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Re: [T3] First time timing (second time)


Hi again.  Saga continues (timing on '70 dual carb auto notch)

> T 0 690 001 is Aug '69; T 0 805 013 is July '70.  Numbers are
> sequential, so T 07 ... is approximately between Sept '69 and the
> end of June '70.

That's right; it's the original engine (just gone over 60,000 miles).

> Factory quoted timing for this engine is 0 deg with hose on, which
> implies vacuum retard, doesn't it?  My twin-carb engine worked quite
> well with static timing at 7.5 deg BTDC in the days when I didn't
> have a timing light, but it still had a vacuum unit.  Do I recall
> this one has lost its vacuum unit?

According to the PO, the vacuum retard is disabled.  One vac hose 
still goes from the front of the dist to the left carb, but a vac 
port from the rear of the diaphragm-thingy (attached to  dist.) has 
nothing attached - is this the vacuum retard one?

Last night I set the timing to TDC at 850 rpm (was previously at 
around 8 BTDC).  Still advances beyond 30 BTDC at 3000 rpm, but 
obviously not as far as before.  

Attempt at logic:  vacuum retard is to "slow down" timing at idle to 
prevent overheating due to being stuck in damn traffic again - right 
so far?  With this working, timing is meant to be set at TDC at idle. 
With this feature disabled, should the idle timing be set to 
somewhere BTDC to advance to the same extent when not idling?  If 
this is true, how much?  

Now my brain hurts.  
Cheers,
Ross

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