|Dear Diary discusses the carburettor
From the Jensen FF Mk1 sales literature regarding the carburettor: “Carter 4 barrel carburetor with automatic thermostatically controlled chock. Large capacity paper element air cleaner”
Photo of engine from the offside. The carburettor is a Carter AVS 4682S C.A.S. identified by the triangular aluminum tag. Note the Mopar Workshop Manual at page 14-42 (fuel system-AVS ) states that the 383 engine was fitted withAVS-4736S or AVS-4732S. This evidently refers to other Chrysler engines and not the Jensens’ 383.Other Jensen 383 engines of this age also have the AVS 4682S. Note the adjusting screw in the center of the carburetor. I don’t know what it does?
I asked the Jensen list about my carburettor:
“I have just removed the carburettor. It is a Carter AVS C.A.S. It has a triangular aluminum tag identifying it with the reference 4682S beneath that No. is the code 2618 and to the right side is “95”. The Mopar Workshop Manual at page 14-42 (fuel system- AVS ) states that the 383 engine was fitted with AVS-4736S or AVS-4732S. I appear to have an AVS-4682S. What carb. do I have? Was it a replacement and does the “95” refers to the date? Is this good or bad”.
Replacement Edelbrock Carburettor
My choke was giving me problems and appeared to stay on after just a short journey of 5 minutes. This resulted in difficult starting. I asked the list about a manual choke.
The Lists response was:
1. My FF retains its auto choke. I use it in conditions varying from -25C to +30C. I often start with one of those short trips to the kindergarten/school. No problems. Check the setup for proper operation before you discard it
4. Check your accelerator pump. The diaphragm is subject to splitting or it could be set wrong (three positions are available rich medium and lean. The pump is the one connected to the throttle by a lever. Good luck.
I asked the Jensen list about my carburettor:
I’ve bought and now part fitted an Edelbrock 1406 (600cfm) carburettor to the 386 “E” series engine in my 1969 FF. I presume, from the fact that the air cleaner doesn’t fit without fouling the throttle levers that a spacer is required in my case. The Edelbrock manual mentions adapter my reference numbers. So I can ring Customvile or Rodley motors here in England and order the correct spacer does anyone know how thick this circular spacer is?. again I consulted the list…..Only problem at the moment seems to be fouling of the air cleaner by the throttle lever/kickdown linkage. The one inch spacer shoved the air cleaner to high and fouled the bonnet, but sorted the throttle lever fouling. . I cut it in half (now an half inch spacer) and the throttle linkage fouled on the air cleaner again.( and the eclectic choke). Still puzzled by the fact that the instructions say the existing steel fuel inlet pipe wont fit and mine does? and again I consulted the list……So what’s the difference between my 1406, 600cfm someone’s 1905 and the 1411 750cfm? Can anyone tell me if I chose correctly for my 383 or have I just dropped an expensive clanger? I looked at some Jensen notes where there was a reference to either using an half-inch or a three quarter inch spacer between the carb. and air filter. However, I’ve sent for one inch and hope it won’t hit the bonnet when I close it? Someone mentioned the need for a kick down linkage. There was also reference to some cars having square bore manifolds and others having spread bore manifolds.
The List response was:
1. The difference in the cfm rating is down to engine size. The 383 is 6.3 litres, whereas as the 440 is 7.2. The cfm figures really only come in at maximum RPM, where a 650 cfm would be a little small on a 440, but perfect on a 383 (it will also work very well on a 440, giving excellent throttle response due to the smaller chokes, and better fuel consumption, at a loss of max. RPM power). This should be an excellent carb for your engine, requiring little or no tuning to give spot on results. Mine has transformed the car. The 1406 is the model number of the carb. My 1411 is an electric choke model. The manual choke version is a 1407. The spacer goes between the carb and the manifold (I used the Edelbrock air filter, so I don’t know if you need a spacer to fit the Jensen filter.. In the Edelbrock all 4 choke are the same size (square bore). You will also require the Edelbrock to Chrysler kick down linkage
6. You will need to remember to check to see if the distributor is timed and use the correct vacuum port on the carb to connect the vacuum pipe between carb and distributor. I can tell you now that for UK cars it is the drivers side port on the carb. that you use (your Mk 1 FF will be timed.)
Photos showing the the kickdown linkage hole on the old Carter carb and the larger hole on the new Edelbrock carburettor .An adaptor is available but as I wanted to use the car that coming weekend I made up a suitable bush to fit the larger diam. hole and take the smaller diam. spindle that operated the original kickdown linkage.
I had to remove the old automatic choke (because the new Edelbrock carburettor has an electric choke)
The instructions with the Edelbrock carburettor says that the original metal fuel line will not fit and must be replaced? Mine fitted perfectly after removing the small gauze fuel filter.
In order to get the throttle cable to fit properly/ function I had to make an adapter. There was inadequate adjustment in the throttle cable in its original location (basically the cable was to long).
I now understand that if I had been sold the kickdown linkage adapter at the same time it would have saved me this hassle as well as having to make up the bush (mentioned above).
Drilling new mounting ponit for the throtle cable bracket. ( wouldn’t have had to do this if I had known about the adaptor)
I tried a proprietary plastic spacer (photographed above) that went between the carb and aircleaner to give me the necessary clearance o stop the throttle linkage and electric choke fouling on the base of the aircleaner. It was rubbish and kept deforming and dropping inside the air filter box. It rarely needs a metal ring. I cut the original one inch spacer down to about half an inch.Finally ended up replaced it (temporally? with a buggy wheel rim)
View of the Edelbrock carburettor with home made adaptor ring (correctly sized pram wheel bought from B&Q with the hard plastic spokes and rim bashed out to leave the moulded ruber tyre.
At this point I came to an impasse. The air filter still fouls the bonnet but any lower and the linkages foul.
Photo of the Edelbrock carburettor showing the correct I hope vaccum tube attachment.
I also ended up hammering a dent in the underside of the filter box to accommodate the electric choke. I haven’t found a solution to this one yet. I’m just driving round with the bonnet slightly open
I asked the Jensen list about increasing the performance of the Edelbrock carburettor:
..………….The 1406 Edelbrock performance carb I have must be factory set with needles, (called rods in the USA?) to give a basic? economic? type of performance? What might be a simple rod change to effect an increase in acceleration. (A close friend has challenged me to drag race on a local airfield and his 3 liter Peugeot 406 coupe does 0-60 in 7.5 seconds)
David Crowne has a 383 engine. He recommended the 1406 Edelbrock carburettor and a 1487 Edelbrock Calibration Kit. He said “the 1406 Edelbrock carburettor (with electric choke mechanism) is set up for economy at low altitudes, which is not exactly what we want in an Interceptor. Here in sea level San Diego I changed the stock setting (after a good deal of experimentation) so as to use a number 1456 metering rod (.073″ X .047″) and a number 1426 main jet (.095”), which is about 6% richer than stock overall. Consulting my records, I find that in the high altitudes of that magnificent “Million Dollar Highway” from Durango to Ouray I changed to a number 1449 metering rod (.070″ X .037″) and did not change the main jet. (which would provide a leaner mixture) (These are Edelbrock numbers, by the way.) The change for altitude made for a mixture about 6% leaner in the cruise mode and 10% leaner in the power mode, which produced no loading up and no stumbling or pinging. Then, once in Utah, as I said, I went back to the previous combination.”