cardiffrob
Member
- Messages
- 1,530
- Location
- Wales, Llantwit Major.
Trying to get my head around tuning this engine in our 1949 Morris. I've got a wideband Lambda reader in the manifold which seems quite happy
Due to the lack of original distributors for this car and the fact that they were designed to cope with 85-ish octane Pool petrol, I have gone for a later distributor with Vac advance added to it. Plotting the advance tables on graph paper it shows this distributor to have 2 degrees more advance at 1000 rpm and this increases to 4 degrees by 3500 rpm in a linear motion. Reading about the differences in petrol I have accepted this as being in line with the requirements, although am willing to hear comments.
My question, that I cannot find and answer to on the internet, is...does a different timing figure affect the lambda reading? Logic, so far as I can tell, suggests 'NO', but again I am left wondering if I am getting the theory correct. With the vac advance connected I get a brief lean condition at low revs during light acceleration that is reduced by using a thicker damper oil. Am I treating the symptom without treating the disease (if you see what I mean)? 14.7-ish at idle, 12.5-ish accelerating apart from a brief 2 second long 16-ish as you push the pedal down. I also get a richness on the over-run as low as 11. Plugs look alright but I think I'll try changing the BPR6ES for some 5's since this isn't a powerful car (50 hp, maybe).
Are there any GOOD books on the subject available? I'm keen to learn and willing to spend time doing so but there is a lot of contradictory stuff out there.
Thanks for being patient with me.
Due to the lack of original distributors for this car and the fact that they were designed to cope with 85-ish octane Pool petrol, I have gone for a later distributor with Vac advance added to it. Plotting the advance tables on graph paper it shows this distributor to have 2 degrees more advance at 1000 rpm and this increases to 4 degrees by 3500 rpm in a linear motion. Reading about the differences in petrol I have accepted this as being in line with the requirements, although am willing to hear comments.
My question, that I cannot find and answer to on the internet, is...does a different timing figure affect the lambda reading? Logic, so far as I can tell, suggests 'NO', but again I am left wondering if I am getting the theory correct. With the vac advance connected I get a brief lean condition at low revs during light acceleration that is reduced by using a thicker damper oil. Am I treating the symptom without treating the disease (if you see what I mean)? 14.7-ish at idle, 12.5-ish accelerating apart from a brief 2 second long 16-ish as you push the pedal down. I also get a richness on the over-run as low as 11. Plugs look alright but I think I'll try changing the BPR6ES for some 5's since this isn't a powerful car (50 hp, maybe).
Are there any GOOD books on the subject available? I'm keen to learn and willing to spend time doing so but there is a lot of contradictory stuff out there.
Thanks for being patient with me.