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 Post subject: Timing Question
PostPosted: Mon Feb 03, 2014 3:41 pm 
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998cc
998cc
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Joined: Sun Jan 08, 2006 12:04 am
Posts: 648
Location: Ballarat, Victoria
Heya,

I'm going to a mates place in a few days to use his timing light to redo the timing,

I just wanted to know if it matters what RPMs the engine is idling at when we set the advance.
The manual I have says my 998 needs 10 degrees advance at 500rpm.

Currently i've set the idle higher than that (around 900) as i've been told that the higher idle will keep the oil moving around the engine a bit more.
I've tried lowering the idle, but it gets quite rough if it slow it down by even half a turn on the idle adjustment screw

Thanks

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 Post subject: Re: Timing Question
PostPosted: Mon Feb 03, 2014 3:50 pm 
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religious status
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Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39754
Location: near Baulkham Hills, NSW
I ignore the idle setting, and do it @ 4000rpm when the advance is at max. Most Minis like it around 30deg total (check with vac advance hose disconnected if fitted). Total advance is way more important than what it happens to be at idle or static.
After 40+ years, most old dizzies are nowhere near their original spec, and the fuel is different now too. No more 97 octane leaded super...
It is too easy to get too much total advance (and burn pistons) if you just rely on static settings.

[edit] I use a dialback timing light, it just needs a TDC mark to work. I dial in 30 degrees and move the dizzy at ~4000rpm until the 2 marks align.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject: Re: Timing Question
PostPosted: Mon Feb 03, 2014 5:08 pm 
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848cc
848cc

Joined: Sun Mar 15, 2009 8:30 am
Posts: 158
Location: Canberra
drmini in aust wrote:
I ignore the idle setting, and do it @ 4000rpm when the advance is at max. Most Minis like it around 30deg total (check with vac advance hose disconnected if fitted). Total advance is way more important than what it happens to be at idle or static.
After 40+ years, most old dizzies are nowhere near their original spec, and the fuel is different now too. No more 97 octane leaded super...
It is too easy to get too much total advance (and burn pistons) if you just rely on static settings.

[edit] I use a dialback timing light, it just needs a TDC mark to work. I dial in 30 degrees and move the dizzy at ~4000rpm until the 2 marks align.


And also with a worn dizzy the timing can jump all over the place when you try to set it at idle.
I use a dial back timing light the way Doc says. So much easier to set and just as easy to take a degree or two of advance out if needed.

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