, your explanaton makes sense. So, the connection between the manifold and carburator is a steel line.

The other 2 tubes originate in the same general area of the same exhaust manifold as the choke tube. They are routed to the back of the intake manifold. Again, your explanation seems to make sense. If a butterfly is closed in the cold exhaust manifold that could route the exhaust through the intake manifold and back out beyond the closed butterfly. The butterfly mechanism is represented on the model as a part that looks like half of a metal disc.

Count DeMoney: that website is very informative but it only covers the earlier Hemis (which have a different layout). 426 is a newer design.

Thank you both! Peteski

Reply to
Peter W.

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