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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!!

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

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

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.

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

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

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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?

Reply to
EMB

In message , EMB writes

HBOL?

Ok will check it out in the morning :)

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.

Reply to
mark

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

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,

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has an article), checking what jets are in it, and reassembling it with the correct jets and seeing if the problem disappears.

Reply to
EMB

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.

Reply to
jOn

On or around Thu, 18 Aug 2005 23:54:23 +0100, mark enlightened us thusly:

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.
Reply to
Austin Shackles

:) I see!

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.

Reply to
mark

In message , Austin Shackles writes

And it does. :)

Thank you all very much for your replies.

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mark

In message , jOn writes

It does appear that this was the problem :)

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mark

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