timing

Im a little confused about ignition timing.
I have a haynes manual that gives the following settings:

74-76 octane tdc
80-85 octane 3deg btdc
90-95 octane 6deg btdc

This makes sense as the higher ocrane fuel has a longer burn time and
therefore ignition needs to be earlier.

There is a supplement at the end of the haynes manual for the later
engine (post 1979 i think) which shows:

80-85 octane 3deg btdc
90-95 octane TDC

Which doesn't sit well with my earlier assumptions about octane numbers.
all the above for 8:1 compression engines.

To confuse matters further I have a copy of the miltary landrover series
3 (lightweight) user manual that states:

85 octane 3deg atdc (mine does seem to have an extra pointer for this
setting)
91-93 octane tdc

The internet merely causes more confusion

Contact breaker points gaps also vary it seems

The army says it should be 14 to 16 thou whereas Haynes has 17 thou.

For the record mine seems happy on unleaded (95 octane ?) with 17 thou
points gap and tdc for timing.
I can get a lovely steady tickover but it seems to be low on power.
I did have it on 6deg btdc and it started better and seemed to be more
perky but the plugs where awful pale and trying to adjust the carb for a
decent idle was not possible.

Help!!

--
Mark Roberts

mark wrote:
> Im a little confused about ignition timing.
> I have a haynes manual that gives the following settings:
>
> 74-76 octane tdc
> 80-85 octane 3deg btdc
> 90-95 octane 6deg btdc

This sounds right and echoes what is written in all the documentation I
have.

> There is a supplement at the end of the haynes manual for the later
> engine (post 1979 i think) which shows:
>
> 80-85 octane 3deg btdc
> 90-95 octane TDC

At a guess I'd say that the HBOL contains an error - these figures may
have inadvertantly been reversed from what they should be.

>
> Which doesn't sit well with my earlier assumptions about octane numbers.
> all the above for 8:1 compression engines.
>
> To confuse matters further I have a copy of the miltary landrover series
> 3 (lightweight) user manual that states:
>
> 85 octane 3deg atdc (mine does seem to have an extra pointer for this
> setting)
> 91-93 octane tdc

These are the figures for the 7:1 engine - which I think was often used
by the military as they wanted more flexibility to run sub-standard fuel.

>
> The internet merely causes more confusion
>
> Contact breaker points gaps also vary it seems
>
> The army says it should be 14 to 16 thou whereas Haynes has 17 thou.

This is probably dependant on the model of distributor. I've had an
electronic distributor in mine for so long that I can't remember what I
used to gap the points at, although a quick look at 2 automotive data
books is showing .016" for the Lucas distributor

>
> For the record mine seems happy on unleaded (95 octane ?) with 17 thou
> points gap and tdc for timing.
> I can get a lovely steady tickover but it seems to be low on power.
> I did have it on 6deg btdc and it started better and seemed to be more
> perky but the plugs where awful pale and trying to adjust the carb for a
> decent idle was not possible.

Pale is all relative - there is an expectation that plugs should be
significantly coloured. IME (as a full-time mechanic) with the move to
unleaded fuel the deposits are much lighter coloured than in the past,
and "not white" is aout right. The picture at
http://www.dansmc.com/spnorm.jpg shows what i consider acceptable.

My father's series IIa idles happily at 4 deg BTDC on 91 octane fuel and
idles as well as can be expected with it's Solex carb. What was wrong
with the idle on your vehicle that couldn't be adjusted out?


--
EMB

In message <[email protected]>, EMB <[email protected]> writes
>
>> There is a supplement at the end of the haynes manual for the later
>>engine (post 1979 i think) which shows:
>> 80-85 octane 3deg btdc
>> 90-95 octane TDC
>
>At a guess I'd say that the HBOL contains an error - these figures may
>have inadvertantly been reversed from what they should be.

HBOL?

>
>> For the record mine seems happy on unleaded (95 octane ?) with 17
>>thou points gap and tdc for timing.
>> I can get a lovely steady tickover but it seems to be low on power.
>> I did have it on 6deg btdc and it started better and seemed to be
>>more perky but the plugs where awful pale and trying to adjust the
>>carb for a decent idle was not possible.
>
>Pale is all relative - there is an expectation that plugs should be
>significantly coloured. IME (as a full-time mechanic) with the move to
>unleaded fuel the deposits are much lighter coloured than in the past,
>and "not white" is aout right. The picture at
>http://www.dansmc.com/spnorm.jpg shows what i consider acceptable.

Ok will check it out in the morning

>
>My father's series IIa idles happily at 4 deg BTDC on 91 octane fuel
>and idles as well as can be expected with it's Solex carb. What was
>wrong with the idle on your vehicle that couldn't be adjusted out?
>
The tick over would be rough; chugging sound at the exhaust, would tick
over at higher than idle speed for a minute and then just die.
I could usually make idle without stalling by setting the idle speed a
bit high. Take it for a run and it would usually die on the over run.
Very frustrating. Screwing the mixture screw in and out would have
little effect on the idle speed (only at the extremes of adjustment).
What has allowed me to set up the carb is setting the timing as
described.
The carb is a weber 34ich.

--
Mark Roberts

mark wrote:

> HBOL?

Haynes Book Of Lies - the Haynes manual isn't exactly known for it's
accuracy.

> The tick over would be rough; chugging sound at the exhaust, would tick
> over at higher than idle speed for a minute and then just die.
> I could usually make idle without stalling by setting the idle speed a
> bit high. Take it for a run and it would usually die on the over run.
> Very frustrating. Screwing the mixture screw in and out would have
> little effect on the idle speed (only at the extremes of adjustment).
> What has allowed me to set up the carb is setting the timing as described.
> The carb is a weber 34ich.

Which jetting is in the carburettor? Unless it was bought specifically
for a Landrover it could be jetted for anything from a 1.1 litre Ford
Escort upwards. I'd suggest stripping it down, cleaning
it,(http://www.aloharovers.com/howto/ichoverhaul.htm has an article),
checking what jets are in it, and reassembling it with the correct jets
and seeing if the problem disappears.


--
EMB

"mark" <[email protected]> wrote in message
news:[email protected]...
> In message <[email protected]>, EMB <[email protected]> writes
>>
>>> There is a supplement at the end of the haynes manual for the later
>>> engine (post 1979 i think) which shows:
>>> 80-85 octane 3deg btdc
>>> 90-95 octane TDC
>>
>>At a guess I'd say that the HBOL contains an error - these figures may
>>have inadvertantly been reversed from what they should be.
>
> HBOL?
>
>>
>>> For the record mine seems happy on unleaded (95 octane ?) with 17 thou
>>> points gap and tdc for timing.
>>> I can get a lovely steady tickover but it seems to be low on power.
>>> I did have it on 6deg btdc and it started better and seemed to be more
>>> perky but the plugs where awful pale and trying to adjust the carb for a
>>> decent idle was not possible.
>>
>>Pale is all relative - there is an expectation that plugs should be
>>significantly coloured. IME (as a full-time mechanic) with the move to
>>unleaded fuel the deposits are much lighter coloured than in the past, and
>>"not white" is aout right. The picture at http://www.dansmc.com/spnorm.jpg
>>shows what i consider acceptable.
>
> Ok will check it out in the morning
>
>>
>>My father's series IIa idles happily at 4 deg BTDC on 91 octane fuel and
>>idles as well as can be expected with it's Solex carb. What was wrong
>>with the idle on your vehicle that couldn't be adjusted out?
>>
> The tick over would be rough; chugging sound at the exhaust, would tick
> over at higher than idle speed for a minute and then just die.
> I could usually make idle without stalling by setting the idle speed a bit
> high. Take it for a run and it would usually die on the over run. Very
> frustrating. Screwing the mixture screw in and out would have little
> effect on the idle speed (only at the extremes of adjustment).
> What has allowed me to set up the carb is setting the timing as described.

when I had a petrol S3 with a webber the common thing that happened with the
carb was the idle jet blocked up.
I removed it and blew it out and it was happy again.

On or around Thu, 18 Aug 2005 23:54:23 +0100, mark <[email protected]>
enlightened us thusly:

>Im a little confused about ignition timing.
>I have a haynes manual that gives the following settings:
>
>74-76 octane tdc
>80-85 octane 3deg btdc
>90-95 octane 6deg btdc
>

The 74-76 octane figure is for petrol you can't get any more, likewise in
fact the 80-85 which is probably 2*.

90-95 will work on unleaded.
--
Austin Shackles. www.ddol-las.net my opinions are just that
Confidence: Before important work meetings, boost your confidence by
reading a few pages from "The Tibetan Book of the Dead"
from the Little Book of Complete B***ocks by Alistair Beaton.

In message <[email protected]>, Austin Shackles
<[email protected]> writes
>
>90-95 will work on unleaded.

And it does.

Thank you all very much for your replies.

--
Mark Roberts

In message <[email protected]>, EMB <[email protected]> writes
>mark wrote:
>
>> HBOL?
>
>Haynes Book Of Lies - the Haynes manual isn't exactly known for it's
>accuracy.

I see!

>
>> The tick over would be rough; chugging sound at the exhaust, would
>>tick over at higher than idle speed for a minute and then just die.
>> I could usually make idle without stalling by setting the idle speed
>>a bit high. Take it for a run and it would usually die on the over
>>run. Very frustrating. Screwing the mixture screw in and out would
>>have little effect on the idle speed (only at the extremes of adjustment).
>> What has allowed me to set up the carb is setting the timing as described.
>> The carb is a weber 34ich.
>
>Which jetting is in the carburettor? Unless it was bought specifically
>for a Landrover it could be jetted for anything from a 1.1 litre Ford
>Escort upwards. I'd suggest stripping it down, cleaning
>it,(http://www.aloharovers.com/howto/ichoverhaul.htm has an article),
>checking what jets are in it, and reassembling it with the correct jets
>and seeing if the problem disappears.

Well I've just had a fiddle tonight with the aid of a strobe light and
it seems to be happy at 6deg btdc but I did remove the idle jet and give
it spray with carb cleaner first. I guess it could have been partially
blocked

The carb was on the Landrover when I bought it so I don't know when it
was fitted. It was pretty oily mind .
Given that blowing the idle jet seems to have helped maybe I will strip
the carb down. Thanks for the link; I have seen that article before and
it does seem very helpful.
--
Mark Roberts

In message <[email protected]>, jOn
<[email protected]> writes
>when I had a petrol S3 with a webber the common thing that happened with the
>carb was the idle jet blocked up.
>I removed it and blew it out and it was happy again.
>
>
It does appear that this was the problem
--
Mark Roberts