CD 175 Retro/Modification

[RadioGuy]

Ok, this is going to be an academic question because I am going to proceed without this modification because we are going to finish this job <font size="4">TODAY</font id="size4">.

While rebuilding the carbs on the 1980 DHC this weekend I wanted to add a manual choke from a set of 1976 or so carbs. The 80 carbs had the FASD on it and I took that rotted out thing-a-ma-jig off and threw it as far as I could down in the woods behind the cabin a couple of years ago and plugged the holes with set screws. Ok I knew I was going to need a choke some day but I wanted to see if the car/engine was going to be reliable before I started spending any money on it. Turns out the car is going to be a keeper and has been more or less a daily driver between my son's and me...(read..who is going to get to drive the "coupe" today...or...if it's going to rain..who is going to cover the "car" up?)But, I digress.

Some of you are smiling about now because you know the manual choke from the early carb is not going to work on the FASD type carbs...or will it?

Question: If I can drill the hole from the semi-circular cut out through the runner into the carb throat like the earlier carbs and plug the other holes that were used by the FASD will the choke/carb work as is should or am I missing something?

I know this had to be covered on the forum but after a couple of searches came up without joy I pushed the easy button and presented it here.

<font size="3">Oh, a gallon can of carb cleaner and an ultrasonic cleaner really cleans up a carb for the rebuild !!</font id="size3">





Ken


Maintained on Saturday…Drive on Fun-Day !!! 1976 FHC - 1980 DHC

[windy one]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by RadioGuy</i>

the manual choke from the early carb is not going to work on the FASD type carbs...or will it?<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Why wouldnt they? I was about to attempt the same. In my pile-O-parts I found a set of twin ZS's with manual chokes, and the appropriate cable to operate them. If I remember correctly, with a lil modifying it will work.
If I get to it before you do Ill let you know of my progress.

Johnny

[RadioGuy]

Ok Johnny, here we go.

Manual choke circuit: The fuel route when the choke is pulled on goes like this.

Fuel is drawn from bowl through hole A though the choke mechanism to hole B and then though runner C into the throat of the carb in front of the butterfly valve.(A-B-C)

The FASD circuit goes from the bowl though hole A(this might not be correct, but it is one of the holes, good carb is back together now[:I]) though the mechanism to hole D and then though runner E to the throat of the carb behind the butterfly valve.(A-D-E)

The manual choke carb is pictured below with the hole cut into the semi-circular groove. The FASD version has no hole here only a dimple. The FASD version has a hole drilled from D to runner E.

Notice the gray circular area encompassing holes A and B, this is where the manual choke mechanism moves on the carb. Notice this area does not include hole D so there is no route for the manual choke from an older carb to work on a newer carb...That's the way I read it anywho.....that's why I'm asking.

I guess if you buy one of the aftermarket manual chokes they have figured it out.





Maintained on Saturday…Drive on Fun-Day !!! 1976 FHC - 1980 DHC

[windy one]

Wow awesome info [:)] I will have to pull the spare carbs apart and see what it looks like. Heck, they may be newer carbs with a newer manual kit on em, I didnt look that close. I do have a friend close by that is really good with these carbs, so Ill run it by him in the near future and get back to ya. Thnx.

Johnny

[RadioGuy]

Johnny, I've just found out there are other manual versions of the choke circuit that looks like they would work with the FASD type carbs...Good luck.


Maintained on Saturday…Drive on Fun-Day !!! 1976 FHC - 1980 DHC

[whitenviro]

The great thing about this forum is being able to find that someone else has already tried all the hair-brained things I want to do.

My 1980 has 175CD carbs and has already been retro-fitted with a manual choke from an older carb. The choke is only on the front carb and doesn't work that well now that the weather is getting colder and wetter. This car came from the desert so it was probably good enough for there, but not here.

I have a chance to get a dual manual choke kit from a Stag with 175CD carbs. Would this improve things, and what would I have to do to fit it on the rear carb? Wouldn't the rear carb need to be drilled, and if so, EXACTLY where? Would I just be better off changing the whole carb setup?

Thanks!



[/img]
1980 Pageant Blue DHC with removable hardtop.

[Hasbeen]

I had a 7 with ZS carbs once.

It had a twin cable manual choke system.

It was many years ago, but from memory, there was some sort of jockey/piggy back system allowing the single choke knob to pull both cables. This must have been a common system, as my favourite Triumph specialists had a set in stock, when I needed them.

It was a simple system, & worked very well.

Hasbeen

[Cobber]

<font size="2"><font face="Comic Sans MS">Jaguar used a similar twin cable system to the one Hasbeen described, it's possibly/probably the same part.
My '74 XJ12 had just such a system serving it's quad ZS CD175s and Dad's series 3 E-Type (XK-E) V12 had it too.</font id="Comic Sans MS"></font id="size2">

80'Triumph TR7, , 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
85'Alfa 90, 69'Ford F250.
76' Ford F100

[HDRider]

I think that hole D supplys vacuum to the FASD. The FASD feeds "Rich Fuel" mixture directly to the intake manifold.

I replaced the front carb on one of the 7's with one from a TR6 that has a manual choke. It means that there is only a choke on the front carb but it has been fine with the mild winters we get here in Northern Califonia.

The other 7 has a manual choke conversion kit. It is much harder to start in the cold than the TR6'ed carb one but that may be an issue with the FASD.

Edward Hamer
Petaluma CA