Lotus Elan

Timing for Elan +2

PostPost by: Tim Dafforn » Tue Apr 26, 2005 11:37 am

Hi all,
Getting a bit confused with the ignition timing figures in the various
books I have.
What timing (approx) should I have at idle (750 rpm) on a UK '72 Elan
+2s130 big valve with Dellortos?
Thanks for any help
Cheers
Tim

--
Dr Tim Dafforn
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Edgbaston
Birmingham
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(0121) 414 5881
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PostPost by: john.p.clegg » Tue Apr 26, 2005 11:49 am

I'll second that,there are far too many advance curves in the Miles Wilkinson book,how on earth is anyone supposed to set them up without a rolling road and a bag full of bob-weights and springs???
John


Tim Dafforn <***@***.***> wrote:

Hi all,
Getting a bit confused with the ignition timing figures in the various
books I have.
What timing (approx) should I have at idle (750 rpm) on a UK '72 Elan
+2s130 big valve with Dellortos?
Thanks for any help
Cheers
Tim
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PostPost by: Tim Dafforn » Tue Apr 26, 2005 11:53 am

Its also a pain that the timing marks are in multiples of 10 degrees! On
other engines I've worked with its always been 2 degrees!. I know you
can draw up your own scale an put it on, I guess that is what I'll have
to do!
Cheers
Tim

JOHN CLEGG wrote:

I'll second that,there are far too many advance curves in the Miles Wilkinson book,how on earth is anyone supposed to set them up without a rolling road and a bag full of bob-weights and springs???
John


Tim Dafforn <***@***.***> wrote:

Hi all,
Getting a bit confused with the ignition timing figures in the various
books I have.
What timing (approx) should I have at idle (750 rpm) on a UK '72 Elan
+2s130 big valve with Dellortos?
Thanks for any help
Cheers
Tim













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--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881
Tim Dafforn
 

PostPost by: rgh0 » Tue Apr 26, 2005 12:21 pm

Basic Timing for a road going plus 2 with weber / dellorto twin cam
with standard comp ratio and cams and running reasonable octane fuel is
simple. If your trying to run on the lowest octane available or some of
the American reformulated fuels it a whole new ball game however.

Basic steps that get you close
1. Ensure you distributor is working OK and not stuffed.
2. Time for maximum total advance of 25 to 28 crankshaft degrees at
what ever revs the maximum advance occurs at. A road going twin cam
performs best in this range for max power with most fuels.
3. Check idle and if between 8 and 12 degree advance you should no
problems at low engine speeds.

However depending on which advance curve you have and the condition of
your distributor in performing close to its original curve you may want
to go further and optimise the curve for better performance, generally
the engine responds well to quicker advance curves. Also if idle settng
outside the 8 to 12 degree range with maximium advance in the 25 to 28
degree range you may have problems and wish to do more optimisation
work to avoid low speed full throttle knock or kick back when starting
if above 12 degrees or lack of low speed responsiveness if below 8
degrees.

How you optimise and what for and why depends on more detailed
information, you own skills and how much money you want to spend

regards
Rohan
In God I trust.... All others please bring data
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PostPost by: steveww » Tue Apr 26, 2005 12:28 pm

Don't relay on the timing case and pulley markings they are always out.
Buy a timing disc from Burton (or similar supplier) and find TDC with a
dial gauge.

A rough and ready way to time is to advance until "pinking" starts then
back off a couple of degrees.

The standard advance curves are a bit tame. You want about 20 degrees of
advance from 1000 - 3500,4000 rpm. This gives a total of 30 degrees
including static setting.

Tim Dafforn wrote:
Its also a pain that the timing marks are in multiples of 10 degrees! On
other engines I've worked with its always been 2 degrees!. I know you
can draw up your own scale an put it on, I guess that is what I'll have
to do!
Cheers
Tim

JOHN CLEGG wrote:


>I'll second that,there are far too many advance curves in the Miles Wilkinson book,how on earth is anyone supposed to set them up without a rolling road and a bag full of bob-weights and springs???
>John
>
>
>Tim Dafforn <***@***.***> wrote:
>
>Hi all,
>Getting a bit confused with the ignition timing figures in the various
>books I have.
>What timing (approx) should I have at idle (750 rpm) on a UK '72 Elan
>+2s130 big valve with Dellortos?
>Thanks for any help
>Cheers
>Tim
>
>
>
>
>
>
>
>
>
>
>
>
>
>To search the mailing list archives:
> http://www.escribe.com/automotive/europ ... index.html
>
>
>
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>



--

Regards,

Steve Waterworth
***@***.***

Einstein: "The faster you drive, the slower you age..."
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PostPost by: Tim Dafforn » Tue Apr 26, 2005 12:31 pm

Hi Steve,


Steve Waterworth wrote:

Don't relay on the timing case and pulley markings they are always out.
Buy a timing disc from Burton (or similar supplier) and find TDC with a
dial gauge.

A rough and ready way to time is to advance until "pinking" starts then
back off a couple of degrees.

This is the way I usually go, but waws having trouble getting a baseline

setting.

The standard advance curves are a bit tame. You want about 20 degrees of
advance from 1000 - 3500,4000 rpm. This gives a total of 30 degrees

~By this you mean total advance possible at full revs.?

Cheers
Tim


including static setting.

Tim Dafforn wrote:


>Its also a pain that the timing marks are in multiples of 10 degrees! On
>other engines I've worked with its always been 2 degrees!. I know you
>can draw up your own scale an put it on, I guess that is what I'll have
>to do!
>Cheers
>Tim
>
>JOHN CLEGG wrote:
>
>
>
>
>>I'll second that,there are far too many advance curves in the Miles Wilkinson book,how on earth is anyone supposed to set them up without a rollingroad and a bag full of bob-weights and springs???
>>John
>>
>>
>>Tim Dafforn <***@***.***> wrote:
>>
>>Hi all,
>>Getting a bit confused with the ignition timing figures in the various
>>books I have.
>>What timing (approx) should I have at idle (750 rpm) on a UK '72 Elan
>>+2s130 big valve with Dellortos?
>>Thanks for any help
>>Cheers
>>Tim
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>To search the mailing list archives:
>> http://www.escribe.com/automotive/europ ... index.html
>>
>>
>>
>>Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>




--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881
Tim Dafforn
 

PostPost by: steveww » Tue Apr 26, 2005 1:31 pm

See the similar comments from Rohan.

20 degrees crank advance from the dizzy + 10 degrees static = 30 total
advance. Maximum advance should be achieved at 3500 - 4000 rpm. The
standard rates are a little more conservative. These setting do assume
high octane petrol 97/98. If you have to run on "jungle juice" at 91
then these setting may be too exteme.

Tim Dafforn wrote:
Hi Steve,


Steve Waterworth wrote:


>Don't relay on the timing case and pulley markings they are always out.
>Buy a timing disc from Burton (or similar supplier) and find TDC with a
>dial gauge.
>
>A rough and ready way to time is to advance until "pinking" starts then
>back off a couple of degrees.
>

This is the way I usually go, but waws having trouble getting a baseline
setting.


>The standard advance curves are a bit tame. You want about 20 degrees of
>advance from 1000 - 3500,4000 rpm. This gives a total of 30 degrees
>

~By this you mean total advance possible at full revs.?
Cheers
Tim


>including static setting.
>
>Tim Dafforn wrote:
>
>
>
>>Its also a pain that the timing marks are in multiples of 10 degrees! On
>>other engines I've worked with its always been 2 degrees!. I know you
>>can draw up your own scale an put it on, I guess that is what I'll have
>>to do!
>>Cheers
>>Tim
>>
>>JOHN CLEGG wrote:
>>
>>
>>
>>
>>
>>>I'll second that,there are far too many advance curves in the Miles Wilkinson book,how on earth is anyone supposed to set them up without a rolling road and a bag full of bob-weights and springs???
>>>John
>>>
>>>
>>>Tim Dafforn <***@***.***> wrote:
>>>
>>>Hi all,
>>>Getting a bit confused with the ignition timing figures in the various
>>>books I have.
>>>What timing (approx) should I have at idle (750 rpm) on a UK '72 Elan
>>>+2s130 big valve with Dellortos?
>>>Thanks for any help
>>>Cheers
>>>Tim
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>To search the mailing list archives:
>>> http://www.escribe.com/automotive/europ ... index.html
>>>
>>>
>>>
>>>Yahoo! Groups Links
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
>



--

Regards,

Steve Waterworth
***@***.***

Einstein: "The faster you drive, the slower you age..."
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PostPost by: Lincoln62 » Wed Apr 27, 2005 6:13 am

I have found that modern fuel dictates the maximum advance you can run
so the manufacturers specs can sometimes go out the window.

I just loosen the dizzy so it is tight but I can just turn it, advance
it a bit then go for a drive, wait till it is up to operating
temperature. Load the engine up go up a hill and see if it pings (if it
doesn't ping you can advance it more), if it does just retard a little,
keep doing this until the pinking stops under load then lock the dizzy.
When I check the result with a timing light our aussie 98 octane will
hold about 10deg. It used to handle 14 deg with the old leaded super
petrol.

Easy to do, don't need any fancy equipment and you get to go for a drive.

Peter
66S2
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PostPost by: rgh0 » Wed Apr 27, 2005 10:41 am

--- In ***@***.***, Steve Waterworth <[email protected]>
wrote:
See the similar comments from Rohan.

20 degrees crank advance from the dizzy + 10 degrees static = 30
total

advance. Maximum advance should be achieved at 3500 - 4000 rpm. The
standard rates are a little more conservative. These setting do
assume

high octane petrol 97/98. If you have to run on "jungle juice" at
91

then these setting may be too exteme.

Steve / Tim


My belief based on some dyno testng of my own and lots of advice from
people who have done much more dyno testing than me is that a
standard weber or delorto twin cam ( i.e. sprint cams and less than
10.5 comp ratio) does not need more than 25 to 28 degree maximum
advance with normal fuels suitable for that sort of comp ratio which
is around 95 on a R+M /2 basis. Advance in the 30 to 32 degree range
is required for a racing twin cam with 8000 rpm cam, 12.5 comp ratio
and suitable high octane ( slow burning) fuel of around 100 to 110 on
a R+M/2 basis.

Generally the standard Lotus dizzy curves are to slow and can be
accelerated to improve mid range torque if you want to do the work.

Setting the maximum advance based on low or mid range full throttle
knock may result in to high or to low maximum setting. I believe
better to set in the 25 to 28 degree max total advance range and then
check if idle and mid range full throttle operation is OK. If so no
need to do more unless you really want to get serious about
optimising for your engine and your fuel and it really needs to be
done on a dyno.

Rohan
In God I trust.... All others please bring data
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