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8 & 10 cyl Bristol cars From Type 407 onwards

torqueflite part throttle kick down

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  #1 (permalink)  
Old 01-05-20, 09:19 AM
Join Date: Mar 2015
Posts: 14
Default torqueflite part throttle kick down

I never much liked the fact that my 411 refuses to shift from third to second on part throttle. I was told that Bristol deleted this function but always found this hard to believe.Up until 1971 A727 transmissions did in fact not have "partial throttle kickdown" and as of this year is when Chrysler changed the valve throttle body inside the box to allow for this function. This of course gives the car a much livelier drive.
My car was built late 1972 and first registered Jan 73 and should logically have had this feature. It doesn't as I discovered when we rebuilt the gearbox during the winter months, and of course nothing was deleted by Bristol. It was standard pre-71.
The answer was quite straightforward. Checking the engine number showed that it was a 383 built in 1970 and as engines and gearboxes were shipped over as units it seems more than likely my car was given a 2 year old engine when it was built. So much for the "delete for safety reasons" story.
I now found a small company in the US specialised in Chrysler gearboxes and they have developed a small inexpensive module which bolts right onto the valve body allowing partial throttle kickdown. It's on its way to me but who knows how long it will take to get here under the current circumstances, but when it does and I have installed it I'll report on how it works. It might just make a lot of cars a bit briskier.
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  #2 (permalink)  
Old 01-05-20, 10:39 AM
Join Date: Nov 2010
Posts: 62
Default Chrysler gearboxes

Very interesting...and not surprising that a small carmaker might not use up its gearbox/engine stock for a year or 2, especially if it had to buy in batches. Or they might not have been first in Chryslers queue - after all did I hear that Chrysler made 20 million v8s?
The Heritage Trust has recently acquired copies of all the Advice sheets from late 60s onwards and it is evident that small volume sales meant that older parts - and even cars - would not be thrown away.
I've been really impressed with the Chrysler Master Technicians conference booklets , by the way- an educational programme to educate chrysler mechanics on troubleshooting for engine gearbox etc etc.
They made a series of these from postwar onwards for every model -easy to read and great flow diagrams for how to fix, tune, sort out stuff like carbs and gearbox work,.
The Heritage Trust has some in its archive but Id like to assemble a whole set for reference
Where can I find a simple list of engine/gearbox types with dates?
I will then try to buy those handbooks we lack.
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  #3 (permalink)  
Old 01-05-20, 11:06 AM
Join Date: Jul 2008
Location: woodhouse australia
Posts: 126
Default kick down

I recently had my 411 gear box rebuilt and demanded that the kick down be added. They simply replaced the throttle body for a later model. This has transformed my cars performance. Interesting I read in an article in Motor in 1975 , the last of the 411s and the first of the 412s that the boxes had been modified by Bristol . I never discovered whether the late model 411s suffered this fate .

NB my 411 is a series 2.

Having just purchased an early 412 but not yet taken delivery I will be interested in its change down pattern .
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Old 01-05-20, 11:48 AM
Join Date: Mar 2015
Posts: 14

Find these kinds of lists on the web> the engine has 2 id numbers a long and a short one.
The short one will be enough to tell you the year it was built. if it's (as in my case) a 383 the prefix tells you the year. eg D383= 1968, E383= 1969 etc.
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  #5 (permalink)  
Old 01-05-20, 11:50 AM
Join Date: Mar 2015
Posts: 14

Yes correct, I was about to order a throttle body when I came across this gearbox co, and at US$ 95 I thought why not give a go.
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