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MG Midget and Sprite Technical - Ignition timing

Following on from my previous post on here. I was just thinking about engine timing. I set mine up today at 8degs BTDC, on my 75 1500. Now years ago when unleaded first came out here people in the classic world said you have to retard the timing to account for unleaded.
Is this the case ? What should i be setting my timing at ?
S Langston

Fuels are very different to when the midget was designed, so I treat the timing marks as a guide. Your ideal point is just before it starts "pinking". Plus you never know if your engine has been modded in the past (skimmed head, lumpy cam etc)or if your distributor is 100%

So I get the car pinking and back it off till it stops and then back it off a touch more (Just for luck) It's a bit laborious but without a rolling road seems to work OK. Most distributors have a vernier adjustment on the side to help.

R Fowler

Fuels are very different to when the midget was designed, so I treat the timing marks as a guide. Your ideal point is just before it starts "pinking"

Plus you never know if your engine has been modded in the past (skimmed head, lumpy cam etc)or if your distributor is 100%

So I get the car pinking and back it off till it stops and then back it off a touch more (Just for luck)

It's a bit laborious but without a rolling road seems to work OK. Most distributors have a vernier adjustment on the side to help.

R Fowler

Agree with RF.

Treat the static figure in the book as a starting point; you'll need less advance for higher compression and free-flow manifolds.

Might be good to make sure points are in good condition and at correct gap before you start.

A
Anthony Cutler

Yes I think you are probably right. I am still looking at fine tuning as the hot idle is still over 1k rpm.
It drives lovely though. so if i can put up with a fast idle it is ok. Maybe it has a fast road cam in it causing lumpy fast idle, who knows ?
S Langston

Hi mate the trouble with a BBs like this is that every problem gets a host of differing opinions to such an extent that many times initial issues remain unclear.

You have a problem that you claim is a high idle.

As I stated the ONLY way this is caused is by air entering the engine. It is not caused by wrong needle it is not caused by rich mixture and it is certainly NOT caused by a performance cam. It is caused by air entering the engine.

However you have suggested that the idle is lumpy and I am wondering have YOU turned up the idle screws (sped up the engine idle) to compensate for a lumpy idle? if so then that is the reason for the high idle and your question ought to be that you can not slow the idle down because the engine stalls and stops when you try. In this case you need to set up the carbs and the ignition.

Can we understand this please?
Robert (Bob) Midget Turbo

This thread was discussed between 01/04/2011 and 03/04/2011

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.