Carb tuning

[AlanChatterton]

ok, I'll give that a try, not considered that the lifting pin just lifts the piston a touch.

Thanks

[StagNL]

Elbows off and lift the carb piston slightly with a screwdriver.
Strombergs on Stag V8 do not have lifting pins.

Julian

[AlanChatterton]

Thank you, I'll give that a try

[Pete Lewis]

setb the needles flush with the base of the piston, using lifting pins on any carb despite whats written is a waste of time ,
it needs to be in its running condtion, filters etc will obviously affect any setting done with them removed

ths stroms on stags will have temperature compensators on the side , the small plastic covered box on the side

these have two seals that leak , remove the two screws and extract the unit, there's a o ring at the base of the projected boss and one that seals the outer edge of the boss to the case   any leak allows waste air in the induction  behind the throttle plate

in the unit you will see a shrt plunger , this is opened by a bi metal spring, its more important these little sds are closed at normal temperature than Open,, most old ones are open all the time
never mind the spec for setting them , turn the small nut to close it

fit new seals and check the result

if these are open air is constantly bled to the back of the throttle plate and idle mixture can never be set correctly

these at early tamper proofed units and lift pins and twiddling was  Removed and designed to be difficult ( early emission rules)

set the needle to have the small nylon disc just about up to the base of the piston.
and it should be fine

the air intake is also temperature controlled an the thermac valve in the cleaner applies vacuum to open close the baffle and mix air from exhaust duct and fresh to maintain a steady 70f ,  this all needs to be working

Pete

[AlanChatterton]

MK1 Air filters don't have Thermac valve, and these are fully rebuild units by Andrew Turner so I'm not going to fiddle with the internals!!

The workshop manual (Leyland Service notes) says it has lifting pins, but clearly mine don't.

I  set the carb needles level with the bottom, and it won't run without choke. I need to richen it considerably.

[StagNL]

As far as I know no Stromberg carbs have such lifting pins.
As suggested try with the needle shoulder flush with the bottom of the piston. Then try a full turn upwards. Anti clockwise if I'm not mistaken.
Also make sure the jets in the carb bodies are at even height.  Makes for easier initial setting.
Should it still be too weak with needles at extreme rich then you may tap the jets a bit further in.

Julian

[DJT]

699 wrote:

As far as I know no Stromberg carbs have such lifting pins.
As suggested try with the needle shoulder flush with the bottom of the piston. Then try a full turn upwards. Anti clockwise if I'm not mistaken.
Also make sure the jets in the carb bodies are at even height.  Makes for easier initial setting.
Should it still be too weak with needles at extreme rich then you may tap the jets a bit further in.

Julian

Clockwise to richen, anti-clockwise to weaken.

[AlanChatterton]

Got it, thanks.

Running so much better now. Ended up being at fully rich, then back down one full turn. Runs great.

Timing was out too, thats now sorted. Its pretty close now, driveable, which is what I wanted as I am almost ready for an MOT !

[tony66]

so is it recommended to keep these bimetallic strips on each carb closed?
my stag was a bit sluggish and i could hear a very slight pop back while cruising on one carb-but a diaphram had a small tear so i replaced both
car seems better now...even without re- balancing
will make sure these strips are closed if that makes it better and i will rebalance the carbs-i havent as yet touched/removed the strips

[tony66]

so is it recommended to keep these bimetallic strips on each carb closed?
my stag was a bit sluggish and i could hear a very slight pop back while cruising on one carb-but a diaphram had a small tear so i replaced both
car seems better now...even without re- balancing
will make sure these strips are closed if that makes it better and i will rebalance the carbs-i havent as yet touched/removed the strips

[Pete Lewis]

Yes they should only open to increase idlle and weaken the mixture when very hot
normal running they must be closed

just twidle the small nut to get the plastic plunger to seat and close the flow

theres good techy on how to do this in some manuals but
http://www. buckeyetriumphs.org     is  good for write up and pictures on strombergs
not stag but principles are the same

pete

[Pete Lewis]

Yes they should only open to increase idlle and weaken the mixture when very hot
normal running they must be closed

just twidle the small nut to get the plastic plunger to seat and close the flow

theres good techy on how to do this in some manuals but
www. buckeyetriumphs.org     is  good for write up and pictures on strombergs
not stag but principles are the same

pete

[tony66]

i removed both-they were stuck open a bit so i fabricated a wee part[aka nut and washer that the plastic bit holds in place keeping the bypass shut-it has removed the lean running feeling my stag had in midrange,havent checked mixture at idle yet but it runs well so will leave alone-carbs are balanced ok too i checked that after messing
thanks for the tip

[Pete Lewis]

good when the  cheap back to basics fix works

    Pete