So, I am looking at this apparatus on the intake manifold of my 303 and I'm not sure what it's purpose is.
It looks as if it is some kind of vacuum can but I think it is just a throttle stop.
I find no reference in the FSM so I am turning to the collective.
What is this thing? It must serve a purpose or it wouldn't have been installed. Is it serviceable? Adjustable?
Posted 2019-04-17 7:38 PM (#581040 - in reply to #581038) Subject: RE: WCFB throttle stop?
Expert 5K+
Posts: 9900
Location: Lower Mainland BC
ABloch - 2019-04-17 4:32 PM
So, I am looking at this apparatus on the intake manifold of my 303 and I'm not sure what it's purpose is.
It looks as if it is some kind of vacuum can but I think it is just a throttle stop.
I find no reference in the FSM so I am turning to the collective.
It's called a "dash pot" and it is there to slowly close the throttle plate when you take your foot off the gas. Often (or always) associated with automatic transmission cars.
That said, my 56 D500 with 4 bbl WCFB and Powerflite 2 spd auto does not have one and there has never been an issue.
Your dash pot's PN is likely 1538 426 (or 1538426 when Googling). It was replaced by a DP-307. Here is one on eBay:
Posted 2019-04-17 9:20 PM (#581059 - in reply to #581052) Subject: Re: WCFB throttle stop?
Expert 5K+
Posts: 9900
Location: Lower Mainland BC
ABloch - 2019-04-17 5:34 PM
I'll look in the FSM again for any reference to the dash pot. Are they adjustable? Part of the curb idle setting perhaps?
Pg. 156 of the 55-56 Plymouth FSM:
"PowerFlite Dash Pot—The Dash Pot is a device
which retards the closing of the throttle when the
accelerator pedal is suddenly released, thus preventing
engine stalling. Maximum dash pot action
is obtained by loosening the lock nut and adjusting
the unit so that the dash pot plunger shaft can be
moved inwardly, approximately 3/32 inch, when
the throttle valve is tightly closed. After adjustment
is made, retighten lock nut. See Figure 39.
The dash pot unit is serviced only as an assembly."