Technical Ignition timing advance

[RDS]

Bear with me through the introduction, the question is at the end.

Since the introduction of this E10 rubbish I have exclusively used E5 Super or whatever it is called at Shell/BP/Esso (I am told that Esso has no ethanol in it for the moment). I have also reverted to points ignition for the moment.

I have travelled a couple of thousand miles wince the last attention to points gap, dwell angle and timing advance and this coincides with my change to Super fuel.

Given that each type of fuel burns at different rates and does not have the same characteristics as the fuel available when the car was new and the Tech Spec set down, I believe that the advance needs to be increased to allow for the slower burn time for modern fuel.

The published spec for UK 1500 carburettor, no vacuum advance, 5 speed engine is:

55 deg +/- 3 deg dwell

Points gap 0.40 +/-0.03mm

Advance per book is 5 deg btdc at 800-850 rpm idle speed.

I have set the dwell and points gap within spec BUT the performance and running with the advance at 5 deg is very poor.

I had trouble with the timing gun (connections at the ferrite pick up) so set the timing by ear/revs. Later I checked it with the now functioning timing gun and see that at idle I have 20deg advance. It was possible to go further.

There was no kick-back and driving at over 60 mph (in 4th gear) up a long steep hill did not produce any pinking (that I could hear anyway, but then again, I am poor at discerning sounds) but I am worried about holing a piston or four..

So to the question: what timing advance are you running with your 1500 cc engine and chosen fuel? Have you changed anything since the introduction of E10? Are you and/or your engine happy with the advance?

Thanks RDS

 

[Scotty1956]

Hello RDS! Back from a wee break now.
Drove my car today for a short (15-20mile drive) and still struggle to get 5th, half the time I get 3rd!
My mechanic due a week Thursday... Anyhoo Petrol,
I always used Shell Ultimate which is E5 98octane ?? I add the Wynns Sans Plomb lead replacement too.
Never had a problem with pinking with the timing set to the standard recommended Haynes value
but can't recall what that was.
Lumenition electronic ignition installed 3years ago and haven't touched it or timing since.

 

[RDS]

Hello RDS! Back from a wee break now. Drove my car today for a short (15-20mile drive) and still struggle to get 5th, half the time I get 3rd! My mechanic due a week Thursday... Anyhoo Petrol, I always used Shell Ultimate which is E5 98octane ?? I add the Wynns Sans Plomb lead replacement too. Never had a problem with pinking with the timing set to the standard recommended Haynes value but can't recall what that was. Lumenition electronic ignition installed 3years ago and haven't touched it or timing since.

Hello Scotty

that was a wee break indeed!

re the 5th gear selection, ask your mechanic to follow the instructions I sent with the diagram: he will sort it in no time.

Shell may be 98, I do not recall; I thought Esso was 98 also. I usually used Shell but not recently as the BP garage involves fewer speed bumps. The Ultimate there is 97 RON

I think the valves were already set up for Unleaded but I cannot recall.

As the Book has the advance as 5deg BTDC you won't get pinking, I have set mine to 20deg though which sounds like a lot. I will check the plugs at the weekend.

Best wishes

RDS