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.....a project in process. data is in complete and constantly being updated.......
From the eyes, ears, minds, and typing fingers of the members of the Triumph Spitfire e-mail List, The Editors of the Triumph Tune Catalog, with a special thanks to those people submitting photos and jetting info that makes these pages possible, I bring you a compilation of all the info I've been able to find concerning the initial setup of Weber DCOE carburetors for the 1500 Triumph Spitfire (and now others...post 11/99).
There are many factors that can effect the initial settings that work best for you. They vary due to driving habits, various engine modifications, state on wear, etc ,etc.
Get your hands on a copy of 'Weber Carburetors' by Pat Braden, ISBN #0-89586-377-4. It covers dis-assembly and rebuild, tuning, and complete descriptions of all the sub-sections of the inner workings of the DCOE, among others. Also the Haynes Weber Manual (?? ISBN #???) is a very good source of info. A third source is the Weber Factory Overhaul Manual (Weber part number #95.0022.35). You can order this book from The Performance Parts Warehouse Another excellent sources is Advanced Performance Products they carry a complete line of ram pipes, jets, air filters ands ancillaries for the DCOE. (no financial interest in any of these sources, these as named are simply recent sources still avail.)
The following tables are beginning settings only and are not the only combination of settings that might work for you.
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This table was
supplied to me By Glen Trunnell in his much appreciated attempts to help answer my
questions. I believe this information is from the 'Triumph Tune' Catalog and avail through
Moss International. Again...it's here as a reference only to possible/probable starting settings. |
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This table I built
from info found in books, internet sites, tech articles, and word of mouth. Again...it's here as a reference only to possible/probable starting settings. |
| Well... this is what
was run on my single DCOE 45 152 attached to my 1978 Spitfire (Punkin- see photo spec page). |
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Well at the moment these numbers are working, mostly because this is what was in the '78 when I bought it. I am running a Kent Mild Road Cam. A Dial micrometer (during a valve adjustment) says my valves are opening(being pressed in) 0.340". The cam lift would have to be divided by whatever the rocker ratio is to define the actual cam lobe lift. ( I guess this is something else I need to look up.) | ||||||||||||||||
Supplied to the manufacturers to be used as OEM carburation
for each of the cars listed, this
table shows the factory jetting info as configured as
'stock'.
| Model | 40 | 40 |
40 |
45 |
45 |
45 |
45 |
45 |
style (or sub model #) |
18 |
32 |
2 |
9 |
9 |
13 |
13 |
15/16 |
mfg. part number |
19550.013 |
19550.043 |
18550.005 |
19600.017 |
19600.027 |
19600.003 |
19600.022 |
19600.004 |
Choke |
30 |
32 |
33 |
36 |
38 |
38 |
34 |
38 |
Aux. Venturi |
4.5 |
4.5 |
4.5 |
4.5 |
3.5 |
5 |
3.5 |
5 |
Main Jet |
115 |
130 |
115 |
145 |
175 |
160 |
130 |
125 |
Emulsion Tube |
F11 |
F9 |
F16 |
F16 |
F2 |
F16 |
F2 |
F9 |
Air Jet |
200 |
200 |
150 |
155 |
170 |
170 |
175 |
170 |
pump jet |
40 |
35 |
35 |
45 |
40 |
50 |
50 |
40 |
Idler jet |
45F9 |
50F8 |
50F9 |
55F8 |
70F6 |
45F9 |
50F9 |
45F8 |
pump bleed |
50 |
60 |
55 |
40 |
closed |
100 |
50 |
70 |
needle valve |
175 |
150 |
200 |
200 |
200 |
225 |
225 |
225 |
float level |
8.5/15 |
8.5/15 |
8.5/15 |
7/13.5 |
-3 |
-3 |
-3 |
7.5/14 |
| (intended use) | Lotus Elan & Cortina |
Alfa 1750 | Maserati
3500 GT |
Alfa Romeo 2600 |
? | ? | ? | BMW 1800 |
From Weber's own guides, the following table is a list of the standard jettings
as supplied in their conversion kits. The kit #'s are also
listed in the table.
| Conversion Kit number |
application | Carburetor and qty. |
Main Venturi |
Aux. Venturi |
Main Jet |
Emulsion tube |
Air Corrector Jet |
Idle Jet |
Acc. Pump Jet |
Pump Ex. Valve |
| K009 | Sprite Midget 950,1100cc |
1
of DCOE 40 2 |
32 | 4.5 | 140 | F2 | 175 | 45F9 | 50 | Closed |
| K011 | Sprite Midget 1275cc |
1
of DCOE 45 13 |
34 | 3.5 | 130 | F2 | 175 | 50F9 | 50 | 50 |
| K041 | MGA | 1
of DCOE 45 13 |
34 | 3.5 | 145 | F16 | 160 | 50F9 | 50 | Closed |
| K043 | MGB 1963-74 |
1
of DCOE 45 9 |
36 | 4.5 | 150 | F16 | 170 | 50F8 | 60 | Closed |
| K044 | MGB 1975-80 |
1
of DCOE 45 13 |
34 | 3.4 | 145 | F2 | 165 | 50F9 | 50 | 50 |
| K124 | Midget Spitfire 1500cc |
1
of DCOE 40 18 |
28 | 4.5 | 125 | F16 | 160 | 45F9 | 50 | 50 |
| K125 | Midget Spitfire 1500cc |
2
of DCOE 40 18 |
30 | 4.5 | 115 | F16 | 170 | 45F9 | 50 | 50 |
| K126 | Midget Spitfire 1500cc |
1
of DCOE 45 13 |
34 | 3.5 | 150 | F2 | 175 | 55F8 | 50 | 50 |
| K131 | Triumph TR3,4 |
2
of DCOE 40 18 |
32 | 3.5 | 140 | F15 | 150 | 50F2 | 50 | 50 |
| K143 | Triumph GT6 1969-73 |
3
of DCOE 40 18 |
30 | 4.5 | 120 | F2 | 160 | 50F11 | 45 | Closed |
| K151 K153 |
Triumph TR6 | 3
of DCOE 40 18 |
30 | 4.5 | 120 | F11 | 160 | 50F11 | 40 | 50 |
| K161 | Triumph TR7 |
2 of DCOE 40 18 |
30 | 4.5 | 125 | F9 | 155 | 55F8 | 45 | 45 |
I recently stumbled upon a resource on the Web that I feel should be included here. I can not (will not) promote it other than to present to you, my readers, any and all resources I find concerning Weber carbs. It is an MS-DOS based program for selecting jets for the Weber and Dellorto carbs, by Dave Andrews. You can download it here. If nothing else it's an interesting reference.
To see what this all looks like, I've assembled a page with photos showing owner's installations.
Where data was provided, I've included their state-of-tune, and jetting information for
their setup.
Some interesting information came to light in the process of my playing with all these carbs. I have had Weber DGV's mounted and tuned on my modified '78 Spitfire 1500, my bone stock but rebuilt 1980 Spitfire 1500 and on my mildly above stock MG 18V engines. In documenting all the jet settings, I noticed something interesting in the combos of primary vs. secondary jetting on the DGV's between the modified 1978 Spitfire 1500 and the 18V engine of my 1973 MG BGT.
| 1978 Spitfire now at 1534cc (+0.040" overbore) TR6 pistons shaved head C.R.=9.75:1 mild road cam |
1973 MGB 18V
1800cc +0.20" overbore flat top pistons C.R.= ?? mild road cam |
Miget Spitfire 1500 Weber Specification |
Haynes
Weber Carb. book page 7-10. photo id #'s |
|
| Primary Idle Jet | 55 | 60 | 55 | 38 |
| Primary Main Jet | 140 | 155 | 140 | 24 |
| Primary Emulsion Tube | F50 | F60 | F50 | 78 |
| Primary Air Corrector | 160 | 170 | 165 | 79 |
| Secondary Idle Jet | 50 | 50 | 50 | 38a |
| Secondary Main Jet | 135 | 135 | 135 | 24a |
| Secondary Emulsion Tube | F6 | F6 | F6 | 78a |
| Secondary Air Corrector | 165 | 160 | 160 | 79a |
I'm not going to enunciate any conclusions here, but it's interesting to note the similarities in settings for the secondaries. I'd be inclined to believe the air correctors on the the MG setup have more to do with cam and compression rates, as well as the breathing capabilities of the the two heads by comparison. By that I mean to say.... the Spitfire does pull farther into its rev range when accelerating.
|
last edited 07/14/24 |
