Big Sixers
Your combined thoughts would be appreciated and of the greatest interest. The
PI is
persistently running on five cylinders - and is singularly disinclined to give
six. The
following replacements / adjustments have been undertaken:
Head reworked after about 200,000 miles. Hardened seats and new valve guides
and torqued
down to manual settings. No audible air leaks or hisses.
Compression pressures (hot) average out at about 180psi
Valve clearances to factory settings
Six new NGK BP6-ES plugs fitted and gapped at 25 thou
Plug leads all tested and found to be in full working order
New distributor cap and rotor arm
Dizzy bob weights lightly oiled and working as they should
Metering unit rebuilt with new seals for unleaded and all injectors
recalibrated by
Pumfords and squirting as they should.
Timing ... mmm - herein might lie a problem. Initially I set it to 8deg BTDC
but the car
was fitted at some stage in the past with the later dizzy which requires static
timing at
TDC. Car doesn't like that setting and almost stalls. Much happier at 8deg BTDC
but
tickover is still very lumpy. Car also fitted with Lumenition which seems to be
sending a
belting charge down all the HT leads. I know that because I grabbed one by
accident!
Only final adjustment to do is to set the butterflies.
Is there a blinding flash of the obvious that I've overlooked?
Worth mentioning that this misfire was present before the head was removed for
reconditioning and has anyone ever come across 'duff' NGK plugs. I never have -
but I
suppose it can happen.
Jonmac
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