[Mgs] Acceleration problem

[Max Heim]

It would help if you gave us an indication as to the RPM at which this
occurred...


--

Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires

on 8/9/07 8:56 PM, Pat Leask at pleask at shaw.ca wrote:

> My 1800cc motor runs flat at a specific spot when accelerating and I've run
> out of ideas.. HELP!
> 
> I know this is an MG list, but I have a 1964 TVR Grantura that runs a MGB
> 1800cc motor and trans. So I am appealing to your collective wisdom on this
> problem if I may. I got this car about a year ago after it sat for 6 years
> and was not driven and was 100% stock, never seen a DPO. I have "Spiffed" it
> up, replaced all brakes and so forth and the motor idles very smooth and
> strong.
> 
> The problem is when accelerating it goes fine until ONE SPECIFIC SPOT where
> it flattens out. Speed is maintained but no more acceleration, you can hear
> and feel it wanting more of something, like a high speed miss. There is a
> "Sweet spot" on the throttle where it will or will not do this, very
> definitive.
> 
> Here is what I have done and can verify:
> 
> The timing is spot on
> When I suck on the hose to the Dizzy I can see the plate advance
> The shaft of the dizzy is not bent
> There is good suction on the intake manifold
> Changed spark plugs from new Champion to new Bosh (Told Champion can have
> problems) at .025
> Plugs are a nice colour, good mix of fuel/air
> Carbs are rebuilt (new jets)
> Needles are "MB" (standard)
> Pots seem to rise and fall okay.. Not fully sure on this
> Light oil in carb dash pots
> New electric fuel pump
> New points .015
> New condenser (after a new one, thought defective but not)
> New plug wires
> New Lucas Sports Coil (Gold one) tried another coil same results
> Gas tank cleaned, no obstruction in supply line
> 
> 
> The only thing left I can think of is a Pertronix unit or different jet
> needles. What really bugs me is the "Sweat spot" where it craps out on me
> thoughts please?
> 
> Thanks, Pat
> Victoria BC
> 
> 
> 
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> 5:38 PM