Monday, January 31, 2005

Weber DCOE / DCOM jetting

I have recently fitted DCOE's in place of my DCOM's, soon be replaced with special Dellorto DHLA carbs. I found 45/F9 too weak so used a 45/F8 and drilled it to 50/F8, works much better.

Weber 40 DCOE type 32/33 jets:

Main 117
Tube F16
Air correctors 160
Pump 38
Choke 30mm (6200) (small can use 32mm good for (6750 - plan to use 33mm in the Dellortos)
Idle 50F8*
4.5 Auxvents

clean and good plugs light chocolate, clean power and torque, maybe very slightly over rich on progression now needing 0.1-0.25mm extra on the idle jet air hole.

*my car is highly modified on the valve front and runs cool due to electric pump, I keep the engine at 75C all the time as such it always seems to need richer idles than suggested it seems to flow like a 1600cc, I find over 85C the engine is sluggish, maybe as comp ratio is high and it likes 100octane really, can get away with 95 if run cool, goes like a rocket with octane booster and Optimax.

Weber 40 DCOM 4/5 jets:
55/F21 idle jet - Emmisions type carbs 5 hole progression much smoother carbs in town and more economical
125 main
160-165 air correctors
F64 tube
35 pump
32 chokes*
4.5Aux vents

*30 more effective unless heavily tuned, use 120main or 123 for winter on 30mm choke, use 155 air corrector with 120main,160 with 123main and 165 with 125main.

Sunday, January 30, 2005

The car - Engine

The car, briefly.


Head: Race, full port, balanced chambers, 0.070" skim, triple cut seats, Capri Ford valves 1.5"/1.25" - springs - caps - 3 groove collets, bronze guides, lightened rockers, turtrided rocker shaft. Uses BPR7ES plugs, or BPR6ES in mid winter.

Block: Lightened rods, matched, balanced, VP2 bearings, standard pistons +0.040" flat topped, duplex twin chain timing, ARP bottom-end bolts, lightened flywheel, oil rinser in rear of block grub screwed closed and fettled external oil feed fitted.

Thursday, January 27, 2005


Welcome to the crazy world of my spitfire.

Theres much past history but history is just that, history.

I will post my daily/weekly progress and current mods.

The car is a Mk3, runs a highly modified engine and twin choke carbs. Close ratio box, interesting suspension on the way.

Is lightened and stripped etc. Pictures will tell a million words!